Home made 3D printer extruder Hot End

When the first extruder of my Rapman 3.1 broke I tried to fix it, as it was beyond the repair point I went to the manufacturer website to buy a new one but, at 200€ a pop, was too expensive for the durability it had so I decided to make a new one myself.

I found most of the information I needed at the manufacturers website and started the buildup.

The main component was a brass M6 bolt to which I made two holes, not at the first try I must say. First hole was a 3mm one through the threaded part of the bolt and was made with a dill press with the depth calculated to almost reach the head of the bolt. The second hole was an 0.4 mm hole from where the plastic was going to exit.

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The washer was installed to keep everything in place

The chosen heating element was the nichrome kindly donated by an air heater, I used fire cement as an isolator and put a coat every column of turns, then waited for it to dry up. As a temperature sensor used a 100K NTC resistor, the website mentioned a 200K NTC resistor but it couldn’t find one, that meant that from that moment on, I had to compensate the temperature of the plastic that I selected for the prints as the resistor was going to give a different value than the expected by the electronics. NTC stands for negative temperature coefficient which means that as the temperature increases the resistance lowers.

For the first versión I bought a PEEK plastic bar that cost me a kidney (50€) and machined a 3mm hole through it and an M6 thread to hold the bolt. In later evolutions I found that PTFE (Teflon) is much cheaper and has a much lesser friction than the peek so I sticked with it. Both PEEK and PTFE are chosen for the very high temperature tolerance, ideal for this kind of application.

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The finished Hot End

As the finishing touch I always isolate the extruder with Teflon or Kapton tape to reduce the heat loss and the heating time.

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Original Hot End with the home made isolation

So if you find in the same situation as I did I hope you can learn from my experience, anyway nowadays the Hot End and extruders are much more easily available and are much cheaper.

Hope you enjoyed!!

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