Is torch height control really needed for a plasma table?

I certainly see the benefit of a THC, especially on a big table. That said, we use straightline cutting tracks quite often at work and it of course just has a manual height control. There isn;t a whole lot of piercing done, but it is done sometimes.

If a small tale is made, say 2" X 4" or so, and used for thinner materials, is there a need for the THC? Will consumables last significantly longer?

I am thinking about throwing together a small table, I already have access to a machine controller, currently on a small homemade router, running Mach3. It has quick disconnect cables so that we coudl plug it into a different machine in the future and configure for the different motors and dimensions.

I am thinking of a very simple machine with only manual Z height and steppers for X/Y, either a small gantry or a small cantilever machine, hooked to a yet to be purchased PP50 or similar.
John

I would think that if your machine is accurate, it would be ok but you might have issues with the following:
1. Thin material with enough cutting to cause warpage. (water table might help that)
2. Tip up, the torch might crash on rapids. (you could program dwells to enable you to lift out parts between cuts)
3. Non flat material would be an issue.
4. Pierce height problem. (maybe just mount a simple solenoid or door lock linear actuator, to move the torch between cutting and piercing heights)
There are plenty of tables with power Z but no THC, so that is known to work fine, but it sounds like you want no Z moves at all. I guess if you do all edge starts, a fixed torch could work, but I would at least go for the two position Z, and make those positions screw adjustable or something.

I think you could get a table to work fine without THC, but it would take time to figure out your cut heights. I would go with a touch and go style setup. Acoutjester has the right idea with a 3 axis cross drive setup. I'm not sure two motors on the X axis are necessary; unless you have a heavy gantry. You could easily do a three axis setup with the third axis being the Z.
http://www.youtube.com/watch?v=Otdkuluv334

The THC I am going to is suppose to work with every plasma cutter.
http://www.youtube.com/watch?v=560knsCBqNk

The THC I am going to is suppose to work with every plasma cutter.
http://www.youtube.com/watch?v=560knsCBqNk

Quote:

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Originally Posted by Rambozo

I would think that if your machine is accurate, it would be ok but you might have issues with the following:
1. Thin material with enough cutting to cause warpage. (water table might help that)
2. Tip up, the torch might crash on rapids. (you could program dwells to enable you to lift out parts between cuts)
3. Non flat material would be an issue.
4. Pierce height problem. (maybe just mount a simple solenoid or door lock linear actuator, to move the torch between cutting and piercing heights)
There are plenty of tables with power Z but no THC, so that is known to work fine, but it sounds like you want no Z moves at all. I guess if you do all edge starts, a fixed torch could work, but I would at least go for the two position Z, and make those positions screw adjustable or something.

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Thanks,
I am certainly not against going with a powered Z Axis, or a full THC. Just checking for input.

I was thinking something without a Z axis. The Torchmate Growth series is available as the base model with no Z movement.


http://www.youtube.com/watch?v=vcvWk263kKQ&feature=plcp

There's no reason why it would not work. On a small table like a 2x2 where you are most likely cutting one part at a time it would be fine. I have read where the torch has ran into parts that flipped up after cutting and cause some problems. You could also add a break away torch holder and not worry about it. I did notice the torchmate had a nob on the side of the torch mount. I'm guessing that would allow you to adjust the torch height. You have to have some way to adjust the torch height to compensate for material thickness.

I still think Torchmate is probably the best on the market, I looked into the growth series, but they are still pricey.

My, 2 cents. I just studied all the "turnkey" systems out there that are sold to civilians and came to the conclusion that they're just silly on the pricing for what you get. I too wanted THC and it could have been as much as a 3K option on units like the PlasmaCam. I encourage anyone that is considering building or engineering their own table and controls to visit PrecisionPlasma.com and look at the tables available and then visit CandCNC.com to see what available. I purchased systems from both (4x8 Patriot table) and (Bladerunner DragonCut 620-5) and coupled with a HT PowerMax 65 all in it cost me about 13K - plus I got the HD bridge gantry and plate marker too. The system is strong enough for carrying and working a router yet light enough to really move when needed for plasma, I'm very happy so far.

I can't really comment on whether THC is needed or not - I wanted it simply because of some of the concerns stated here and elsewhere. But, I can tell you, it adds a level of complication and concern that is not for the weak at heart. You can get in trouble in an instant when the torch plunges into your material, bends the sheet stock (it's that strong) and then drags everything around - you can't hit the E-stop fast enough. Ask me how I know. But . . . . when it's dialed in - it's beauty in motion.

All the best, Don