I realized that I never made a post about the assembly of our MakerBot. I will rectify this now. Lots of pictures incoming. All the pictures are courtesy of one of our members, Rolando Quintanilla.
All of the wood parts are 5mm thick birch and laser-cut to be extremely precise. We sealed them with a polyurethane spray but decided to leave them natural instead of painting or staining them. The parts are notched to fit together easily and have slots for captive nuts to hold it all together. It is really well engineered.
The electronic components and assembly hardware all came in individual bags. You can see the motherboard, stepper motor controllers, extruder controller and some assembly hardware.
Assembly is all done with metric nuts and bolts. Patrick is assembling the bearing brackets to the middle layer. The bearings for the Z-axis will fit inside these.
You may notice a lack of pictures during certain steps, the excitement was high during assembly and pictures were the last thing on everyone’s mind at the time. This is the fully assembled MakerBot body. All the pieces slide together and are held by captive nuts and bolts. Make sure not to tighten the bolts too tight or you could damage the wood.
The next step is assembling the z-axis rods with bearing nd nuts and then inserting them into the MakerBot. The bearings press fit into the bearing brackets and the nuts keep the rods from moving inside the bearings. The extra nut on each rod is for moving the z-axis up and down. This will be assembled later.
The stepper motors will move the stages. Two of the motors install in the MakerBot body, the third one installs on the Y-Axis
Magical CNC fairies managed to assemble the X and Y stages and put them in while we weren’t looking. Here are some good pics of the assembled stages. You can see how each stage runs on two guide rods and is moved by a toothed belt that is held by a loose pulley an a toothed pulley that is attached to the stepper motor. You can adjust the tension on the belt by moving the white idle pulley back and forth in its groove and tightening it down. We have found that loose is better, as long as the belt isn’t slipping. An interesting thing to note is that the white pulleys are printed on other MakerBots. Several other pieces of the MakerBot could theoretically be printed from a MakerBot, but unfortunately not the whole thing.
Here is Patrick putting some final touches on the MakerBot. The motherboard is a Sanguino, which is based on the Arduino, but with an ATmega644P instead of the 328 or 168 that comes with the standard Arduino. It is built for the RepRap project. The smaller boards are stepper motor controllers for controlling the three axis. You can also see the belt system on top that turns the four Z-axis screws which raises and lowers the plastic extruder. Unfortunately, I don’t have any pictures of the plastic extruder assembly at this time, so this is as far as we go. I will get some more photos soon to show the complete assembly and some various stages of printing as well.