[toolbox911]

I have just finished building a 5'X5' 2 axis cnc plasma table and looking for a suitable plasma cutter. Cutting thickness will be 1/2" mild steel, any recommandation?
I have been told to avoid high frequency start type, but could it be ok with a good grounding (earth) and torch sheild?

[DanOSB]

are u going to use a machine torch or regular torch?

im interested in what other people are answering.. im planning on doing the same capacaity as u.. and anything thicker than that will use oxy/acent torch.. from what i heard oxy/acent will be more cleaner and accurate cut anything thicker than 1/2 and plasma will do better on less than 1/2 inch thickness

[toolbox911]

Cutting machine come standard with hand torch, machine torch sell separately and I think is different brand too.
The actual capacity is 32mm, so I guess it should be able to do 100% duty cycle for 1/2" plate.
But, what I am worry is the interference it might create, because the arc start method is not the contact start type like the Hypertherm.

Does anybody successfully uses the high frequency arc starting cutter?

ps: Oxy fuel torch will be use for thicker plate, too bad it won't work for stainless steel.

[DanOSB]

for machine torch they do sell it seperately.. or if u request it and u can get machine torch instead of hand torch.. im going to do bit research about those two.. duty cycles are different for those two i beleive.. so i probably will do machine torch if its lot difference for the duty cycle.. and consumables wear and long term costs.. i know the machine torch itself is about +600 more extra for cutting torch....

[toolbox911]

Surprisingly the machine torch doesn't cost much from my local supply. Moreover, it is easier to mount and locating the starting point. The hand torch thus keep as a back-up or occasionally manual cutting.

Bellow is a link to the article about grounding issue http://www.centricut.com/New_Lessons/lessons_14.html

Does the solutions suggested in the article necessary if using the Powermax cutter that has relatively low frequency arc start?

[Death Adder]

I use a HF start plasma cutter on our burn table. I don't remember the brand of plasma cutter though.

Anyways, we had AWEFUL trouble at first. We kept blowing out encoders left and right. We had to thoroughly make sure everything had a nice big connection to ground and had to basically build a faraday cage around the controller. Once we did that we were able to cut as much as we want w/ the plasma w/o problems. So, if you use a HF start type then do yourself a favor and make sure you've got everything grounded properly! Then double check.

Cutting machine come standard with hand torch, machine torch sell separately and I think is different brand too.
The actual capacity is 32mm, so I guess it should be able to do 100% duty cycle for 1/2" plate.
But, what I am worry is the interference it might create, because the arc start method is not the contact start type like the Hypertherm.

Does anybody successfully uses the high frequency arc starting cutter?

ps: Oxy fuel torch will be use for thicker plate, too bad it won't work for stainless steel.

[Rigid Racing]

I am using a hypertherm 1000 on my table and it seems to have a real hard time making good cuts on 1/2" mild steel. The kurf simply tapers off too much at the bottom to make anything usable at that thickness.

[DanOSB]

rigid racing u using machine torch or hand torch?

[Rigid Racing]

I am using the hand torch. I think it is a T60(?) torch if I remember correctly. If I had to do it all over I probably would have gone with the machine torch because it is much easier to align the head with the table.

[DanOSB]

ya.. thats one of main reason why im thinkin about having machine torch..

so those two torches will be sitting right next to each other

i already got the oxy/acent torch 180 degree head not machine oxy/acent torch but will use some cam for the valve for oxygen trigger.. simlar concept to http://www.cnconabudget.com/torch.html but my torch head is 180 degree so it will be straight up instead..

[freak_brain]

Rigid Racing,

I was thinking about buying that exact cutter. It is rated much higher (rating doesn't mean reality) than 1/2". Maybe you have something else going on that is causing the problem? That cutter is about 1,000 USD cheaper than say a miller with the same rating. We all know you get what you pay for but a grand in my pocket means alot. Your comment, eventhough I appreciate it, really changes things for me. I thought I knew what I was going to buy but now I'm not sure. How old is your cutter?

Maybe someone can help out here. Is this normal for a hypertherm 1000??

Thanks
Allen

[Rigid Racing]

Its about 5 months old. It may very well be ok for what you are doing. I was wanting to cut parts that had holes with a diameter less than half inch. That is what it seems to have a problem with. I found it better to cut out larger profiles and drill holes after. What sort of parts will you be doing?

[freak_brain]

I looked at my parts lists and realized that something like 70% is 1/4" or less, maybe 20% up to 1/2" and 10% or less over 1/2". I make a lot of parts that I guess could be best described as weldments, even though they aren't really. I make a ton of brackets, special gussets ect. for those weldments. I do have a lot of holes but I am thinking about adding a small spindle motor on my machine which I would use to pre-drill any holes smaller than 1/2". Not really sure that will work since my machine has an extruded aluminum crossrail (see picture if I loaded it correctly).

Anyhow, I appreciate any help and advice you could give.
Allen

[ViperTX]

Well you could use the Plasma to cut the holes and then follow up with a drill or reamer to square up the sides of the hole.

[freak_brain]

Rigid Racing,

I just talked to hypertherm's tech department...Great guys there. You can contact them at 800-643-9878. They say that there is no reason that your machine wouldn't cut those 1/2" holes for you. They did ask if you had a dwell, for about a second, after triggering the cutter. This gives the cutter time to fully pierce the material before moving the machine.


ViperTX

Great idea. One could do that, even use an endmill.


thanks
Allen

[DCparts]

Well you could use the Plasma to cut the holes and then follow up with a drill or reamer to square up the sides of the hole.

That's what I do, cut them .040" under size, then clean them up with a drill.

I use the Hypertherm HPR130, works real nice.

http://www.hypertherm.com/mech_systems/hpr130.htm

Cuts stainless perfect using F5/N2 gas, perfect clean edge.

The Miller Spectrum 1000 cuts nice for a smaller machine, machine torch is pretty cheap also.

[Rigid Racing]

Strange. Anyone have pictures of something 1/2" thick that they have cut 1/2" holes in? Mine will measure in at about .5" on the top side of the hole and the bottom measures in at about .3". I just assumed it was the kerf tapering off. Maybe mine is [censored] up. Seems everything I buy comes out of the box broken in some way! My air compressor came out of the box with a blown head gasket on one cylinder, my cnc controller fried after about 10 hours. Opened the crate on my welder and it had a big dent in the side pressing into a circuit board. Just assumed the plasma to be working, guess I should probably call them tomorrow.

[Rigid Racing]

I've been doing some searching.... and found this on torchmates website.
http://www.plasma-cutter.com/comparison.htm

It shows the taper I was talking about on small holes. The 3/8" plate picture on that site with the 1/2" hole looks just like some stuff i've cut. I think my machine is ok.

[Blindchicken]

I have a torchmate with a hypertherm 1100 and a Thermal Dynamics one-torch machine torch. I have never been happy with punching holes in anything thicker than 3/16. Between the blow through and the kerf, it needs to be re-drilled anyway and trying to re-drill a plasma-cut hole does not make for very good hole alignment. When it comes to holes in the thicker stuff I just set the machine to dimple at each hole location then punch them out.

-Mark

[miljnor]

The shop i used to work in had a hypertherm 1000 and it kerfed something fierce on the 3/8 - 1/2" range stuff. But like someone said earlier you get what you pay for.

and we had a similare problem with blowing encoders and the main drives all the time..(they still had not fixed it by the time I left)