Tweco SC-3000 - Manual (Page 52)

SC-3000
OPERATION 4-12 Manual 0-5100
7. End of Cut
a. The SC3000 requires 3 things happen to recognize the cut has ended.
• Start signal (Initial Position Start) from the CNC is removed.
• Cutting arc has ended (Ok to Move at Ready input is removed).
• Plasma Power supply output voltage reduces to a % of the normal cutting voltage set by
the End of Cut parameter (default 85%).
8. Retract
a. Following the end of cut the torch retracts to clear tipped up parts while moving to the next
cut position. The retract distance is set by the Retract Position parameter.
4.07 LOSS OF PLASMA ARC
It is possible that the plasma arc is lost during cutting process
The Linear Drive moves back up to the reference position as arc voltage is missing and the clearance
control cannot operate anymore.
4.08 DETECTION OF KERFS AND EDGES DURING CUTTING
This feature avoids that the plasma torch moves down into the kerf which has already been cut whilst
moving across.
If the adjustable Upper Threshold exceeds the limit during cutting, the clearance control will be disabled
when crossing kerfs.
Upper Threshold
When crossing a kerf or hole or going off the edge of the plate, arc voltage rises very rapidly. System
will respond to the rise in voltage by lowering the torch trying to keep voltage constant. To prevent this
an Upper Limit is set so when arc voltage exceeds the cutting voltage by the % specified by the Upper
Limit setting system stops trying to control height.
NOTE
For thicker metal which tend to be fairly flat and using lower cutting speeds the arc voltage doesn’t change very
rapidly except when crossing kerfs & holes so using a lower % will respond quicker, typically 5-10%. For higher
speeds on thinner or warped metal where normal cutting voltage changes more rapidly, use a higher number around
10-15% or even 20%.