Cutting holes in pipe

[grindergary]

I am looking at a job of cutting a lot of holes into a 3 inch pipe with a wall thickness of 3/16 thick. The holes will be about 13/16 in diameter and in a straight line down the side of the pipe. I can draw the holes on a line and run thru sheetcam and create the G code. I am just curious if anyone has ever done this. The holes do not have to be perfect but close as they need to be cleaned out for welding on fittings. I have to opportunity to get a lot of this work if it does work.

I have a hypertherm 85 with CandCNC Bladerunner with THC. Any suggestions are appreciated.

Thanks

Gary

I also posted on CNCZone.com

[Largemouthlou]

I believe the only way to do this is with a fifth axis and rotary chuck

[jimcolt]

Should be easy to do. You will likely have to modify the cutting bed on your table a bit to get the pipe down low enough....and spend some setup time getting the first piece right...then build a jig or some stops so that each piece always cuts the same. Your torch height control will compensate adequately to cut very nice holes....I have done this type of job a few times on my machines.

Jim Colt Hypertherm

I am looking at a job of cutting a lot of holes into a 3 inch pipe with a wall thickness of 3/16 thick. The holes will be about 13/16 in diameter and in a straight line down the side of the pipe. I can draw the holes on a line and run thru sheetcam and create the G code. I am just curious if anyone has ever done this. The holes do not have to be perfect but close as they need to be cleaned out for welding on fittings. I have to opportunity to get a lot of this work if it does work.

I have a hypertherm 85 with CandCNC Bladerunner with THC. Any suggestions are appreciated.

Thanks

Gary

I also posted on CNCZone.com

[grindergary]

Thanks Jim,
I am going to try a set up this weekend. Seems like a good way to do these.

Would you suggest 45 amp at or should I use fine cut if I still have some.

Thanks

Gary

[muzza]

As Jim says, should be fine it's only 5/16 so the extra thickness at the outside edges of the circle due to tangent angle of the cut shouldn't be a problem, you may have to bump the amperage a little or work on 3/8" settings to compensate this.

Lou, a fifth axis doesn't really help in this situation as the rotating axis ensures the torch always cuts at right angle to the surface so the angularity of the cut at the outsides of the circle would prevent the other pieces fitting through the hole.

Murray

[Largemouthlou]

Murry, thank you for setting me straight,, After rereading the size of the pipe and the hole size I can see how this can be done by using the altered table method like Jim suggested...
may have to try it one day

[grindergary]

Well, I tried to cut these holes in the pipe and everything went fairly well. I was set up with 45 A tips so I gave it a try. All the holes cut beautifully except the last one which happens to be larger.The hole is 1.125 diameter and it did not cut out properly. Seems the THC dropped the tip into the pipe on the cut. Seeing as it was a temporary set up to see if it would work I am very pleased. On the next run I am just going to shut off the THC and see if that helps only on the last hole. I am still learning but having fun. I will post pictures as soon as I can get them off my phone.

Thanks for all the help

Gary

[grindergary]

Ross' cut holes and slots all the time with our machine. Sounds like you have a handle on it now. Having fun while you learn is what it is all about......especially on scrap metal

Yes your right about the fun part. I got the job and have also got more work from them for more of the same style just longer with more holes.
I just shut off the THC on the larger holes and they turn out really well.

Thanks for all the responses!!

Gary

[grindergary]

Great News. Every CNC Plasma Cutting System has a slightly different flavor. We don't turn off our THC to cut
any size hole.

Well after fine tuning the settings, I found that I could cut larger holes with THC on. Works awesome!

Thanks for the encouragement to try again.
Gary