Makerbot Howto / Tutorial

Overview

Before you start, it's nice to have the big picture of what's going on. Here's an outline of the steps that you'll be taking, and why you take them.

• Download the replicator-G software that controls the machine.

• Download/create a 3-D model in .stl format.

• Using skeinforge, (some python routines bundled with replicator-G) turn the 3-D model into a toolpath for the bot's extruder head to follow. At this point the toolpath will be in an industry-standard text format called "gcode".

• Warm up the machine. (You could have been doing this all along...)

• Convert the gcode into the makerbot's native format (.s3g) and send it across. This is done transparently in one step when you press the "Build" button.

• Confirm that the test extrusion worked. If not, it'll need to warm up more or you may need to straighten out the feedline.

• Watch it print. Let it cool a bit when it's done. Hooray!

The rest of this page is a step-by-step that you can follow. Enjoy.

Set up the Software Side

Get your bits set up.

• Download the latest version of replicator-G: replact.org

• Run it at least once. It creates a secret .replicatorg directory in your home directory.

• Replace the ~/.replicatorg/machines.xml file it creates with the one found here: Makerbot machines.xml. If you don't do this, you will fail when using the makerbot in the space. (Ugh. They've moved the location of the machines.xml file in version replicatorG-0022. The path to machines.xml will depend on the version you install. Placing "machines.xml" into the "machines" directory in the install directory seems to work.) You will know you have it right when you see "Andy Walker's Cupcake with 4 axis board" in the Machine...Driver pulldown menu. (Current as of Jan 2011)

• Download something fun to print. If this is your first time, something cool but quick like the penny bottle opener or a dodecahedron is a good idea. You should now have a .stl file.

• Open up your .stl file in replicator-G. You should see a 3-D representation of it on a wireframe of the build platform. If it's too big, scale it. I always press "Move...Center" which puts the object on the build platform for you.

• Feel free to follow the replicator-G usage tutorial, but start the machine warming up first. (Next step.) That way, the ten minutes you spend monkeying with replicator-G will serve double-duty as time warming up the machine.

Fire up the Machine

Here we connect to the machine, and start it warming up.

• Make sure the power switches on the power supply and the bot itself are flipped on.

• Plug in the USB cable that's coming out of the Makerbot.

• Select Machine...Driver and choose Andy's Cupcake. (You _did_ replace the machines.xml file in the step above, right?)

• Select Machine...Serial Port and choose /dev/ttyUSB*

• The top bar should now be green and the machine's name ("Slick") visible. If not, try clicking on the disconnect and re-connect icons. The next time you connect, replicator-G will remember these settings and it should just connect automagically.

• The four-way arrow icon opens up the Control Panel. Do that.

• On the right-hand side are controls for temperatures. Since it takes a while to heat up, we're going to pre-heat the machine now. Set the extruder temperature for 220 and the build platform for 100 (celcius). You will need to wait at least 5 minutes (maybe 10) until it's ready to go. _DO NOT_ start extruding when the extruder temperature gets up to 220 -- the thermistor is on the outside of the barrel and it heats up before the plastic is melted. You need to wait another five minutes after it says it's at 220.

• On the left are the platform controls. Honestly, it's easiest to zero the machine by hand. Press the "Set Zero" button. Now, push the platform so that the nozzle is in the center, and using the crank on the top right of the machine, lower the nozzle until it's almost touching the platform (0.1-0.2 mm above).

• (Optional test extrusion) If it's been 5 minutes already and the extruder head is good and hot, you can raise the nozzle (press z+ to step up 10mm) and do a test extrusion. Type "255" into the PWM box at the top right, and select "Forward". If a noodle doesn't start coming out in a few seconds, make sure that the cord is feeding in. Sometimes it helps to reverse it back out, clip off the end, and re-feed. The extruder is slightly temperamental. If you do a test extrusion, be sure to place the nozzle back down at zero when you're done.

Build the G-code for your Model

G-code describes the path that the extruder head needs to follow to make your object, along with temperatures and motor speeds and other necessary details. Skeinforge is the program that turns your 3-D model into a tool path for the machine. (This is where all the bodies are buried.) Skeinforge is part of the replicator-G package that you've already downloaded. You're gonna need to click some buttons.

• While the bot is warming up, press the "Generate GCode" button. It will open up a dialog box with a choice something like "cupcake-mk4-heated-platform-abs". Select that. Check the "Use raft" checkbox if it's not already.

• For now, we'll be using the vanilla settings, but if you were going to change some of the skeinforge parameters, you'd click "Edit" or "Create" to edit or duplicate and edit the skeinforge settings to your liking.

