Sunday, 24 June 2012

Mendel 90 Extruder Nozzle

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I have mentioned previously that I've experienced some problems with the hot end of my Wade extruder. Some time ago it failed completely and I was unable to restore it. It has failed me with both black and white ABS. I decided to try making my own. As I was unable to print anything, nophead kindly printed me the ABS parts of his Mendel90 extruder. I still needed to make the actual hot end though. nophead had a proven design available so I used that. I bought some 16mm peek rod, hexagonal brass bar and PTFE rod from ebay. I started by drilling the 0.5mm extrusion hole in the brass. To do this I used a small centre drill to make an indentation in the face of the bar to ensure the drill stayed central. I then used a 0.5mm tungsten carbide drill in a small chuck to bore the hole:

The drilled the hole about 3mm deep and managed to do it without breaking the rather expensive drill bits, in this picture the 0.5mm hole is visible in the centre of the small depression made by the centre drill:
I then turned down a section of the brass bar to 6mm to allow me to put a thread on it:

Then I used an angled tool to turn the tip to a point:

Here it is in the vice:

The piece was then parted from the bar and reversed in the chuck to allow me to drill a 3.2mm hole almost to the tip for the filament, and to turn the other section down to 6mm. I then used a split M6 die held pushed against the piece by the tail stock chuck. This ensures that the die is held at 90 degrees to the piece:

I turned down the peek bar to 12mm, and drilled an 8mm hole to within 5mm of one end. I then put an 8mm PTFE liner drilled with a 3.2mm hole along its length inside. The peek and PTFE were then tapped M6 to allow the brass nozzle to be screwed into both the peek and PTFE. With the nozzle screwed into the peek and PTFE, it is held in place with a 3mm grub screw. Here it is fitted to the extruder body:

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