Originally Posted by engrbhadz  Mr. Mike, our torchmate cnc does not automatically adjust the height whenever it touches the plate, is there a sensor that can do the adjusting? |
Do you have an Automatic Height Control already, or are you running a manual torch setup?
Originally Posted by jimcolt Mike,
As a long time veteran with Hypertherm....we take exception to your statement below regarding that AVHC (automatic torch height control) is not needed in some plasma cutting applications.
In order to get acceptable life and good cut quality...today's plasma torches require that torch to work distance is controlled to within plus or minus .020" of the recomended standoff height from the plate during the cut. (With our industrial class high definition systems, height must be controlled to within plus or minus .004") In many cases...the recomended standoff is .060" to .080" off the plate while cutting. There really are not any large plates of steel....that will stay flat within .020" over their entire area, and further, as the cutting bed slats get used..the variation in torch to work distance can vary quite dramatically over the perimeter of a plate. Add normal heat induced warpage caused by plate stress to the equation....and expect height variations that must be corrected on all plasma cut plates.....without this correction you can surely expect collisions with the plate which will damage consumables and torch as well as situations where the torch is too far from the plate...which will cause extreme cut edge bevels and dross.
As important as accurate control of height whicle cutting....is the need to sense the surface of the plate before every cut , then retract to the manufacturers recomended pierce height. This function is called IHS (initial height sensing). One pierce too close to the plate will destroy the nozzle and shield on a plasma torch.
Torch height control should be installed on every plasma cutting application for acceptable ct angularity and for the best consumable life....as well as for better productivity. With a good THC you can push the start button and walk away from the cutting machine....without it, you need to stay at the machine and tweak the torch height every few seconds!
Jim Colt Hypertherm
Originally Posted by Mike@Torchmate
This is an option on our tables, and if the material remains flat (say a heavier gauge plate) then an AVHC is not needed.
-Mike
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Jim,
I do agree to your points that you will experience a better cut, with longer consumable life, and you won't have to watch the machine as much when you have an AVHC unit. I know several customers running very well on non AVHC machines. It does take more work to watch for tip ups, and adjust the height if the material height changes, and you probably will get less consumable life from this process and less production (time).
With that being said, the machine does function without an AVHC unit, and on thicker materials the height does vary less then with a lighter gauge material that will warp easier. We do sell most of our machines with AVHC units, but not everyone can afford to buy one up front, or have the knowledge to build one themselves. If someone is not satisfied with the machine without an AVHC, it can always be added later. I have never heard a customer complain about not having one, because they realize it is not the 2 axis machines fault, nor the plasma cutters fault that their consumable life may not be that great, or that they have to watch the machine closely.
-Mike