CncExtruder
Release status: Development
| Description | Simple CNC-compatible Extruder
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CNC Extruder Overview
This is a simple adaptation of a Wade-style extruder with a minimal control system and an exceptionally simple Arduino program that we put together here at Diamond Age Solutions. It is intended to hook into existing proprietary CNC systems by being turned on and off as the "Coolant" or "Pump" or suchlike, for which most CNC machines provide Gcodes. It does not do fancy acceleration as this would require too tight an integration with existing proprietary CNC machines. If you have an Open one, then the task is much simpler and you can reprogram it as a giant RepRap. If you cannot or do not want to change the code, use this hack.
HOWTO
A few things you need to know about this design:
It runs off 12V for the steppers and a convenient USB port for the 5V (which makes the blue light come on). You can fix that no doubt - plenty of stuff on http://arduino.cc about the Nano and that's where you'll find the full development kit. I have already sent you the code.
I have not fused it. Fusing and safety is your problem :)
When you apply 5V it will try to turn the extruder heater on. This causes the yellow light to come on. it is possible for the yellow light to come on and the heater not work, but one thing at a time,eh?
DO NOT EVER run the extruder until the yellow light is slowly blinking on and off. It is not currently very smart and you can seriously wreck the hot end while it's cold. Keep the control lines grounded.
For your first time, I strongly suggest connecting some kind of thermal probe to the extruder tip's body with as much contact as you can get. If the temperature continues to rise at the same rate 10 seconds after the yellow light goes out, you may have a fault and need to disconnect the 12V.
You can vary the temperature by changing the annotated analog sensor target value in the Arduino code. I aim for a nozzle temp of around 180C.
You will see attached a black wire with a little plug on marked "GND", the ground pin. Two other wires are marked "Go" and "R" which are floating input pins. If "Go" is raised to 5V, the extruder motor will move. To change the movement speed, either add more "step" sequences to the Arduino code that twiddles the stepPin or change the delay at the end of the main loop.If "R" is raised to 5V the extruder will run in reverse when "Go" is high. This is extremely useful for getting the filament out and for retracting before movement.
I suggest you design a simple interface to allow your CNC machine's coolant and spindle contacts, for example, to activate the "Go" and "R" lines. Typically CNC machines have additional Gcodes to turn these on and off and a simple find/replace text filter of a gcode control program will allow you to turn "Motor On" commands into "Go".
That's it. I said it was simple, right?
