Installing a Metal 3D Printer: Part 5 (Housekeeping)

Download all 5 parts of this series as a single PDF here.

This is my final post in our 5 part series discussing things we learned installing a metal 3D printer (specifically, a laser powder bed fusion machine). If you haven’t already done so, please read the previous posts using the links below.

If you prefer, you can register for a webinar to be held on July 26, 2017 @ 2pm EDT (US) where I will be summarizing all 5 parts of this blog series. Register by clicking on the image below:

Housekeeping may seem too minor a thing to dedicate a post to, but when it comes to metal 3D printing, this is arguably the single most important thing to do on a regular basis once the equipment, facilities, safety and environmental considerations are addressed up front. In this post, I list some of the activities specific to our Concept Laser MLab Cusing R machine that we do on a routine basis as indicative of the kinds of things that one needs to set aside time to do, in order to maintain a safe working environment. In this post, I break down the housekeeping into the 3D printer, the wet separator and the filter change.

1. The 3D Printer

All 3D printers need to be routinely cleaned, but for powder based metal 3D printers, this needs to be done after every build. Three steps need to be performed during cleaning of the printer:

  • Powder Retrieval: After the build, the powder is either still in the dose/feed chamber or not. All powder that is not in the dose chamber needs to be brushed to the overflow chamber for recycling. While it is possible to vacuum this powder, that is not recommended since it results in greater loss of powder and also increases the burden on cleaning the vacuum and creating wet waste.
  • Process Chamber Cleaning: The process chamber after a build gets covered with fine combustion particles (soot) that need to be wiped away, as shown in Figure 1. The recommendation is to do this cleaning using lint-free or clean room wipes moistened with an ammonia based cleaner like Windex Original.
  • Lens Cleaning: Special lens cleaning wipes are to be used to clean the protective lens that separates the chamber from the laser. Standard lens cleaning wipes can be used for this, in a gentle single-pass movement.

It is important to wear appropriate PPE and also NOT contaminate the lens. Improper or irregular cleaning will result in soot particles interfering in subsequent builds. Soot particles can occasionally seen in subsequent builds especially when the inert gas and the ventilator (circulating fan) are turned on – this is more likely to happen if the chamber is not routinely and properly cleaned.

Figure 1. Post-build cleaning of the 3D printer and required materials

2. Wet Separator

The wet separator (vacuum) sucks up stray powder and suspends it in a water column. The metal particles will descend to the bottom of the water column (as shown in Figure 2) and need to be routinely cleaned out. This cleaning procedure is recommended daily for reactive metals – failing this, the metal particles will weld themselves to the metal container and prove to be very difficult to scrape out. For non-reactive metals, a daily flush may be excessive (since this will add to the cost in terms of labor and disposal) and a weekly routine may be preferable for a wet separator that serves 1-2 machines.

To reduce the water needed to flush out the powder sludge at the bottom, a standard pump sprayer is very effective. Further reduction in water usage and disposal can be achieved by a filtration device such as the one developed by the folks at Kinetic Filtration.

Figure 2. Cleaning a wet separator

 

3. Filter Change

Filters need to be changed periodically as shown in Figure 3. A video below (set to start at the 2:58 mark) shows how the filter change is performed for our MLab, for a non-reactive metal, so I shall not describe the procedure further. A reactive metal alloy filter needs to be stored in water to passivate it at all times, even through disposal. Other OEMs recommend sand and other materials, so it is important to follow the specific instructions provided by your supplier for passivation.

Figure 3. Removing, passivating and disposing the filter

 

Summary

Good housekeeping for metal 3D printing is vital and more than just aesthetic – there is a modest chance that failing to follow your supplier’s instructions on one or more of the items above will result in a safety incident. This is especially true for reactive alloys, where filter changes are recommended after each build and wet separator clean on a daily basis.

Disclaimers

  • This is intended to supplement the supplier training you must receive before using the equipment and not meant to replace it – in case of conflicting information, your supplier’s training and equipment requirements override any discussion here. PADT and the author assume no legal responsibilities for any decisions or actions taken by the readers of this document.
  • My personal experience derives specifically from the use of Laser-based metal 3D printing tools, specifically Concept Laser’s MLab Cusing R equipment. I expect majority of this information to be of use to users of other laser based powder bed fusion metal systems and to a lesser extent to Electron Beam systems, but have no personal experience to vouch for this.

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Final Thoughts

This concludes my 5-part post on what we learned installing a metal 3D printer. If you have any thoughts on the content or would like to discuss this subject further, please let me know by messaging me on LinkedIn or by sending an email to info@padtinc.com, citing this blog post. I will be happy to include any suggestions in my posts with due credit.

Thank you for reading – I hope this has added value to the discussion on safely and effectively advancing metal 3D printing technology.

Installing a Metal 3D Printer: Part 3B (Safety Risks – Prevention & Mitigation)

Download all 5 parts of this series as a single PDF here.

How can you minimize safety risks in powder-based metal 3D printing?

This is the second half of my third post in a 5-part series discussing things we learned installing a metal 3D printer (specifically, a laser powder bed fusion machine). If you haven’t already done so, please read the previous posts using the links below, in particular, part 3A which is a prequel to this post. I also recommend reading my post on the difference between reactive and non-reactive alloys in the context of this process.

In the previous post, I identified four main risks associated with operating a laser-based powder bed fusion metal 3D printer such as the one we use at PADT, a Concept Laser MLab Cusing R. In this post, I address three of these risks in turn and first discuss how the risk can be prevented from manifesting as a hazard (prevention) and then address how it can be mitigated in case it does result in an incident (mitigation). I will deal with the fourth risk (environmental damage) in the next post. As with the previous post, my intent is to inform someone who is considering getting a metal 3D printer and not be comprehensive in addressing all safety aspects – the full list of disclaimers is at the end of this post.

If you prefer, you can register for a webinar to be held on July 26 @ 2pm EDT (US) where I will be summarizing all 5 parts of this blog series. Register by clicking on the image below:

Risk 1: Fire and Explosion

1.1 Prevention:

Fig 1. ESD wrist-strap

The key to preventing a fire is to remember that it needs three things (“the fire triangle”): fuel (metal powder or soot), an ignition source (laser or spark) and oxygen. While certified equipment is designed to operate in a safe manner when bringing the laser and the metal powder in contact by doing so in an inert gas environment, you as the operator, are responsible for avoiding any ignition sources when handling powder or soot outside of the inert environment. This is because two of the three aspects have been met: fuel (powder or soot) and oxygen (in the ambient). As long as basic risks are eliminated (sparking equipment, smoking etc.), the primary risk that remains is Electro Static Discharge (ESD) and thus the main piece of preventive equipment is an ESD wrist-strap, as shown in Figure 1, or equivalent ESD management methods.

It helps to appreciate the life cycle of the powder, as it goes from purchased jar to ending up returned as recycled powder (the majority of the powder), or in the wet or dry waste streams. This is shown in Figure 2. While this looks quite complex, coming out of the machine, the powder and soot only have 4 streams that you have to follow: the powder trapped in the part, the powder that you will recycle, the soot and powder trapped in the filter and finally, what will be cleaned with wipes and accumulate on gloves. While this is not comprehensive (internal hoses and shafts can also accumulate powder), these are the ones operators will deal with on a regular basis.

Fig 2. Metal powder life-cycle

1.2 Mitigation:

In addition to doing everything we can to prevent fire, we also need to be prepared in case it does happen. There are (at least) four aspects that need to be considered, dealt with in turn below:

1.2.1 Personal Protective Equipment (PPE)

Fig 3. Extended PPE

PPE is your self-defense in case of a fire and it is thus a critical element of the safety procedures you need to pay attention to and remember. Tasks are of varying risks, and our supplier recommends PPE for this process in three categories:

  • Protective Clothing: A lab-coat that covers your arms, protective gloves, ESD strap if working with reactive metals
  • Standard PPE: Respirator, nitrile gloves, face mask (if not integrated with respirator), ESD strap
  • Extended PPE: Standard PPE PLUS
    fire-rated bunny suit, fire-rated gloves (see Figure 3)

Below is a list of all activities that involve some risk of ignition (or inhalation, to be discussed in the next section) and the associated level of PPE recommended.

Table 1. PPE recommendations for different tasks (Courtesy: Concept Laser, Inc.)

PPE can be tricky to implement consistently since as seen above, there are several tasks of varying risk levels that require different PPE. The conservative approach is to prepare for the worst case and wear Extended PPE at all times, but this can make you uncomfortable for long periods of time, reduce your mobility for some tasks, and introduce human error. Instead, here is the 3-step logic I use for remembering what to wear:

  • Always wear gloves, goggles and protective clothing (lab-coat) when you work with the machine – make this a rule even for the simplest of tasks like using the keyboard and mouse
  • If you are directly handling (i.e. not through a glove box) virgin or recycled non-reactive metal alloy powder (i.e. no reactive powders or combustion products), standard PPE is adequate
  • For everything else, you need extended PPE

1.2.2 Fire Extinguishing

Fig 4. Class D Fire Extinguisher (must be mounted or on a trolley, NOT as shown here on the floor)

There are several recommendations for how to manage fire extinguishing. This is an area where you need to get your fire marshal to weigh in. What is clear is that water and CO2 are not safe choices for metal fires [NFPA 484 6.3.3.5(1)]. For extinguishing fires, the consensus is to use Class D fire extinguishers, such as the one shown in Figure 4. The fire extinguisher needs to be a Class D since this is the one rated for metal fires. The main training aspect is to ensure it is pointed down at the base of the fire rather than at it, followed by sweeping.

