Tuesday, December 11, 2012

Mk IV is printing

Today Mk IV got ready.

After making the parts

they were assembled.

It extrudes ABS very well.

For the first time I dared to bore a nozzle with a cheap 0.3 mm PCB drill on my drill press. The drill went through the brass without any difficulty.

The nozzle prints very well. Unfortunatly I broke my 1 mm center drill on Saturday, so I had to use and ordinary 3.5 mm drill for the inside of the nozzle.


  1. Can you try to replicate "prusa nozzle"? I think thin alum spacers (9-10 pcs) on steel tube will work good.
    http://www.flickr.com/photos/prusajr/7855243338/in/photostream/ or google "prusa nozzle"

    1. Soldering aluminium on a stainless steel tube would increase the thermal conductivity of the tube. This would contradict my intention to keep the transition zone (between glass transition and melting) short.

  2. Ok steel spacers can be used with thickness less than 1mm
    and gap about 2mm. Prusa uses 0.5mm wall thickness tube and small "spacers" and mystically does not require cooler.

    1. But if you solder them with silver the heat conductivity will be high in the vertical direction. Prusa's barrel can't be made without a lathe. And to bore a centric 3.5 mm hole along a 65 mm stainless steel tube actually doesn't sound like fun. ;)

      Personally I believe that a hotend with a cooler allows you to control the length of the transition zone much better than without.

  3. I plan not to solder spacers but use tight fit. So heat will do not go up through soldering. And yes do not make tube myself but buy a tube, solder one tip and drill a nozzle.
    BTW Measurements of allmetal hotend with cooler were made by french reprapper http://forum.allinbox.com/aspectgeek/AutresElectronique/3DPrint/termine-repstrap-imprimante-sujet_8600_3.htm