Re: Plasma table - ramp speeds

> By the way I should mention that the numbers I used will give
> a VERY high performance machine. It can ramp from a dead stop to
> 240 ipm in 42 milliseconds. It can traverse a corner at full speed

with

> a 0.16 in radius. If you're gonna make one why not make it good?

Hi Les,

That then becomes a second question and that is how fast do you need
to go for a plasma table ?

I assume that on a pierce, one then ramps to the actual cut line and
during that ramp, the head gets to full speed for the cut.

But, for 90 degree turns, one axis would just stop and the other
should move quickly.

Just how critical that is becomes a question.

Another problem becomes the frame. Moving a 10,000 pound weight with
a ramp speed of 1 inch per hour would make the think rock steady, but
a 1 pound weight at 10 feet per ms would make things bend and twist.

Ergo, with higher speeds, one needs more re-inforcement leading to a
larger motor and more mass and....it just seems that at some point,
half the motor use is to move the heavier motor.

I think that there is a sweet spot on plasma. since the edge is
slightly tapered, it would be more pronounced on larger parts so
holding an accurate cutting speed is more important on thicker
parts. A square edge on thinner parts is less important.

Also, since a slower than desired table will cut a wider than desired
hole this seems to be more of a factor on thinner stuff.

Anyone have any ideas on the 'best' ramp speeds for the axes ?

Dave

Dave