Well, there’s your problem

I’ve been fiddling with settings on my MakerBot for the last week or so trying to improve print quality.  Skeinforge setting this, Skeinforge setting that.  Up, down, left, right, set it to pi, increase the print temperature, decrease the raft radius, adjust the feedrate speed.  Unfortunately, all I managed to do was decrease print quality.  Over the last two days I noticed the filament was coming out fairly slowly and today I noticed I kept stripping the filament.

Well, it’s because ABS oozed down the barrel threads and around the nut.  Yay.  Time to break out the blow torch, eh?

In disassembling (mostly) the extruder I found:

  1. Plastic down the threads of the barrel
  2. Plastic that had oozed onto the nut below the barrier
  3. Plastic still stuck inside the barrel itself
  4. A plastic plug inside the PTFE barrier and a slight bulge to the barrier

Plastic on the threads is not a huge deal, but not trial either – it mostly peeled off in spirals.  Plastic on the nut is not a big deal – I pulled that off with some needle nose pliers.  Plastic inside the barrel can be drilled out using my drill bit and rubber band trick.1

Plastic inside the PTFE barrier…  well, now, that’s a different animal.  I’ve succeeded once in rescuing my PTFE barrier from PLA oozing down the threads, but in that case there wasn’t a plastic plug inside the PTFE.  The problem with a plastic plug inside the barrel is that I can’t really drill it out.  If I try to drill it out from the top, I’ll probably still leave a bit of plastic where the barrier meets the barrel.  If I try to drill from up from the bottom, I stand a good chance of ruining the part where the PTFE meets the barrel – creating a small gap where plastic can get stuck.

Thus, I think I will drill out the barrel and slap in a new PTFE barrier.  Since I have this old (ruined?) one lying around, I have sliced off about a 2mm wafer to use as a washer on my next heater assembly. Using a small hacksaw blade did the trick – even if it left me with a relatively uneven slice.

While I’ve been putting off buying additional parts for my MakerBot, I think it’s time to invest in some new bits.  I’m liking the MakerGear modular thermistor kit ($5), MakerGear modular heater core ($15), MakerBot heated build platform ($42), MakerBot SMT Soldering Toolkit ($50), and a hotplate.2

  1. Think of it as a poor man’s precision vise. []
  2. Cue George Plimpton: “And a hotplate!” []

5 Responses to “Well, there’s your problem”

  1. Rick Pollack says:

    If you will be printing ABS – save yourself a lot of trouble and go with PEEK. When you print PLA then PTFE or a hybrid PEEK/PTFE is needed (at least until a better PLA solution is developed).


  2. MakerBlock says:

    Forgive my ignorance – why is PEEK preferable to PTFE when printing ABS? Why is PTFE better for PLA?

  3. Nate True says:

    PEEK is more rigid and won’t bow out and leak everywhere with ABS. It would be better for PLA except that PLA likes to stick to everything. So PTFE (being not sticky) is preferable for PLA. ABS is very slippery by comparison so PEEK is more than adequate for it.


  4. MakerBlock says:

    Nate – that’s some fantastic info! And deserving of it’s own blog post!

  5. […] still rockin’ my black ABS coil, so I’ll probably have to add a PEEK barrier to my MakerBot wish list.1 […]