Press Release: PADT Acquires Stratasys Business from CADCAM Systems

PADT_Logo_Color_100x50At the beginning of this month, CADCAM Systems agreed to sell their Stratasys 3D Printer sales and support business to PADT.  With customers in Colorado, New Mexico, and Utah this acquisition will increase PADT’s presence and investment in those states. This is PADT’s first acquisition in our 21 year history and we are very excited about the whole thing.  If you have worked with us in the past you know we are all about win-win situations.  We feel that this move will be a win for our customers, CADCAM System’s customers, and Stratasys.

We would like to begin by welcoming all of CADCAM System’s customers to the PADT family. Over the coming months we will be working to get to know you and to show you the variety of products and services that PADT offers.  although a few of you are already customers for other things PADT does, we really look forward to meeting the rest of you and understanding how we can help you bring your products to market better and faster.

Secondly, we want to let our existing customers know that this will give us additional customers and revenue that we  will use to fund expanded services in Utah, Colorado, and New Mexico.  Once we have time to get a feel where these new customers are and what they need, we will plan our sales and support staff to better serve everyone. A larger and stronger community will be one of the key ways this will be a win-win for everyone.

You can read more about the acquisition in the press release below or view a PDF version here.

The new customers will grow PADT’s customer base for 3D Printing systems by around 20% to 40%  depending on how you count things. About half of the new customers are in Colorado and the rest are split between Utah and New Mexico; with a few single customers in other states in the west.  Our staff in those states (Littleton, CO, Albuquerque, NM, and Murray, UT) have already started reaching out to the new customers.  As an example of our growing commitment, we recently moved to a new larger suite in the Utah office to make room for a new Application Engineer, more demo machines, and additional space for training and meetings.

We are usually pretty bad about documenting these things for posterity, but fortunately someone remember to snap a picture on their phone during the signing.  From left to right are Ward Rand (PADT Co-Owner), Gloria Ontiveros (CADCAM Co-Owner), John D. Clark (PADT’s Council), and Mario Vargas (PADT’s Sales Manager for 3D Printing):

Official-Signing-CADCAM-Acquisition

 

Customers who have existing support contracts with CADCAM Systems, will continue to be supported by them until those contract expire, including the purchase of their consumables and materials.  When the contracts are up for renewal, they have the option to renew with PADT and we will be the source for their consumables and materials.  Customers who are not on maintenance can contact PADT now for support:

Repair and Maintenance:  480.813.4884 or 3dps@padtinc.com

Those who wish to purchase material and consumables can do so over the phone, via email, or at our online store: padtmarket.com.

Material: 480.813.4884, sales@padtmarket.com, or www.padtmarket.com.

This is an exciting time and we look forward to the growth and mutual success that this acquisition will bring.

Press Release:

PADT Expands 3D Printer Activities with Acquisition of the Stratasys Reselling Business of CADCAM Systems

Strategic move positions PADT as the largest provider of industrial 3D Printing solutions in the Four Corners region.

Tempe, Ariz., May 13, 2015 Phoenix Analysis & Design Technologies, Inc. (PADT) the Southwest’s largest provider of Numerical Simulation, Product Development, and 3D Printing services and products, is pleased to announce the acquisition of the Stratasys Reseller business of CADCAM Systems, based in Boulder Colorado. This move immediately boosts PADT’s existing 3D Printer sales and support customer base by approximately 30%, adding clients in Colorado, Utah, and New Mexico, making PADT the largest distributor of 3D Printing systems to commercial customers in the Four Corners region.

PR-Stratasys_profesional_serires-1

CADCAM Systems, like PADT, has been a leader in 3D Printing sales and support, working with global manufacturer Stratasys to help build usage in the Rocky Mountain States. Throughout the course of its history, CADCAM Systems has built a reputation for outstanding technical ability and customer service. As customers transition to PADT for system support, consumables and future machines, they will receive the same exceptional service they are used to, now from PADT’s offices in Littleton, Colorado, Murray, Utah, and Albuquerque, New Mexico. Additional support will come from PADT’s headquarters in Tempe, Arizona. Customers will have the added advantage of access to PADT’s other products and services, including 3D Printing services, ANSYS simulation software, product development, and simulation services.

“When we heard that CADCAM Systems was interested in selling their Stratasys business, we were immediately interested. Said Rey Chu, co-owner at PADT and a recognized expert in the Additive Manufacturing industry. “We knew they took excellent care of their customers and had strong client bases in Colorado, New Mexico, and Utah, three states that we’ve been growing aggressively in. It was an obvious fit for both companies.”

