Installing a Metal 3D Printer: Part 4 (Environmental)

What waste streams are generated in powder-based metal 3D printing? Are they hazardous? How should they be disposed responsibly?

This is the fourth part of 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 parts using the links below.

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:

1. Sources of Waste

As shown in Figure 1 below, metal powder used in this process ends up in dry and wet waste. The dry waste can be composed of wipes and gloves with powder and soot, and the wet waste is mostly composed of water and suspended metal particles (from the wet separator and ultrasonic cleaner), and for reactive alloys, can also consist of filter cartridges that need to be suspended in water throughout. Because the wastes contain metal powders, we must stop and ask if this is safe for sending to our landfills and into our sewers where there is a risk of contaminating groundwater and creating other long term environmental havoc.

Thus, the first question is: are these wastes hazardous?

Fig 1. Powder Life Cycle

2. Is this Waste Hazardous?

There are two sources for this information: the EPA (in the US) and the powder supplier’s data sheets. It helps to begin by understanding some definitions – statements in italics are quoted from the EPA, the rest of the text is mine.

  • Waste: “A waste is any solid, liquid, or contained gaseous material that is discarded by being disposed of, burned or incinerated, or recycled
  • Hazardous Waste: There are several types of hazardous waste and associated definitions of each. The two main categories are:
    • Listed Waste: “Your waste is considered hazardous if it appears on one of four lists published in the Code of Federal Regulations (40 CFR Part 261).” I have looked at this list and to the best of my knowledge, no metal powders of concern to the metal 3D printing process appear on this list (as of July 10, 2017). The metal powders currently used are also not considered acute hazards.
    • Characteristic Waste: In addition to listed wastes, the EPA specifies certain characteristics that a waste may possess (even if not listed) that would make it hazardous. In the context of metal powders, the potentially relevant categories are:
      • “It catches fire under certain conditions. This is known as an ignitable waste”.
      • “It is harmful or fatal when ingested or absorbed, or it leaches toxic chemicals into the soil or ground water when disposed of on land. This is known as a toxic waste.”

Due to the generality of the definitions of “Characteristic Waste,” and the lack of available data in the public domain such as from a TCLP test (Toxicity Characteristic Leaching Procedure), it is hard to dismiss these as not being relevant. For each of our waste streams, consider the arguments below:

  • Dry Waste: We know that given the right conditions and an ignition source, that these powders, especially reactive alloys and combustion products, can ignite.
  • Wet Waste: We also know that while water serves as a passivation for powders, we cannot guarantee that the powder will always stay in wet state if it is not disposed as such. Evaporation, for example, can leave behind combustible powder.

Another source of hazard information is the Safety Data Sheet (SDS) or Material Safety Data Sheet (MSDS). Some metal powders are more hazardous than others, so when planning, consider looking at all the alloys you may possibly be using in the future and ask for SDS sheets on all of them. One example, is of Ti6Al4V powder below, clearly showing significant hazards present.

Fig 2. Sample hazards identification from SDS (shown here for Ti6Al4V)

3. What Regulations do I need to be aware of?

The EPA established three categories of waste generators in their regulations, listed below along with the relevant quantity of waste generated and stored, for our purposes (visit EPA’s site for the full list, this is not comprehensive) – EPA cites these numbers in hundreds and thousands of kilograms, hence the strange numbers below (in lbs):

Note this is the sum total of all hazardous wastes your site is generating (in our case, dry and wet wastes combined), not a limit per category. Depending on what category you fall in, you will need to follow EPA’s regulations, available here. Additionally, some states may have additional regulations and this is where I only have studied this problem for my home state of Arizona, which is in line with the EPA’s federal guidelines and does not, to the best of my knowledge, impose additional restrictions. The full list by state is here. If you are a “Very Small Quantity Generator” as we are at PADT, the regulations are fairly straightforward and involve three items (quoted from the EPA’s site) – the requirements are more stringent for larger quantities.

  • VSQGs must identify all the hazardous waste generated.
  • VSQGs may not accumulate more than 1,000 kilograms of hazardous waste at any time.
  • VSQGs must ensure that hazardous waste is delivered to a person or facility who is authorized to manage it.

