Old torchmate table retrofit

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FlushingFabrication
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Old torchmate table retrofit

Post by FlushingFabrication »

I have an old torchmate table that I’m looking to retrofit with an centroid acorn and thc controller. I’m looking for some cheap stepper motor drivers that will work with the tables current steppers.

These are the specs for the current steppers
https://dl8tialdmhqzt.cloudfront.net/wp ... 4-2013.pdf

Any suggestions would be greatly appreciated.

Rich
weldguy
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Re: Old torchmate table retrofit

Post by weldguy »

Not real familiar with Torchmates setup but are you sure that the current stepper drivers won't work with the centroid controller? Might be worth contacting them to ask and if they are not compatible they will likely have a product for you to use that they are familiar with.
FlushingFabrication
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Re: Old torchmate table retrofit

Post by FlushingFabrication »

The current drivers are integrated into the control board. I’m just looking for a separated style driver. Amazon has a bunch of different ones, I was hoping someone here has had good success with a certain one and I’d try that.
adbuch
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Re: Old torchmate table retrofit

Post by adbuch »

Something like this should work fine for driving your 6 amp motors.

https://www.amazon.com/STEPPERONLINE-Di ... 194&sr=1-1

I converted one of my AvidCNC tables with Nema 34 motors from Mach4 to Centroid Acorn/CNC12 and used similar drivers.

David
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tcaudle
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Re: Old torchmate table retrofit

Post by tcaudle »

FlushingFabrication wrote: Wed Apr 02, 2025 11:38 am I have an old torchmate table that I’m looking to retrofit with an centroid acorn and thc controller. I’m looking for some cheap stepper motor drivers that will work with the tables current steppers.

These are the specs for the current steppers
https://dl8tialdmhqzt.cloudfront.net/wp ... 4-2013.pdf

Any suggestions would be greatly appreciated.

Rich
What are you going to do about a THC? If? you have the normal "Smart Motor" that is a servo type motor and specail controller , you cant simply swap out the servo and it's high speed RPM for a stepper . Then there is touch-off to deal with.......If its got 6A motors than its a later model after Lincoln took over. Motors are mounted vertically with 5:1 gearheads,
adbuch
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Re: Old torchmate table retrofit

Post by adbuch »

Tom - what are your specific recommendations for THC and material sensing for his conversion?
Thanks,
David
FlushingFabrication
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Re: Old torchmate table retrofit

Post by FlushingFabrication »

It has the smart motor currently with a blue screen avhc. My plan was to swap that with a closed loop stepper. I have the acorn thc setup to replace it. It does say Lincoln on the table. It has a belt reduction for the X. I’m not sure what the reduction is though
adbuch
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Re: Old torchmate table retrofit

Post by adbuch »

FlushingFabrication wrote: Wed Apr 02, 2025 9:11 pm It has the smart motor currently with a blue screen avhc. My plan was to swap that with a closed loop stepper. I have the acorn thc setup to replace it. It does say Lincoln on the table. It has a belt reduction for the X. I’m not sure what the reduction is though
This sounds like you are on the right track! Keep us posted as you make progress with your upgrade.

David

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tcaudle
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Re: Old torchmate table retrofit

Post by tcaudle »

Not that easy. The smart motor RPM is around 9000. Steppers top out at about 900 so the mechanics will have to change to get Z speeds you can use. The leadscrew on that torch lifter is a really fine thread count. To get vertical speeds you divide the RPM by the threads per inch (TPI) to get IPM.
Then you have the important touch off sensing issue: The Smart Motor, being a DC servo, has a predictable amps versus load linear value. So you can measure the motor current and sense the force its using and detect it hitting a solid object . By making that a low value during a touch off move it takes very little resistance to trip it. Steppers are not as simple. Each step is done at full current just at varying step lengths and while you can detect some changes in force from measuring current its not very linear and does not work well in the low range . You will need another method of touch off (either mechanical switch or Ohmic) . Then if it misses, something's going to break.
FlushingFabrication
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Re: Old torchmate table retrofit

Post by FlushingFabrication »

Thanks for the help. I’ll measure the lead screw to see what I need. The acorn thc uses an ohmic sensor. I’ve thought of using a clear path servo for the z if I need the rpm or just replace the lead screw with something more manageable.
tcaudle
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Re: Old torchmate table retrofit

Post by tcaudle »

Ohmic is good. By itself there are problems. WHEN it misses (and it will ) , you either need a backup , a limit or a breakaway torch holder
The finer the leadscew the more force it has and would take a lot to stall the motor. It will try to lift your gantry using the torch and you can imagine how that ends. You might consider replacing the whole lifter with a full Z made for plasma but you will have to machine an adapter plate to match the 4 hole bolt pattern of the old TM lifter to the new Z.

The Clearpath has stall detection and shutdown but if your controller has no feedback it wont stop its signals. You might want to download the Clearpath setup manual . You don't just plug it in and it runs. They also need a different power supply than what your steppers will use , They achieve full RPM at 72 VDC. On a servo volts = RPM so at half voltage you get 1/2 the max RPM of 330, so it still may need another leadscrew. They have an interesting boot up requirement. They take a few seconds to initialize and stabilize after you apply power
Having conventional steppers on XY and Clearpath on Z can get tricky .
FlushingFabrication
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Re: Old torchmate table retrofit

Post by FlushingFabrication »

It has a breakaway on it. I’m gonna measure the lead screw tomorrow.
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