[agrifabs]

Hi all, I have just purchased a boc sparrowhawk profile cutter what is running a gas cutter and plasma, it has a Stewart Warner magic eye, the magic eye has a problem on one of the PCB`. Does anyone know how I would go about converting this profile cutter to cnc? Any help would be much appreciated, thanks Chris

[agrifabs]

Has Anyone Got Any Thoughts On The Above?!

[Torchhead]

Has Anyone Got Any Thoughts On The Above?!

Yes. Don't do it. The eye tracer is 20 year old technology and will cost you a lot of money and time to try and make it into a decent plasma cutter. You can build a CNC Plasma and oxy fuel cutter from scratch for less than it is going to cost yoo to retro the old eye tracer.

[agrifabs]

thanks torchhead, i kind of gatheres that it would cost alot of money, would i be able to do away with the tracer head and the drive motors and replace them with a cnc kit like this off ebay?
Digital 3 Axis Driver kit - 3Nm Stepper motor driver kit for CNC | eBay

therefore i would be using my own bed rails etc,

thanks for getting back to me
regards

chris

[LeeWay]

Any chance you can snap a picture or three of this machine? Just curious about it.
I don't know if that particular kit would be ideal. Most plasma cutters use 4 motors. Two slaved on the long axis.

I have read good things about those Leadshine digital drives though.

[Torchhead]

Those arr 420 oz-in motors. Would they work and move the machine around.....probably. Would you be able o cut with oxy fuel....probably. Would it give you the acceleration you would need for plasma cutting on thinner material....probably not.

It's all about Physics. The motor torque gets converted to linear torque through the final drive train. The three factors that control acceleration are:

MASS of the gantry (expressed in MASS units from the weight under earths gravity)
Ft-lbs or NM o force the drive train can exert on the load
EFFICIENCY (frictional and mechanical losses in the system)

It may be a bit like turning a dump truck into a Sports car.

Then there are issues like THC for plasma.

Dirty Little Secret #3: Plasma cutting i(correctly) is more difficult than most other types of 2D or 2.5D cutting.

The first thing you have to do is cut off half of the gantry (with the eye tracer) to try an lighten the load. The final drive train needs some engineering because what you have now probably has smaller servo motors and high ratio gearheads on the motors.

In the end about all you will be left with from the original is half of the frame and part of the gantry and maybe the rack unless it is friction drive.


If have a lot of spare time on your hands and need a "Learning" project than doing a retro fit would be a challenging project. If you goal is to try and get it running to make money cutting than perhaps not.