Wednesday, December 24, 2008
The photo shows one of the last prints from the machine. The object is straight off the table with no post finishing.
The machine is a Bits from Bytes Laser cut machine running one of their extruder's. I have done little to modify the machine, just make sure everything is straight and true. The extruder has two gear motors driving the spindle and a few detail changes to the hot end.
Control is PIC32 running a G-Code Text file straight from an SD card.
Temperature as measured on the nozzle 210DegC
The head is moved at 8mm/sec and this is matched to the filament extrusion rate.
Your extruder is almost certainly slipping on the filament or you have a blockage somewhere.
Once you have the drive slipping it does not take long to carve a chunk out of the filament, the debris then tends to fill the thread profile.
Several things could help with the slipping, tighten down the bearing onto the filament, sharpen the thread and maybe undercut the thread with a junior hack saw.
The best advice when you have rebuilt the extruder is to get it up to temperature before you start the motor and try to extrude. I have no experience with HDPE so I do not know at what temperature this will be.
8mm/sec extrusion rate is well within the capability of the standard extruder.
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