At PADT, we contract with an industrial waste disposal company that picks up and replaces our waste containers. Yes, this adds cost to the process and at least one company has developed a method to significantly reduce wet waste (which tends to be the larger of the two) by employing a filtration device. Similar innovations and a general focus on reducing waste can drive these costs down.

4. Opinion

As with all regulations, one can approach them by focusing on the specificity of the language. While this is important, it is also useful to seek to understand the intent of the regulation. When it comes to these wastes, I ask if I would be comfortable carrying it in my car and disposing it in my hypothetical backyard landfill (dry waste) or my local water body (wet waste) – and the answer to both, for me, is a NO. So why should I ask my city to do this? This is understandably an exaggerated way of looking at the problem, but I believe at a minimum, serves as a risk-conservative upper-bound that is useful when addressing uncertainty in these matters.

5. References

  1. EPA, Hazardous Waste Generators Home Page
  2. EPA, Categories of Waste Generators
  3. EPA e-CFR, Title 40, Part 261
  4. US Environmental Agencies by state 

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.
  • Local, state and federal regulations vary, and are important – partner with your local environmental authorities when making decisions
  • 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.
  • PADT and the author assume no legal responsibilities for any decisions or actions taken by the readers of this document or of subsequent information generated from it.

Video Tips – Two-way connection between Solidworks and ANSYS HFSS

This video will show you how you can set up a two-way connection between Solidworks and ANSYS HFSS so you can modify dimensions as you are iterating through designs from within HFSS itself. This prevents the need for creating several different CAD model iterations within Solidworks and allows a more seamless workflow.  Note that this process also works for the other ANSYS Electromagnetic tools such as ANSYS Maxwell.

Phoenix Business Journal: Why architecture matters

I’m an engineer. If pushed I will tell you that function should dominate design and that spending time and resources on aesthetics or styling is a waste of money. But a little voice in my head would be screaming “No! Wrong!” because there is value in the visual beauty of something. Nowhere is that truer than in architecture

Importing and Splitting Solid Models for ANSYS HFSS 18.0

Importing solid 3D Mechanical CAD (or MCAD) models into ANSYS HFSS has always been and remains to be a fairly simple process. After opening ANSYS Electronics Desktop and creating an HFSS design, from the menu bar, select Modeler > Import. A dialog box will open to navigate to and directly open the model.

The CAD will automatically be translated and loaded into the HFSS 3D Modeler. If the geometry is correct and does not require any editing, the import process is complete and analysis can begin! However, if there are any errors with the geometry, there is excessive or invalid detail, or if it’s not organized into separate bodies conducive for electromagnetic analysis, you may soon realize that the editing capability is limited to scaling, reorienting, or Boolean operations. This approach can be particularly troublesome when portions of the model (or all of the model) which consist of different materials are not split into different objects. For example, notice the outer conductor, inner conductor, and dielectric of the imported SMA below are all one solid object.

Unless you’re lucky enough to work with the creator of the CAD, you will need to find a way to split this model into the inner and outer conductors, and the dielectric. However, since the release of ANSYS R18.1, the power of SpaceClaim Direct Modeler (SCDM) and the MCAD translator will be packaged together. The good news is, the process described above will continue to work. The better news is, SCDM offers new capabilities to directly edit or clean imported geometry. So, here are a few simple steps to quickly split this SMA connector using SCDM. You can download a copy of this model here to follow along. If you need access to SCDM, you can contact us at info@padtinc.com. It’s worth noting, at this point, that the processes discussed throughout this article work the same for HFSS-IE, Q3D, and Maxwell designs as well.

[1] First, after opening ANSYS SpaceClaim, the step file can be imported through the menu File > Open or by simply dragging and dropping the file into the SCDM window. [2] To separate the dielectric from the outer conductor, select Design > Intersect > Split Body. [3] Click and hold the center mouse button to rotate the model so the boundary between the dielectric and outer conductor is visible. Hold the Ctrl key and click the center mouse button to pan, and use the center mouse scroll to zoom in and out. Finally, press ‘z’ on the keyboard to fit the view window. [4] When positioned, click on the object to split (in this case it is the entire model). [5] Then, click on the face which defines the boundary between the dielectric and outer conductor. [6] Finally, press the Esc key. The first split is done!

