AVC and Oscillation

Hello tech experts,

I recently found stepper motors, controllers and PLC units extremely interesting by accident. Initially I am from a mechanical side of things and in the effort to expand and improve services I found that I have to combine electronics with mechanical.

The current challenge that I would LOVE to build but I am lacking the skill to do so...yet. The first project is Oscillation.

I have a stepper motor connected to a lead screw in a housing that clamps a welding torch. What I need now is a controller that will allow me to the following:

  • Allow me to set the oscillation distance (time/distance motor steps in one direction)
  • Dwell time (adjustable milliseconds before motor starts to step in the opposite direction)
  • Speed of motor

Once this is done I would like to build a AVC unit. (Arc Voltage Control). Basically what it does it measures the real time voltage and when the welding torch gets closer or further from to the substrate the voltage drops or increases, then the unit should lift or lower the torch to maintain voltage to the desired voltage.

This is also done via a lead screw stepper motor. Challenge yet again is the electronic side of things. I need a controller that will measure the voltage and tell the motor in which direction to step for how long to maintain the required voltage. I also need to set the required voltage.

Any ideas for a heavy amateur which would love to start building the things?


What I need now is a controller

First you need to know the specs of the stepper motor so that you can choose the proper driver. Is the stepper unipolar or bipolar? How many wires from the stepper? What is the rated coil current and voltage? A data sheet will have that information, if you can find one. Will you want microstepping?

Well that information I don't know as I literally don't have experience with stepper motors :confused:

I am hoping someone here could help me. I don't think micro stepping will be necessary. conventional 1.8 degree stepping should be as one can differ the lead screw thread pitch also and in this case higher speed will be more of an advantage than slower.


Are there part numbers on the steppers that we can use to try to find the required data?

The torch weight is around 2KG so my initial idea was to use DFR hybrid stepper motor 3.5KG as shown in the picture. I don't know if you would rather recommend a different motor? See picture attached of a unit I am trying to build. I don't know if one can get a stepper motor that will last much longer than 6000 hours?

Oscillation and AVC unit - https://www.google.co.za/search?q=tiptig+oscillation+and+avc&rlz=1C1VASI_enZA510ZA530&espv=2&biw=1821&bih=933&source=lnms&tbm=isch&sa=X&ved=0ahUKEwiIvs_K2KDSAhXkDMAKHUT0ANgQ_AUIBigB#imgrc=_NaG61H9L_oFOM:

DFR Hybrid stepper motor - http://www.communica.co.za/catalog/Details/P0965070680


DFR Stepper Specifications It comes with 4 pin JST connector which is compatible with ultimaker control board, the cable length is 50cm. Specifications Model No:42BYGH1861A-C Step Angle (degrees) :1.8 2 Phase Rated Voltage : 3.4V Current : 1.7A/PHASE Holding Torque : 3.5kg*cm (48.6 oz/in) Detent Torque: 180g*cm 5mm Diameter Drive Shaft Winding resistance: 2±10% O/PHASE Winding inductance: 2±20% mH/PHASE Max flux linkage: 1.8 Vs Maximum Detent Torque: 0.016 N.M Total inertia (kg.m.m): 3.5 Kg.m.m Total friction (kg.m/s): 4 Kg.m/s Step Angle Accuracy : ±5% (full step, no load) Temperature Rise: 80°C Max.(rated current,2 phase on) Ambient Temperature: -20°C~+50°C Isulation Class: B Life: 6000 hours Cable Length:50cm Weight: 270 gram Size:42x42x40mm