The last few weeks have been quite tense for the Mooltipass team as we were impatiently waiting for our smart cards, cases and front panels to come back from production. Today we received a package from China, so we knew it was the hour of truth. Follow us after the break if you have a good internet connection and want to see more pictures of the final product…
We’re not surprised to see a car manufacturer using 3D-printing technology, but we think this may be the first time we’ve heard of 3D-prints going into production vehicles. You’ve likely heard of Christian von Koenigsegg’s cars if you’re a fan of BBC’s Top Gear, where the hypercar screams its way into the leading lap times.
Now it seems the Swedish car manufacturer has integrated 3D printing and scanning into the design process. Christian himself explains the benefits of both for iterative design: they roughed out a chair, adjusting it as they went until it was about the right shape and was comfortable. They then used a laser scanner to bring it into a CAD file, which significantly accelerated the production process. He’s also got some examples of brake pedals printed from ABS—they normally machine them out of aluminum—to test the fits and the feeling. They make adjustments as necessary to the prints, sometimes carving them up by hand, then break out the laser scanner again to capture any modifications, bring it back to CAD, and reprint the model.
Interestingly, they’ve been printing some bits and pieces for production cars out of ABS for a few years. Considering the low volume they are working with, it makes sense. Videos and more info after the jump.
A lot of the ‘prosumer’ – for as much as I hate that word – 3D printers out there like the Makerbot Replicator and countless other Kickstarter projects only officially support PLA filament. This has a few advantages from a product development standpoint, namely not necessitating the use of a heated build plate. There are other reasons for not supporting ABS and other filaments, as one of the Kickstarter updates for the Buccaneer printer elucidates (update available to backers only, here’s a mirror from somebody on reddit).
The main crux of the Buccaneer team’s decision not to support ABS is as follows:
We spoke to our legal counsel about it and they told us that if we officially support a certain “material” type then our printer has to go through massive certification to prove that it is totally safe to use or we will/can get sued badly.
Despite the Buccaneer team’s best efforts, we’re sure, their lawyers were actually able to find some studies that showed ABS could affect a person’s health. The issue isn’t with the ABS itself – LEGO are made of ABS and kids chew on blocks all the time. The issue comes from the decomposition of ABS when it is heated.
ABS and PLA are the backbones of the 3D printing world. They’re both easy to obtain and are good enough for most applications. They are not, however, the be-all, end-all filaments for all your 3D printing needs. Depending on your design, you may need something that is much tougher, much more flexible, or simply has a different appearance or texture. Here are a few alternative plastics for your RepRap, Makerbot, or other 3D printer:
We’ve seen a few advances in the finishing processes of 3D prints over the last few months that result in some very attractive parts that look like they were injection molded. Smoothing ABS prints is now a necessary skill for anyone looking to produce professional parts, but those of us using PLA for our RepRaps have been left in the cold. After some experimentation, the guys over at protoparadigm have come up with a way to smooth out those PLA prints, using the same technique and a chemical that’s just as safe as acetone.
Instead of acetone, the guys at protoparadigm are using tetrahydrofuran, or THF, as a solvent for PLA. Other PLA solvents aren’t friendly to living organisms or are somewhat hard to obtain. THF has neither of these qualities; you still need to use it in a well ventilated area with nitrile gloves, but the same precautions when using acetone or MEK still apply. It’s also easy to obtain, as well: you can grab some on Amazon, even.
The process for smoothing PLA prints with THF is the same as smoothing ABS prints with acetone. Just suspend the print in a glass container, pour in a tiny amount of the solvent, and (gently) heat it. The evaporated solvent will smooth all the ridges out of the print, leaving a shiny and smooth surface. You can, of course, hand polish it by dedicating a lint-free cloth and a pair of gloves to the task.
When you want to print a 3D object you run into problems if there is a part that has nothing below it. The hot, soft filament coming out of the extruder will droop with gravity if not given something to rest on while it hardens. The solution is to use a second material as a support. But then you’ve got to find a way to remove the support structure when the printing is done. That’s where this beauty comes in. It’s a heated stir plate for dissolving PLA.
The PLA is printed using a second extruder head. Once the part is cooled [Petrus] puts it into a heated bath of sodium hydroxide (lye). The solvent will remove the PLA but not harm the ABS. Speaking of ABS, [Petrus] also mentions that this can double as a temperature controlled hot plate for polishing ABS prints using acetone vapor.
There’s all kinds of good stuff inside of this beast so do check out the full plans to learn more. Our favorite part is the stir bar which is a piece of threaded rod and a couple of nuts. To make it safe to submerge in the chemicals he 3D printed a pill-shaped enclosure for it.
[Chris] has been having some real problems getting PLA to stick to the build platform of his Printrbot. This is of course not limited to this brand of printers, and affects all extruder-based hardware using the PLA as a source material. He came up with a couple of ways to fix the problem.
The first is something we’re quite familiar with. The image above shows [Chris] applying a thin layer of hairspray to the platform. This is a technique the we use with our own 3D printer. The sheets of paper are used as a mask to help keep the sticky stuff off of the threaded rod. For more info on the hairspray trick [Chris] recommends that you read this article.
The second technique uses a slurry made from saturating a bottle of acetone with ABS leftovers. In the clip after the break he shows off a glass jar of the solvent with scraps from past print jobs hanging out inside. After a couple of days like that it’s ready to use. He takes a paper towel, wets it with the solution, and wipes on a very small amount. He does mention that this will eventually eat through the Kapton tape so apply it rarely and sparingly.