Repeat the Split Body process to separate the center conductor from the dielectric. Notice under the structure tree that there are now three separate objects.

The split body function is also useful to simplify a structure for analysis. For example, the female side of the SMA could be simplified as a solid center conductor. [1] Reposition the connector to view the female side. [2]-[3] Control the visibility of each body with the object’s checkbox in the structure tree. [4] Measure the length of the female side by pressing the letter ‘e’ on the keyboard and selecting the top edge (note the line length of 2.95mm for later). [5] Then, repeat the Split Body process to split the center conductor at the boundary between the male and female sides. [6]-[7] However, rather than pressing the Esc key, click on the female receiver to automatically remove the body.

[1] To extend the center pin to its original length, select Design > Edit > Pull. [2] Click on the face where the female side was originally attached and select the Up To option. [3] Type in the previously measured length of 2.95mm. [4] Finally, press Enter (press Esc 3x to exit the Pull command).

Repeat the Split Body and Pull processes until the model has been divided into different bodies for each material type and is sufficiently simplified.

Once the model is ready, select File > Save As to save the geometry as the preferred format. Perhaps the most familiar approach to HFSS users would be to save the new model as a STEP file, then to import the model into HFSS as described in the first paragraph.

Phoenix Business Journal: Developing a product in a global market

Everyone has adjusted to the fact that these days products are manufactured and sold globally. What many companies have not accepted, is that fact that the product development process is also global. If you don’t accept that and adjust, your competition will. “Developing a product in a global market” goes over the basics to successfully leveraging global resources to develop new products.

Phoenix Business Journal: Using small amounts of capital to make a big difference with microloans

Ten years ago PADT, deposited $1,000 into an online service called Kiva. Kiva makes small loans to people all around the world.  We just made our 100’th investment, bringing us to $7,900 lent to different businesses in 40 different countries around the world. Take a look at “Using small amounts of capital to make a big difference with microloans” to learn more about how you or your company can make a real difference in people’s lives.

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

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

This is my fourth post 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).

~

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.

PADT Open House 2017, image courtesy James Barker

Overset Meshing in ANSYS Fluent 18.0

One of the tough challenges in creating meshes for CFD simulations is the requirement to create a mesh that works with very different geometry. With Overset meshing you can create the ideal mesh for each piece of geometry in your model, and let them overlap where they touch and the program handles the calculations at those boundaries. All of this is handled simply in the ANSYS Workbench interface and then combined in ANSYS FLUENT.

PADT-ANSYS-Fluent-Overset-Meshing-2017_07_05-1

Towards Self-Supporting Design for Additive Manufacturing: Part 1 (Standard Guidelines)

1. Background:

When it comes to Additive Manufacturing (AM), there is a lot to consider before hitting the print button. One of the biggest constraints in most AM processes is the need for supports for overhangs, which are aspects of the design that will not print properly without supports either due to the force of gravity acting on the material (natural free-falling state of the material with no support forcing it into position), or the thermomechanical effects associated with printing with no underlying thermally conductive and warpage-constraining material.

The solution is to either redesign any of the problem areas or reorient the whole piece to avoid any overhangs that need these supports. During my internship at PADT Inc., I will be focusing on strategies to minimize the need for supports, towards the ideal goal of manufacturing only self-supporting structures, because it’s never a bad idea to decrease waste, both in terms of additional material used and the labor involved in removing the support materials after the print. This post (part 1) of this blog series is going to be about evaluating the most basic guidelines of printing a self-supporting structure to extract some insight.

2. Methodology:

Using inspiration from some machine accuracy tests found online, I designed my own prints to evaluate the Makerbot Replicator 5th generation’s ability to print overhangs using angles, upright holes, bridges, arched bridges, and 90 degree overhangs—and I present each one of these standard guidelines below. My process parameters for almost all of the tests with, of course, supports OFF were as follows:

  • Extruder Temp: 212 C
  • Travel Speed: 70 mm/s
  • Infill Density: 10%
  • Layer Height: 0.20 mm
  • Number of Shells: 2

 

 

3. Observations:

3.1 Angles

For testing overhangs with angles, I printed out two different sets of trapezoids. The first was a set of six ranging from 25-75 degrees (or 65-15 degrees from the leveled plane).

