3D Scanning and 3D Printing for Makers

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Off to a great start sharing the Capture Scanner and Geomagic Software at TechShop in Chandler. Great group, great questions.

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PADT Medical Team at AZBIO Expo 2014

Representatives of the PADT Medical team are having a great day at this years AZBIO Expo in Scottsdale.  We brought along some of the medical device projects we have worked on and have been chatting with past, current, and future customers.

Margaret and our “assistant” posed for this picture of the booth:AZBIO-2014-expo
Insert skeleton jokes here. 

The event is a fantastic reminder of how vibrant the local Bioscience community is in Arizona. From genetics to algae, pharma to med devices, the state has key players in almost every industry. And every year our three state universities make stronger and stronger contributions to basic research in this area.   There is a lot going on and this event is one of the best places to catch up on the wide ranging impact Arizona Bioscience companies are making. 

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An inside look at our Connex500

We wanted to see what 3d printing looked like from the inside of the machine so our new intern, Diserae Sanders, placed a GoPro inside our Connex500 during a print job.  The item being printed is a demo bicycle pedal printed in multiple materials.  

This video is the first in a series we plan to do on 3D printing. If there is something you would like to see us do a video on, please post it in the comments below.

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3D Scanning & Printing for Makers

Attention Makers, Tinkerers & 3D Enthusiasts

 When :   Monday, June 23, 2014 
                   6:00 PM to 7:00 PM

Where: TechShop Chandler
                 249 E. Chicago Street
                 Chandler, AZ 85225

Attend Live – Register Now
Attend Virtually – Register Now


Join us for an evening of 3D Scanning and Printing!!!

We will be discussing some practical ways to utilize 3D scanning and printing specifically for Makers.

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Whether you are new to 3D printing or you need a refresher on how 3D scanning can help with your designs, this workshop is for you. Anyone, novice to seasoned expert, is invited and encouraged to attend and share their knowledge and questions.

 
Two ways to participate:

In Person

If you are in the area, please join us at Tech Shop Chandler by registering HERE.

 Virtually

If you can’t be here in person, you can join us virtually by registering HERE.Robot_Montage_MG_4605_preview_featured
Light refreshments will be served (only to in-person attendees, sorry virtual participants)

Registration is required as space is limited.

If you have any questions, please contact Kathryn Pesta at kathryn.pesta@padtinc.com or 480.813.4884.

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Stratasys adds flexible color to their digital material palettes

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Earlier this week, Stratasys announced the addition of 10 new color pallets expanding the digital materials offering to represent hundreds of new options of both flexible color materials and rigid gray materials available for the Objet500 Connex3 Color Multi-material 3D Printer

connex3_flexpalette_cyt_hands_portrait  connex3_flexpalette_myt_hands_portrait  connex3_flexpalette_mct_hands_portrait

The first three pallets are built using TangoPlus combined with combinations of VeroCyan, VeroMagenta and VeroYellow. These new pallets allow for the printing of a range of colors and translucent tints in nine Shore A values (Shore A 27-95).

connex3_flexpalette_cyk_hands_portrait  connex3_flexpalette_mck_hands_portrait  connex3_flexpalette_myk_hands_portrait

Three additional pallets using TangoBlack Plus and combinations of VeroCyan, VeroMagenta and VeroYellow allow for users to blend a wide range of subtle vibrant-to-dark shades into the same part with TangoBlack Plus in seven Shore A values.

connex3_mkw_palette_portrait  connex3_ykw_palette_portrait  connex3_kwt_palette_portrait

The final four palettes that were introduced offer additional combinations of VeroWhite and VeroBlack with either VeroCyan, VeroMagenta or VeroYellow allowing for users to build sophisticated prototypes in a range of subtle grays alongside muted or vibrant color. 

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The addition of these ten palettes combined with their existing palettes allow for virtually limitless combinations of flexible, rigid and translucent colors in one print job.

“The Objet500 Connex3 is the only 3D printer that combines colors with multi-material 3D printing. The ability to mix rigid, flexible, transparent and opaque colors offers users unprecedented versatility to design and perfect products faster,” says Stratasys Director of Materials & Applications Fred Fischer. “By extending the range of material options available, users can improve workflow speeds and enhance efficiency.”

These new options are available immediately to Objet500 Connex3 Color Multi-material 3D Printer owners through a free software update. 

Check out this great video on the new materials.

