MakerBot Industries

Some say that necessity is the mother of all invention, and I’d have to agree with them. When we decided to start MakerBot and launch a complete 3D printer kit for under a grand I knew we had a lot of work cut out for us. Transitioning the RepRap technology from a research project to something that is more of a product presents many challenges. One of my main tasks was preparing the Plastruder MK3 for production.

I had been developing the 3rd generation extruder as part of RepRap for a while and it worked great. However, there were parts of the process that just weren’t suited for a DIY kit at all. The main problem was attaching the nichrome wire and thermistor to the heater barrel so you can accurately control the temperature. For years (literally) we’ve been attaching the nichrome wire to the heater barrel with some form of high temperature cement: first JBweld, then with fire cement and stove cement. The latest revisions for doing this all work, but I didn’t like them.

Why? Because they are horribly messy. Stove cement is an awful, black compound that stains and is probably toxic as hell. Fire cement only comes in 55lb bags. Stove cement only comes in giant 5 oz tubes. All you need is a tiny amount of this stuff to insulate and bond the nichrome. Plus, it is a very delicate process to wrap the nichrome and then apply the goop the whole time hoping that you don’t jiggle it the wrong way and have everything fall apart. If some of it gets in your extruder nozzle? Game over. Oh, did I mention that you have to let it sit OVERNIGHT to fully cure? You’re all fired up to build your extruder and WHAM! Instant timeout.

So, what did I do? Well, aside from the intial panic, I decided to try about 10 different techniques and go with the best one. I tried all the various forms and techniques for dealing with high temperature cement when I stumbled upon this blog entry by Limor Fried of Adafruit fame. Something there sparked my eye: it was here use of the Kapton tape. Up until now I had not even heard of it, and maybe its the same for you as well.

After doing a few hours of research on it and realizing it was PERFECT for what I wanted, I quickly ordered a tiny little roll from McMaster for $4. As soon as I got it, I built a heater barrel assembly from it. It took me 15 minutes and I was able to use it right away. It was the fastest and easiest extruder build I had ever done. Usually when I built extruder barrels, I had to use some sort of tape to hold down the leads while I build it anyway. With Kapton tape, I didn’t have to remove them and they simply became an integral part of the extruder itself.

Wow, that turned out to be longer than I thought. I managed to find a good supplier of Kapton tape so you can get it from the MakerBot store, and it will be a part of our upcoming Plastruder MK3 Kit which will start shipping Monday.

3d printed ceramics!

Some talented mechanical engineers at the University of Washington have shared the home-brew recipes for the ceramic slip and binder that they use in their 3d inkjet printer. This is a different sort of printing than the fused deposition that Cupcake and its siblings (currently!) do; instead of extruding a bead of warm thermoplastic, these machines lay down successive layers of powder and then use an inkjet head filled with an adhesive binder to create solid zones in each layer.  Finally, the loose powder is cleared away to leave the solid object.  You can use a wide variety of materials with this technique– plastic, ceramics, or even sugar!