  

   

As shown by the photos above, the prints were of good quality and only started to show visibly poor quality on the 65 and 75 degree samples. The thinnest edge on the 65 degree sample curled up due to the heat of the extruder. The same issues were present on the 75 degree piece, but this is more exaggerated because of how harsh the angle is.

  

My hope of printing self-supporting pieces was shattered when I printed out an 85 degree trapezoid. To save material, I only printed out a section of the trapezoid, but the angled edge did not print smoothly at all. Not only that, but it did not print at a true 85 degree angle. With these tests, it is safe to say that a machine can handle up to a 65 degree angle with light finishing needed, but further experimentation can be done to see if these angles can be improved.

3.2 Upright Holes

   

For these, I did 2 quick tests. The first was printed with the settings listed above, and the second was printed with only one shell (contour). The numbers next to the circles (1, 2, 4, 6, 8, 10) represent the radii in millimeters. The double-shelled print came out a lot better than the single-shell replica on the edges of the piece, but the single-shelled piece had slightly cleaner holes due to less weight on the overhang. However, both pieces had defects that can easily be sanded down.

3.3 “H” Overhangs/Bridges

  

Bridges are sometimes referred to as an “H” overhang due to the overhang having two sides to support it. When testing bridges with 90 degree overhangs of 0.25, 0.75, 1.25, 1.75, and 2.25 inches, the results showed increasing stringing with length for all but the 0.25 inch sample.

3.4 Arched Bridges

  

The inspiration for these came from the shape of an egg. That’s because I learned during an egg drop lab that an egg is stronger when weight is being put on it length-wise than if the sides are pinched. As expected, the pieces where the curves are less steep (like an egg laying so the shorter distance is perpendicular to the ground) have more defects, and the steepest curve (as if the top of an egg was the mold for this piece) was almost perfect. The wider the curve becomes, the less it can support itself and the more the piece is unrecoverable.

3.5 “T” Overhangs/Cantilevers

  

The final test for this section is the “T” overhang, which only has a support on one side. This happened to be the only test that completely failed, as none of these pieces are usable – it’s safe to say that pieces should not be made without supports on both side of the overhang.

4. Insight

A rule-of-thumb “overhang rule” used in the industry is that a piece can be self-supporting as long as the overhang does not exceed the angle to the horizontal by more than 45 degrees. A back-of-the-envelope (literally) calculation shows that if we approximate an angular edge with stair-steps of thickness t, the overhang length l equals t/tan(Θ). According to this equation, this means that to increase the allowable angle, the layer thickness can be increased or the unsupported length should be reduced.

This observation is confirmed by a previous investigation into the angles of self-support for ULTEM-9085 on Stratasys Fortus systems showed how the maximum angle that can be self-supported is indeed a function of layer thickness, but also a function of the contour width (see graph below). In the graph, the lower the angle, the lesser the support needed, since everything above that angle will need to be supported. Thus, thicker layers result in lesser support. Due to the nature of contouring in the FDM processes, a thin contour that forms the edge of the overhang is likely to droop off. But as it gets thicker, it maintains greater contact with the supported portion.

The fact that thicker layers and contour widths may yield larger support angles is counter intuitive since we generally assume thinner layers improve print quality – and this is in general true. But if the aim is to design parts without supports, both these variables can push the limits of the process.

5. Conclusions

Basic design guidelines for overhangs can be, to a first order, simplified to one design rule: the angle below which material needs to be supported. This angle in turn, for the Fused Deposition Modeling process on a given machine and material, can be optimized by manipulating layer thickness and contour width.

In my next post, I will look for inspiration for self-supporting strategies from other disciplines. Stay tuned.

Secant or Instantaneous CTE? Understanding Thermal Expansion Modeling ANSYS Mechanical

One of the more common questions we get on thermal expansion simulations in tech support for ANSYS Mechanical and ANSYS Mechanical APDL revolve around how the Coefficient of Thermal Expansion, or CTE. This comes in to play if the CTE of the material you are modeling is set up to change with the temperature of that material.

