Saturday, October 4, 2014

Operating 3D Printers As Small Factories


Frog and Fly – Ollie
The job flow running through a 3D printer or set of printers should be managed using processes like those used in small-scale factories or other job shops that handle small runs of custom piece work. The requirements for this job handling process includes a readily accessible and easy to understand form customers fill in to unambiguously describe the details of the job being submitted. The process must also provide the printer operators with an interface that enables them to process the job flow efficiently, optimize the quality of the objects being produced, keep costs down and track invoicing and payment for completed work.

In my presentations to teachers and administrators, I've demonstrated a spreadsheet that I've evolved for tracking 3D print jobs. I've also demonstrated a web form that my students are using to submit their jobs for printing and the complete set of Google Sheets -based backend tools used to process this work flow. I've used this new package of workflow tools to support a camp that I ran this past summer, in my 3D modeling classes, and in professional development seminars that I run at schools across the Bay Area. When taken together, the tools have so far been used for print production amounting to about 50kg of filament. In the last few months have I been able package up this set of production tools for others to use in their environments.

The web form that my customers, a.k.a. students, use to submit print jobs is based on a wonderful product called JotForm. After you create a free JotForm account you can create a copy of this form using the template I've made public here. As jarring as the form might feel the first time you see it in all it's yellow glory, this unique and unforgettable look helps students, some as young as 3rd graders, remember the job submission process so that I only have to explain it to them once. The "Show Instructions" checkbox near the top of the form is available for those that need their memories refreshed. As simple as the form is, it's complete enough to support single and dual extrusion jobs using any raw material and any configuration of outer shells and infill ratio.

An important feature of JotForm is what they call "integrations". These are processes that can be invoked when a form is submitted. I use the Google Sheets integration. This causes a fresh row to be added to a Google Sheets workbook for every job submitted. The Google Sheets integration wizard that is used to make this connection is very straightforward. But JotForm's behind-the-scenes code that adds these rows to the spreadsheet works by overwriting the workbook every time. This means that this workbook can’t be modified with custom calculations or additional sheets. Instead, IMPORTRANGE function of Google Sheets is used to synchronize these rows of job data into a range of cells in a separate tracker workbook.


I don’t need to fill out a web form when I set up a print job for myself. So this JotForm-based workflow is used only in an educational setting. The tracker workbook that I developed for tracking production of student jobs can be found here. The first sheet, named Submissions, uses Google’s IMPORTRANGE function in Columns F and beyond to import the data taken from the JotForm-generated workbook. Columns A to E of the Submissions sheet are used by the printer operator to denote the state of each job as to flows through the production process. (Note that the workbook referred to by the first argument of IMPORTRANGE must be changed to refer to the Google workbook that YOUR JotForm populates.)

Notice that column E is titled ‘Paid”. This workbook supports the use of 3DBucks. Teachers use 3DBucks to optimize printer demand and motivate students to maximize their progress through each lap of the innovation cycle. 3DBucks are credits that students must spend in order to print something. The cost of each print job is based on the amount of filament it consumes. Available 3DBucks denominations are 1 gram, 5 grams, 10 grams, 25 grams, and the special Dual credit. Students may be given Stipends, which are some 3DBucks given at the start of the semester, when a project is assigned or at some other point that makes sense in your classroom. Some classes use themed competitions and award the students who succeed the furthest beyond their range. I reserve dual passes for “amazing” designs that are best rendered in two-color print jobs. The Balances, Stipends, Awards and Prints sheets of the tracker workbook are used to track the flow of credits in a 3DBucks -based economy.

My tracker workbook can be used as-is, or as a starting point for other tracking work flows better suited for small to mid-sized industrial, retail or creative environments. Have at it.

Friday, May 2, 2014

3DBucks – A Classroom Currency For The 3D Age

3D Bucks – Bob Krause


Classroom 3D printing is expensive and time-consuming. There's always more demand than capacity. It's the slowest step in the innovation cycle. Yet all too often kids choose to print more versions of their designs than necessary rather than waiting to submit a job only once it's been sufficiently refined and a print is necessary in order to test and confirm their working assumptions.

Another common classroom challenge is how to motivate students to move beyond their comfort zones and how to reward them for doing so. 

