Originally Posted by
joeavaerage
Hi,
Well there we part company. Its my experience that the true utility and usability of a plasma table is determined by the anti-dive features, assuming
that basic THC is functioning correctly.
When a plasma is cutting at the correct speed the effective arc length is slightly more than the torch height above the material surface. The arc is
'attached' to the material approximately 1/2 way through its thickness. What happens when the machine slows down as it approaches a corner?. The machine must decelerate
and therefore the arc will penetrate the material somewhat deeper with a consequent increase in arc voltage for which the THC tries to compensate by reducing the
torch height. As the machine slows its possible for the torch to 'dive' into the material. This will occur whenever the machine is traveling at less than optimum speed.
It also occurs if the path crosses an already cut path, at the crossing point the arc voltage will spike high because at that instant there is no material directly under the
torch and the THC unit will attempt to 'dive the torch' to compensate.
Both the customers that I was working with had high throughput demands and the anti-dive features really determined the ease of use. In both cases they used Mach4, the Hicon Integra
and the Proma, ostensibly because at that time the Hicon was the only Mach4 ready controller to support realtime THC. More recently the ESS and TMC unit have realtime THC support
and with even better anti-dive features.
Craig