Wednesday, March 25, 2009
Since it's my first post to the RepRap builders blog, I thought I'd better make it a good one. I've been blogging my RepRap build at Renoir's Rants and I've just started experimenting with extruders.
Although my RepRap isn't quite there yet ( the ABS extruder isn't quite working), I have experimented by building a chocolate extruder from copper pipe fittings and a drill:
Drive for the auger is provided from a Tesco Value 3.6v rechargeable screwdriver. Currently, this is manually operated as I'm having a problem driving the motor using the PWM DC driver.
The heater took a while to heat up, but the entire apparatus reached target at 60 degrees C. Shoving a few chunks of chocolate in, it melted very quickly.
Extrusion worked much better than I expected: when the motor was off, there was a very slow drip of chocolate through the 0.6mm welding tip (approx 1 drip every 5 seconds).
With the motor on, I was able to extrude a steady stream at several mm/sec and drew some lines on the plate. With the motor in reverse, chocolate was actually sucked back up the nozzle!
Still to do :
- Drive the motor from the RepRap electronics DC motor driver board
- Design/build a mount (probably when I get my reprap working)
- Print a chocolate object!
You can do it with the PWM driver board if you gang two channels together and put a EMF kickback diode across the output.
You will then have a single rotation direction and vast difference between the load and no load speeds.
I replaced it with the standard BfB extruder motor/gearbox - which appears to have *plenty* of torque!
That motor already connects nicely to the electronics.
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