hello listmates,
the last few months i did some work on hot wax extrusion. i started out with a pressure system, based on the frostruder. this kind of worked but had problems with the even matrial flow and volumetric dosing.
so i switched to richraps excellent universal paste extruder. my hotend is a brass cylinder, in the middle a 0.3mm nozzle. above is a teflon cylinder, as an isolation, to prevent the wax sticks to melt upwards. i'll post pictures when i dissemble the extruder again. above that is a pipe which holds the wax sticks.
this works quite well, but has no retract possibility. the major problem i have right now is the i get frequently noozle blockage, consistently every 1-4 hours. i am using matt wax that is used in a matt wax gun ( [
www.riogrande.com] ) the matt gun has a much bigger nozzle, about 1mm i suppose. maybe the problem for the nozzle blockage is that the wax is not filtered fine enough.
another problematic thing about wax is that it is not forgiving to any mistakes in a layer. is there a small problem in one layer, this problem then continues through many layers upwards. this might be less problematic at higher speeds, at the moment i print at about 20mm/s.
wax has one major advantage over other printing materials. you can easily rework it, polish it, modell more details or more accurate details. so after rework by hand, you would have a really nice looking modell, which would not be possible with a 3d printer. so my aim is not to make perfect wax prints, i think that would be really too difficult and not possible with repraps, but to print a rougher base for hand modelling afterwards.
if anybody has any ideas to help youre more than welcome.
michael
