Thermal Dynamics A80 Plasma Cutter Problems & Possible Solutions

[plasmamatt]

I'm relatively new to plasma cutting but I have had to learn a great deal in a short period of time. We have a TD A80 that we are using on a Shopsabre 4896 table. I should also mention that we are running the TD recommended 2-stage filter. I found that right from the start my consumable life was horrible (regardless of tip part # and amp setting). I was doing well to get 100 peircing and about 10 mintes of run time. I found that the orfice in all of my tips would always errode off to one side. This causes a large increase in kerf and a horribly slanted cut. I had contacted tech support at TD a number of times and they were always easy to reach and talk to but they had no idea how to resolve my issues. It became obvious that we were either going to have to purchase a different brand of plasma cutter or come up with our own solution. Another issue that always annoyed me was the fact that molten beads of steel would always catch on the sheild cap. This happened even with anti-spatter spray. These beads would affect the touch off and intial piece height which would end up only compounding the problem of molten metal hitting the sheild cap. In the process of trying to resolve my consumable life issues I decided to try and run without the sheild cap. Because of how the ohmic clip attaches this wasn't an option. There has to be some kind of outer metal piece to touch off with. You can not touch off with the tip itself because it does not make contact with the ohmic clip. I decided to drill out the entire center of the sheild cap on a lathe. When I got done I basically had a thin ring that left the tip fully exposed and allowed the touch off system to work fine. After a couple tries I found that the modifed sheild cap ring works best if it is roughly .05-.06 lower than the tip itself (when you set your peirce and cut height this must be compensated for). I immediately found that the tip and electrode life tripled and in some cases was over 4 times greater. My best tip life has been 450 peircings and a couple hours of run time now. I also found that the tips would now wear evenly without erroding to one side. Another issue that was drastically reduced was the molten metal buildup on the sheild cap. My modified sheild cap ring has far less surface area for molten metal to catch on. I still have the occasional bead of metal stick to my new ring but it is greatly reduced and the bead will often times get blown off just before touching off for the next peirce. I do find that cleaning the tip and modified sheild cap ring is necessary every 100-150 peircings. If I get a chance I will take a picture of a modified sheild cap.

Another issue that I found was that the O.D. at the top of the tips will vary by a couple thousands. It is just enough that when you push the tip back into the spring loaded starter cartridge the tip can sometimes get caught. This will cause a poor arch with poor peircings and cutting speed. I resolved this by mounting the tip in a lathe and slighly filing the outside O.D. where it makes contact with the starter cartridge. If you ever take your torch apart and the tip does not come out freely with the sheild cup than this might be the problem.

Another issue that TD told me about is that the amp dial on a TD plasma cutter can be off by as much as 10-20%. I have now started setting my dial slighly above the amp rating that I want to cut at. I have found that this helps quite a bit.

My most recent issue is that I think I have a batch of bad electrodes. On some of my new electrodes I have to run at half speed for a period of time until the electrode is worn back slighly and then I can run at full speed. During this time the torch takes on a different sound and even though it is cutting at half speed it doesn't sound normal. By accident I found that when I have an electrode like this I can just run the torch for about 30 seconds in open air and then it will work find.

I think TD is having some problems with quality control on their consumables. At least these are the issues that we have come across within the last couple months. I doubt we are the only ones experiencing these problems. Hopefully our findings will help others out.