Installing a welder with a relay switch instead of an extruder

Hello, I was wondering how can I implement a welder instead of an extruder for my system. I have already created and configured a wire feeder since this is a TIG welder. I am just having trouble connecting the welder to the ramps and being able to configure it to act like the heat source for my system.


  • Can you explain how this gets used? I mean that is nothing you switch on/off 20 times per second I guess and does it have a thermistor for feedback? As I see I have no idea how that should work so can not say what to do in firmware.
  • The welder is connected to a relay switch which could connect to the ramps but I'm unsure on where to connect it and how to configure it. Should I connect it to a 2nd extruder port and fake thermistor sensor?
  • The question is more how do you need to control it in gcode. A second extruder would not be used by slicers just to enable something. If you need a simple switch you can do so with M42 for any output pin. If you need to control temperature it gets unclear. Since I guess you use E for extrusion just set thermistor to fake thermistor. Enable cold extrusions with M302 S1 and just extrude when it is enabled.
  • edited May 25
    The goal is to just have an on/off effect for the welder during every layer; somewhat like a laser not including temperature.
  • that will not work, you need a little delay after ignition in order to melt the material before adding more with
    your extruder(wire feeder).
    think it might work adding something like laser warmup function and as repetier said use fake thermistor and enable cold extrusion.
    isn´t there a need to control welding current depending on amount of wire feeded?
    (just know about handheld tig welding controlling current with footpedal)
  • As of now, we would like to somehow develop a code where we can turn the welder torch on and off using a relay switch every time the system feeds wire. After that, we would figure out how and where to insert that code in repetier, most likely in the extruder code. The other solution is to connect the relay switch right on the extruder port where the wire feeder motor is connected so that every time the motor moves, it triggers the relay switch to turn on/off the torch. 
  • You might want to look at how Repeteir handles laser controls. It will send a high signal through a declared pin whenever it sees a G1 move. It also has a laser warmup time that tells the machine to wait for the laser to heat up before moving. You could connect the declared pin to the relay controlling the feed wire, and set warmup time to whatever you need to melt the material.
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