What to do with Water Sprinklers?: Water can be dangerous for metal fires, but the risk of not having any sprinklers may outweigh the risk of water exacerbating the fire. This is a function of how much risk you are introducing (amount of powder, proximity to other flammable sources, area surrounding the printer etc.) and is a decision best made together with your fire marshal.

1.2.3 Powder Storage

Fig 5. Flammables Cabinet

Powder storage will involve powder in unopened jars, opened jars as well as in the overflow collector which is on the machine. It is best to store opened and unopened jars in a flammable cabinet as shown in the adjacent figure. This is not essential for non-reactive alloys, but necessary for reactive metal alloys. For large quantities of reactive alloys, blast proof walls may be necessary – this is again something your city officials and fire marshal can guide you on, but do not neglect the importance of getting their buy-in early. Finally, most cities will require you to fill in some paperwork and show on a plan (map) where you are storing your powders, and what their composition is. This is to help inform the fire-fighters that there are metal powders onsite, and where they are located, in case of a building fire. If you do plan on working with reactive alloys in particular, you must involve your fire marshal sooner rather than later.

 

Risk 2: Powder Inhalation and Contact

2.1 Prevention

The main method of minimizing risk of powder inhalation is through the use of a respirator. These come in many forms, but the two most recommended ones for this process are respirators with built-in face-masks (as shown in Figure 3), and more preferable, the PAPR respirator, which delivers a positive pressure of air (for more information, read OSHA’s guide on respirators). N95 and higher respirator filters are recommended, though N100 are ideal.

Contact with powder is avoided by wearing gloves at all times when handling the machine. It is also useful to minimize risk of carrying powder outside the metal 3D printer area:

  • Before starting work, put away watches, wrist jewelry and cell phones.
  • Once done with the work, take off your protective coat and wash your hands and arms up to elbows before handling anything else.
  • Consider installing an adhesive floor mat for you to step on as you walk out of the room.

2.2 Mitigation

Fig 7. SDS binder

What to do in case of exposure is typically documented in the SDS (Safety Data Sheets), which is specific to the material in question, as shown in Figure 6 below. Ensure you have an SDS from your powder supplier for all powders you order, and collect them in a folder that is stored close to the entrance for easy retrieval, as shown in Figure 7.

Fig 6. Example of SDS information on responding to exposure

 

Risk 3: Inert Gas Asphyxiation

3.1 Prevention

Fig 7. O2 Sensor

Inert gas (Nitrogen or Argon) is used for every build and is either stored in cylinders (argon) or piped from a generator (Nitrogen). Proper, leak-free facilities setup and equipment performance is essential, as is following recommended supplier maintenance on the equipment itself. An inability to drop to required oxygen PPM levels in the build chamber, or large fluctuations in maintaining them may be associated with a leak and should be addressed with the supplier before proceeding. Users of the equipment must know where the shut-off valves for the gases are, in case they need to turn it off for any reason.

3.2 Mitigation

The main mitigation device is an Oxygen sensor such as the one in Figure 7. This is an important sensor to have especially in confined spaces around any equipment that relies on inert gases, including the 3D printer and furnace. If oxygen levels fall below safe values, an alarm is triggered and immediate evacuation is required.

4. References

  1. National Fire Protection Association’s standard for combustible metals, NFPA 484
  2. OSHA on Oxygen Deficiency
  3. OSHA’s Guidance on Dust Explosions
  4. OSHA Respirator guide
  5. J.M. Benson, “Safety considerations when handling metal powders,” Southern African Institute of Mining and Metallurgy, 2012
  6. R. G. Goldich, “Fundamentals of Particle Technology,” Chapter 15, Midland IT and Publishing, UK, 2002

Disclaimers

  • This is intended to supplement the supplier training you must receive before using the equipment and not meant to replace it – in case of conflicting information, your supplier’s training and equipment requirements override any discussion here. PADT and the author assume no legal responsibilities for any decisions or actions taken by the readers of this document.
  • My personal experience derives specifically from the use of Laser-based metal 3D printing tools, specifically Concept Laser’s MLab Cusing R equipment. I expect majority of this information to be of use to users of other laser based powder bed fusion metal systems and to a lesser extent to Electron Beam systems, but have no personal experience to vouch for this.
  • Local, state and federal regulations vary, and are important – partner with your local fire marshal (or equivalent authority) as a starting point and take them along with you every step of the way. If in the US, familiarize yourself in particular with OSHA’s guidance on dust explosions and NFPA 484, the National Fire Protection Association’s standard for combustible metals (links above).

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Any other tips or ideas I have not covered, please let me know by messaging me on LinkedIn or by sending an email to info@padtinc.com, citing this blog post. I will be happy to include them in this post with due credit. My aim is only to add to the discussion, not be the last word on it – and I look forward to suggestions that can make operating this technology safer for all of us and the ones that rely on us coming home every day.

Please find the 4th part of the series here.

PADT Open House 2017, image courtesy James Barker

Installing a Metal 3D Printer: Part 3A (Safety: Risks)

Download all 5 parts of this series as a single PDF here.

What are the safety risks in laser powder bed fusion metal 3D printing?

This is the first half of the 3rd post in a series of 5 on things we learned installing a metal 3D printer (laser powder bed fusion). Links to previous posts are below:

The most important discussions around installing and operating a metal 3D printer involve safety. The requirements can be difficult to pin down since they depend on several things: whether you are using reactive or non-reactive alloys (read a previous post on this subject here), the risk perception of your local building safety director and fire marshal, local regulations (and exceptions) and the volume of material you are dealing with. As with all things safety and more so because of how nascent metal 3D printing technology is, I list a few disclaimers at the bottom of this page.

There is so much to say about safety in this process that half-way through writing this post, it became clear it would not fit in one post. Therefore, I have split the content into two: in this post (3A) I talk about the risks: where they come from and why they matter. In the next post (3B), I will discuss how these risks can be mitigated.

1. Sources of Risk

Broadly speaking, I like to think of two sources of risk in this process since as an operator of these machines you have to think differently about how you interact with these sources.

1.1 Metal Powder

Metal 3D printing involves fusing together powder in a bed. Typical metal powders used for laser based 3D printing are spherical in shape and range from 10-70 microns in diameter, as shown in Figure 1. At this size, a metal can be prone to fire and explosion (under the right circumstances) and there is also the physiological concern of long-term inhalation of, and contact with, these powders. The powder also has a long life cycle and requires human interaction at many steps – from arriving in a container (as shown in Figure 2), through multiple recycling steps through final disposal. These risks come into play just when handling the powder (independent of its use in the process) – an additional risk comes from the melting process itself.

Fig 1. Typical powder particle size distribution is in the range of 10-70 microns for the laser powder bed fusion process.
Fig 2. Metal powders are delivered and stored in plastic containers such as the one shown above

1.2 The Laser Fusion Process

The powder in the bed described before is fused together into a solid using a laser that locally melts the powder one layer at a time. This is conducted in an inert atmosphere (Argon or Nitrogen) and is the second source of risk since these gases can displace Oxygen from a closed environment. Additionally, the process of laser melting of metals creates vaporized soot (see video below), some of which deposits on the process chamber and in the extraction module and filter. The smoke particles can be even finer than the powder itself, and need to be cleaned out with care on a regular basis.

2. Risks

There are 4 main risks arising from the laser powder bed fusion process: fire and explosion, powder inhalation and contact, inert gas asphyxiation and the environmental impact of the wastes generated.

2.1 Fire and Explosion

In May 2014, OSHA cited a 3D printing company for 10 violations deriving from the workplace safety standards surrounding the operation of a metal 3D printer (including not having the proper Class D fire extinguisher). The disregard of multiple safety measures during a routine build setup procedure resulted in a fire which caused life-threatening burns to the operator of the printer. While this incident was the result of gross negligence, it is nonetheless a cautionary tale that should drive us to understand the fundamental reasons why a metal 3D printer can cause fires and to appreciate the underlying reasons for why suppliers recommend the safety measures they do.

Fire and explosion require a combination of conditions as shown in the commonly cited image below used by OSHA and other agencies to communicate risks of powder handling.
As shown in Fig. 3, when handling powder in ambient atmospheres (with oxygen), all that is needed is a suitable ignition source to initiate a fire. Further, if this occurs in the presence of a dust cloud with many particles dispersed in a contained area (such as a small room or an air duct), this could lead to a more damaging explosion.

Fig 3. The oft cited fire triangle and explosion pentagon. Users of powder based metal 3D printing are often working with 2 of the 3 elements in the triangle and the key is to avoid the third.
  • Fire: When handling metal powder, the user needs to be aware that she/he already has 2 of the 3 requirements of a fire met and the main aim must be to ensure protection against any ignition source. There are several sources that could cause an ignition, the most likely one for a user of a metal 3D printer is static electricity. Additionally, it is possible that a fire can be initiated by hot surfaces, flames, hot gases and particles, mechanically generated sparks and strayelectrical currents.
  • Explosion: With regard to explosions, in addition to the 3 requirements above, dust clouds in contained areas can exacerbate any ignition to a much larger impact within milliseconds. Therefore, the prevention of the formation of metal dust clouds (as unlikely as that may seem), is of paramount importance.

In addition to the requirements above, there are levels associated with each requirement that need to be met together for an actual fire or explosion to occur. The risk of ignition increases with reducing particle diameter and given a certain particle size, the most significant factor governing risk is the nature of the metal. Reactive metals (Aluminum alloys, Titanium and its alloys, as well as smoke particles from both reactives and non-reactives) pose much higher risk than non-reactive metals (steels, Inconels, bronze, Cobalt Chrome alloys) – this is a subject I wrote about in more detail in a previous post.