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Slide Rules, Logarithms, and Compute Servers

If any of you have been to PADT’s headquarters in Tempe, Arizona, you probably noticed the giant slide rule in the middle of our building.  You can see a portion of it in the picture below, at the top of our Training, Mentoring, and Support group picture.

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This thing is huge, over 6 feet (2 m) from side to side, in its un-extended position hanging on the wall.

In theory a gigantic slide rule could provide more accuracy, but our trophy, a Kueffel & Esser model 68 1929 copyrighted 1947 and 1961, was intended for teaching purposes in classrooms.  Most engineers had essentially pocket size or belt holder sized slide rules, also known as slip sticks. 

For the real thing, here is a picture of a slide rule used by Eric Miller’s father Col. BT Miller while at West Point from 1955 to 1958 as well as during his Master’s program in 1964.

Burt-Miller-SlideRule-D2

Why do we care about the slide rule today?  Have you ever seen World War II aircraft, submarines, or aircraft carriers?  These were designed using slide rules and/or logarithms.  The early space program?  Slide rules were used then too.  Some phenomenal engineering was accomplished by our predecessors using these devices.  Back then the numerical operations were just a tool to utilize their engineering knowledge.  Now I think we have a tendency to focus on the numerical due to its ease of use and impressive presentation, while perhaps forgetting or at least de-emphasizing the underlying engineering.  That’s not to say that we don’t have great engineers out there; rather it’s a call to energize you all to remember, consider, and utilize your engineering knowledge as you use your simulation tools.

By contrast, here is a picture of PADT’s brand new server room, with cluster machines being put together in the big cabinets.  Hundreds of cores.

servers

What about the giant slide rule?

My father found a thick book at an estate sale a few months ago.  There are a lot of retirees living in Arizona, so estate sales are quite common and popular.  They occur at a life stage when due to death or the need for assisted living, folks are no longer able to live in their home so the contents are sold, clearing out the home and generating some cash for the family.  This particular estate sale was for a retired engineer.  The book caught my father’s eye, first because it was quite thick and second because the title was, Mechanical Engineers’ Handbook.  Figuring it was a bargain for the amazing price of $1.00, he bought it for me.  This book is better known as Marks’ Handbook.  It’s apparently still in publication, at least as late as the 11th Edition in 2006, but the particular edition my father bought for me is the Fifth Edition from 1951.

marks-handbook

Although the slide rule is mostly a curiosity to us today, in 1951 it was state of the art for numerical computation.  While Marks’ has a couple of paragraphs on “Computing Machines”, described as “electrically driven mechanical desk calculators such as the Marchant, Monroe, or Friden”, the slide rule was what I will call the calculator of choice by mechanical engineers at the beginning of the 2nd half of the 20th century. 

As an aside, these mechanical calculators performed multiplication and division, using what I will describe as incredibly complex mechanisms.  Here is a link to a Wikipedia article on the Marchant Calculator:  http://en.wikipedia.org/wiki/Marchant_Calculator

Marks’ Handbook devotes about 3 pages to the operation of the slide rule, starting with simple multiplication and division and then discussing various methods of utilization and various types of slide rules.  It starts off by stating, “The slide rule is an indispensable aid in all problems in multiplication, division, proportion, squares, square roots, etc., in which a limited degree of accuracy is sufficient.” 

The slide rule operates using logarithms.  If you’re not familiar with using logarithms then you are probably younger than me, since I recall learning them in math class in probably junior high in the late 1970’s.  The slide rule uses common logarithms, meaning the log of a number is the exponent needed to raise a base of 10 to get that number.  For example, the common log of 100 is 2.  The common log table in the 1951 edition of Marks shows us that the common log of 4.44 is 0.6474.  For the sake of completeness, the ‘other’ logarithm is the natural log, meaning the base is the irrational number e, approximated as 2.718.

log-table

Getting back to common (base of 10) logs, the math magic is that logarithms allow for shortcuts in fairly complex computations.  For example, log (ab) = log a + log b.  That means if we want to multiple two fairly complicated numbers, we can simply look up the common log of each and add them together.  Similarly, log (a/b) = log a – log b. 

Here is an example, which I will keep simple.  Let’s say we want to multiple 0.0512 by 0.624.  On a calculator this is simple, but what if you are stranded on a remote island and all you have is a log table?  Knowing the equations above, you can look up the log of 0.0512 which is 0.7093-2 and the log of 0.624 which is 0.7952-1.  We now add:
adding_numbers

Writing that sum as a positive decimal minus an integer is important to being able to look up the antilogarithm or number whose log is 0.5045 – 2.