Forget Bitcoin. We’re 3D’ers! So we use 3DBucks to optimize printer demand and motivate students to maximize their progress through each lap of the cycle. 3DBucks are credits that students must spend in order to print something. The cost of each print job is based on the amount of filament it consumes. Available denominations are 1 gram, 5 grams, 10 grams, 25 grams, and the special Dual credit. The cost of a job that uses both extruders on the dual-headed printer is based both on the amount of filament it consumes as well as a Dual credit. 

You can give students some 3DBucks at the start of the semester, when a project is assigned or at any other point that makes sense in your classroom. 3DBucks encourage healthy saving, spending and design habits.They may also be used as rewards for good behavior, perseverance, helping others, winning a design contest, or any other deserving achievement.   

Saturday, April 5, 2014

Today’s Biggest 3D Printing Challenges


Devil – Skyler
The state of 3D printing today reminds me of the days when the Commodore 64 ruled the PC world. As much as we struggle with today’s printer technologies, we also love the doors it has opened to us. Yet just as we eventually moved beyond the Commodore, the capabilities of each successive printer generation overcomes some of the limitations of those that preceded it. Unimaginable as it may seem, we may wake up one morning, shuffle down to the kitchen and have our Jean-Luc moment as we utter the command, “Earl grey tea, hot.” In the meantime, lets take a moment to briefly discuss the really big 3D printing challenges we’re now up against.


Glacial Print Speeds

I give a fair number of talks and attend many a school event introducing 3D to teachers, students and parents. I often hand out colorful 3D printed mushrooms with a hole in the stem at these events so that kids can zip tie them to their backpacks and parents can bury them in the junk drawer after a week of wondering, "What am I supposed to do with this?" I’ve probably produced some 500 of these tchatchkis. Perhaps enough to fill a 5 gallon Home Depot bucket. Each mushroom is an assemblage of 3 pieces — a stem, a head and a cap. My lab is converted into a cybernetic mushroom farm the night before an event as shrooms are ganged up 10 or 20 to a printer. The average build time for the 3 parts that go into each mushroom works out to about 45 minutes. 

That’s right, it's taken something like 375 build hours to fill a bucket with 3D printed mushrooms. As amazing as it may seem, I’m not troubled that it takes as much time as it does to produce small batches of parts. This is inherent to the very nature of production in an industrial age. A primary advantage that 3D offers is not faster production times, but rather innovation times. Knowing this, I arrange my production schedule to replicate batches of parts while I sleep or while I’m off doing other productive things. The incremental march toward ever more advanced printers will certainly result in faster machines. But I’m just as interested in innovations in post-production automation that allow multiple batches to be run unattended, thus extending the scale at which a custom production business remains competitive. Printers are called “bots” for a reason. Shouldn't they also cleanup after us?

What I find unacceptable about 3D printers today is the amount of time it takes to iterate during the design process. I come from a software background where a key metric of programmer productivity is how long it takes a developer to make an incremental code change then re-compile and get back into the program debugger to confirm that the bug's been squashed and move on to the next challenge. Production printers should be chosen based on the requirements of production, such as cost, capacity, reliability and product quality. Printers used during the product design process are different animals. They need to be fast — as in one or two orders of magnitude faster than they are today.


High Cost

With a budget of $300, I get to choose between several different models of Chromebooks. Acer has one for $200. I see on Amazon that Dell has a netbook running Windows XP that can be mine for just $99. When I’m ready to splurge I can get a new iPad for as little as $400. A top of the line iPad Air will run me about $900, about the same price as a 13” Macbook Air.

For more than three times the price of Dell’s XP netbook, $350, I can zip tie together a Printrbot Simple kit with a wood frame that doesn’t work very well nor last very long. Makerbot’s lowest cost 3D printer, the Mini, costs $1,400 with a spool of filament. The mid-size Replicator is more than twice that price at $2,900. And the “massive” Z18 is again more than twice the price of the Replicator, flying out the door at a massive $6,500.

