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.

1 comment:

  1. I can't agree with you any more. All those limitations are crucial when planning any 3d printing workshops, especially for kid whose easily get impatient and lost attraction. I also like your idea of 3D Bucks, maybe I will try it in my next class.

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