Looking up the number whose log is 0.5045 we get 3.195, using a little bit of linear interpolation.  The “-2” tells us to shift the decimal point to the left twice, meaning our answer is 0.003195.  Thus, using a little addition, some table lookup, a bit of in the head interpolation, and some knowledge on how to shift decimal points, we fairly easily arrive at the product of two three digit fractional numbers.  Now you are free to look for more coconuts on the island.  Or maybe get back to a hatch in the ground where you need to type in the numbers 4, 8, 14, 16, 23, and 42 every 108 minutes.  Oops, I’m really becoming Lost here…

sliderule-book

Getting back to the slide rule, one way to think of it is a graphical representation of the log tables.  In its most basic form, the slide rule consists of two logarithmic scales.  By lining up the scales, the log values can be added or subtracted.  For example, if we want to multiply something simple, like 4 x 6, we simply look from left to right on the scale on the ‘fixed’ portion of the slide rule to get to 4, then slide the moving portion of the slide so that its 1 lines up with the 4 found above on the fixed portion.  We then move left to right on the movable scale to find the 6.  Where the 6 on the movable slide lines up with on the fixed portion is our solution, 24.  What we’ve really done is add the log of 4 to the log of 6 and then find the antilog of that result, which is 24.  Now that we’ve found 24, we’re not Lost

We don’t intend to give detailed instructions on all phases of performing calculations using slide rules here, but hopefully you get the basics of how it is done.  There are plenty of online resources as well as slide rule apps that provide all sorts of details.  Besides multiplication and division, slide rules can be used for squares and square roots.  There are (were) specialty slide rules for other purposes.  Note that with additional knowledge and skill in visually interpolating on a log scale, up to 3 or even 4 significant digits can be determined depending on the size of the slide rule.

ted-slide-ruleThe author, attempting to prove that 4 x 6 is indeed 24

After having studied the Marks’ section on slide rules, experimenting with a slide rule app on an iPad as well as the PADT behemoth on the wall, I conclude that it was a very elegant method for calculating numbers much more quickly than could be done by traditional pencil and paper.  It’s must faster to add and subtract vs. complicated multiplication and long division.  My high school physics teacher actually spent a day or two teaching us how to use slide rules back in the early 1980’s.  By then they had been made functionally obsolete by scientific calculators, so looking back it was perhaps more about nostalgia than the math needed.  It does help me to appreciate the accomplishments made in science and engineering before the advent of numerical computing.

The preparation of this article has made me wonder what the guys and gals who used these tools proficiently back in the 1930’s, 40’s, and 50’s would think if they had access to the kind of compute power we have available today.  It also makes me wonder what people will think of our current tools 50 or 60 years from now.  When I first started in simulation over 25 years ago, it would have seemed quite a stretch to be able to solve simultaneously on hundreds if not thousands of compute cores as can be done today.  Back then we were happy to get time on the one number cruncher we had that was dedicated to ANSYS simulation.

Incidentally, this article was inspired by my colleague David Mastel’s recent blog entry on numerical simulation and how PADT is helping our customers take compute servers and work stations to the next level:

http://www.padtinc.com/blog/the-focus/launch-leave-forget-hpc-and-it-ansys

If you are ever in our PADT headquarters building in Tempe, don’t forget to look for the giant slide rule.  Now you will know its original purpose.

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PADT Customer GlobalStar Featured in News Report

We were pleased to hear from customer GlobalStar that two of the products PADT  worked on for them were featured on a New Orleans television station. The Spot Gen3trace_title_banner_atv3 and Spot Trace are great devices that communicate to the GlobalStar satellite network no matter where you are, telling people where you are, that your assets have moved, or informing emergency services that you need help.  We learned in the story that SPOT systems had resulted in over 3,000 rescues world wide.  As the Spot Trace usage grows, we hope to see similar statistics for lost and stolen assets recovered.

View the video here:

You can review the work that PADT did on the Spot Gen3 in a case study here.

They haves some great product videos. Here is one for the Spot Trace and another for Spot Gen3.

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3D Printing brings history to life

640px-Vincent_van_Gogh_-_National_Gallery_of_ArtDid you hear that they have 3D printed Vincent van Gogh’s ear? How about the 3D printed spine of King Richard III?  This week alone 3D printing has given us two amazing examples of how this technology can be used to look at history in amazing new ways.