If we look back we see that high prices are the norm when disruptive products are first introduced. The original 128K Macintosh was initially priced at $2,495, which amounts to $5,595 today after you adjust for inflation. The cost of printers will come down as capabilities improve. But don’t expect the same price curve, because Moore’s Law doesn’t apply to machines with moving parts. Still, that we’re buying printers with wood frames would seem to imply that the innovation cycle is rife with opportunity and that there’s ample reason for optimism that prices have a long way to fall.


Small Build Volume

The PrintrBot Simple has a build volume of less than 4” cubed. Which is too small to print a teacup. The Makerbot Mini is an inch taller. Even the Z18 is only one foot square and a foot and a half tall — big enough to accommodate a teapot. The problem is, few schools can afford a Z18.

I contend that we shouldn't let the small build volume of school printers be a limitation. We must look at it as an opportunity to design beyond the bounds of a single print job through the use of joinery, assemblies and modular designAn overriding curriculum objective is to advance students' modeling skills while offering a path to success that’s long enough to support students’ imagination yet wide enough to include every kid regardless of their innate abilities. I view joinery as a skill central to real-world success. It's also the means by which to develop at scales beyond the bounds of the build volume. Real world objects are an assemblage of parts connected together via screws, pegs, slots and cotter pins. Sliders, levers and ball joints allow parts to move. Weight and other forces are distributed using beams, rods and cables. Modeling curriculum must teach the use of kits of standard parts like these.


Low Reliability

In 1995 I bought an HP 5MP laserwriter printer. It's been about 5 years since I was last able to find toner cartridges for it. So I don’t use it regularly any more. In fact, I don’t even keep it plugged in except when I’m occasionally feeling nostalgic and print a page to verify that it still works. And 19 years later it does still work.

The first 3D printer I bought was a dual extruder Makerbot Replicator Dual clone out of China. The mean time between failures on that first unit was 30 build hours. That’s right, some piece of hardware hard-failed about once a week on average. It got to the point where I was so experienced repairing it that I could strip the unit down to the motherboard and put it back together again in about an hour. The most difficult problem though was sourcing parts. The only supplier of parts was the manufacturer in China. So I sat through a lot of downtime waiting for parts to arrive. When I realized how unreliable the printer was I ordered one of every mechanical and electrical part I could get my hands on, and two of those that failed most often. To their credit, the company felt so bad about my experience that they proactively sent me another printer. They said I could pick the price I chose to pay for the second unit. I told them I’d pay full price if they agreed to give me free support, including free express shipment of replacement parts. We had a deal. But 3 hours into my first print job on the new unit the whole gantry exploded in a shower of parts because the factory hadn’t tightened any of the screws keeping it in place. I emailed asking to return both printers, but never heard from them again.

What portion of new users are having buzz-kill experiences like mine? How is the overall market potential affected by these poor quality machines?


Design Complexity

In many ways, the world of 3D printing today is similar to the dawn of the computer age in that modeling tools offer a limited set of operations on a small collection of primitive shapes. It’s the geometric equivalent of programming in assembly language. Modeling programs need to evolve and fresh ones introduced that widen the path to success to include a greater proportion of students and non-professionals.

Another aspect of design complexity that slows the innovation cycle of non-professional designers is the lack of standard components. Must every designer be required to reinvent ball joints and hinges instead of using standard, well-designed parts that have been fully vetted by a global crowdsource community? Just as software frameworks are the fuel that power object-oriented programming environments, 3D modeling innovations will surge with the availability of standard geometric component kits that designers can pull primitives, parts and assemblies from for use in their designs.


Limited Materials

Various forms of soft plastic are the most common artifact of a 3D print job today. These materials are certainly colorful, which is important to an emerging technology like 3D printing. The objects produced are strong enough for some applications (like selling 3D printers) though they can hardly be referred to as durable. A steady stream of exotic feedstock materials with interesting properties are regularly announced. But few make significant inroads as compared to the PLA and ABS stalwarts. Users are deterred by the downsides of each new and improved material, whether the downsides be cost, durability, appearance, toxicity or something else. From a materials standpoint, electrical conductivity on par with aluminum, durability on par with polycarbonates, and food-safety (and dishwasher safeness) are each generally considered “killer apps” that will propel 3D printing to the next level.

