So, my Makerbot is now working. It took some doing. My first complete build is shown--a Darth Vader helmet, which worked pretty well for a first try. But as you can see, I've still got some tuning to do.
In the meantime, here are ten things I learned the hard way getting to this point (some of them because of changes in the Makerbot hardware in the latest rev, some because of problems in the documentation and some because I'm an idiot):
Unbelievably, I didn't notice that the motherboard has an on-off switch. It just controls power to the stepper motors and extruder head, and as far as I can tell it's not mentioned in the documentation, but if you don't turn it on, nothing will happen other than LEDs lighting on the motherboard.
Most of the endstop slots (for the sticks that are supposed to go into the optical endstops when you hit the end of the travel) are in the wrong place. Don't worry about it. You actually don't need or even necessarily want to use the endstops, since it's best to center the head manually.
A lot of the default settings in Skeinforge, which creates the g-code version of the 3D model that tells the printer what to do, are suboptimal for the Makerbot. The settings suggested in this post
are much better.
The new Makerbots (Batch 9) have a 1mm thermister as a temperature sensor. Previous batches used a 3mm thermister. The new, smaller one has a totally different temperature response curve, and as a result the default settings will leave the head not nearly hot enough, which leads to all sorts of problems, from clogged heads to builds that don't stick to the build table or even to themselves. Basically, to get the recommended 220 degrees Celsius, you've got to set it to 240, and all the other settings should go up by about 20 degrees.
Until Makerbot releases new pastruder firmware, you should change the temperature settings in Skeinforge's Raft settings. Here's the new recommended settings, courtesy of Andrew Plumb
"The default "3mm" thermistor settings are as follows:
Temperature of Raft: 230.0
Temperature of Shape First Layer Outline: 215.0
Temperature of Shape First Layer Within: 215.0
Temperature of Shape Next Layers: 220.0
That final "Temperature of Shape Next Layers" is what sets the temperature for the majority of the build. You can probably get away with simply adding 20C to all those numbers; 250.0, 235.0, 235.0, 240.0.
Aside: Make sure all the "Temperature Change Time Before ..." numbers are 0.0. If they're non-zero you get long pauses that don't seem to help much with MakerBot builds."
You may have trouble getting the build to stick to the acrylic build platform, especially if you're running at lower temperatures than you should. The first thing you should do is to sand the platform, to create a rough surface. If that's not enough (it wasn't for me), spray the surface with 3M "Super 77" spray adhesive. One application should do it!
Spraypaint your Makerbot before you build it! I sprayed mine matte black and it looks way more industrial chic than the naked plywood versions you see everywhere. One can should do it, with about three coats. You can touch up the smaller bits with a brush after assembly.
is the main control software. Before you start doing any builds, get very familar with its control panel. You can move the heads, set the head temperature and extrude plastic via the control panel, which is a great way to test your hardware. I found that both my X and Z axis were inverted, which I could correct via ReplicatorG's settings.
You may get confused by what "home" means. I kept putting the head in the middle of the build tray and pressing the "set zero" button. Then I was confused when I'd do a build and the head would go to the end of its travel and jam out. Turns out that "zero" is the far extreme of all the positions (I guess that would be full left, down and front), following Cartesian coordinates. The best thing to do is ignore the "set zero". Just use the arrows to put the head at the center of the build platform, using the Z arrow so the head is almost touching the platform, and start your build. The machine will figure out everything else.
You may still get clumps of plastic on the surface of your build while it's printing, which become hard protrusions that deflect the head and can mess up your calibration (as happened in the lower layers of the Darth head above). I'm not quite sure what to do about that. I'll update this when I come up with a solution. [UPDATE: Andrew Plumb suggests: "In the Skeinforge Speed preferences I have "Feedrate (mm/s)" set to 24.0. I think the default is something like 26.5"]
When it comes time to upgrade your firmware, either for the motherboard or the plastruder board, get ready for a funky trip down the side alleys of Arduino derivatives. The boards are actually Sanguino (they're red--sang
--not blue like the Arduino boards), and need you to load some Arduinio extensions and libraries before you can compile and upload code. It's a hassle to find all the right ones, so be prepared for some digging around online. Perhaps the Makerbot team will release binaries and some utility that can upload them automatically? A guy can hope...