In the case of van Gogh, researchers used real living cells from his great-grandson to bioprint the cells to resemble van Gogh’s severed ear.  The ear is being kept technically alive in a nutrient solution and is said to be able to actually “hear”.  You can read more about this amazing application here.

Richard_III_earliest_surviving_portraitKing Richard III has been famously written as having a hunched back by William Shakespeare.  Anthropologists at the University of Cambridge wanted to determine if the description was accurate or exaggerated. Utilizing CT scans to create a model of the spine they were able to create 3D printed replica of his spine based on the models.  It turns out that while he did have terrible scoliosis, there was no evidence that he had a hunch as described by Shakespeare.  You can read more about this research here.

Just two of many new and innovative ways to integrate 3D printing into just about anything!

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IGES Can’t Stand IGES Anymore!

Users:

I got some errors when I imported my geometry.
I have some holes and stray surfaces in my geometry.
The edges are twisting around on my geometry import.
ANSYS blows up when I’m trying to mesh my imported geometry.

Me:

What geometry format are you using?

Users:

IGES.

IGEEEEEEESSSSSS!!!

The vast majority of the time, geometry import errors are attributable to the choice of geometry format. And that choice is IGES. To understand the problems with IGES, it helps to know a little bit of IGES history.

IGES, which stands for Initial Graphics Exchange Specification, was released in 1980 as a neutral format for sharing data between CAD systems. The most recent version, 5.3 came out in 1996.

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IGES: The “Izzy” of geometry formats

Besides being old, there are a few other problems with this format:

  • IGES only contains surface information. When the IGES file is read in, ANSYS has to take the additional step of creating a volume from the region enclosed by the surfaces. The IGES file contains no additional information about how the surfaces should be stitched together, so ANSYS has to figure it out, leading to possible errors, particularly with assemblies.
  • Each CAD application has its own tolerances when exporting to IGES, and loose tolerances are more likely to lead to errors in the ANSYS import.
  • Somewhat related to the previous bullet point, IGES is a middleman between the CAD system and ANSYS, creating two paths for error propagation: Exporting from CAD to the IGES file and importing the IGES file into ANSYS.

Generally speaking, IGES is typically the worst geometry format to import into ANSYS.

Now that I’ve trashed IGES, here is what I recommend:

Native Geometry

ANSYS offers several native geometry readers, such as Connections for Pro/E, NX, Solidworks, SolidEdge, etc. that bring in geometry directly from the CAD modeler. There are two advantages here:

  1. Geometry comes over directly from the CAD tool, therefore no tolerance errors propagating through a neutral geometry format “middleman.”
  2. CAD readers allow for bi-direction associativity between the CAD tool and Workbench, so a Workbench model can be refreshed to reflect updated geometry which still retaining mesh settings, loads, etc. Also, the CAD model can be refreshed based on updated geometry in Workbench.

The only catch when it comes to native geometry readers is that they require a separate license. However, about 90% of the tech support calls I’ve received about IGES import errors are from people who have licenses for native geometry readers and just aren’t using them.

Even if you have a native geometry reader license, you’ll need to be sure to check the box to install the reader during ANSYS installation. You may also need to use the CAD Configuration Manager (found in the Utilities folder in the ANSYS start menu) to configure the CAD reader if you didn’t do so during installation.

The one unfortunate exception to this is CATIA. The CATIA kernel is a bit more guarded than the other CAD kernels, and this is frequently noted in CATIA geometry import errors. Also, you can only import CATIA geometry, not associate to it as with other CAD tools.

Neutral Files That Aren’t IGES

Your ANSYS installation comes with the capabilities to import both IGES and STEP files without having to purchase an additional geometry connection license. Of the two, STEP is typically the better option. There are two reasons for this:

  1. STEP (which stands for “Standard for the Exchange of Product model data,” because these people do not bow down to society’s piddly  rules of acronym construction) contains true 3D volume definitions, instead of having to construct volumes between enclosed surface regions post-import, so the solid model definition ends up being more robust.
  2. STEP was first developed in 1984 and continues to be developed, even as recently as 2011, so export/import errors are regularly addressed, unlike with IGES.

You may also have licenses for Parasolid and/or ACIS readers, which can lead to some confusion as to which format to use. This is easily addressed by considering the underlying geometry kernel for the originating CAD tool*.