• OK, I lied. There's one setting you might want to change. (Optional.) With "cupcake-mk4-heated-platform-abs" selected, click "Edit" and then "Raft". Set "Interface Layers" to 1. Press save and close.

• Back at the first menu, pressing "OK" will start compiling. This can take a while. Good thing the machine is warming up... Pace around expectantly for a few minutes.

• When it's done, you should have a tab labelled "gcode". Click it if you want to see what gcode is like.

• The leftmost button on the top row (arrow pointing to a ghostly jelly bean) enables you to simulate the build. Click it, wait a few seconds, and then watch as it traces out the planned object path. Cool, huh? This will be an important pre-flight check in the future, once you get used to what it means.

Print

Here goes nothing...

• Are you ready to rumble?

• Has the extruder heated up? (Feel free to re-open the control panel to check that it's been at temp for a while.)

• Does the machine think it's at zero? (Feel free to re-open the control panel and press "Set Zero" again.)

• Is the nozzle physically at zero? (Move the nozzle to the center of the platform, almost touching.)

• Press the arrow-pointing-to-solid-jelly-bean button ("Build") to start the build!

• The nozzle will raise up. In a few seconds, it will run a test extrusion. If it worked, pull the extra plastic off of the extruder and click "yes" and it will start the print in earnest.

• (If it didn't extrude, you'll need to see the section on troubleshooting.)

• The nozzle will move back down to the zero position and it'll start printing out the raft.

• The first layer of the raft is slow and low, and ends up being fat. That's to make it stick better to the platform.

• The next layer (or layers) are skinnier. They're just there to get the height right and the surface level. They will peel off your model when it's all done.

• Watch in amazement for a few minutes. It's neat.

While Printing...

You're going to have some down-time here. Feel free to grab a drink. But don't stray too far from the machine. It needs babying.

• First thing to check is that the filament is unspooling properly. Sometimes it kinks up. You may want to rotate the whole reel until there's a decent amount of slack for insurance. (Mostly historical -- the current skate-bearing spool has not failed yet.)

• Smell that? That's the smell of melting ABS in the morning. It's probably toxic. Don't inhale directly above the machine.

• Is everything sticking to the platform? Are the platform lights going on and off? These are good signs. It means the heater's working and around the right temperature.

• Is the raft peeling up and jamming the head? Press stop. Do over from the pre-heat instructions onward. This time, you might try putting the nozzle closer to the platform, which can help. Of course, too close and it won't extrude right. The raft will also peel if the build platform is not yet up to temperature. Check that it's hit 100C.

• Listen to the noises. It'll change when it transitions from a solid layer to a fill layer as the pattern changes. Get to know these noises and you won't have to watch it so closely.

• Relax. It takes a while.

• When it's done, wait another minute or so for the part to cool down.

• Sometimes you'll need to peel it off the platform. I use a tiny screwdriver tip under the raft corners.

• Peel off the raft from your part.

• Feel free to trim off the excess plastic bits that inevitably stick out. Diagonal wire cutters are good for this.

• You win. Nice part.

• You can stop here, or download another file and repeat. If you're a tuner (and you know if you are) read on.

Advanced Tricks for Your Second Print

There's a bunch of options in rendering to g-code that you may be interested in changing. You should probably preview your model before printing it out. Read this section while you're watching it print, but don't change anything -- there's a glitch where sometimes it will abort your print if you try to render g-code.

• See how it's doing multiple laps around the perimeter? That's a setting in skeinforge. "Fill..Solid Surface Thickness (layers)" I often set it down to 2 instead of the default 3.

• See how much fill it's making? Another setting in Fill. "Infill Solidity (ratio)". The default is 0.20. I usually use 0.15.

• If the raft took "forever" and you're impatient, feel free to drop "Raft...Interface Layers" down to 1 or even 0.

• As you saw, there's a billion skeinforge parameters. The defaults aren't bad for most models, but sometimes you'll want to change them, even on a per-model basis. I have more than ten tuned-up skeinforge preference sets. I'll have to share some.

Quirks

• The z-axis lead screws are modified and super-beefy on Andy's bot. You'll need to modify your machines.xml file to get it to work. See Makerbot machines.xml.

• The motor-driver board is also non-standard now. We're using John Yang's 4-axis motor controller board, which lets us do 1/16th step microstepping. This means that the steps-per-mm in machines.xml needed to be multiplied by eight relative to the default half-stepping. See Makerbot machines.xml.

• As noted above, the temperature indicated on the nozzle is _not_ the interior temperature that's relevant for melting the plastic, but the exterior temperature right next to the heating elements. You'll need to give it 5 min or so to soak in and melt the plastic.

Troubleshooting

Here I list all the things that can go wrong. And they will...