Getting my Plastruder MK5 running [09/06/2010]

[Only 300 draft posts remaining unpublished! What’s a little sad about these posts is that the things they used to refer to, no longer point to valid websites. The MakerBot store and all associated documentation links probably haven’t worked for more than a decade. But, I guess it’s just as well. I haven’t used my Cupcake CNC in a very, very long time and there’s not likely anyone building or upgrading a Cupcake CNC that could find the below of any use. That said… and when stupid legislatures decide to regulate 3D printers into oblivions, the only 3D printers people will have are those that they make themselves…]

When the Plastruder MK5 I ordered hadn’t arrived on Friday I was a little disappointed because I was hoping to build it over the long weekend. Luckily it arrived late Saturday! Huzzah! My weekend was saved! I had put off soldering the Relay Board I got with my heated build platform since I haven’t gotten around to picking up a hotplate yet. However, since the Relay Board was needed to run the Plastruder MK5, I busted out my soldering kit and got to work putting together the Relay Board, LED strip, and Plastruder.

Assembling the Relay Board v1.0 was pretty straightforward. I didn’t have a problem following the assembly instructions on the wiki. Follow the directions and you’ll be fine.
Unfortunately, the assembly pictures for the LED Strip v1.1 were… non-existent. (Do not be alarmed – this story has a happy ending.) For those first-time readers – I’m a complete soldering/electronics newbie. If I don’t have detailed pictures and directions, I’m completely lost. The good news for you is – if I can assemble a MakerBot and get it working, you definitely can. ¹ In any case, with the kind help from JohnA and Theron Trowbridge I discovered the secret to soldering this kit up. I haven’t tested it out yet, so I’ll hold off on posting the pictures. Once I’ve confirmed that I didn’t totally roast this kit, I’ll put up the pictures and some directions on the wiki.
The Plastruder MK5 assembly instructions and usage/troubleshooting guide were great as well. Once I get my plastruder online, I’ll add some notes.
- When attaching the thumb wheels to the bolts, definitely use a vise. I tapped the bolts into the thumb wheels – and smashed the threads just enough to make the bolts useless. :/ If I did this again, I would definitely put the nut partway onto the bolt and tap the NUT rather than the bolt itself. This would keep the force away from the threads and probably keep them from being damaged.
- When threading the nuts onto the retainer mounting plate, I found it easier to put the nuts about halfway onto the bolts – rather than almost all the way to the plate. If you put them halfway on, it’s easier to tighten each bolt individually.
- The MK5 thermistor preparation instructions direct you to the MK4 directions for wrapping the thermistor. The MK4 directions suggest you essentially sandwich the thermistor leads in between two long pieces of Kapton tape. This is exactly how I built my MK4 plastruder – and it’s not exactly easy to trap these two thin leads in between pieces of thin sticky tape. An easier way, and what appears to have been done in the MK5 pictures, is to separate the thermistor leads and wrap the Kapton around the leads – making sure they never touch.
- I would test the thermistor’s resistance and temperature measurement before attaching it to the plastruder. If there’s something wrong with the thermistor, I would want to know long before I taped it to the plastruder, insulated it, and mounted everything inside the ‘bot. Both tests are quick and easy to do before you assemble everything – just check the resistance with your multimeter then plug the unattached thermistor leads into the extruder board. This quick sanity check could save you a lot of time and supplies by not having to undo a lot of work. This would be a good time to test resistance on the power resistors too.
- With all the wires running from the plastruder and relay board, it can get confusing. I picked up some heat shrink tubing the last time I was at an electronics store and am using them to color code each of the sets of wires – one small band at each end. This helps me keep everything straight. By just looking at the end of the wires and doing a sanity check against the bands on the motor, thermistor, or heating element I can quickly verify I’m wiring everything up correctly.
- After adding a colored band of heat shrink to each end of the sets of wires, I braid the wires together to keep them all in check.
- Stupid mistakes I made that you probably won’t make:
  - I can’t believe this – but I actually mounted the drive gear upside down. The result was I couldn’t hand feed the ABS filament – since the base of the gear was blocking the filament’s path. Another symptom was that no matter how much I crunched down on the filament with the thumbscrew,² the filament would extrude about 1cm or so, then nothing for 30 seconds, and this cycle would repeat. The last symptom was that when I pulled the filament out it had some nasty chew marks in it. These are not the sort of marks I would expect to see from this drive gear with its super small teeth. Flip the extruder motor and the problem magically went away.
  - I replaced one of my threaded rods – the one that was the most severely bent. However, after installing a new threaded rod and

Drafts Zero - The Lost Blog Posts

And probably do a better job of it too! [↩]
The only thumbscrew to survive my testosterone driven smashing. [↩]

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