Monday, March 10, 2014

Fixing The Tinkercad Ruler

Mac & Cheese – Bob Krause
The purpose of the Tinkercad ruler has never been explained. All the original team could say in their May, 2012 blog post announcing the ruler was, "Hmmm....how best to explain what this new feature does? Visually, of course! Click on the image to see a larger view." That's it.

I believe that the ruler's never been explained because it hasn't been well thought-out. Is it useful? Certainly. But it's also very "information noisy". The amount of information the ruler shows about the current selection is often more than users expect, want or can make sense of. This is particularly true of young and inexperienced users.

I contend that the ruler has been overburdened and that its function should be separated into two different tools and that the options available when positioning the ruler be expanded.

The ruler should display the distance between it’s origin and the current selection, but NOT also show the dimensions of the selection. I further believe that the user should be able to rotate the orientation of the ruler without having to dismiss the ruler, rotate the canvas and then re-place the ruler. Additionally, while the ruler is being placed Tinkercad should recognize the use of modifier keys to indicate either that the position of the ruler should ignore the current snap grid setting, perhaps using the shift key, or that the position of the ruler should magnetically snap to the edge of a shape within a certain distance, perhaps using the alt key.

A different tool, call it the "dimension tool", should be used to show the dimensions of the selection. Though, because the location of a dimension tool wouldn’t affect the display of that information, perhaps this dimensioning feature should be a mode of the canvas. If presented as a mode, under no circumstances should it be necessary for the user to open the "Edit Grid” dialogue to change modes, both because the dimensioning mode shouldn't necessarily be persistent and because the dialogue is too inaccessible from the mainline workflow.

Fix the ruler. Distance and dimensioning are orthogonal and not sufficiently inter-related to be conjoined as they are.

Teaching With Tinkercad


Egg – Faith

Autodesk's Tinkercad web application is an almost ideal tool for developing students' understanding of basic modeling principles. Tinkercad models consist of two basic object types -- shapes and holes. A shape adds volume to a model. Holes subtract volume. Both types of objects can be moved, resized, and colored. Shapes and holes can be spatially aligned and combined into a group, as can other groups. The app also supports cut, copy and paste. But that's pretty much the entire feature set -- if you ignore imported shapes, STL exporting, and a server-side JavaScript-based geometry library called ShapeScript.

Tinkercad is a very good environment for teaching basic 3D modeling skills. And yet, the site has been experiencing significant growing pains since the product was purchased by Autodesk in the spring of 2013. The team at Autodesk insists that the Tinkercad internals they inherited were a mess. And yet, under the tutelage of the founders the site was there when you needed it, response times were reasonable, and support was superb. Coming up on a year under their stewardship, I think Autodesk is just beginning to appreciate the importance of 24/7 reliability, sub-second response times and a vocal user community. But better late than never.

Tinkercad is a valuable teaching tool that every 3D instructor should be familiar with. Just make sure to prepare alternative lesson plans because you never know whether the Tinkercad website will be up when class convenes.

Monday, January 27, 2014

There Are Three Kinds Of People In The World

Those who can count, and those who can’t

Porcupine – Cooper

So goes the joke currently making the rounds at lower-schools everywhere. This joke comes to mind because I’ve found that there are three types of interests motivating students to excel in 3D classes. I refer to these three mindsets as the Explorer, the Artist and the Engineer.

Explorer – The Explorer is in awe of the images and open-source projects other designers have posted on Thingiverse, Google Images and in the Tinkercad gallery. Explorers spend their time rummaging through these sites expanding their own imaginations in the process. 

Artist – Wow, 3D really does bust the doors open on kids’ imagination! Every kid’s an Artist. Though some come to class with more natural talent than others. A well designed and properly run 3D modeling class offers a wide path to success for all young Artists.

Engineer – The Engineer is a creator, a builder and an inventor. They are generally more aware of details and more structured in the way they work. I was surprised at first by how few engineers I found when I first started teaching 3D to lower-school students, then surprised again by how many there in middle and upper school classes.

In truth, most every kid has a unique mix all three points of view. My son was a Lego enthusiast from ages 2 to 8. Yet he never once followed instructions or built a contraption pictured on the box. Inventors are like that. One of my fifth-grade students, Cooper, has designed and programmed 2D and 3D video games, though he’s also a very talented and imaginative artist. Every 3D designer, myself included, has played the Explorer spending countless hours rummaging through other people’s designs for tips and inspiration.

