Originally Posted by
Beefy
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.