First off, a slight update. I'm working on the 3rd version printer, which should actually be able to print. Since I won an NXT 2.0 in the Toy challenge with this, I should be able to make another one for the next contest that features a Makerbot.
I originally wanted to create a lego 3D printer for the makerbot challenge, but wasn't able to finish it in time. So, since another makerbot is up for grabs, I decided to do a second version of the printer. Since I have no extruder, I can't actually have it be a 3D printer. That's why it's currently configured as a pen plotter. Also, this takes a massive number of parts. I had to scrounge around for all the little pieces I need.
This is my first instructables, so I've decided to do the guide with a combination of two different techniques. I'm using Lego digital designer to design some of the sub-builds. I've exported each sub-build as an html file and html files are each given a number. (All of which are in the "building instructions.zip" file) I'll reference them by B#. ie, B1, B2 or whatever. So when I say build 2 of B1, I mean open up 1.html and build it twice. If you have Lego Digital Designer (LDD) and would rather use it, the "models.zip" file has all of them by the same number. It's just B1 is 1.lxf instead of 1.html. Sorry if that's confusing. The second approach was to take pictures of putting the sub-builds together.
So the first thing to build is the sides. I'm going to show you with the Z axis rail, but we will remove that later to put in the Z platform. Don't worry, it's pretty easy to do. I designed it mostly in Lego digital designer, but there were two pieces it didn't let me put in, so I'll show you that in the picture. Go ahead and build 2 of B1 (Open 1.html in the building instructions folder, and build it twice). I've also included the 1.lxf file if you have LDD and would rather use that. The html file is just a little bit weird. I think they need to work on their building instructions algorithm. Anyway, see the pictures for the two pieces that were missing and where they go. (One piece for each side.)