2.2 Powder Inhalation & Contact

As discussed before, most metal 3D powder particles range in size from 10-70um. This is at the very edge of what is considered respirable and damaging to our lungs. While contact physically is to be avoided since it may initiate irritation and potential dermatitis, there is greater concern about the long-term inhalation exposure risks of these powders. Particles of the size range in this process can get deposited in the tracheo-bronchial region per Jenson [1] and Goldich [2]. Ultimately, these particles are discharged from the body or swallowed, but effects of long term exposure for the wide range of metals and alloys is not fully studied – which is why suppliers insist on respirators (more on that in the next post). It is worth pointing out though, from the work published by Jenson and Goldich, that it appears that while metal 3D printing powders are small enough to travel past the nasal cavity if inhaled, their sizes are large enough that respiratory damage in the lungs is highly unlikely – only particles under 2 microns are at risk of making it all the way to the alveoli and causing lung disease [2].

Fig 4. The human respiratory system. Particles in the 20-100 micron range, if inhaled, can make it to the trachea and bronchial regions [1, 2]  (Image Credit – public domain: National Institute of Health: National Heart, Lung and Blood Institute)

2.3 Inert Gas Asphyxiation

Inert gases are used in laser metal 3D printers to reduce the reactivity of the metal for processing purposes. Most metal 3D printers either use Nitrogen or Argon. Inert gas asphyxiation is the main risk due to oxygen being displaced by either of these gases that have leaked for some reason. Since both gases are not detectable by humans, victims do not realize that they are inhaling air depleted of oxygen and as a result this can have a serious impact. The human body is used to atmospheric percentages of oxygen (21%) and values below 19.5% can be harmful and are defined as oxygen-deficient per OSHA [3]. Thus, any user of nitrogen or argon gas (and this applies not just to any process using inert gases), especially in small spaces such as a closed room, needs to be aware of this risk and protect against it.

2.4 Environmental Impact

A key challenge with powder based processes lies in collecting and disposing the stray or “fugitive” powder from different locations such as the tool, PPE, containers and vacuum systems into temporary storage, during which the above risks of fire/explosion and inhalation remain. Additionally, the storage typically results in loose powder and solid waste as well as water with powder particles, both of which need to be disposed into the outside world and could pose an environmental hazard. I will discuss this further in a future post, when I attempt to look at some of the environmental aspects around this technology.

Fig 5. Metal powder settled at the bottom of the water column in the wet separator (vacuum cleaner). Where does it go next?

3. Disclaimers

  • This is intended to supplement the supplier training you must receive before using the equipment and not meant to replace it – in case of conflicting information, your supplier’s training and equipment requirements override any discussion here. PADT assumes no legal responsibilities for any decisions or actions taken by the readers of this document.
  • My personal experience derives specifically from the use of Laser-based metal 3D printing tools, specifically Concept Laser’s MLab Cusing R equipment. I expect majority of this information to be of use to users of other laser based powder bed fusion metal systems and to a lesser extent to Electron Beam systems, but have no personal experience to vouch for this.
  • Local, state and federal regulations vary, and are important – partner with your local fire marshal (or equivalent authority) as a starting point and take them along with you every step of the way. If in the US, familiarize yourself in particular with OSHA’s guidance on dust explosions [4] and NFPA 484 [5], the National Fire Protection Association’s standard for combustible metals (links below).

4. References

  1. J.M. Benson, “Safety considerations when handling metal powders,” Southern African Institute of Mining and Metallurgy, 2012
  2. R. G. Goldich, “Fundamentals of Particle Technology,” Chapter 15, Midland IT and Publishing, UK, 2002
  3. OSHA on Oxygen Deficiency
  4. OSHA’s Guidance on Dust Explosions
  5. National Fire Protection Association’s standard for combustible metals, NFPA 484
  6. D. Bhate, “Reactive and Non-Reactive Metal Alloys in Laser-based Powder Bed Fusion,” PADT Blog Post, 2016

Acknowledgements

Thank you to Perry Harlow-Leggett, the AM team at UL whose articles and webinars I have benefited from, and all the folks behind the scenes at OSHA and NFPA.

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Continue to Part 3B here, where I address mitigation strategies to address the risks described in this post. In the meantime, please read my prior posts below if you haven’t already, or send your inputs to me via message on LinkedIn. Thank you!

Installing a Metal 3D Printer: Part 2 (Facilities)

Download all 5 parts of this series as a single PDF here.

This is part 2 of a 5-part series on the lessons we learned installing our first Metal 3D printer, a Concept Laser MLab Cusing R. Please read the first post if you haven’t already, where I listed all the different equipment (in addition to the 3D printer itself) one needs to run this process.

A reminder at the outset: these posts are meant to be informative only, to give you a sense of what questions you need to ask and get answers to. Specific requirements will vary by equipment and your site specific needs.

1. Electrical

Most metal 3D printers, including the Concept Laser machines, are manufactured in Europe and have electrical requirements that differ from what most American machine shops are setup for (which is the scope of this section). If you have installed 230 V European equipment before and know what L-N and PE stand for and how they differ between European and American systems, you can skip this section. If not, read on.

There are two key items here one needs to be aware of: first of course is the fact that these pieces of equipment typically run on single-phase 230 V (3-phase 400V for the very large machines like Concept Laser’s XLine 2000R) as opposed to the standard 110V. Secondly, and this is easier to miss, European electrical connections have one “hot” line (L) for a single-phase, one Neutral line (N) and one Protected Earth (PE) – this is different from the US standard where you have 2 “hot” lines and 1 ground. The reason for these differences and how to address them electrically is beyond the scope of this post (or my understanding), but the main point is to have an electrician familiar with European codes review this early on. A dedicated custom transformer for all your European 230V equipment is one solution, and the one we employed here at PADT, as shown in Figure 1. (I rarely give shout-outs, but our experience with Fargo Electric on procuring a custom, affordable transformer was one of the best transactions I have ever had.)

electrical-european
Fig 1. Dedicated transformer in use for PADT’s metal 3D printer. Also note the L-N-PE connections and the plugs used on the different equipment.

2. Inert Gas

nitrogen
Fig 2. Nitrogen line running to our MLab

Laser melting of powder metals needs to be conducted in an inert atmosphere. Most suppliers recommend using Argon for Aluminum and Titanium alloys, but that Nitrogen is fine for the non-reactive alloys such as steel, Inconel and Cobalt-Chrome alloys. At PADT, we leveraged our existing nitrogen generator and added an additional line running to our metal 3D printer (Figure 2). Before doing this, you need to add up all the consumption rates for the machines (at their peaks) to make sure you don’t exceed the generator’s capabilities. It is a good idea to demarcate space for Argon cylinders should you need them at a later stage.

3. ESD Mats or Floors (for Reactive Metals)

As we will see in the next blog post in this series, avoiding charge dissipation into metal powder is a key safety requirement for operating metal 3D printers – this is achieved through a range of strategies like ESD (Electro Static Discharge) armbands, grounding ElgiloyHastelloy C4 wires etc. If you plan on running reactive metals and especially if you expect to have many operators, an ESD coated floor with ESD shoes or boot straps, along with an ESD meter (like the one Honeywell installed at their facility) is a good strategy. From personal experience with ESD boot straps, I know these can be fickle in passing an ESD meter test. Connecting the ESD meter to the entryway door so entry is only provided after passing the test is one way to ensure only those with functioning straps enter the workspace. For those without this strategy, grounded ESD mats and ESD armbands connected to the machine are also alternative strategies which I will discuss in more detail in the next post. From a facilities standpoint, if you do want to enable ESD coated floors, boot straps and ESD meters, you need to plan this early, which is why I have included it here.

4. Water

Fig 3. Water column in a wet separator – this has to be cleaned out and replenished frequently

Access to running water is essential for cleaning the wet separator (vacuum) that is used for sucking up fugitive powder – ideally the water source is near your liquid waste storage so you can clean out the wet separator and pour the powder-contaminated water into storage. Alternatively, you can also use a garden sprayer for smaller machines, like we do at PADT. Fill up the sprayer with water and use it to rinse out the wet separator right on top of the waste storage bin.

Another reason you need access to water is to passivate the filter. While not all OEMs recommend water passivation, Concept Laser does and we find it to be very user friendly, as I demonstrate in the video below (video starts 2:58 in, which is when I discuss filter passivation with water).

 5. Access Control

It is important to restrict access to your metal AM laboratory through badge scanning or key pad entry to those who are trained on using the machine, and your building facilities team. It also helps to provide as much visibility through glass windows so that folks that are entering can study what activity is in progress before entering.

Fig 4. Door lock with combination to restrict access, window to provide visibility

6. Structure & Ventilation

Here I move into the subjective (gray area) domain – I request anyone who has more specific information on these matters to kindly share them with me for inclusion in this post (with due credit). I have heard anecdotally that in some places the city has required the supplier to install blast walls and other explosion resistant infrastructure – yet others have not required such infrastructure (including ours). I am not well informed in this space and can only emphasize the need to have these discussions out in the open in the early stage of planning your facility and ask your city’s building safety person if the walls you have planned (or already have installed) are adequate or not – this is likely to be a function of the amount and reactivity of the powder you are handling, proximity to vulnerable areas, human occupancy and other concerns. With regard to ventilation, the more open the space the better (these machines can heat up a small, closed room) – at the same time the space needs to be sealed off from the elements including wind. I know this too is a subjective matter, so discussions with city representatives are the best way to go.