The acquisition will have no impact on the number of people employed at either company. During the transition, customers who purchased maintenance agreements from CADCAM Systems will be serviced by them until they expire, at which time they have the option to renew with PADT. Some 3D Printing material supplies will be available from CADCAM Systems as well during the transition, with PADT taking over that service in the coming months.

This acquisition was made as part of PADT’s long term strategy to strengthen their position as the premier supplier of mechanical engineering products and services in the Southwest. The company continues to make investments in staff, services offered, and products represented to meet the demands of existing and future customers, continuing to prove a commitment to the company’s motto “We Make Innovation Work.”

To learn more about this exciting expansion visit http://www.padtinc.com/cadcam, email sales@padtinc.com or call 480.813.4884.

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 Rapid Prototyping 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 75 employees, PADT services customers from its headquarters at the Arizona State University Research Park in Tempe, Arizona, and from offices in 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 http://www.PADTINC.com.

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PADT Joins America Makes

America-Makes-Logo-2As part of our long-term commitment to the advancement and growth of Additive Manufacturing (3D Printing), PADT is now a Silver Member of America Makes. We join many of our customers and partners in supporting this National Institute that is focused on "helping the United States grow capabilities and strength in 3D printing, also known as additive manufacturing."   This is an important step in our journey, which started in 1994 when PADT purchased our first Stereolithography machine.  Our Rapid Prototyping team, lead by PADT Co-Owner Rey Chu, has been a key player in the industry over the years – as leaders in the Additive Manufacturing User Group (AMUG), an early channel partner for Stratasys, and as the largest provider of Additive Manufacturing services in the Southwestern US.

We joined America Makes because it is delivering on its mission of collaborating on innovation, overcoming challenges that the industry faces, and accelerating overall time to market for companies that use additive manufacturing. As a member we will be able to work closer with others, have access to intellectual property developed by America Makes, and gain access to consolidated technical information.  One of our first efforts will be to work with America Makes on our initiatives to advance simulation and design for Additive Manufacturing.  We will also work with other companies in the Southwest that are already engaged with America Makes to support them and further the growth of the technology in the region.  Membership will also facilitate our ongoing support of the educating of students on Additive Manufacturing and 3D Printing. 

It was extra special to see that ANSYS, Inc. became a Platinum member at the same time as PADT joined as a Sliver member. As many of you know, PADT is a long time ANSYS Channel Partner and a close collaborator with the ANSYS development teams. Working together on Additive Manufacturing simulation efforts with ANSYS was another key reason why we joined. 

The future of Additive Manufacturing looks bright, and PADT is proud the play the role we have in the past, and look forward to the additional contributions we will be able to add through America Makes. 

America-Makes-FrontExteriorTo learn more about America Makes we recommend the following:

– Watch the introduction video here.
– Visit their website.
– See who the other members are.

Based in Youngstown, Ohio, the National Additive Manufacturing Innovation Institute was founded in 2012 as the flagship institute of the National Network for Manufacturing Innovation. It is a true public-private-academic initiative.

 

Encore Lunch and Learn: Designing and Simulating Products for 3D Printing

3dprinting-production-1PADT would like to invite you to a free seminar or webinar on how to use 3D Printing to manufacture parts for your products.

In February, PADT held a Lunch and Learn with the AZ Tech Council on "Designing and Simulating Products for 3D Printing."  The event sold out and we received a lot of interest in being able to attend over the web. So we have scheduled a second version of this presentation to be given live at CEI in Phoenix on March 23rd, 2015 that will also be broadcast over the web.  

Here is some info on the presentation:

This proven technology has moved from prototyping to tooling and now the creation of final parts.  However, you can't just print your existing design. PADT will cover the techniques and processes needed to evaluate existing designs to find parts that can be switched to 3D printing as well as how to design new parts to take advantage of 3D printing. 

3dprinting-production-2

When:
Monday, March 23, 2015
11:30am – 1:00pm 
Where:
CEI
275 N. GateWay Drive
Phoenix, AZ 85034
Webinar:
WebEx
Please Register, we will send you login information 
  Lunch will be Served for those attending live

We will begin with a review on the current state of 3D Printing technologies, including the creation of accurate and usable metal parts. That will be followed with design guidelines and processes and finishing up with a look at how you can use simulation to drive the design your 3D Printed components so that they work.