This detailed presentation goes in to explaining what the differences are between the Secant and Instantaneous methods, how to convert between them, and dealing with extrapolating coeficients beyond temperatures for which you have data.

PADT-ANSYS-Secant_vs_Instantaneous_CTE-2017_07_05

Phoenix Business Journal: It’s time to take control of your newsfeed, leverage RSS feeds

It is hard to keep up with all the news you need to know, and easy to fall into the trap of picking one online news source. But there is an answer, subscribing to RSS feeds is how I get the headlines from a dozen different sources, all in one place.  I go over the ins and outs of this technology in “It’s time to take control of your newsfeed, leverage RSS feeds

Phoenix Business Journal: Five 3-D printing breakthroughs everyone needs to know about

The world of 3-D printing is changing fast. New materials are announced and new systems are proposed almost every month. And as with any fast-growing technology, there is a lot of hype. When something is announced it will get a lot of press and attention, but what do you really need to know to follow the industry? In “Five 3-D printing breakthroughs everyone needs to know about” I take a look at the changes that should have the most impact on product development.

PADT makes 100th Microloan through Kiva over 10 years

Today PADT hit a bit of a milestone, we gave out our 100th microloan over the past 10 years, to a guy named Roger Yester who makes adobe bricks in Peru.  Microloans are small loans, created by pooling bite-sized amounts of money from many people, given to individuals or small groups to help them with their business. It may be to buy raw materials to fulfil an order, as is the case with our 100th loan, or to buy inventory for a small store they operate out of stall in the local village.  The movement started as an alternative to high interest rate loans from predatory lenders and has grown as a way to fund people all over the world from every economic level.

We put $1000 into Kiva back in June of 2007, ten years ago.  (I like round numbers).  We added another $500 a few years later and have been reinvesting that same capital over and over again since.  This re-use of funds has lead to $7,900 lent across 100 loans. We have only had two defaults and have donated $935 to Kiva to cover overhead during that time.

The loans have gone to 50 different types of enterprises, mostly agricultural. We have helped buy breeding pigs and chickens in several countries, funded a new motorcycle for a taxi service in Cambodia, and backed a furniture maker in Mongolia.  Over the years PADT’s investments have supported 5 different beauty salons in Vietnam, Tanzania, Nigeria, Peru, and Jordan.  Our most common investment is in clothing sales with 8 different entrepreneurs backed for that industry.

We have even given loans to help families send their daughters to secondary school.

You can see some of our key loans and more statistics at:www.kiva.org/lender/padtinc.

If you think this sounds like something you, your family, or your company might like to do, sign up through this link and they add $25 to our loan pool when you make your first loan: www.kiva.org/lender/padtinc. 

 

 

Getting to Know PADT: Flownex Sales and Support

This is the second installment in our review of all the different products and services PADT offers our customers. As we add more, they will be available here.  As always, if you have any questions don’t hesitate to reach out to info@padtinc.com or give us a call at 1-800-293-PADT.

The PADT sales and support team focused on simulation solutions is best known for our work with the full ANSYS product suite.  What a lot of people don’t know is that we also represent a fantastic simulation tool called Flownex. Flownex is a system level 1-D program that is designed from the ground up to model thermal-fluid systems.

What does Flownex Do?

Flownex Simulation Environment is an interactive software program that allows users to model systems to understand how fluids (gas and/or liquid) flow and how heat is transferred in that same system due to that flow.  the way it works is you create a network of components that are connected together as a system.  The heat and fluid transfer within and between each node is calculated over time, giving a very accurate, and fast,  representation of the system’s behavior.

As a system simulation tool, it is fast, it is easy to build and change, and it runs in real time or even faster.  This allows users to drive the design of their entire system through simulation.

Need to know what size pump you need, use Flownex.  Want to know if you heat exchanger is exchanging enough heat for every situation, use Flownex.  Tasked with making sure your nuclear reactor will stay cool in all operating conditions, use Flownex.   Making sure you have optimized the performance of your combustion nozzles, use Flownex.  Time to design your turbine engine cooling network, use Flownex. Required to verify that your mine ventilation and fire suppression system will work, use Flownex. The applications go on and on.

