Re: plasma accuracy

<snip>

> The challenge is to first ionize and "ignite" the air to make the
> 30,000 deg plasma flame and then *control* it so it doesn't cook

all

> of the surrounding components. Most torchs have specially designed
> swirl chambers to spin the air as it exits the tip. The torch

handle

> and it's design are what largely controls the quality of the cut.
>
> Hypertherm makes a "Fine cut" series of consumables for some of

their

> torch models that will hold .025 under perfect conditions, but .010
> is doubtful.

When talking accuracy, there is theoretical (my driller has a step of
1/26,000 of an inch, but I doubt if I really get 0.02") and then
there is real world.


Jim Colt, an engineer at Hypertherm has the fine cut, high
deffination in his shop. IIRC, a $35,000 machine, and he claims
"you could probably fine tune the process and get tolerances of .005"
with high definition"

and... "1/2" wide x 2" long slots with radiused ends on 1/4" carbon
steel plate could be cut with plus or minus approx .010" accuracy
with a high definition oxygen plasma on a precision cutting
machine. "

And, in reading the notes, I think Caudlet is saying overall and Jim
C. is saying plus or minus. That means to either half Caudlet's or
double Jim's numbers.

The question becomes one of cost. How precice can you afford to go ?

Dave