Please Register

Lunch is included so we need a headcount for those joining us at CEI, and we need to send login information to those attending over the web.  So Please Register

 

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. 

Seminar Info: Designing and Simulating Products for 3D Printing

Note: We have scheduled an encore Lunch & Learn and companion Webinar for March 23, 2015.  Please register here to attend in person at CEI in Phoenix or here to attend via the web.

ds43dp-1People are interested in how to better do design and simulation for products they manufacture using 3D Printing.  When the AZ Tech council let us know they had a cancelation for their monthly manufacturing Lunch and Learn, we figured why not do something on this topic, a few people might show up. We had over 105 people register, so we had to close registration. In the end around 95 total people made it to the seminar, which is more than expected so we had to add chairs. Who would have thought that many people would come for such a nerdy topic?.

For an hour and fifteen minutes they sat and listned to us talk about the ins and outs of using this growing technology to make end use parts.  Here is a copy of the PowerPoint as a PDF.

We did add one bullet item in the design suggestions area based on a question. Someone pointed out that the machine instructions, what the AM machine uses to make the parts, should be a controlled document. They are exactly right and that is a very important process that needs to be put in place to get traceability and repeatability.  

Here are some useful links:

As always, do not hesitate to contact us for more information or with any questions.

If you missed this presentation, don't worry, we are looking to schedule a live/web version of this talk with some enhancements sometime in March.  Watch the usual channels for time, place, and registration information. We will also be publishing detailed blog posts on many of the topics covered today, diving deeper into areas of interest.

Thank you to the AZ Tech Council, ASU SkySong, and everyone that attended for making this our best attended non-web seminar ever.

Design and Simulation for 3D Printing Full House

The Real Revolution in 3D Printing: It’s Normal

3D-printed-printerReading through my email this morning I saw an update from the "maker" site Instructables and I glanced at it quickly: "floating bed, how to make a sword, that's cool, 3D printable printer, folding chair charcoal forge, what?, parachord hammer holder, just buy one, duh, blah, blah, blah how do people have time for this… wait, 3D printable printer?" CLICK.  

So this 17 year old kid used his 3D Printer, an arduino board and parts he scrounged from old DVD drives to make a 3D Printer. Read about it here.  This kid, wootin24, designed and built an X, Y, Z positioning device that could be fited with a dremel tool to be a CNC machine, or an extruder to be a 3D Printer.  No CAD experience, no formal engineering training, just a smart person.  And the ad that popped up on the side of the how-to this kid wrote was for a Dremel 3D Printer, available at Home Depot. Not some kickstarter funded rehash of an opensource printer, Dremel. The big guys.  As I was feeling bad about how I spent my time when I was 17 (I'm not going to go there but I never did become a the backup bass player for Rush nor did I get a second date from T—–) and starting to worry about how systems from very capable companies like Dremel will impact our sales of Stratasys equipment, I realized that the true revolution in 3D printing happened and most of us involved day-to-day in the industry didn't even notice.  

3D Printing is Now Normal

When a revolutionary technology comes out there is a lot of hoopla and press. Tons of people start jumping on the bandwagon and your Aunt's friend in Topeka is sending you links on Facebook about 3D Printing and how it is "going to change everything."  Do not get me started on how 3D Printing is not new, we've been doing it at PADT for over 20 years, and certainly do not ask about the "3D printed gun.  The false-newness and fear-mongering stories are what the mainstream press picked up on. The good news is that the hype got the word out. And then smart people like this kid and the engineers at Dremel said "hmmm, that is useful. I can do something with this" and boom, the real revolution happened.  

After all these years this tool that was really a special tool used when needed, has become just another screwdriver in the toolbox.  A standard part of the process it is something most engineers understand well, and a majority of non-engineers are aware of. When we first started showing people our SLA machine back in the 90's they would either not understand what they were looking at or become flabergasted and amazed, treating it more like a magic box than a fairly simple additive curing system.  Now when we give tours we hear "that one looks like the one we have in our office" or "oh yea, an Objet, I'd love to trade my older system in for one of those." And the dreaded "oh, we have three of these in our robotics lab at school, do you have anything interesting?"  

3d-printers2
Amazon now has a section for all the 3D Printers they sell, just like headphones or video games.