Please send any of your comments, questions or suggestions for improvement to info@padtinc.com, citing this blog post, or connect with me on LinkedIn.

And now go on to PART 3a (SAFETY)

Acknowledgements

Special thanks to Gregg Rand at PADT, Martin Perez (City of Phoenix) and Dave Tallman (City of Tempe), and engineers at Concept Laser Inc.

Installing a Metal 3D Printer: Part 1 (Equipment)

concept-laser-mlab
Fig 1. Concept Laser MLab Cusing R in PADT’s Metal 3D Printing Lab

Download all 5 parts of this series as a single PDF here.

What equipment does one need for metal 3D printing? 

This is the first in a five-part series that brings together the different lessons we learned installing our first metal printer, a Concept Laser MLab Cusing R at PADT, shown in Figure 1. In this post I list the different equipment needed to enable metal 3D printing end-to-end, along with a brief explanation of its purpose. In subsequent posts, I deal with (2) Facilities, (3) Safety, (4) Environmental & (5) Housekeeping aspects of the technology. I hope this information adds to the conversation in a meaningful way and help those who are thinking about, or in the process of installing a metal 3D printer.

The specifics of some of this information will vary depending on the equipment and materials you handle, but my hope is the themes covered here give you a sense of what is involved in installing a metal 3D printer to aid in your preparation for doing the same and for having good discussions with your equipment supplier to ensure these are addressed at a minimum.

One way to look at classifying the equipment needed (beyond the obvious metal 3D printer!) is by its purpose, and I do so here by dividing it into two broad categories: Ancillary Equipment (necessary to the printing itself) and Post-Processing Equipment (focused on the part).

At the outset, it is crucial that the difference between reactive and non-reactive metal alloys be comprehended since a lot of the use of the equipment differs depending on what kind of metal alloy is being used. A previous blog post addressed these differences and these terms will be used in the following sections.

1. Ancillary Equipment

1.1 Wet Separator

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Fig 2. Wet separator used to vacuum fugitive powder

The wet separator is essentially a vacuum cleaner that is designed to safely vacuum stray (“fugitive”) metal powders that cannot be cleaned up any other way. When dealing with powders, the typical recommendation is to first brush whatever you can into the overflow bin so you can reuse it. The next step is to try and wipe up powder with a moist lint-free cloth (to be covered in the housekeeping post). The wet separator has a water column that passivates the metal powder and renders it non-reactive to allow for easier disposal (to be covered in the environmental post). Wet separators require a significant amount of maintenance, particularly when dealing with reactive metals like Titanium and Aluminum alloys, where the supplier recommends the wet separator be cleaned out on a daily basis. At least one company has developed a kit to help with wet separator cleaning – which gives you an indication of how significant of an issue this is. Most suppliers provide a wet separator along with their equipment.

1.2 Glove Box

glove-box
Fig 3. Glove box used to interact with the build chamber in a safe manner, and in an inert atmosphere for reactive metals

A glove box is a useful piece of equipment for dealing with reactive metals in particular. The glove box allows an operator to manage all the powder handling in the build chamber to be done in a closed environment. For non-reactive metals this is not a necessary piece of equipment but it is highly recommended for reactive metals. The glove box when used in concert with reactive metals will allow for inert gas flushing out of oxygen to low PPM levels prior to operator intervention, and also includes grounding connections for the box to the machine. The nice thing about having a glove box is it reduces the amount of time you need to have a respirator on by allowing you to add powder and unpack builds in a closed environment. The glove box may also be integrated into the machine itself – ours is a stand alone device on wheels that we roll over to the machine when we need it.

1.3 Powder Sieve

Unless you plan on disposing all the powder in each build after it is completed, you need a sieve to separate out the larger particles and contaminants from the powder you wish to reuse in subsequent builds. The sieves are also typically provided with the machine and can be enabled with inerting capability (as shown in Fig 4 on the left, or as shown on the right, come as a small desktop unit that can sieve about 3-5 lbs of powder at a time). While the sieve on the left may be used for reactive metal sieving, it is uncertain if one can safely use the desktop sieve for the same, even with grounding the table it sits on and the operator – this is a gray area and I am keen to hear thoughts on this from those that have the expertise/experience in this space.

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Fig 4. Mechanical sieving: (left) for large quantity sieving, (right) tabletop model for smaller quantities

1.4 Ultrasonic Cleaner

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Fig 5. Ultrasonic cleaner used to help isolate metal powder trapped inside parts and supports

The purpose of the ultrasonic cleaner is to remove as much trapped powder as possible before the part and the build plate are subjected to any post-processing – this is to minimize the risk of trapped powder getting airborne during downstream processes – which cannot be completely eliminated (which is why PPE should be used all the way through till the final part is in hand after cleaning).

The Ultrasonic cleaner is used twice: first before the parts are removed from the build plate, and again after they are removed. Sometimes I will even use it a third time after all supports have been removed, if the part has internal p. I typically use the 40 kHz and 60 C temperature setting but have not sought to further optimize the parameters at this time.

2. Post-Processing Equipment

2.1 Furnace

Fig 6. Radiation heating furnace with inert gas capability. The Nabertherm 7/H has a maximum temperature of 1280 C, suitable for stress relief.

The purpose of the furnace is to relieve residual stresses built in the parts prior to removing them from the build plate. So this is the first step after the parts and the plate come out of the ultrasonic cleaner. We use a furnace that allows for nitrogen or argon flushing, and place our parts wrapped in stainless steel foil in a gas box. Instructions for heat treatment (time and temperature profile) are typically provided on the technical specifications that come with the material. Metals like stainless steel can be stress relieved in a nitrogen atmosphere but Inconels and Ti6Al4V for example require higher temperatures of between 800-1000 C and argon atmospheres – so you need to be setup for both gases if you are considering running more than 1 metal in your operation.

2.2 Support Removal

All parts are connected to the build plate by between 3-5mm of supports that need to be removed. This is a two step process: the first step involves removing the parts with supports off the build plate, and this is most commonly done with a table saw or a wire EDM. At PADT, we stumbled upon a third way to do this, using an oscillating hand tool and a carbide blade – which works well for small parts (<3″ in X-Y space). It is important to always wear gloves and a supplier recommended (N95 or higher) respirator while removing supports since there could be trapped powder in the supports that was not removed with the Ultrasonic cleaner. The second step is to use hand tools to pry out the supports from the part – this is why it is important to design supports that have weak mechanical connections to the part itself – ideally you can tear them off with hand tools like a perforated sheet of paper [Video below courtesy Bob Baker at PADT, Inc].

2.3 Die Grinder

Fig 7. Die grinder used for removing burrs at the support interfaces on the part

A carbide die grinder is then used to grind away the support-model interface – for tiny parts, this can be achieved with a hand file as well for some parts but is easier to do with a die grinder. For large parts, this need can be eliminated by designing in regions that are to be machined later and aligning these regions with supported regions, so as to reduce the need for finishing on these surfaces.

2.4 Face Milling

This may come as a bit of a surprise, but you also need some way of replenishing the build plates after use so you can re-use the plates – this involves using a face milling technique to remove all the remnant supports on the build plate and take off a thin slice at the top of the build plate, while retaining flatness to within 100 microns (0.004″). Having this capability in-house will greatly speed-up your ability to start successive prints and reduce the need to keep large inventories of build plates [Video below courtesy Bob Baker at PADT, Inc].

2.5 Surface Finishing

A combination of techniques can be used for surface finishing. At a minimum, you must have the ability to do glass bead blasting – this is both for the printed parts, but also for the build plate itself – a bead blasted finish is recommended to improve the adhesion of the first layer of powder to the build plate.

Fig 8. (left) Bead blaster and (right) post-processed build plates, ready for use again

2.6 Other Capabilities

The list above is what I would consider a minimum list of capabilities one needs to get started in metal 3D printing, but is not comprehensive and does not include facility, safety, environmental and housekeeping requirements which I will cover in future posts. Additional CNC equipment for machining metal AM parts, heat treatment and HIP, and superior surface finishing and cleaning techniques are often called upon for metal AM production, but these are highly dependent on application and part design, which is why I have left them out of the above list.

Move on to part 2 of this series where I discuss the facilities requirements for metal 3D printing (electrical, inert gas etc.). Did I miss anything or do you have a better way of doing the things described above? Please send your thoughts to info@padtinc.com, citing this blog post, or connect with me on LinkedIn.

Acknowledgements:
Garrett Garner at Concept Laser, Inc and Bob Baker at PADT, Inc. for their insight and expertise that helped us select and bring in the above capabilities at PADT.

CLICK HERE for part 2

Engineering.com: Metal Additive Manufacturing Keeps Legend Flying

What do you do when you want to replace the exhaust on a 1944 P-51D Mustang warbird and you also happen to be a pioneer in additive manufacturing?  You work with Concept Laser and PADT to can and print a replacement stainless steel part.  In “Metal Additive Manufacturing Keeps Legend Flying” Engineering.com details the project that involved blue light scanning and 3D Printing of new metal part in modern Stainless Steel, replacing the three-piece weldment with a single part.

They also did a fantastic video about the effort:

If you would like to learn how PADT can help you reverse engineering your legacy geometry and recreate it using Additive Manufacturing, contact us.

Tour ConceptLaser’s Metal 3D Printing lab at AeroDef

Attending AeroDef this year in Fort Worth? Make sure you register to tour Concept Laser on March 6th before AeroDef! You’ll hear an update on the GE acquisition and presentations on customer applications and machine safety. Registration ends February 24th, 2017, so don’t miss this opportunity!

