Mechanics has always been a problem in my robotic projects but now that the 3D printing is such a hot topic I decided to test it out.
It seems that the 3D printing services use STL format and many of the popular 3D modeling applications can export it, so there are plenty of applications to choose from. I wanted to use Blender for the modeling as I have used it briefly in the past and I would like to know it better. It was easy to use boolean operators to shape my model but it turned out that even though the model looks nice on the screen, it is not enough for real world printing. I had some broken surfaces, holes, etc. in there. As I am a Blender rookie I ended up creating the simplest cylinder and modifying its subdivided surfaces to shape my model. Easy and quite fun :)
Now that I had the model, the next step was to print it. The nearby public libraries provide 3D printing services for free or nearly free with printers from MakerBot and MiniFactory. After a couple of visits I realized that it is not that easy to jump into the 3D printing world with them. You need to know how to tune the parameters of the software, how to clean up and prepare the printer, how to preheat it, etc. You also need to model your creation in such a way that the printer can print it. The plastic is hot during the printing and not very strong so you may need to add some supporting structures during modeling. At least some of the 3D printer applications can add the supporting structures automatically but I was told they might not be very good at it.
Below is a photo showing the first three layers of an automatically created supporting structure. That looked OK but the actual model started to go wrong already on the first layer so the printing was canceled.
First layers of a 3D printed supporting structure.
After a couple of miserable failures somebody hinted that Shapeways is a much easier way to get 3D prints and the price is low enough. They seem to be using selective laser sintering and I didn’t need to worry about supporting structures or fine tuning parameters. They also have a bunch of different materials and colors to choose from. I chose “Coral Red Strong & Flexible Polished”:
Original part and the 3D printed version with my additions.
The 3D printed part fits perfectly.
I have used cable ties and Meccano parts earlier but I needed something more lightweight (and better looking) and the Shapeways might very well be the solution for me.