Push your MakerBot Cupcake to the limit
A couple of weeks ago I wrote about upgrades for the MakerBot that you can print using the MakerBot. My favourite upgrade of the bunch, Zydac’s Z-axis extender kit, is now complete on my own MakerBot so it’s time to show how it’s done.
Printing the parts
These are the parts that you’ll need to print:
- - 4 x Z-Extender Base75.stl
- - 4 x Z Extension FBUpper.stl
- - 4 x Z Extension FBLower.stl
- - 4 x Z Extension SideLower.stl
- - 2 x Z Extension SideUpperR.stl
- - 2 x Z Extension SideUpperL.stl
Once those are done, take an FBLower and FBUpper to a hardware store and pick out a set of twelve wing nuts and bolts. The bolt heads should be low-profile so that the Z-stage can pass by the new bits on the inside of the chassis wall. Make sure that the bolts are long enough to pass all the way through the risers. Personally I screwed this up the first time by buying thumbscrews instead of bolts… So don’t do that.
Prepare the parts
Put the sets of risers (FBLower/FBUpper and SideLower/SideUpperR/SideUpperL) together, then slide them opened and closed until it takes only a little bit of force to do so. This will make height adjustment easier later on. The FBLower parts also have two thin strips of support material that need to removed before they can be used.
For the base tower pieces, you might need to widen the openings a bit. I pressed them onto a spare skate bearing a few times, but if you have a Dremel tool that could work too.
Remove your Z-stage and extruder and put them somewhere safe. Now it’s time to pop the top off of the MakerBot. Unscrew the obvious bolts holding the top in place, then unscrew the first row of bolts from the top on the left and right sides of the chassis. That will let you (gently!) bend the sides away so that the top can come off. Stand the top and threaded rods off to the side.
Now remove the bolts holding the threaded rod brackets in place at the bottom four corners of the chassis. As long as you didn’t over-tighten these when first assembling your MakerBot, the process shouldn’t be too difficult. Make sure that you save the nuts and bolts that you remove here! (The wooden bracket pieces aren’t needed.)
Add the new parts
Time to attach the base tower pieces. Insert the bolts that were previously removed first, then slot each piece into the corners of the MakerBot and put the nuts back in place.
Now add the riser pieces to the top of the walls. The risers at the back of the chassis must be installed in this orientation or there won’t be enough room for the Z-stage to pass by later on:
Go ahead and add the wing nuts and bolts to the risers, but obviously don’t tighten them yet.
Put the top back on
I strongly recommend that you apply some 3-in-1 oil to the threaded rods at this point. Without doing so the Z-stage will almost certainly have trouble traveling the full range. Also, if you wait to apply the oil after everything is reassembled, you might spill it on the electronics the way that I did. Oops.
Lower the chassis top and threaded rods into place. Make sure that the skate bearings fit snugly into the base towers. (I used a book to press the threaded rods down from the top.)
Now you can finalize the riser positions and bolt everything in place. Zydac added additional spots to the printed parts for bolts in case you need them, but they weren’t necessary for me.
Replace the extruder
Time to put the Z-stage and the extruder back in place. The nuts that hold the Z-stage in place will have shifted, so be sure to re-level them.
Here’s where things get a little tricky. You’re going to have to do some cable routing. On my MakerBot I had to:
- - Replace the ethernet cable between the motherboard and extruder with a longer one
- - Re-route the Z stepper motor’s power cable up through the top
- - Use a longer power cable for my ABP’s relay board
This will vary depending on your setup, but you’ll want to route whatever you can out through the top of the MakerBot. (However, the three grey cables coming off of the ABP are thin enough to fit between the Z-stage and the chassis wall as the print height increases.)
Test it out!
Start your extruder at the 0 position, then use ReplicatorG to move it up and down the full range of the threaded rods until there’s no skipping. When the motion is smooth, do a final run upwards until the Z-stage hits the underside of the skate bearings at the top of the chassis. That Z value in RepG is your maximum range of movement – but - don’t try to print a model exactly that high. You want to leave some wiggle room for the raft and in case you need to move the nozzle up a little bit.
My max range is 194mm so I’ve decided on a maximum model height of 185mm. I used this bottle model by aubec for my first test print because it was easy to scale a version to exactly the height I wanted using OpenSCAD. It’s also very thin so it didn’t take hours and hours to print.
Do this upgrade. It’s awesome.
When you’re doing your first tall print, pay attention to your newly-routed cables to make sure that there are no snags as the Z-stage rises. Now you’re ready to browse Thingiverse for all of the too-tall things that you couldn’t print before. (My project this week is the bathtub u-boat by Skimbal!)
Derek Quenneville is a 3D printing evangelist who posts weekly on the Ponoko blog. Follow him on Twitter @techknight.