So What

There is a lot of power in 3D Printing.  That is the real reason why the technology has blossomed as it has.  The power of 3D Printing is that it lets you make physical objects without special equipment or knowledge, the laser printer of manufacturing. However, as long as the tool is treated as something to be used in special cases or as a mystical new magic bullet, it will not be used correctly.  Now that it is mainstream, the use of additive manufacturing becomes mainstream and the power it brings to the table can be fully realized.  We see this every day at PADT. Product managers have "3D Printed Prototypes" as a standard line item in their budget templates.  Customers are increasingly talking about going back to their current product lines and identifying parts that are machined, injection molded, or cast and determining which can be replaced by 3D printed parts.  And most importantly, the supply chain and quality people are sniffing around and starting to make paperwork to control and manage 3D Printed components.  

As proponents of the technology since the early days, we could not be happier than when we see a check box for "Created with additive manufacturing" on a quality form. When it becomes part of the bureaucracy, the revolution has truly happened. 

Celebrate Arizona Manufacturing

arizona-manufacturing-month-2014-header

WE ARE CELEBRATING MANUFACTURING IN ARIZONA

The state of Arizona has a vibrant and robust manufacturing community, something that most people do not know. To highlight this strong part of the state’s economy, the month of October has been designated as Manufacturing Month. Learn more at the ACA website.

PADT has been busy participating in a variety of events throughout the month of October.  We are excited to celebrate the culmination of this amazing month.

Everyone is welcome!

What:  Celebrating Arizona Manufacturing – The Special Closing Event of the 2014 Arizona Manufacturer’s Month

When: October 30th, 4-7pm

Where: PADT – 7755 S. Research Drive, Tempe, AZ 85284

Please register at: bit.ly/MMclosing

Food and drinks will be provided. 

In addition to networking and celebrating, several companies involved in Manufacturing will be in attendance for an exhibit focused on the future of manufacturing.  

Exhibitors attending include:

…..and more

If you have questions about the event or are interested in exhibiting, please contact Kathryn Pesta at kathryn.pesta@padtinc.com

Join us in Colorado for a 3D printing Demo

happyhour563dprinting

PADT Colorado is excited to be partnering again with Alignex for a 3D printer demo/happy hour at their upcoming networking event.  

The event is from 10 am to 6pm and will feature guest speakers discussing the latest in engineering and design productivity.  PADT will be on site to discuss 3D printing during their happy hour from 5 to 6pm. 

For more details and to register for the event please click here.

Spreading the Word on 3D Printing at 3 Events in 3 States this Month

PADT-Logo-Stained-Glass-Rendering1PADT has been asked to share our expertise in 3D Printing at three different events in the month of September.  We look forward to the opportunity to talk about how additive manufacturing is being used today, and how it can be used in the future.  

September 11, 2014 – Salt Lake City, Utah
Utah Manufacturers Association Summit
We will have a booth and will be participating in the summit, representing the application of additive manufacturing. This informative all-day seminar will teach you about the revolutionary UtahCAN Database and how it can benefit your company, how to utilize social media to your advantage, better handle impacts on your business and leadership strategies to change your workplace.

September 12, 2014 – Albuquerque, New Mexico
TechFiestaABQ2014 TechRev: State of the art and Digital Fabrication
PADT’s very own Jeff Strain will be on the “State of the art and digital fabrication” panel from 9:00 to 10:00. TechRev is a full day conference featuring tracks for technologists, entrepreneurs and the business community produced by the NM Technology Council.

September 18, 2014 – Phoenix, Arizona
SAE Arizona Section September Meeting
PADT co-owner Eric Miller will be giving a presentation on Additive Manufacturing technologies.

We hope to see you at one of these events.  If you would would like PADT to participate as a speaker, panel member, or an exhibitor, please contact us and we will check our schedule. We truly do love talking about this stuff.
Look for even more chances to interact with PADT on 3D Printing in October, during the Arizona Manufacturing Month.

Additive Manufacturing Motor Trends

Additive manufacturing (AM) has been used in the motor sports world for years.  Now more than ever, race teams have found that additive manufactured parts have the quality and durability to meet their demands. From NASCAR to the World Rally Championship, race teams around the world are excited about the possibilities that AM brings to the table. For an interesting webinar on-demand and a great whitepaper, click the image below. 68905-Motor-Trends-Webinar_960x350

3D Thursday – 4th of July Style

I was in search of something Independence Day/3D printing related to celebrate the 4th of July.  It seems like a lot of people had the same idea.  Thomas Jefferson……yup, he was 3D printed at RedEye on Demand.  President Obama was 3D printed at the first ever White House Maker Faire last month.   So, after sifting through replicas of the Statue of Liberty or American Flags, I came across something really cool.  

