Cross posted to rec.crafts.metalworking for Ernie etc

On Wed, 21 Jul 2004 12:34:19 GMT, I AM WHO I AM
wrote:


Has anyone used or heard anything about the Plasmacam machine. plasmacam.com
I am installing one in a machine shop in Ontario Canada.

I was called in when the owners could not get it running properly. I have a
recent computer background and a past mechanical background but no welding or
machine shop experience. The owner of the shop here ran a large CNC system
for Caterpillar until they took off for Mexico. The other guy is a real good
beer drinker.

The main problem right now is trying to get good clean cuts. Even though
their website does not list it and in fact suggests avoiding it, the phone
support person says the Thermaldynamic Cut Master 75 which we are using is
one of the most popular models in use and will do the job (this I find very
strange). We get slag build up on the bottom of the cuts and on top. I have
experimented with different currents on the plasma cutter and different air
pressures and different cut heights and different pierce heights and it's
still not great. Does anyone get nice clean cuts like their video shows?

I am working with 1/8 inch sheets of steel. I have done the setup of the
perice height adjustment (z shift) and the cut height (Arc voltage shift),
about 40 times. Every time it comes out slightly different every time. Next I
would like to do the X and Y location adjustment but the 1 inch square I cut
for it is just too rough to measure properly, to do this accurately. I am
just now thinking that maybe I should make it a 2 or 3 inch square and try
that?

Can someone give me some general ideas on Plasma cutting so I can try to get
this torch cutting properly?

Lets say for 1/8 steel,

What is generally the best pierce height above the sheet? I have tried .1 to
.4 and spots in between. The Plasmacam guy suggested twice the material
thickness, in this case .250.

What is the best cut height? Is it very close to the material say .02 above?

What current should I use. 40 amps and below does not seem to pierce the
material, but maybe I have to increase the pierce time?? Does too high a
current create the slag?

What about air pressure? I have tried from around 65 to 100 lbS with no
difference that I can see.

What is the best size of torch tip for 1/8 material?

Plasmacams support is not 24 hour like they say and it takes them 24 hours to
call back after you finally get a hold of someone (maybe that is what they
mean). Thermaldynamic is not interested in helping unles we buy a machine
torch instead of the hand held. Any help I can get here would be very much
appreciated. I will check back tonight.

Thanks Johnnie


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