Why is Flownex so Much Better than other System Thermal-Fluid Modeling Solutions?

There are a lot of solutions for modeling thermal-fluid systems. We have found that the vast majority of companies use simple spreadsheets or home-grown tools. There are also a lot of commercial solutions out there. Flownex stands out for five key reasons:

  1. Breadth and depth of capability
    Flownex boasts components, the objects you link together in your network, that spread across physics and applications.  Whereas most tools will focus on one industry, Flownex is a general purpose tool that supports far more situations.  For depth they have taken the time over the years to not just have simple models.  Each component has sophisticated equations that govern its behavior and user defined parameters that allow for very accurate modeling.
  2. Developed by hard core users
    Flownex started life as an internal code to support consulting engineers. Experienced engineering software programmers worked with those consultants day-in and day-out to develop the tools that were needed to solve real world problems.  This is the reason why when users ask “What I really need to do to solve my problem is such-and-such, can Flownex do that?” we can usually answer “Yes, and here are the options to make it even more accurate.”
  3. Customization and Integration
    As powerful and in-depth as Flownex is, there is no way to capture every situation for every user.  Nor does the program do everything. That is why it is so open and so easy to customize and integrate. As an example, may customers have very specific thermal-pressure-velocity models that they use for their specific components. Models that they developed after years if not decades of testing. Not a problem, that behavior can be easily added to Flownex.  If a customer even has their own software or a 3rd party tool they need to use, it is pretty easy to integrate it right into your Flownex system model.Very common tools are already integrated. The most common connection is Matlab/Simulink.  At PADT we often connect Excel models from customers into our Systems  for consulting.  It is also integrated into ANSYS Mechanical.
  4. Nuclear Quality Standards
    Flownex came in to its own as a tool used to model the fluid system in and around Nuclear Reactors.  So it had to meet very rigorous quality standards, if not the most stringent they are pretty close. This forced to tool to be very robust, accurate, and well documented. And the rest of us can take advantage of that intense quality requirement to meet and exceed the needs of pretty much every industry.  We can tell you after using it for our own consulting projects and after talking to other users, this code is solid.
  5. Ease of Use
    Some people will read the advantages above and think that this is fantastic, but that much capability and flexibility must make it difficult to use. Nothing could be further from the truth.  Maybe its because the most demanding users are down the hallway and can come and harangue the developers. Or it could be that their initial development goal of keeping ease of use without giving up on functionality was actually followed.  Regardless of why, this simulation tool is amazingly simple and intuitive.  From building the model to reviewing results to customization, everything is easy to learn, remember, and user.  To be honest, it is actually fun to use. Not something a lot of simulation engineers say.

Why does buying and getting support from PADT for Flownex make a Difference?

The answer to this question is fairly simple: PADT’ simulation team is made up of very experienced users who have to apply this technology to our own internal projects as well as to consulting jobs.  We know this tool and we also work closely with the developers at Flownex.  As with our ANSYS products, we don’t just work on knowing how to use the tool, we put time in to understand the theory behind everything as well as the practical real world industry application.

When you call for support, odds are the engineer who answers is actually suing Flownex on a customer’s system.  We also have the infrastructure and size in place to make sure we have the resources to provide that support.  Investing in a new simulation tool can generate needs for training, customization, and integration; not to mention traditional technical support. PADT partners with our customers to make sure they get the greatest value form their simulation software investment.

              

Reach out to Give it a Try or Learn More

Our team is ready and waiting to answer your questihttp://www.flownex.com/flownex-demoons or provide you with a demonstration of this fantastic tool. .  You can email us at info@padtinc.com or give us a call at 480.813.4884 or 1-800-293-PADT.

Still want to learn more? Here are some links to more information:

 

  

Aerospace Summit, Additive Manufacturing Peer Group, and Industry-Education Partnership – A Three Event, Three State Hat Trick

Sometimes everything happens at once.  This June 22nd was one of those days.  Three key events were scheduled for the same time in three different states and we needed to be at all of them. So everyone stepped up and pulled it off, and hopefully some of you reading this were at one of these fantastic events.  Combined they are a great example of PADT’s commitment to the local technology ecosystem, showing how we create true win-win partnerships across organizations and geographies.   Since the beginning we wanted to be more than just a re-seller or just consultants, and this Thursday was a chance to show our commitment to doing just that.