3D-printed-Ellis-Island-3D-Model-Don-Foley-via-3D-Printing-IndustryDesigner Don Foley  has created a very detailed model of the Ellis Island Customs House which you can download for free for the next 2 weeks.   

instructions-for-3D-printed-Ellis-Island-Customs-House-by-Don-Foley-via-3D-Printing-Industry
His design is in 4 separate sections that can be taken apart to see the beautiful and intricate detail on each of the floors.  It’s a beautiful design of a very important part of American history.

And just for fun, here is an interesting article about the creation of an exact replica of the Liberty Bell using 3D scanning.

Happy 4th of July!

Reblog: Terry Wohlers Predictions at Inside 3D Printing Conference & Expo

If you are interested in 3D Printing and you don’t follow Terry Wohlers, you should. He has been following this industry since it started and he is one of the best at separating hype from reality.

Here is a link to a blog post on 3dprinter.net on his predictions at this years Inside 3D Printing Conference & Expo.

He brings up some very good points on where the technology is being used today and where growth may occur.  Also some thoughts on the global growth of additive manufacturing, and the obstacles and challenges the industry faces. 

My favorite take-away from the posting is Terry’s that “more and more effort is needed to not just take a traditional design and 3D Print it, but rather to re-think the entire part design to take into account the capabilities and limitations of AM.”

3D Color Printing: Stratasys Publishes Nice White Paper on Maximizing Multi-Material and Color 3D Printing

connex3-machine
Stratasys just released a nice white paper on the uses of their new color technology in the Objet500 Connex3 system.  This machine is more than just a way to print parts in a variety of colors, it allows you to load three different materials, including colors. 
3D-Color-Printing-Colors-1The paper goes in to some detail on how the technology works, what the advantages are, and offers some use cases where beta testers in industry were able to apply the technology on their projects.  If you are interested in 3D Printing in general, and printing color parts in particular, you should download the white paper.

 3D-Color-Printing-Pressure-Contour-1As always, if you can contact PADT at 480.813.4884 or sales@padtinc.com. Or visit our website.

Triplex-Helmet_960x350

Wohlers Associates Lists Top 3D Printing News of 2013

Wohlers Associates just blogged their list of the top news stories for 2013 in 3D Printing.  It is worth a read to look beyond the hype we have seen this year and focus on the stories that will be having an impact in the future:

http://wohlersassociates.com/blog/2014/01/top-3d-printing-developments-in-2013/

As a Stratasys distributor and provider of additive manufacturing services, PADT can attest to the importance of the stories listed.  The first one, the GE Fuel Nozzle, had an especially significant impact on the world of commercial additive manufacturing, especially with the Aerospace customers we work with.  In many ways, GE’s move was the tipping point for metal additive manufacturing and for companies to really look at AM as an end part manufacturing solution.

2014 is already shaping up to be a big year.  We expect to see consolidation and a weeding out in the consumer and prosumer 3D printer market, better material options across all of the technologies, and more adoption of the technology in new industries and applications.

Wholers Associates has been consulting in additive manufacturing for over 27 years and is PADT’s go-to resource for what is really going on in the AM world.

A Guide to Creating Good STL Files

imageThe STL file is the linqua-franca of the prototyping world, the file format that all geometry creation tools write, and that all prototyping systems read. When you make a prototype it will be an exact copy of your STL file. If your file is not accurate, then your prototype will not be accurate. If there are errors in your file, you may not be able to get a prototype made. Therefore, a little bit of time understanding STL files and how to create a good one is a good investment that will pay off in the long run.

About STL Files

When additive manufacturing was just starting the manufacturers of machines faced a problem – they needed a way to get 3D solid models from a large number of CAD systems to their machines for processing. The common file format for geometry interchange, IGES, was not robust enough because of toleranceing issues. Writing a program to slice up each CAD format was also not practical. So they looked at the problem and realized they did not need exact mathematical models made up of NURB, Bezier, or analytical geometry. The algorithm that sliced up each layer just needed polygons on the surface. So the STL file just needed to have those polygons. And the STL file was born.

Lets talk about that slicing process. If you remember, almost all additive manufacturing processes work by creating stacked layers that are a cross section of the part you want. To build the part you must slice the geometry in software, calculating that cross section. Doing the intersection of a plane with a complex NURB surface is hard math, but the intersection with a triangle is very easy and results in a line segment. This makes creating the path for each layer much easier.