Register now: http://aerodefevent.com/sessions/concept-laser-tour/

Speed, superior quality monitoring, and an open architecture that enables innovation – that is what makes Concept Laser’s Direct Metal Laser Melting (DMLM) technology a leader in the metal additive manufacturing industry. Come and hear about how Concept Laser is investing to bring you innovation through new products and processes that will lead to revenue-generating opportunities for your business.

The Tour is March 6th from 8:30am to 11:30pm and includes round trip transportation from the conference and more.

What you will see on the tour:

  • Direct Metal Laser Melting
  • In-situ Quality Assurance
  • Best-in-class safety guidelines when interacting with reactive and non-reactive materials
3D Printed Exhaust Gas Probe (RSC Engineering and Concept Laser Inc.)
Titanium implant leveraging lattice designs (Concept Laser)

Be Alert and Always Inert – The importance of an inert environment with Metal 3D Printing (Video)

Metal 3D Printing is one of the more exciting areas of additive manufacturing, and we are learning a lot about how to safely operate our new system.  Our very own Dhruv Bhate, PhD shared those lessons learned in this new video:

The video stresses the importance of keeping an inert environment to keep part quality and to ensure a safe operating environment. Our Concept Laser Metal 3D Printer uses high powered lasers to melt metal powder one layer at a time to build 3D Parts. This process produces soot that is highly flammable.

Dhruv shows the process we use to break the part from the machine, clean the chamber of soot, and replace the filter that captures the soot.

To learn more about PADT and how we can help you with your 3D Printing, product development, or Numerical Simulation needs, please visit www.padtinc.com

Use this link to see all of our blog posts on Metal 3D Printing

Press Release: Concept Laser, Honeywell, and PADT Build Largest Additive Manufacturing Center in Southwest at Arizona State University

PADT-Press-Release-IconOn January 18th, ASU will officially Launch their Manufacturing Research and Innovation Hub, the Largest Additive Manufacturing  research and teaching center in the Southwestern US.  PADT is proud to have partnered with ASU as well as with Concept Laser and Honeywell to get this important piece of the local manufacturing ecosystem started and to keep it growing.

Located on the Polytechnic School at ASU in Mesa, Arizona, this facility is amazing.  And you can see it for yourself, the public is invited to the launch on January 18th, 2017 at 9:00 am.  ASU Polytechnic Dean Kyle Squires and the Director Ann McKenna will be speaking as will our very own Rey Chu, John Murray from Concept Laser, and Don Godfrey from Honeywell.  Tours will follow. Learn more and register for this free event that will bring together the local 3D Printing community here.

You can also learn more by reading the official press release from Concept Laser that outlines what the center does and the partnerships that make it possible:

Press Release:

Concept Laser, Honeywell, and PADT Build Largest Additive Manufacturing Center in Southwest at Arizona State University

GRAPEVINE, Texas, January 11, 2017 – The Polytechnic School at Arizona State University (ASU) offers the only manufacturing engineering undergraduate degree in Arizona; it is also one of only 22 ABET accredited manufacturing engineering programs in the United States. By forming a partnership with Concept Laser, Honeywell Aerospace, and PADT, Inc. the largest additive manufacturing research facility in the Southwest is now on the Polytechnic campus. The 15,000 square foot center holds over $2 million of plastic, polymer, and 3D metal printing equipment.

The lab has a Concept Laser M2 cusing and Mlab cusing machine which are dedicated to 3D metal printing, also known as metal additive manufacturing. Unlike conventional metal fabrication techniques, additive manufacturing produces fully-dense metal parts by melting layer upon layer of ultra-fine metal powder. The Polytechnic School is using the machines for a wide range of research and development activities including materials development and prototyping complex mechanical and energy systems.

Supporting quotes:

Don Godfrey, Engineering Fellow at Honeywell: “Honeywell is thrilled to be participating in the opening of the new additive manufacturing laboratory at the Arizona State University Polytechnic campus.  For many years, we have worked with ASU seniors on their capstone projects with three of these projects this school year additive manufacturing focused. In addition to our own additive manufacturing operations, we have provided mentorship to students in the program and assisted in the procurement of one machine for the schools’ new lab.  We look forward to growing our relationships with the university in developing brilliant minds to tackle and overcome industry challenges associated with aviation and additive manufacturing.”

John Murray, President and CEO of US-based subsidiary Concept Laser Inc: “Changing the future of metal additive manufacturing begins with educated teachers and curious students. The educational leadership that the ASU Polytechnic School provides to the Southwest region and the industry will certainly be impactful. Concept Laser is proud to be a partner in this initiative.”

Rey Chu, Principal, Manufacturing Technologies at PADT, Inc: This partnership is the next and obvious step in the progression of additive manufacturing in the Southwest.  With Concept Laser’s outstanding technology, Honeywell’s leadership in applying additive manufacturing to practical Aerospace needs, PADT’s extensive network of customers and industry experience, and ASU’s proven ability to educate and work with industry, the effort will establish a strong foundation for the entire regional ecosystem.

Ann McKenna, Director of ASU’s Polytechnic School: “Partnering with these industry leaders provides us the capability to do additional research and enhance our education programs. With so few of these types of centers, this makes ASU more attractive among academic partners, federal agencies and corporations to advance additive manufacturing.

The ASU Polytechnic School will be hosting an open house to celebrate the launch of their Manufacturing Research and Innovation Hub on January 18, 2017 at 9am. There will be guided tours showcasing student projects. Honeywell, Concept Laser, and PADT will be in attendance. Please register your attendance at  www.mrihlaunch.eventbrite.com.

About Concept Laser  

Concept Laser GmbH is one of the world’s leading providers of machine and plant technology for the 3D printing of metal components. Founded by Frank Herzog in 2000, the patented LaserCUSING® process – powder-bed-based laser melting of metals – opens up new freedom to configuring components and also permits the tool-free, economic fabrication of highly complex parts in fairly small batch sizes.

Concept Laser serves various industries, ranging from medical, dental, aerospace, toolmaking and mold construction, automotive and jewelry. Concept Laser machines are compatible with a diverse set of powder materials, such as stainless steel and hot-work steels, aluminum and titanium alloys, as well as precious metals for jewelry and dental applications.

Concept Laser Inc. is headquartered in Grapevine, Texas and is a US-based wholly owned subsidiary of Concept Laser GmbH. For more information, visit our website at www.conceptlaserinc.com

LaserCUSING® is a registered trademark of Concept Laser.

About Phoenix Analysis and Design Technologies

Phoenix Analysis and Design Technologies, Inc. (PADT) is an engineering product and services company that focuses on helping customers who develop physical products by providing Numerical Simulation, Product Development, and 3D Printing solutions. PADT’s worldwide reputation for technical excellence and experienced staff is based on its proven record of building long term win-win partnerships with vendors and customers. Since its establishment in 1994, companies have relied on PADT because “We Make Innovation Work.” With over 80 employees, PADT services customers from its headquarters at the Arizona State University Research Park in Tempe, Arizona, and from offices in Torrance, California, Littleton, Colorado, Albuquerque, New Mexico, and Murray, Utah, as well as through staff members located around the country. More information on PADT can be found at www.PADTINC.com.

 About Arizona State University

The Ira A. Fulton Schools of Engineering at Arizona State University include nearly 19,000 students and more than 300 faculty members who conduct nearly $100 million in research, spanning a broad range of engineering, construction and technology fields. Across the six schools contained within the Fulton Schools, 24 undergraduate and 32 graduate programs are offered on ASU’s Tempe and Polytechnic campuses and online. The schools’ educational programs emphasize problem solving, entrepreneurship, multidisciplinary interactions, social context and connections. Arizona State University includes more than 80,000 students and 1,600 tenured or tenure-track faculty on multiple campuses in metropolitan Phoenix as well as online. For more information, please visit www.asu.edu or asuonline.asu.edu.

Press contact:
Joyce Yeung, Director of Marketing
Concept Laser
Phone: (817) 328-6500
E-mail: j.yeung@conceptlaserinc.com

PADT Contact
Eric Miller
PADT, Inc.
Principal & Co-Owner
480.813.4884
eric.miller@padtinc.com

Technology Trends in Laser-based Metal Additive Manufacturing

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Figure 1. Concept Laser’s M2 Cusing at AMUG 2016

One of the more difficult things about being at the Additive Manufacturing Users Group (AMUG) is dealing with the fact that there is more to do than you can hope to accomplish in four and a half days. So I decided to focus on two themes: laser-based metal additive manufacturing (AM); and design & simulation for AM. In this post, I focus on the former and try to distill the trends I noticed across the laser-based metal AM system manufacturers that were present at the conference: Concept Laser, SLM, Renishaw, EOS and 3D Systems (listed here in the decreasing order of the time I spent at each supplier’s booth). While it is interesting to study how 5 different suppliers interpret the same technology and develop machines around it, it is not my objective to compare them here, but to extract common trends that most suppliers seem to be working on to push their machines to the next level. For the purposes of this post, I have picked the top-of-the-line machine that each supplier offers as an indication of the technology’s capabilities: they span a range of price points, so once again this is not meant to be a comparison.

As a point of observation, the 5 key trends I noticed turned out to be all really aspects of taking the technology from short run builds towards continuous production. This was not my intent, so I believe it is an accurate indication of what suppliers are prioritizing at this stage of the technology’s growth and see as providing key levers for differentiation.