Albuquerque: New Mexico Technology Council 3D Printing Peer Group Kickoff

Everyone talks about how they thing we should all work together, but there never seems to be someone who is willing to pull it all together. That is how the additive manufacturing committee in New Mexico was until the New Mexico Technology Council (NMTC) stepped up to host a peer group around 3D Printing.  Even though it was a record 103f in Albuquerque, 35 brave 3D Printing enthusiasts ventured out into the heat and joined us at Rio Bravo Brewing to get the ball rolling on creating a cooperative community.  We started with an introduction from NMTC, followed by an overview of what we want to achieve with the group. Our goals are:

  1. Create stronger cooperation between companies, schools, and individuals involved in 3D Printing in New Mexico
  2. Foster cooperation between organizations to increase the benefits of 3D Printing to New Mexico
  3. Make a contribution to New Mexico STEM education in the area of 3D Printing

To make this happen we will meet once a quarter, be guided by a steering committee, and grow our broad membership.  Anyone with any involvement in Additive Manufacturing in the state is welcome to join in person or just be part of the on-line discussion.

Then came the best part, where we went around the room and shared our names, orginization, and what we did in the world of 3D Printing.  What a fantastic group.  From a K-12 educator to key researchers at the labs, we had every industry and interest representing. What a great start.

Here are the slides from that part of the presentation:

NMTC-PADT-3D-Printing-Peer-Group-2017_06_22

Once that was done PADT’s Rey Chu gave a presentation where it went over the most important developments in Additive Manufacturing over the last year or so.  He talked about the three new technologies that are making an impact, new materials, and what is happening business wise.  Check out his slides to learn more:

NMTC-PADT-New-3D-Printing-2017_06_22

After a question and answer period we had some great conversations in small groups, which was the most valuable part.

If you want to learn more, please reach out to info@padtinc.com and we will add you to the email list where we will plan and execute future activities.  We are also looking for people to be on the steering committee and locations for our next couple of meetings. Share this with as many people as you can in New Mexico so that next event can be even better!

Denver: MSU Advance Manufacturing & Engineering Sciences Building Opening

Meanwhile, in Denver it was raining.  In spite of that,  supporters of educating the next generation of manufacturers and engineers gathered for the opening of the Advanced Manufacturing and Engineering Sciences Building at Metropolitan State University.  This 142,000 sqft multi-disciplinary facility is located in the heart of downtown Denver and will house classes, labs, and local companies.  PADT was there to not only celebrate the whole facility, but we were especially excited about the new 3D Printing lab that is being funded by a $1 million gift from Lockheed Martin.  A nice new Stratasys Fortus 900 is the centerpiece of the facility.  It will be a while before the lab itself is done, so watch for an invite to the grand opening.  While we wait we are working with MSU, Lockheed Martin, Stratasys, and others to put a plan together to develop the curriculum for future classes and making sure that the engineers needed for this technology are available for the expected explosion of use of this technology.

Stratasys and PADT are proud to be partners of this fantastic effort along with many key companies in Colorado.  If you want to learn more about how we can help you build partnerships between industry and academia, please reach out to info@padtinc.com or give us a call.

Phoenix:  2017 Aerospace, Aviation, Defense + Manufacturing Conference

The 113f high in Phoenix really didn’t stop anyone from coming to the AADM conference. This annual event was at ASU SkySong in Phoenix and is sponsored by the AZ Tech Council, AZ Commerce Authority, and RevAZ.  PADT was proud to not only be a sponsor, but also have a booth, participate in the advanced manufacturing panel discussion, and do a short partner presentation about what we do for our Aerospace and Defense Customers.

Here is Rob’s presentation on PADT:

PADT-AeroConf-AZTC-2017

We had great conversations at our booth with existing customers, partners, and a few people that were new to us.  This is always one of the best events of the summer, and we look forward to next year.

If you want to know more about how PADT can help you in your Aerospace, Defense, and Manufacturing efforts, reach out and contact us.