[agelkom]

Hi.
Visit :: CNC4PC :: iNtRo for capacitive torch height controller.
It never touch the plate for IHS, it can be use with your voltage based THC also.
Air pressure fluctuation during the cut will cause the height to fluctuate.And this causr bevel cutting.

If the torch-height controller find its initial height by pushing against the plate, and if the plate is thin enough to be pushed down, then the retraction of the torch will not set the correct initial height. The torch will fail to clear the plate because the plate follows the torch back up to its initial height setting. Snuffing of the plasma gas leads to uncontrolled double-arcing in the plasma chamber, causing catastrophic failure of the electrode and nozzle.
It also affects large beve cutting.

regards
Argun

Hi Jim,

thanks very much for the response.

I'll have to spend some time eliminating each of the six possible causes you mentioned.

It's a Powermax 1250 hand torch being used on my cnc table (Candcnc with digital torch height control and mechanical touch off for initial height sensing).

The slanting cut is pointing in one direction all the time. The bottom of the cut is angled towards the top left corner of the table. To further clarify this, if the cut direction was towards the top left corner then the cut would be fairly straight but if the cut turned 90 degrees then you'd have the bottom of the cut angled towards the top left corner. It's as though the nozzle is not perpendicular to the table yet it looks very square to the table surface. It's not the typical issue of flare in the cut. Assume for this case the sides of the cut are parallel but sloping in the said direction. This particular cut was on 10 mm steel using brand new 60A nozzle and shield. The electrode had very little wear of the hafnium.

I'll have to go into this problem in more detail so I can gather as much information as possible. I'll go over everything you told me to check then I'll have a play with the torch, rotating the consumables inside, turning the torch around to see if the angle turns around with it. I'll remove the torch and do a manual cut to view the plasma jet and see if I can visually see it coming out of the torch at an angle. I'll also try different size consumeables (I think I may also have a new swirl ring).

The cut was a few holes done at 60% feed rate and THC turned off, then the THC turned back on and the feedrate done at the recommended speed for the rest of the cut. The slant was the same in both cases.

I do have an unrelated question Jim. Is it possible to reduce the period of the post air flow after the arc has extinguished. It's quite long, maybe 10 seconds and my torch is trying to touch off with air blasting out the nozzle. I have a counteract spring on my floating z-axis so it doesn't take much to lift it up (good for thinner metals which can push down on touch off) and I'd be surprised if 80 or 90 psi of air blast isn't stopping the torch tip from touching the metal (acting like a hovercraft if you know what I mean).

Cheers,

Keith.

[will_eng]

I understand the advantage of a THC but that is not my issue. I have set my torch height manually on a flat 1/2" plate and am only cutting in about a 1 square inch area. I'm confident my torch heights are good for pierce and cut. I have also tried to drain my air dryer and installed new consumables, and even the first cut turns out with a bevel in one direction like the torch is cutting on an angle. When I rotate the torch the bevel rotates with it. I am also minding the direction I am cutting with the part on the RH side of the tor,h
Here are some pictures of my setup for what its worth.
Thanks
Will