Support extruder reassembly

After discovering the semi-blockage in the support extruder, I carefully drilled it out with an appropriately sized drill bit and followed up with several pipe cleaners loaded with Mothers Mag & Aluminum Polish.

I then carefully cleaned the extruder tube, and pressed on the last spare inlet buffer I have (made from Vespel, again by John).

I carefully slid the heater coil back over the extruder (and tried to twist it as much as I could in order to keep it as tight as possible on the tube), re-attached the stud for the solenoid paddle, and re-attached the thermocouple probe.

Then I wrapped the woven fiberglass insulation back around the assembly.

The original foil was unusable, so I tried using plain old ‘heavy duty’ aluminum foil from the grocery store.  It wasn’t as thick, so I doubled it up and did my best to wrap it as tightly as I could (using pieces of 3M high-temperature flue tape to hold it all in place).

The next step was to re-insert the pins for the heater and thermocouple back into the circular connector (I had pulled the pins out in order to more easily re-attach the heater and thermocouple to the extruder tube).  Note that the correct insertion/removal tool is the Amphenol M81969/14-01 – it took me several orders from Mouser to finally figure out the right size.

I then used a few zip-ties to neaten up all the wires.

Everything got reassembled back into the housing.

Re-attach the motor drive blocks.

After putting the head back in the printer, I ran a few feet of support filament though the extruder to flush it out.  Things were looking good…  …until I attached the nozzle and tried running more filament through it.  Just as before I started the extruder teardown, it jammed, kinking the filament off to the side between the drive wheels and inlet buffer.  Seeing that the buffer was also now cracked, I said a few choice words and called it quits for the day.

Upon reflection, I figured that the extruder probably wasn’t the issue in the first place (assuming that I had done the rebuild correctly) and that the motor drive block or the nozzle was the culprit.  I removed the motor drive blocks and set the head in the machine so that I could power it up and try feeding the filament through by hand.  I was able to push the ABS filament through pretty easily, but the support filament I could barely budge.  So I removed the support nozzle and put the model nozzle on the support extruder.  Wonder of wonders, I was able to feed through the filament just as easily – the nozzle must be the problem!  I reinstalled the motor drive blocks and sure enough, the support drive was able to feed support filament through the support extruder and model nozzle with no jamming whatsoever.

I’ll try clearing out the support nozzle with a 0.011″ drill bit (even though I know I’ve done so once already), and I believe I have a spare T12 support nozzle floating around in case that doesn’t work.  At least I’ve finally found the core issue and I’ll hopefully have the machine fully functional in only a week or two.  [insert something about 'famous last words']

9 comments so far

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  1. Argggg! What a pain!!

    you know I had trouble with the extruder tips on mine when I first received the printer from you. They seemed to clog easily until I took them off and did a thorough clean job on them. I ended up using a torch to incinerate some of the junk inside.

    I can’t believe that the tip was the source of your trouble.

    • I can’t believe it either, but when switching tips leads to trouble-free extrusion, that’s a pretty clear indicator! Given how much trouble free operation the nozzles on my 1600 have given me, I’m surprised this seems to be such an issue (especially since you ran into problems as well).

    • As an addendum (upcoming blog post), I ran drills down both ends of the nozzle to clear out the inside as best I could (but didn’t do a full solvent cleaning). I was sure I got it cleaned out as well as I could, but when putting it back on, bam – jam city. I’ll give the torch trick a try, thanks!

  2. Should you not have one shoot me a line as I probably do. BTW, how much would you charge to do mine??? ;-)

    • LOL! In restrospect, while tearing down the head was incredibly daunting at first, it wasn’t that awful. I took lots and lots of pictures and documented the full connector pinout in case I had to start clipping wires. Fortunately, finding the correct pin insertion/extraction tool made things much easier, and I was gratified to see that on powering it up, the freshly rebuilt support extruder climbed in temperature a little faster than the model extruder, so I think I did reasonably well.

      So if you’d ever like me to take a crack at it, I’d be willing to give it a shot!

  3. Also, I guess Vespel is NOT a good inlet buffer material — It really did chip when I machined it. I’ve still got some of your Torlon, so perhaps I better start looking for it

    • Yeah, the one I installed was the chipped one you had sent. It wasn’t too bad, though, so I pressed it in (it was pretty tough to press in, though, so that probably didn’t do any favors in terms of the cracks that showed up later. Still, it seems to be holding up okay.

      I’ve got more Torlon left as well – if you decide to ever do another run of buffers let me know and I’ll send it all your way.

    • Hello John and Have Blue.
      I’ve a working fdm 3000 but I need to replace the inlet buffer. Can you sell it to me please?

      • Unfortunately, I haven’t heard from John in some time – I hope he’s okay!