Thursday, May 22, 2014

And then there were two... almost

I've been printing with only one extruder for a while now, since the right thermocouple went out while I was fixing the left extruder. I got the replacement thermocouple a while ago but I've been putting off fixing it while I finished other projects. That was until the ceramic tape on the left extruder started going out.

Welp, no putting it off any longer. So I spent three evenings of free time making the following fixes:

  • Replacing the ceramic tape with a fiberglass tape donated by Andy Cohen of the 3D Printing Today Podcast (which I really should plug in it's own post)
  • Replacing the right heating block with a heating block purchased on eBay
  • Replacing the right feed tube with a PTFE lined feed tube donated by the ever awesome JetGuy
  • And of course replacing the thermocouples
The fiberglass tape was pleastly easy to apply. It had a sticky side so placement was easy. Then I wrapped it with my metal tape to hopefully minimize stickage.

However, the replacement heater block I bought on eBay was somehow tapered where the heater core went, smaller on one side than the other. Of course I didn't discover this until after the tape was already wrapped. Fortunately a 1/4" steel drill bit fixed that, mostly.

The new PTFE lined feed tube worked surprisingly well and I even managed to get it level with the existing nozzle on the first try. So... that's a first.

The new thermocouples had these big ends on them and needed to be bent to fit around the heater block and into the carriage. They're also a little shorter than the old ones, so I had to cut the umbilical I was feeding them through near the end before putting them into the board. Then I fired up the printer and watched the reported temps head towards zero as the y heated up. Apparently that's what happens if you put them in backwards. So I had to flip the machine over again and fix that and then they temps were accurate. There was a funny smell, but I suspect that's the new thermal tape or some junk caught somewhere. I've done a couple long prints and nothing burst into flames, so I think I'm in the clear.

Of course there was one problem. The left extruder's nozzle isn't tight and it's leaking plastic around the nozzle, so I've got to take the left one apart again, clean and fix that.

So that was an adventure, and hopefully I'm back in business, because I've got some 3DHubs and MakeXYZ jobs to finish.

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