CNC Plasma build

[MattH]

Right, started digging into this bevel issue. Up to now i've only been cutting 2mm so it's been hard to tell.

I cut another 6mm coupon and broke out my Starrett protractor:



First two sides are bang on right angles, the next two are somewhere between 6.5-7 degs bevel.

So it looks like it might be a torch alignment issue. I will keep digging.

 

[MattH]

Struggling to wrap my head around this.
Checked torch for alignment which is fine.
Slowed feed right down still the same.
Tried direct earthing of the stock, still the same.
Tried different consumables (Thermacut rather than HT), still the same.

I've seen mention by Jim Holt (HT guy) that the Oring on the torch can cause these issues but I don't have a spare to test with.

 

[chrisg3103]

Is this maybe something to do with swirl direction? Try cutting counter clockwise and see if it changes?

 

[MattH]

Is this maybe something to do with swirl direction? Try cutting counter clockwise and see if it changes?

No, the correct direction for the consumables is clockwise on an outside cut (best angle on right of cut in relation to direction of travel).

I had actually tried it because sheetcam was setup to cut CCW until I changed it.

 

[mtt.tr]

Struggling to wrap my head around this.
Checked torch for alignment which is fine.
Slowed feed right down still the same.
Tried direct earthing of the stock, still the same.
Tried different consumables (Thermacut rather than HT), still the same.

I've seen mention by Jim Holt (HT guy) that the Oring on the torch can cause these issues but I don't have a spare to test with.

is it being pulled out of alignment or pivoting when the direction changes

 

[MattH]

I just rotated the torch by 90degs in the holder.
The results are:

Before: 0,0,6.5,7
After: 3,0,6,4

Seems like it's possibly something with the torch.
I'm going to loosen the torch lead which is cable tied to a number of things at the moment and retry.

 

[Shox Dr]

Is this maybe something to do with swirl direction? Try cutting counter clockwise and see if it changes?

No, the correct direction for the consumables is clockwise on an outside cut (best angle on right of cut in relation to direction of travel).

I had actually tried it because sheetcam was setup to cut CCW until I changed it.

Is the rotation always the same direction? (You know where Im going with this. seriously though)

 

[MattH]

I unclipped the torch lead and loosen the torch clamp to allow to torch to find it's neutral rotation which was about 45degs from where it was.
This has again changed the bevels:

Before: 0, 0, 6.5, 7
After: 3, 0, 6, 4
Now: 4.5, 1, 3.5, 4.5

Seems any twist in the lead is being seen at the arc.

 

[MattH]

Is the rotation always the same direction? (You know where Im going with this. seriously though)

Not following.

Is the direction of cut always the same? Yes, it's now always CW.
The swirl ring only fits one way so the best cut is always CW outside ccw inside.

 

[Shox Dr]

Not following.

Is the direction of cut always the same? Yes, it's now always CW.
The swirl ring only fits one way so the best cut is always CW outside ccw inside.

sorry I thought you were referring to the plasma arc having a Swirl, a bit like water swirls down the plughole. That favoured one direction of cut

 

[MattH]

Is it a genuine Hypertherm machine torch?

yes it is. I tested with genuine HT consumables and with Thermacut consumables with the same results.

 

[MattH]

I found a thread on another forum where someone had been having the same issue. After exhausting all options someone from HT told them to check the torch O ring which he replaced and this fixed the issue.

I’ve checked the O ring which seems ok but is completely dry. I have ordered some silicone grease.

 

[Hood]

Lots of things can cause the bevel but it does seem to be torch related in your case. It could well be the 'O' Ring as I had similar with my Trafimet torch a while back. The 'O' Ring on mine however was visibly damaged so was easily seen.

 

[ukracer]

I found a thread on another forum where someone had been having the same issue. After exhausting all options someone from HT told them to check the torch O ring which he replaced and this fixed the issue.

I’ve checked the O ring which seems ok but is completely dry. I have ordered some silicone grease.

@MattH speak to @doubleboost as his sponsor sells tables and machines.
He might have O rings and or advice.

 

[MattH]

@MattH speak to @doubleboost as his sponsor sells tables and machines.
He might have O rings and or advice.

John’s stuff is all RTech.

I’m running a Hypertherm which is American made and all proprietary.

I have an O ring kit so I’ll try to match one up but I’ll also lube the one that’s in there.

https://www.plasmaspider.com/viewtopic.php?f=4&t=22068

This thread has 3 pages of various people fixing the exact same issue with an O ring so fingers crossed.

 

[Hood]

These people do most 'O' Ring sizes and are very quick on delivery.
https://www.ebay.co.uk/itm/36293226...il=sys&xt=Ctrl_EmailConfirmation_FooterUpdate

 

[ukracer]

John’s stuff is all RTech.

I’m running a Hypertherm which is American made and all proprietary.

I have an O ring kit so I’ll try to match one up but I’ll also lube the one that’s in there.

https://www.plasmaspider.com/viewtopic.php?f=4&t=22068

This thread has 3 pages of various people fixing the exact same issue with an O ring so fingers crossed.

I thought Robert moved away from R-tech and added options. 1 of which was hyper therm.
But I just checked his website and its almost all R-tech machines now.
I could swear I saw hypertherm and swiftcut on there a while back.

 

[Hood]

I thought Robert moved away from R-tech and added options. 1 of which was hyper therm.
But I just checked his website and its almost all R-tech machines now.
I could swear I saw hypertherm and swiftcut on there a while back.

I think he does supply Hypertherm if the customer asks for it.