We’ve seen 3D printers coming out with infinite build volumes, including some attempts at patenting that may or may not stall their development. One way around the controversy is to do it in a completely different way. [Aad van der Geest]’s solution may not give you the ability to print an infinitely long part, but it will allow you to print an infinite number of the same, or different, parts, at least until your spool runs out.
[Aad]’s solution is to have a blade automatically remove each part from the print bed before going on to the next. For that he put together a rail system that sits on the bed of his Ultimaker 2, but out of the way on the periphery. A servo at one end pulls a blade along the rails, sweeping over the bed and moving any parts on the bed to one end where they fall away. This is all done by a combination of special G-code and a circuit built around a PIC12F629.
One of many things that we think is pretty clever, as well as fun to watch, is that after the part is finished, the extruder moves to the top corner of the printer and presses a micro switch to tell the PIC12F629 to start the part removal process. You can see this in the first video below. The G-code takes over again after a configurable pause.
But [Aad]’s put in more features than just that. As the second video below shows, after the parts have been scraped from the build plate, a pin on the extruder is used to lift and drop the blade a few times to remove small parts that tend to stay on the blade. Also, the extruder is purged between prints by being moved over a small ridge a few times. This of course is also in that special G-code.
How do you produce the special G-code, since obviously it also has to include the parts to print? For that [Aad]’s written a Windows program called gcmerge. It reads a configuration file, which you edit, that contains: a list of files containing the G-code for your parts, how many to print, whether or not you want the extruder to be purged between prints, various extruder temperatures, cooling times, and so on. You can find all this, as well as source for the gcmerge program, packaged up on a hackaday.io page. Incidentally, you can find the PIC12F629 code there too.