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Mach4 General Discussion / Re: Mach4 Post Processor for Plasma in Fusion 360 and a ESS motion - Cant Find One
« on: May 16, 2023, 05:34:43 PM »
Hi,
so what plasma machine do you have?.
There are three things that ALL plasmas have that are intended for machine use.
The first is an input to start the arc, it replicates the trigger on a handheld torch. The best solution is s set of isolated relay contacts with the relay
under control of Mach. Sounds like that's what you've got.
The second is ARC_OK. When a plasma arc first starts the tip is energised and the nozzle is earthed. The plasma current is usually limited to 20A
or so otherwise the nozzle will be wrecked. If the arc in in reach of the plate the arc will 'transfer' to the earthed plate, and the plasma machine will recognise this
and release the earth on the nozzle thereby preventing further excessive wear while the arc is now formed between the tip and the plate. Now the plasma current will ramp up
to whatever you have set the machine at. The 'transfer' and current ramp up signal that the machine is ready to cut and it will close a set of relay contacts (typically)
and that is the ARC_OK signal. Mach would use this to determine that the plasma has established an arc and that it has successfully transferred to the plate. It will now
assume the correct pierce height and the cutting will begin.
The ARC_OK signal is critical. If the m3() macro in Mach4Hobby Plasma screenset does not recieve an ARC_OK signal after a few seconds it will fault out.
I noted in a previous post that you start the plasma and wait for a fixed delay, two second or whatever. That might be how you'd do it manually but a machine plasma uses
the ARC_OK signal.
I worked for seven years for a company that sold and serviced welding equipment. I was an electronic repair tech, and used to repair plasmas and plasma tables.
Our premier brand was Hypertherm, but over the years I worked with Kaliburn, ESAB, Lincoln, Miller, Thermal Dynamics and who knows how many Chinese machines.
All of the good ones had an ARC_OK signal.
The last feature that is required for machine use is a arc voltage output. Hypertherm have a 50:1 voltage divider, while some of the other brands copied that same 50:1,
others were 20:1, 25: 1, 30:1 etc. This voltage is used by the THC module to monitor the arc voltage.
One other feature you'll need is a probe input. When you put a piece of plate in the machine the torch needs to descend and touch off the plate to know where the top surface is.
Without knowing that then your Pierce Height or Cut Height don't really mean much do they? And what happens if you take a 3mm plate out and put in a 12mm plate for the next part?
If you don't have some routine to tell where the new surface level is the machine will drive to '3mm off the plate being pierce height' only to find that is still below the surface
of the piece of 12mm plate you just put in. The traditional way to do this is to use a g31 probing move. The torch descends from some safe height until the nozzle touches the
plate and Mach detects that touch or probe event and stops. It latches the Z axis location so it knows where the surface of the plate is. Many plasmas have a connection on the plasma
machine which is hooked to the nozzle of the torch to facilitate this touch off. Its sometimes also called Ohmic probing.
Craig
so what plasma machine do you have?.
There are three things that ALL plasmas have that are intended for machine use.
The first is an input to start the arc, it replicates the trigger on a handheld torch. The best solution is s set of isolated relay contacts with the relay
under control of Mach. Sounds like that's what you've got.
The second is ARC_OK. When a plasma arc first starts the tip is energised and the nozzle is earthed. The plasma current is usually limited to 20A
or so otherwise the nozzle will be wrecked. If the arc in in reach of the plate the arc will 'transfer' to the earthed plate, and the plasma machine will recognise this
and release the earth on the nozzle thereby preventing further excessive wear while the arc is now formed between the tip and the plate. Now the plasma current will ramp up
to whatever you have set the machine at. The 'transfer' and current ramp up signal that the machine is ready to cut and it will close a set of relay contacts (typically)
and that is the ARC_OK signal. Mach would use this to determine that the plasma has established an arc and that it has successfully transferred to the plate. It will now
assume the correct pierce height and the cutting will begin.
The ARC_OK signal is critical. If the m3() macro in Mach4Hobby Plasma screenset does not recieve an ARC_OK signal after a few seconds it will fault out.
I noted in a previous post that you start the plasma and wait for a fixed delay, two second or whatever. That might be how you'd do it manually but a machine plasma uses
the ARC_OK signal.
I worked for seven years for a company that sold and serviced welding equipment. I was an electronic repair tech, and used to repair plasmas and plasma tables.
Our premier brand was Hypertherm, but over the years I worked with Kaliburn, ESAB, Lincoln, Miller, Thermal Dynamics and who knows how many Chinese machines.
All of the good ones had an ARC_OK signal.
The last feature that is required for machine use is a arc voltage output. Hypertherm have a 50:1 voltage divider, while some of the other brands copied that same 50:1,
others were 20:1, 25: 1, 30:1 etc. This voltage is used by the THC module to monitor the arc voltage.
One other feature you'll need is a probe input. When you put a piece of plate in the machine the torch needs to descend and touch off the plate to know where the top surface is.
Without knowing that then your Pierce Height or Cut Height don't really mean much do they? And what happens if you take a 3mm plate out and put in a 12mm plate for the next part?
If you don't have some routine to tell where the new surface level is the machine will drive to '3mm off the plate being pierce height' only to find that is still below the surface
of the piece of 12mm plate you just put in. The traditional way to do this is to use a g31 probing move. The torch descends from some safe height until the nozzle touches the
plate and Mach detects that touch or probe event and stops. It latches the Z axis location so it knows where the surface of the plate is. Many plasmas have a connection on the plasma
machine which is hooked to the nozzle of the torch to facilitate this touch off. Its sometimes also called Ohmic probing.
Craig