1. Quality Monitoring

Most customers of AM machines that wish to use it for functional part production bemoan the lack of controls during manufacturing that allow them to assess the quality of a part and screen for excursionary behavior without requiring expensive post-processing inspection. Third party companies like Sigma Labs and  Stratonics have developed platform-independent solutions that can be integrated with most metal AM systems. Metal AM suppliers themselves have developed a range of in-situ monitors that were discussed in a few presentations during AMUG, and they generally fall into the following categories:

  • Input Monitors:
    • Laser: Sensors monitor laser powder as well as temperature across the different critical components in the system
    • Oxygen Level: Sensors in the build chamber as well as in sieving stations track O2 levels to ensure the flushing of air with inert Argon or Nitrogen has been effective and that there are no leaks in the system
  • Output Monitors:
    • Live video: simple but useful, this allows users to get a live video stream of the top layer as it is being built and can help detection of recoater blade damage and part interaction
    • Meltpool: Concept Laser showed how its Meltpool monitoring system can be used to develop 2D and 3D plots that can be superimposed with the 3D CAD file to identify problematic areas – the video is also on YouTube and embedded below. SLM and EOS offer similar meltpool monitoring solutions.
    • Coater consistency: Concept Laser also described a monitor that captures before and after pictures to assess the consistency of the coater thickness across the build area – and this information is fed forward to adjust subsequent coater thicknesses in an intelligent manner.

Quality monitoring systems are still in their infancy with regard to what is done with the information generated, either in terms of feed forward (active) process control or even having high confidence in using the data to validate part quality. A combination of supplier development and academic and industry R&D is ongoing to get us to the next level.

2. Powder Handling

In a previous post, I touched upon the fire and explosion risks posed by metal powder handling. To lower the bar for an operator to gain access to a metal AM machine, one of the considerations is operator safety and the associated training they would need. Suppliers are constantly trying to improve the methods by which they can minimize powder handling. For a mechanical engineer, it is intriguing to see how reactive metal powders can be moved around in inert atmospheres using different strategies. The SLM 500HL uses a screw system to move the powder around in narrow tubes that stick out of the machine and direct the material to a sieving station after which they are returned to the feed area. The Renishaw RenAM 500M on the other hand uses a pneumatically driven recirculation system powered by Argon gas that is well integrated into the machine frame. Concept Laser also offers automated powder handling on the XLine 2000R, while EOS and 3DSystems do not offer this at the moment. Figure 2 below does not do justice to the level of complexity and thought that needs to go into this.

Figure 2. Two different automated powder handling systems in use in metal AM machines

One of the limitations of automating powder handling is the ability to change materials, which is very hard to impossible to do with high enough confidence with these systems. As a result, their use is limited to cases where one machine can be dedicated to one material and efficiency gains of powder handling can be fully realized. The jury is still out on the long term performance of these systems, and I suspect this is one area that will continue to see improvements and refinements in subsequent model releases.

3. Multi-Laser Processing

In the quest for productivity improvement, one of the biggest gains comes from increasing the number and power of available lasers for manufacturing. In my previous experience with laser based systems (albeit not for this application), an additional laser can increase overall machine throughput by 50-80% (it does not double due to steps like the recoater blade movement that does not scale with the number of lasers).

The suppliers I visited at AMUG have very different approaches to this: SLM provides the widest range of customizable options for laser selection with their 500HL, which can accept either 2 or 4 lasers with power selection choices of 400W or 1000W (the 4 laser option was on display, YouTube video from the same machine in action is below) – the lasers of different powers can also be combined to have two 400W and two 1000W lasers. Concept Laser’s XLine 2000R allows for either 1 or 2 1000W lasers and their smaller, M2 machine that was showcased at AMUG has options for 1 or 2 lasers, with power selection of 200W or 400W. EOS, Renishaw and 3D Systems presently offer only single laser solutions: the EOS M 400 has one 1000W laser, Renishaw’s RenAM 500M has one 500W laser and the ProX DMP 320 from 3D Systems has one 500W laser.

There are a few considerations to be aware of when assessing a multi-laser machine: Each laser drives an increase in machine capital cost. But there is another point of note to remember when using multi-laser systems for manufacturing that centers around matching process outputs from different lasers: laser-to-laser variation can be a dominant source of overall process variation and can drive a need to calibrate, maintain and control both lasers as if they were independent machine systems. Additionally, development of  a process on one particular laser power (100W, 400W, 500W, 1000W) may not scale easily to another and is something to remember when developing a long term strategy for metal AM that involves different kinds of machines, even if from the same supplier.

4. Software Integration

Renishaw spent a significant amount of time talking about their easy-to-use QuantAM software which is designed to integrate Renishaw process parameters and part processing information more tightly and allow for seamless process parameter development without needing third part software like Magics. Additive Industries announced in their presentation at AMUG that they had just signed an agreement with 3DSIM to integrate their support design software solution into their MetalFab1 machine. Software integration is likely to be an increasing trend especially around the following areas:

  • Improving support design methods and reducing its empirical nature and reducing the material, build time and support removal costs associated with them as well as eliminating the need for iterative builds
  • Increasing process options available to the user (for example for the outer skin vs the inner core, or for thick vs thin walls)
  • Simplifying the development of optimized process parameters for the user working on new materials
  • Integrating design and process optimization to increase effective part performance

In a future blog post, I will look specifically at the many design and simulation tools available around AM and how they are connected today even if not well-synergized.

5. Modular System Architectures

In a list of mostly evolutionary changes, this is the one area that struck me as being a step-change in how this technology will make an impact, even if it will be felt only by larger scale manufacturers. Concept Laser and Additive Industries are two companies that delivered presentations discussing how they were approaching the challenge of revolutionizing the technology for true production and minimizing the need for human touch. Common to both is the notion of modularity, allowing for stacking of printing, powder removal, heat treating and other stations. While Additive Industries are developing a flow resembling a series production line, Concept Laser have taken the more radical approach of having autonomous vehicles delivering the powder bed to the different stations, with travel channels for the vehicles, for the operator and for maintenance access (Figure 3). Both companies expect to have solutions out by the end of this year.

Figure 3. Concept Laser’s “Factory of Tomorrow” features swim-lanes for operators and for autonomous vehicles that will deliver powder and parts from one module to another

Concluding Thoughts

It is an interesting time to be a manufacturer of laser-based metal 3D printers, and an even more interesting time to be a consumer of this technology. The laser-material interaction fundamentals of the process are now fairly well-established. Competitors abound both in existing and emerging markets with machines that share many of the same capabilities. Alternative technologies (E-Beam melting, deposition and jetting) are making strides and may start to play in some applications currently dominated by laser-based technologies. A post early-adopter chasm may be around the corner. This will continuously drive the intense need to innovate and differentiate, and possibly also lead to a merger or two. And while most of the news coming out of conferences is justifiably centered around new process technologies (as was the case with Carbon’s CLIP and XJET’s metal nanoparticle jetting at AMUG this year), I think there is an interesting story developing in laser-based powder bed fusion and can’t wait to see what AMUG 2017 looks like!

Reactive and Non-Reactive Metal Alloys in Laser-based Powder Bed Fusion

One of the first concepts you come across in metal 3D printing is the notion of reactivity of the powder metal alloys – in this post, I investigate why some of these powder alloys are classified as reactive and others as non-reactive, and briefly touch upon the implications of this to the user of metal 3D printing tools, scoping the discussion to laser-based powder bed fusion. Ultimately, this boils down to a safety issue and I believe it is important that we, the users of these technologies, truly understand the fundamentals behind the measures we are trained to follow. If you are looking to get something chemical etched visit https://interplex.com/technology/process-capability/chemical-etching/.

Figure 1 below is indicative of the range of materials available currently for the laser-based powder bed fusion process (this selection is from Concept Laser). I have separated these into non-reactive and reactive metal alloys. The former includes steels, Inconels, bronze and CoCrW alloys. The reactive metal alloys on the other hand are Aluminum or Titanium based. The question is: what classifies them as such in the context of this process?

Figure 1.
Figure 1. Typical metal alloys available for the laser-based powder bed fusion process (from Concept Laser), classified as Non-Reactive and Reactive

Reactivity in this process really pertains to the likelihood of the alloy in question serving as a fuel for a fire and/or an explosion, which are two related but distinct phenomena. To truly understand the risk associated with powder metals, we must first understand a few basic concepts.

1. Fire and Explosion Criteria

Figure 2 is a commonly used representation of the criteria that need to be met to initiate a fire (fuel, oxygen and an ignition source) and an explosion (the same three criteria for a fire, plus a dust cloud and confined space). When handling reactive metal alloy powders, it is important to remember that two of the three requirements for a fire are almost always met and the key lies in avoiding the other criterion. When not processing the powder in the machine, it is often subject to ambient oxygen content and thus all precautions are taken to prevent an ignition source (an ESD spark, for example). When the metal is being processed with a high power laser, it is done in an inert atmosphere at very low Oxygen levels. This thought process of appreciating you are one criterion away from a fire is useful, if sobering, to bear in mind when working with these powders.

fireexplosion
Figure 2. The fire triangle and explosion pentagon

2. Terms Used to Describe Fire and Explosion Risk

There are several terms used to describe fire and explosion risk. I have picked 5 here that tie into the overall “index” I will discuss in the following section. All these parameters are in turn functions of the material in question, both with regard to its composition and its size distribution and are co-dependent. These definitions are adapted from Benson (2012) and Prodan et al. (2012).

