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IndustryArena Forum > CNC Plasma, EDM / Waterjet Machines > Waterjet General Topics > Thermal Dynamics A80 Plasma Cutter Problems & Possible Solutions
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  1. #1
    Join Date
    Sep 2011
    Posts
    102

    Thermal Dynamics A80 Plasma Cutter Problems & Possible Solutions

    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.

  2. #2
    Join Date
    Sep 2011
    Posts
    102
    Update:

    In my last post I mentioned that we were having cut and arc quality issues whenever we would change out to a new electrode. This has been an ongoing problem. I recently discovered that cleaning up the flutes on the end of the electrode cures the problem. I mount each electrode in a lathe and gently file the top of the flutes and then I clean up each individual flute. This removes the burrs that are left behind from the manufacturing process. I have now successfully done this to about 5 electrodes and it works everytime. After about 1.5 years of problems with our TD A80 we finally have a system that works great.

    Is anyone else experiencing any of these issues?

  3. #3
    Join Date
    Jan 2012
    Posts
    114
    Talk about hitting a nail on the head, I have been having the same issue with my A80 also and have found that the tip is stuck to the starter cartridge as you mentioned,cause i have been having weak arc at start and wouldn't pierce the material. I will set up a tip in the lathe this weekend and see if that will resolve my issue. Me and a couple of other guys that run same type of plasma table have been having this issue and have been pulling our hair out trying to figure it out and maybe you have solved my problem. thanks for posting this.

  4. #4
    Join Date
    Sep 2011
    Posts
    102
    I'm glad I could help. I was beginning to believe that I was the only one with these problems. I completely understand your frustration. We were to the point of scraping our TD plasma cutter and buying a different brand. We are using our plasma cutter in production so between many hours of problem solving, down time, scrap parts and many wasted consumables this has been a costly piece of equipment.

  5. #5
    Join Date
    Jun 2008
    Posts
    562
    Quote Originally Posted by plasmamatt View Post
    Update:

    In my last post I mentioned that we were having cut and arc quality issues whenever we would change out to a new electrode. This has been an ongoing problem. I recently discovered that cleaning up the flutes on the end of the electrode cures the problem. I mount each electrode in a lathe and gently file the top of the flutes and then I clean up each individual flute. This removes the burrs that are left behind from the manufacturing process. I have now successfully done this to about 5 electrodes and it works everytime. After about 1.5 years of problems with our TD A80 we finally have a system that works great.

    Is anyone else experiencing any of these issues?
    I thought I would try cleaning up some not so old electrodes. I used my, what is called a "sanding mop", a fabric ball with 320 grit abrasive bound to it. I buffed up the electrodes removing the carbon and any burrs. Wow what a difference, the old electrodes cut better than the new. I'm going to give it a shot with some new ones when the next orders come in. The sanding mop removes "all" the burrs from machining. I wonder if these burrs aren't disruting the air flow, not allowing a efficient swirl to take place at the very end of the electrode

    Thanks
    Mike

  6. #6
    Join Date
    Sep 2011
    Posts
    102
    Hi Mike,

    That is great to hear. I'm glad that you found that this procedure works too. The only reason I noticed this was because I had an old bag of electrodes and a new bag. The newer electrodes are very rough compared to the old ones. As you mentioned, I think that the rough edges of the burrs are causing too much turbulence and affecting the arc quality. My guess is that the air needs to stay fairly laminar to across the electrode.

    Matt

  7. #7
    Join Date
    Dec 2008
    Posts
    19
    Do you think a wire wheel on the bench grinder will do the job? I see what you mean by the newer electrodes being so rough. Our old ones are much smoother along the flutes and look even better after using the wire wheel on them.
    Mike, we should have the CNC harness by Friday, and I hope George and I do some cutting with the THC next week.

  8. #8
    Join Date
    Jun 2008
    Posts
    562
    Quote Originally Posted by Orangejbird View Post
    Do you think a wire wheel on the bench grinder will do the job? I see what you mean by the newer electrodes being so rough. Our old ones are much smoother along the flutes and look even better after using the wire wheel on them.
    Mike, we should have the CNC harness by Friday, and I hope George and I do some cutting with the THC next week.
    It should work as long as you are gentle. Just enough pressure to smooth out the burrs. I think a little work with some steel wool might work also.
    Let me know how the THC works(or not).

    Mike

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