STL stands for STereoLithography, or Standard Tessellation Language, depending on which source you check. It was invented for 3D Systems by the Albert Consulting Group way back in 1987 to support the first Stereolithography machines. The format describes a collection of facets, or polygons. Each polygon is defined by a normal “outward” vector and the vertices that define it. Although the format supports more than three vertices per facet, in practice everyone uses three, defining a triangle. The file can be a text file (ASCII) or a binary file.

Users almost never have to worry about the file because the programs they use to create their geometry automatically generate STL files in the proper format. If you do need to write your own routine to output an STL file, it is fairly simple.

Faceting

clip_image001 The way an STL file is made is the program that creates the STL file goes through the topology of the model and meshes it:

1: First it puts points on all of the shared edges of all the surfaces
2: Then it creates triangles on each surface

The algorithm used to create the facets varies from program to program, but most of them use the same routines they use to make facets for the 3D graphics you see on your monitor.

There are two things to note about faceting. The first is that each corner must be coincident with at least one other corner. No corners can touch the edge of another triangle. The second is that a triangle is flat and your surface can be curved. To make your curved surface look curved you need enough triangles to make it appear like a continuous surface.

Leaky Geometry

The most common problem these days with STL files is leaky geometry. When your CAD tool creates the STL file your solid may not be a true solid in that you have holes in your topology. This can be caused by gaps, ill-defined curves and surface, or corners (vertices) not lining up. If you cut out the triangles and glued them together then filled the resulting object with water, the water would leak out.

You CAD package can make leaky STL files if it has loosened up the tolerances on the geometry modeling to the point where edges on its surface do not really line up. They trick themselves into accepting this through some hand waving inside their database, and it really is not a problem till you want to do something with the surfaces. Something like make an STL file.

One way to fix this problem is to clean up the original geometry. Run diagnostics on it and see where there are holes. You should do this anyway because in the end, a messy solid will cause problems when you make your drawings, calculate tool paths, or try and do simulation.

If that is not an option, you can use repair software. If you use an RP service provider, they should be able to repair most STL files. But if you constantly need them to do so, you should really look at changing your modeling practices or investing in some repair tools.

If you are doing your own prototyping, you have two good options. The first is free: Meshlab. It is an open source tool for working with faceted geometry and has repair and diagnostic capabilities. It does a lot so the interface can be a bit confusing, but it is free. If you want to save time and probably money in the long run, we recommend that you purchase a copy of SolidView. It is purpose built for repairing STL files and can really cut down on your repair time.

Faceted Geometry

Even if your prototyping tool can read your geometry and make a valid part, it may come out looking all clunky because your geometry is to faceted. As discussed above, the STL file is made up of triangles. If you have too few triangles on a curved surface then it comes out looking all flat and ugly. Here is a simple example:

The key to controlling this is to set the options in your CAD package to create more facets.

This is such an important topic, we actually have a whole posting dedicated to it:

STL File Tolerance: A Short Explanation of Faceting and Chord Height

In the old days we tried to minimize the number of triangles in an STL file because that file had to be uploaded, often via a modem.  But now we can email very large files, so you can make some pretty big STL files. Don’t go crazy, but don’t sacrifice surface quality either.

Degenerate Triangles and Inverted Faces

It is very rare for a CAD tool to create bad triangles, but it happens every once in a while. When trying to create a build from an STL file you might get a “Degenerate Triangle” or “Inverted Faces” error message.  There is not much you can do with this other than try one of the repair tools mentioned above or try and fix your underlying geometry.  If you get this type of error, there is something very wrong with your solid model.

Feature Sizes

Another problem that people often run across is that some of their small features do not show up on their prototype.  This can be because their STL file is not refined enough and that can be solved by tightening up the tolerance on their STL file creation.  If that does not work, the feature may just be too small for the technology.  Take a look at what the true machine resolution is. Make sure that is is smaller than your smallest features.

Make an Investment in Productivity

Having a bad STL file can really slow down the rapid part of Rapid Prototyping.  That is why PADT recommends that you take the time when you create your solid models to make good, robust, water tight solids that can be used down stream.  If you have nasty geometry or a less than precise CAD tool (can anyone say CATIA) you may have to invest in a repair program like Meshlab or SolidView.  Some up-front investment will pay in the long run, especially when you need that prototype first thing in the morning.