  • Fire Related: These two terms describe the sensitivity of a metal dust cloud to ignition.
    • Ignition Temperature: This is the lowest surface temperature capable of igniting a powder or dust dispersed in the form of a dust cloud
    • Minimum Ignition Energy: This measures the ease of ignition of a dust cloud by electrical and electrostatic discharges.
  • Explosion Related: These terms describe the severity of an explosion arising from a fire once ignited.
    • Minimum Explosion Concentration (MEC): This is the smallest amount of dust which when suspended in air, under a set of test conditions, will initiate an explosion and propagate even after the action of the ignition source has ceased.
    • Maximum Explosion Pressure: This is a measure of the highest pressure that occurs during of an explosion of a flammable mixture in a closed vessel.
    • Maximum Rate of Pressure Rise: This is the maximum slope of the pressure/time curve during a flammable mixture explosion in a closed vessel.

3. Index of Explosibility

Having defined these terms, the question is how they can be tied together to give some sense of the hazard associated with each metal powder. I came across a 1964 US Bureau of Mines study that defined an Index of Explosibility as a measure of the hazard risk posed by powder metal alloys. The index represents both the sensitivity of the powder to ignition, and once ignited, the severity of the resulting explosion. Since this is a subjective metric, it is normalized by comparison against a “standard”, which was selected as Pittsburgh coal dust in the 1964 study. Importantly though, this normalization enables us to do qualitative comparisons between metal powders and have some sense of the hazard risk posed by them. Figure 3 is the equation reproduced from the original 1964 report and shows how this term is estimated.

Index of Explosibility (US Bureau of Mines study, 1964)
Figure 3. Index of Explosibility (US Bureau of Mines study, 1964)
Figure 3. Particle size has a significant impact on explosibility
Figure 4. Particle size has a significant impact on explosibility

The study also showed how the index was a direct function of particle size. Most powders for 3D metal printing are in the 20-100um range, and as shown in Fig. 4 for atomized Aluminum, the risk of an explosion increases with reducing particle diameter. 

The authors tested a range of metals and computed the different variables, which I have compiled anew in the table in Figure 5 for the ones we are interested in for metal 3D printing. The particle sizes in the 1964 study were ones that made it through a No. 200 sieve (less than 75 microns), but did not include sub-micron particles – this makes it an appropriate comparison for metal 3D printing. It is clear from the Index of Explosibility values, as well as the Cloud Ignition Temperatures in the table below why Aluminum and Titanium are classified as reactive metals requiring special attention and care.

Figure . Explosibility study findings from US Bureau of Mines study (1964)
Figure 5. Index of Explosibility comparison for selected metal alloys, adapted from US Bureau of Mines study (1964)

4. Implications for Metal 3D Printing

So what does this mean for metal 3D printing? There are three things to be aware of that are influenced by whether you are working with non-reactive or reactive alloys – I only provide a general discussion here, specific instructions will be provided to you in supplier training and manuals and must be followed.

  • Personal Protective Equipment (PPE): There are typically two levels of PPE: standard and extended. The standard PPE can be used for non-reactive alloy handling, but the reactive alloys require the more stringent, extended PPE. The main difference is that the extended PPE requires the use of a full bunny suit, ESD grounding straps and thermal gloves.
  • Need for Inert Gas Handling: Many tasks on a metal 3D printer require handling of powder (pouring the powder into the chamber, excavating a part, cleaning the chamber of powder etc.). Most of these tasks can be performed in the ambient for non-reactive metal alloys with standard PPE, but for reactive alloys these tasks must be performed in an inert atmosphere.
  • Local authority approvals: It is important that your local authorities including the fire marshall, are aware of the materials you are processing and review and authorize their use in your facility before you turn on the machine. Local regulations may require special procedures be implemented for preparing the room for use of reactive metal alloys, that do not apply to non-reactive metals. It is vital that the authorities are brought into the discussion early on and necessary certifications obtained, keeping in mind that reactive metal alloy use may drive additional investment in safety measures.

5. Conclusion

Safe operation of metal 3D printers requires installation of all the necessary safety equipment, extensive hands-on training and the use of checklists as memory aides. In addition to that, it helps to connect these to the fundamental reasons why these steps are important so as to gain a clearer appreciation of the source of the hazard and the nature of the risk it poses. In this article I have tried to demonstrate why reactivity in metal 3D printing matters and what the basis is for the classification of these metal alloys into reactive and non-reactive by leveraging an old 1964 study. I wish to close with a reminder that this information is meant to supplement formal training from your equipment supplier – if there is any conflict in the information presented here, please revert to your supplier’s recommendations.

Thank you for reading; stay safe as you innovate!

The 3D Printing Value Proposition

At a recent Lunch-n-Learn organized by the Arizona Technology Council, I had the opportunity to speak for 10 minutes on 3D printing. I decided to focus my talk on trying to answer one question: how can I determine if 3D printing can benefit my business? In this blog post, I attempt to expand on the ideas I presented there.

While a full analysis of the Return-On-Investment would require a more rigorous and quantitative approach, I believe there are 5 key drivers that determine the value proposition for a company to invest in 3D printing, be it in the form of outsourced services or capital expenditure. If these drivers resonate with opportunities and challenges you see in your business, it is likely that 3D printing can benefit you.

1. Accelerating Product Development

3D printing has its origins in technologies that enabled Rapid Prototyping (RP), a field that continues to have a significant impact in product development and is one most people are familiar with. As shown in Figure 1, PADT’s own product development process involves using prototypes for alpha and beta development and for testing. RP is a cost- and time effective way of iterating upon design ideas to find ones that work, without investing in expensive tooling and long lead times. If you work in product development you are very likely already using RP in your design cycle. Some of the considerations then become:

  • Are you leveraging the complete range of materials including high temperature polymers (such as ULTEM), Nylons and metals for your prototyping work? Many of these materials can be used in functional tests and not just form and fit assessments.
  • Should you outsource your RP work to a service bureau or purchase the equipment to do it in-house? This will be determined by your RP needs and one possibility is to purchase lower-cost equipment for your most basic RP jobs (using ABS, for example) and outsource only those jobs requiring specialized materials like the ones mentioned above.
PADT's Product Development process showing the role of prototypes (3D printed most of the time)
Figure 1. PADT’s Product Development process showing the role of prototypes (most often 3D printed)

The video below contains several examples of prototypes made by PADT using a range of technologies over the past two decades.

2. Exploiting Design Freedom

Due to its additive nature, 3D printing allows for the manufacturing of intricate part geometries that are prohibitively expensive (or in some cases impossible) to manufacture with traditional means. If you work with parts and designs that have complex geometries, or are finding your designs constrained by the requirements of manufacturing, 3D printing can help. This design freedom can be leveraged for several different benefits, four of which I list below:

2.1 Internal Features

As a result of its layer-by-layer approach to manufacturing a part, 3D printing enables complex internal geometries that are cost prohibitive or even impossible to manufacture with traditional means. The exhaust gas probe in Fig. 2 was developed by RSC engineering in partnership with Concept Laser has 6 internal pipes surrounded by cooling channels and was printed as one part.

3D Printed Exhaust Gas Probe (RSC Engineering and Concept Laser Inc.)
Fig 2. 3D Printed Exhaust Gas Probe with intricate internal features (RSC Engineering and Concept Laser Inc.)

2.2 Strength-to-Weight Optimization

One of the reasons the aerospace industry has been a leader in the application of 3D printing is the fact that you are now able to manufacture complex geometries that emerge from a topology optimization solution and reduce component weight, as shown in the bracket manufactured by Airbus in Figure 3.

Titanium Airbus bracket made by Concept Laser on board the A350
Fig 3. Titanium Airbus bracket made by Concept Laser on board the A350

2.3 Assembly Consolidation

The ability to work in a significantly less constrained design space also allows the designer to integrate parts in an assembly thereby reducing assembly costs and sourcing headaches. The part below (also from Airbus) is a fuel assembly that integrated 10 parts into 1 printed part.

Airbus Fuel Assembly 3D printed out of metal (Airbus / Concept Laser)
Fig 4. Airbus Fuel Assembly 3D printed out of metal (Airbus / Concept Laser)

2.4 Bio-inspiration

Nature provides several design cues, optimized through the process of evolution over millenia. Some of these include lattices and hierarchical structures. 3D printing makes it possible to translate more of these design concepts into engineering structures and parts for benefits of material usage minimization and property optimization. The titanium implant shown in Figure 5 exploits lattice designs to optimize the effective modulus in different locations to more closely represent the properties of an individuals bone in that region.

Titanium implant leveraging lattice designs (Concept Laser)
Fig 5. Titanium implant leveraging lattice designs (Concept Laser)

3. Simplifying the Supply Chain, Reducing Lead Times

One of the most significant impacts 3D printing has is on lead time reduction, and this is the reason why it is the preferred technology for “rapid” prototyping. Most users of 3D printing for end-part manufacturing identify a 70-90% reduction in lead time, primarily as a result of not requiring the manufacturing of tooling, reducing the need to identify one or more suppliers. Additionally, businesses can reduce their supplier management burden by in-sourcing the manufacturing of these parts. Finally, because of the reduced lead times, inventory levels can be significantly reduced. The US Air Force sees 3D printing as a key technology in improving their sustainability efforts to reduce the downtime associated with aircraft awaiting parts. Airbus recently also used 3D printing to print seat belt holders for their A310 – the original supplier was out of business and the cost and lead time to identify and re-tool a new supplier were far greater than 3D printed parts.