As a new teacher, I was at first resistant of kids spending so much class time just looking through other people’s work. But I recognized that explorers tend to be younger students with less experience and not as in touch with their artistic selves. I eventually saw that the successful projects these kids eventually completed were those derived from ideas they’d picked up while exploring. Now I give more license for students to explore in between their projects. The creativity and polish of their work evolves much more rapidly as a result. 

Vector modeling environments, like Tinkercad, 123D Design and SketchUp, which are all viable tools for use in various K-12 classrooms, are fairly structured and provide discreet step-by-step design processes. Most kids respond well to these tools. Yet the artist inside some kids are more successful in more free-form tools such as 123D Creature and 123D Sculpt. I offer access to both sets of applications in my classes.

Consider the following graph. It depicts a loose approximation of the level of interest groups of students of all grades have for playing the Explorer, the Artist and the Engineer in 3D class.


Student Interest Levels By Grade


Younger students tend to be initially drawn into 3D first as Explorers. Why? Because every interested student can explore other peoples’ work. I train students in my lower-school introductory modeling and printing classes on what to look for by providing hundreds of one-page sheets showing my work and that of other designers. These sheets are grouped into general skill areas as diverse as simple 3D navigation, joinery, multi-color projects, geometric patterns, creatures and so on. If I find a student casting about for their next project, I’ll refer them to a particular section of my “skill development sheets” for them to choose from. They’re then expected to complete that project before beginning another.

As students mature developmentally with age and hands-on 3D experience, they’re better able to express themselves, whether it be as Artist, Engineer, inventor or something else. This graph shows that we shouldn’t generally expect students in the lowest grades to be anything more than Explorers. (Though every child is unique.) Artists emerge in a classroom full of kids before Engineers do. But each individual develops their interests based on their natural talents, viewpoints and experiences. 

The distinction I’ve made between Artist and Engineer is admittedly more abrupt than we find in nature. After all, there is the inventor, the game developer and other digital artists/engineers. Yet, unless the makeup of a class is unnaturally skewed, a teacher could reasonably expect middle-school non-introductory classes to consist of a pretty even distribution on a continuum of Artists and Engineers.

Is this the progression and distribution of interests others are experiencing?

Saturday, December 28, 2013

The Jump To 3D Has Begun

Mushrooms - Bob Krause

Forget your assumptions about the upper limits of S.T.E.M. curriculum. The jump to 3D has begun. Scratch and Lego Mindstorms are still relevant, but Tinkercad modeling software, Makerbot printers and Epilog laser cutters are now very much in the picture.

Though the hardware and software tools are coming together, the evolution of classroom 3D is at a stage similar to the introduction of the Macintosh during the PC era, and every bit as exciting. But just as DOS was limited and line-oriented, Google’s free SketchUp software is complicated, cluttered, clunky and in many ways kludgy. Today Autodesk's  Tinkercad provides the best of breed experience for K-12 students, educators and even some professionals. – That is if Autodesk doesn’t mess it up with more bug-riddled updates, mid-day downtime and changes that clutter up the interface.

Printer technologies are evolving rapidly. Yet print times are clocked in hours, hardware breakdowns are common, and only about half of all print jobs are ultimately successful. Still, schools are creating space for printers, scanners and laser cutters and experimenting with curriculum ideas.

Smartphones, tablets, social media and the internet generally has affected the relationships that kids have with technology. To them technology is fashion, it’s entertainment, it’s social, it’s ubiquitous, and its innovation cycle time is shorter than the half-life of an Instagram. More importantly, it’s been all of these things for as long as these kids can remember. Technology, innovation, creativity and expression are fundamental in their world. Perhaps this is why kids immediately grasp the notion of 3D printing when they first see a printer in action while adults are as wide-eyed as my grandparents might have been when first they first experienced black-and-white television. Even if a kid today never imagined that they could design a 3D object, print it and be holding it in their hands within hours, the reality of actually doing so is a more natural experience in comparison.

What are students doing in your 3D classrooms? What tools, hardware and services are you using? Where are you going next?