In this episode, Jim Colt, an industry veteran from Hypertherm, talks about how to cut the best holes with an Air Plasma. Visit [ Ссылка ] for more information on all of our plasma cutting tables.
Lower your material handling costs by cutting holes with plasma. Height, speed, and amperage automatically set with the MaverickCNC CAD/CAM/CNC software ensuring the best plasma cut holes on a light industrial CNC table.
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Video Transcript:
Hi, Jim Colt here with MaverickCNC, what I want to spend a couple of minutes on is hole cutting. Interestingly I was talking with an end-user that has another brand machine, another brand plasma that was purchased from a different location and they were in here looking at the hole quality that we’re getting on this MaverickCNC machine with the Hypertherm and they said “it’s not the same kind of hole quality I’m getting back in my plant with my machine and they actually showed some pictures to us and the holes were relatively round on the top, not perfectly round and on the bottom when you looked at the backside they weren’t round at all.
They didn’t resemble a round hole in any way shape or form. So let’s just talk about the fundamental ways that you can cut round holes. Plasmas a very high powered process that basically melts metal. The machine guides the torch around to get the correct shape of the metal. But also very critical is the electronic control, the height control specifically that controls the torch to work distance or cut height THC (torch height control) we call it.
A very critical function when your cutting a hole is, obviously to have a machine that moves very accurately with no vibration, no motion, or anything like that because that can actually throw the plasma arc off a little bit. It’s important to get good holes by starting in the dead center of the hole. We have to pierce this material and that’s one of the toughest parts of plasma cutting. To pierce through the material and then the torch height control has to move the torch down to the correct cut height to give the best quality and then it moves in on a lead-in in the scrap material and then starts the actual cut, the shape of the hole. In order to cut the best holes, the CNC control has to recognize – has to know the thickness of the material and it will automatically reduce the speed for all holes under a certain size by about 60% as compared to the speed we would run on the contour of the part. That’s critical because it causes the arc to, instead a little bit of lag in the arc, it causes the arc to be a little bit straighter, cuts the holes very round and then at the end of the cut it’s very critical to have the proper kind of end of the cut.
You can’t just shut the arc off, you can’t just go back into the scrap material in the middle. What you basically have to do is a little bit of an overburn, so you actually cut past where the lead-in, the kerf of the cut was, staying at the cut height and it kind of cleans off the end of the cut so that there’s no starting point that’s really noticeable on the front of the cut and the bottom of the cut is round. It doesn’t allow the arc to wobble on the bottom of the cut. So getting good holes is a good combination of the accuracy of the machine, the quality of the plasma torch, the condition of the consumables, the drawing that was done by the operator of the machine to make that hole. If you didn’t draw a round hole, you are not going to get a round hole and also the torch height control system. Those functions all have to work accurately to get good repeatable hole quality.