I said geometry kernel, not…oh never mind… mmmm… fried chicken….

For example, SolidEdge, NX, and Solidworks all use the Parasolid kernel. Therefore the most robust neutral format for geometry exported from these tools will generally be Parasolid (.x_t or .x_b extension), of course. Likewise, AutoCAD uses the ACIS kernel, indicating that ACIS (.sat file) will usually be the best neutral geometry format in this case. For CAD tools that use neither of these kernels, STEP will typically be the best neutral format.

As you can see, even though the IGES people know how to make acronyms, IGES is typically the last geometry format you want to try when importing or associating geometry to ANSYS. This doesn’t mean that IGES is always the worst option for reading in CAD files (especially compared to the CATIA connection), just that it usually is.

*Hat tip to Robin Steed of ANSYS, Inc. for this tip

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why does no1 respon to my request for help (Some Pointers to Students Looking for Help on Forums, Social Media, and Blogs)

xansys.org[Note: I know I misspelled respond... that is the point] As many of you know, PADT hosts a very successful mailing list and forum called XANSYS.org. It is one of the most successful online community help places I have ever seen.  There are a lot of reasons for that success, but the biggest is the moderators and how strongly they enforce rules for those posting.  Especially on using complete sentences, punctuation, showing that you have tried, and fully identifying yourself.

I bring this up because I’ve seen several posts on Facebook and LinkedIn groups for ANSYS users that just don’t get many responses, or don’t get the quality of response that posts on XANSYS get. I thought it might not be a bad idea to make some comments on the subject and share this post on some of those other forums.  Although I’ll focus on the ANSYS community, what is said applies to any community that supports engineering and technology tools.

Show Some Effort 

The thing that posters need to remember is that they are often asking industry experts to take time out of their busy day to help them.  Those experts want to see some effort put in to the question.  It is very important that the requester form the question in proper English, or whatever language the forum uses.  Even if the poster is not a native speaker, an effort needs to be made to use full and complete sentences, even if grammar is a bit off. (I won’t comment about speling, because that is a my weakest area… so I’ll forgive others on that one)

The easiest way to show a lack of respect to the people you want to answer your question is to not use capitalization or punctuation. As someone commented one time on XANSYS

“If you can’t find the time to use a shift key, I don’t have the time to answer your question.”

Do your own Homework/Work 

The most famous “bad post” on XANSYS was something along the lines of:

“i have been told to model a turbine blade in ansys, can someone show me how to do this”

Needless to say, no one helped them.  Before you post a question you need to try and figure things out yourself. Read the manual, search the internet, talk to co-workers. Most importantly, just try it.  Trial and error is a great learning experience. If you can’t get that to work or you still can’t find the information you need, then post your question. But, make sure you let people know what you have already done and tried.

The people who can help you on forums want to help, they don’t want to do your homework or your work for you.

Ask about a Single Item 

The quote above is not just notorious  because it is asking someone to do their work for them, it is also well known because the question is insanely too general.  Questions that are very specific are the ones that are answered the quickest and with the most useful information.  Even if you have lots of questions, break them up – solve one, then try and solve the next.  

Identify Yourself 

Saying who you are and where you go to work or school is huge. It is a professional courtesy that says “I have nothing to hide.”  When you hide your identity, people assume you are trying to get someone else to do your work and that you don’t want your professor or boss to know. Or, more seriously, you could be posting from an embargoed country or using illegal copies of the software. 

Give Back

This is obvious.  Many people who answer a lot of questions also ask a lot of questions. Even if you are new to the tool you are asking about, share what you learned on the thread when you get it all working. And as you get better, go back and answer some other people’s questions. Remember, it is a community.

Learn More

If you want better help from online communities, here are some great links to give you pointers:

The moderators on XANSYS have developed a great set of rules that really work. Follow these and you will do well on almost any site: www.xansys.org/rules.html

A resource that has been around since the dawn of the internet is “How To Ask Questions The Smart Way” by Eric Steven Raymond: www.catb.org/~esr/faqs/smart-questions.html

And the Venerable Guy Kawasaki has a famous post on emails, that has a lot of tips that apply to online posts as well: blog.guykawasaki.com/2006/02/the_effective_e.html 

Check out the posts on Xansys.org/forum.html and CFD-Online . They are both vibrant and intelligent communities with good posts.

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