4. Reducing Costs for High Mix Low Volume Manufacturing

According to the 2015 Wohlers report, about 43% of the revenue generated in 3D printing comes from the manufacturing of functional, or end-use parts. When 3D printing is the process of choice for the actual manufacturing of end-use parts, it adds a direct cost to each unit manufactured (as opposed to an indirect R&D cost associated with developing the product). This cost, when compared to traditional means of manufacturing, is significantly lower for high mix low volume manufacturing (High Mix – LVM), and this is shown in Figure 6 for two extreme cases. At one extreme is mass customization, where each individual part has a unique geometry of construction (e.g. hearing aids, dental aligners) – in these cases, 3D printing is very likely to be the lowest cost manufacturing process. At the other end of the spectrum is High Volume Manufacturing (HVM) (e.g. semiconductor manufacturing, children’s toys), where the use of traditional methods lowers costs. The break-point lies somewhere in between and will vary by the the part being produced and the volumes anticipated. A unit cost assessment that includes the cost of labor, materials, equipment depreciation, facilities, floor space, tooling and other costs can aid with this determination.

Chart showing how volumes drive unit prices and where 3D Printing can be the cheaper option
Fig 6. Chart showing how volumes drive unit prices and where 3D Printing can be the cheaper option for low volumes and high mix manufacturing

5. Developing New Applications

Perhaps the most exciting aspect of 3D printing is how people all around the world are using it for new applications that go beyond improving upon conventional manufacturing techniques. Dr. Anthony Atala’s 2011 TED talk involved the demonstration of an early stage technique of depositing human kidney cells that could someday aid with kidney transplants (see Figure 7). Rarely does a week go by with some new 3D printing application making the news: space construction, 3D surgical guides, customized medicine to name a few. The elegant and intuitive method of building something layer-by-layer lends itself wonderfully to the imagination. And the ability to test and iterate rapidly with a 3D printer by your side allows for accelerating innovation at a rate unlike any manufacturing process that has come before it.

Dr. Anthony Atala showing a 3D printed kidney [Image Attr. Steve Jurvetson]
Fig 7. Dr. Anthony Atala showing a 3D printed kidney [Image Attr. Steve Jurvetson, Wikimedia Commons]

Conclusion

As I mentioned in the introduction, if you or your company have challenges and needs in one or more of the 5 areas above, it is unlikely to be a question of whether 3D printing can be of benefit to you (it will), but one of how you should best invest in it for maximum return. Further, it is likely that you will accrue a combination of benefits (such as assembly consolidation and supply simplification) across a range of parts, making this technology an attractive long term investment. At PADT, we offer 3D printing both as a service and also sell most of the printers we use on a daily basis and are thus well positioned to help you make this assessment, so contact us!

Key Process Phenomena in the Laser Fusion of Metals

Metal 3D printing involves a combination of complex interacting phenomena at a range of length and time scales. In this blog post, I discuss three of these that lie at the core of the laser fusion of metals: phase changes, residual stresses and solidification structure (see Figure 1). I describe each phenomenon briefly and then why understanding it matters. In future posts I will dive deeper into each one of these areas and review what work is being done to advance our understanding of them.

Fig. 1 Schematic showing the process of laser fusion of metals and the four key phenomena of phase changes, melt pool behavior, thermomechanical effects and microstructure evolution
Fig. 1 Schematic showing the process of laser fusion of metals and the three key phenomena of phase changes, residual stresses and solidification structure

Phase Changes

Phases and the mechanisms by which they transition from one to the other
Fig. 2 Phases and the mechanisms by which they transition

Phase changes describe the transition from one phase to another, as shown in Figure 2. All phases are present in the process of laser fusion of metals. Metal in powder form (solid) is heated by means of a laser beam with spot sizes on the order of tens of microns. The powder then melts to form a melt pool (liquid) and then solidifies to form a portion of a layer of the final part (solid). During this process, there is visible gas and smoke, some of which ionizes to plasma.

The transition from powder to melt pool to solid part, as shown in Figure 3, is the essence of this process and understanding this is of vital importance. For example, if the laser fluence is too high, defects such as balling or discontinuous welds are possible and for low laser fluence, a full melt may not be obtained and thus lead to voids. Selecting the right laser, material and build parameters is thus essential to optimize the size and depth of the liquid melt pool, which in turn governs the density and structure of the final part. Finally, and this is more true of high power lasers, excessive gas and plasma generation can interfere with the incident laser fluence to reduce its effectiveness.

Primary phase changes from powder to melt pool to solid part
Fig. 3 Primary phase changes from powder to melt pool to solid part

Residual Stresses

Residual stresses are stresses that exist in a structure after it reaches equilibrium with its environment. In the laser metal fusion process, residual stresses arise due to two related mechanisms [Mercelis & Kruth, 2006]:

  • Thermal Gradient: A steep temperature gradient develops during laser heating, with higher temperatures on the surface driving expansion against the cooler underlying layers and thereby introducing thermal stresses that could lead to plastic deformation.
  • Volume Shrinkage: Shrinkage in volume in the laser metal fusion process occurs due to several reasons: shrinkage from a powder to a liquid, shrinkage as the liquid itself cools, shrinkage during phase transition from liquid to solid and final shrinkage as the solid itself cools. These shrinkage events occur to a greater extent at the top layer, and reduce as one goes to lower layers.
Fig. 4 Residual stresses resulting from thermal gradients and volume changes
Fig. 4 Residual stresses resulting from thermal gradients and volume changes

After cooling, these two mechanisms together have the effect of creating compressive stresses on the top layers of the part, and tensile stresses on the bottom layers as shown in Figure 4. Since parts are held down by supports, these stresses could have the effect of peeling off supports from the build plate, or breaking off the supports from the part itself as shown in Figure 4. Thus, managing residual stresses is essential to ensuring a built part stays secured on the base plate and also for minimizing the amount of supports needed. A range of strategies are employed to mitigate residual stresses including laser rastering strategies, heated build plates and post-process thermal stress-relieving.

Solidification Structure

Solidification structure refers to the material structure of the resulting part that arises due to the solidification of the metal from a molten state, as is accomplished in the laser fusion of metals. It is well known that the structure of a metal alloy strongly influences its properties and further, that solidification process history has a strong influence on this structure, as does any post processing such as a thermal exposure. The wide range of materials and processing equipment in the laser metal fusion process makes it challenging to develop a cohesive theory on the nature of structure for these metals, but one approach is to study this on four length scales as shown in Figure 5. As an example, I have summarized the current understanding of each of these structures specifically for Ti-6Al-4V, which is one of the more popular alloys used in metal additive manufacturing. Of greatest interest are the macro-, meso- and microstructure, all of which influence mechanical properties of the final part. Understanding the nature of this structure, and correlating it to measured properties is a key step in certifying these materials and structures for end-use application.

FIg. 5 Four levels of solidification structure and the typical observations for Ti-6Al-4V
FIg. 5 Four levels of solidification structure and the typical observations for Ti-6Al-4V

Discussion

Phase changes, residual stresses and solidification structure are three areas where an understanding of the fundamentals is crucial to solve problems and explore new opportunities that can accelerate the adoption of metal additive manufacturing. Over the past decade, most of this work has been, and continues to be, experimental in nature. However, in the last few years, progress has been made in deriving this understanding through simulation, but significant challenges remain, making this an exciting area of research in additive manufacturing to watch in the coming years.

References

  1. Mercelis, P., & Kruth, J. (2006). Residual stresses in selective laser sintering and selective laser melting. Rapid Prototyping Journal, 12(5), 254-265.
  2. Simonelli, M., Tse, Y.Y., Tuck, C., (2012) Further Understanding of Ti-6Al-4V selective laser melting using texture analysis, SFF Symposium
  3. King, W. E. and Anderson, A. T. and Ferencz, R. M. and Hodge, N. E. and Kamath, C. and Khairallah, S. A. and Rubenchik, A. M., (2015) Laser powder bed fusion additive manufacturing of metals; physics, computational, and materials challenges, Applied Physics Reviews, 2, 041304

Major Milestone Achieved: 3D Printing of a Full Turbine Engine

3d-printed-jet-engine

Not long ago the sages in the additive manufacturing world said "Someday in the future we will be able to print a complete Turbine Engine."  That someday is now, much sooner than many of us predicted.  Researchers at Monash University in Australia recently created a modified version of a Safron Microturbo Auxiliary Power Unit using 3D Printing.  The whole thing.  Milestone Achieved.

The best article on this amazing story is on the Melbourne Examiner page:
www.smh.com.au/technology/sci-tech/3d-printing-melbourne-engineers-print-jet-engine-in-world-first-20150226-13pfv1.html 

Turbine Engines are really the peak of machine design. They contain every nasty thing you might run into in other machines, but spin faster and run hotter.  It's hard stuff. The geometry is difficult, lots of small features and holes, and significant assembly and tolerance constraints.  Getting a demonstrator built like this is a huge deal.  As a former turbine engine engineer and a long time user of additive manufacturing, I'm amazed. 

Check out their video:

The "3d Printer" they used was a huge Concept Laser Direct Laser Melting system.  The technology uses a laser to draw on the top of a bed of powder medal, melting the medal in small pools the bind and create a fully dense part with cast like properties.  They used three different metals: nickel alloy, titanium, and aluminum.

Concept-Laser-3d-printed-turbine-enginePADT has chosen to partner with Concept Laser for our metal 3D Printing strategy, which gives us additional excitement for this sucessful project.  

Now that someone has achieved this milestone, the industry can move forward with confidence that even more can be done with metal 3D Printing.  Much was learned in the creation of this advanced device that we can build on and apply to other industries and applications. 

Much is said in the twittersphere and press about printing food or custom dog tags, but this sort of high value industrial application is where the real impact of 3D Printing will be felt. It shows that companies can develop new more efficient products in less time and that are not constrained by traditional manufacturing methods.