Hi,
I've designed and built a chocolate extruder for my printer, and have hit on a small snag.
I'm not using a heater at all, instead just putting warmed chocolate inside an insulated syringe. This should be enough for testing, if not I'll build a heated chamber. The problem I've got relates to thermistors. I don't have one on the 2nd (chocolate) extruder, so the printer won't start as the thermistor is missing. To get around this I assigned the same thermistor pin as the 1st(PLA) extruder. I can now print PLA as normal. However, I can't print chocolate without changing the minimum temperature setting in firmware, which risks damaging the PLA extruder due to cold extrudes.
As far as I can tell, I can't see an M302 code in repetier, so I can't just add that in the start-gcode as I would for Marlin. That said, I have a couple of options:
1) Keep the low temperature setting in repetier, and risk accidental cold extrusions.
2) Put a (10k?) resistor on a spare input and assign that to the thermistor for extruder 2, faking the temperature to a level where cold extrude on PLA is not an issue.
Is that about it? I don't mind number 2 except the LCD readout will always look a little odd with 150degree chocolate!
Is an M302 code likely to appear in repetier, it would probably be the simplest route. Either that or a per-extruder setting to define the temperature envelope, including disabling it.
thoughts?
adavidm
