Powermax 45 intermittent arc loss

Hi Guys,

I'm running a powermax 45 on a custom built table using candcnc dthc2 electronics, mach3 software. I'm having an intermittent problem with loosing the arc sometimes whilst cutting. Here's what happens: I can be cutting some parts fine and then when cutting 1 part the torch will loose arc whilst still in motion, re-fire and complete the cut. This is obviously highly annoying as it messes up the part. I tend to find that the thicker the material or the longer the cut the more likely I am to experience this problem... I'm wondering if this is an air issue?? I'm just using a crappy inline moisture filter until I get my drier plumbed in. Is this likely to be the cause, or is there something else I should be looking for?

Thanks

I think I already responded to this question in a direct email...here was my response knowing that the cnc machine was using CandCNC equipment with Mach3 operating software:

A couple of things:

1. The air pressure setting on the front panel of the Powermax 45 should always be set at the optimum setting. This is the secondary (lower) cutting pressure for the torch…….it is different than the inlet pressure which is monitored by a pressure switch. By setting the pressure on the LED bars higher….you are shortening your consumable life rather dramatically!

The rear panel inlet pressure for a Powermax45 needs to be anywhere in the range of 85 to 125 psi….and this is with the air flowing at the torch with the front panel air pressure set correctly. I always suggest installing an air gauge right at the inlet (not upstream in your plumbing system….must be right at the rear)(see picture ). To make the air flow at the torch to set the front panel pressure and monitor the rear inlet pressure…turn the amperage knob fully counter clockwise.

If you have a gauge in place on the rear panel I would suggest monitoring it to see if your inlet pressure is dropping. If it gets to 85 psi or less during a cut….an internal pressure switch will shut off the DC power, extinguishing the arc. This is to protect the torch and consumables from catastrophic failure due to inadequate air flow. It is possible that your compressor may not be keeping up with the demand, and low air pressure may be shutting the system down. Measuring pressure closer to the compressor is not going to show the natural pressure drop through your air plumbing system.

So, if your Mach software is set up to refire the torch after the arc was lost, I suspect that the air pressure momentarily gets below 85 psi, the Powermax45 pressure switch shuts the unit down, the Mach notices loss of arc and releases the start then reactivates it. The plasma will not refire if the start input remains active, it will if the start signal opens then reactivates….so the Mach would have to play a role in this as well.

Hopefully this helps.

Best regards, Jim Colt

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Originally Posted by drumsticksplint

Hi Guys,

I'm running a powermax 45 on a custom built table using candcnc dthc2 electronics, mach3 software. I'm having an intermittent problem with loosing the arc sometimes whilst cutting. Here's what happens: I can be cutting some parts fine and then when cutting 1 part the torch will loose arc whilst still in motion, re-fire and complete the cut. This is obviously highly annoying as it messes up the part. I tend to find that the thicker the material or the longer the cut the more likely I am to experience this problem... I'm wondering if this is an air issue?? I'm just using a crappy inline moisture filter until I get my drier plumbed in. Is this likely to be the cause, or is there something else I should be looking for?

Thanks

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Hi Adam, did you ever get to the bottom of that fault? I still get it on the odd occasion.

This issue is covered in depth on the CandCNC Support Forum where there are hundreds of CandCNC users with Hypertherm machines.
TOMcaudle
www.CandCNC.com

Hi, Yes I did finally solve the problem and it turned out to be a PC issue. Once I changed over to a Dell Optiplex 745 the issue was resolved. I now run at 48khz kernel speed in mach with re reoccurrence of the original fault.

Just a word of advice.... make sure to backup the latest xml file for the screenset you use in mach. My hdd failed a few weeks ago and it caused me a world of pain going through the setup again!!!