Filament Joiner

So as some of you that frequent IRC may know, I’ve been trying to make a filament joiner to facilitate Single-Extruder Multi-Colour prints. SEMC is the future.

I grabbed some aluminium lumps from my friendly neighborhood vendor and got to work.

I don’t have much by way of machine-shop tools, so I carved this thing up using my table saw. Seemed to go okay, but it’s a shit saw so it’s hard to get everything actually square.

Here’s the block in it’s final form. There’s a 6mm hole through it one way to take the heater cartridge, and another 6.5mm hole the other way to take the PTFE lining. Finally there are two small threaded holes to take a grub screw to hold the heater in place and a little bolt to hold the thermistor in place.

Here it is all assembled…

And with some filament in it…

As it’s basically a hot-end I just used the same connectors as my standard hot-end assembly, which means I can simply connect it to my 3D printer and control it as if it were a hot end! No other electronics required.

Ideally I’d like to have a split and hinged block to make it easier to remove from the joined filament, but that was adding all sorts of complications with hinges and cooling.

The first test with scraps worked wonderfully. The recipe seems to be:

  1. Measure and insert filament into the tube so they meet in the middle
  2. Set heat to 150˚C
  3. As soon as it reaches temperature, turn it off again
  4. Wait to cool under about 50˚C
  5. Remove and enjoy

Huge props to the IRC massiv today, I think it was @gingebot that suggested using PTFE, but good input from all.

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v2 needs some active cooling. That block takes an age to cool down. For the test print I popped out the electrics and ran the thing under a tap :slight_smile:

At least you can rest your tea on the block while it cools to keep it warm :wink:

Just found the image of the joined filament. Next test is how accurate I can measure the join.

The little indent near the join is from where I tried to remove the filament before it was solid, so I jammed it back in and waited for it to cool. I fully expect a proper join to be very neat.

This is looking very useful, for not a lot of construction effort !