MATERIAL COMPENSATION FOR NO CORE CUTTING
TECTIP No. 008


SUBJECT:    Material compensation for no-core cutting   
PREPARED BY:    Bob Magee
APPROVAL:    Ken Baeszler
SYSTEM TYPE:    wirecut EDM


OBSERVATIONS:   
When No-core cutting small cavities it is often difficult to determine how much material to leave after the no-core cut main cut to trim for correct size. By taking the following actions, this task should be easy.


ACTIONS:   
During the definition of a no core routine, the programmer will be required to input the finishing allowance amount at the CAM station.  This value can be calculated by the following method:

1. Select the technology desired from the Technology guidelines in Chapter C5 of the C equipment manual.
2. Take the Main cut (Hs) offset of the technology that was selected and subtract it from  the offset for Main cut only(Hs) technology for the same workpiece thickness and wire diameter.

Example:
Required technology:                

Steel 10mm thick
Surface finish = 1.8 Ra
TKM = +/- 10 Micron
One main cut/one trim technology
Hs= .233 microns

Main cut only Technology:
Steel 10mm thick
Surface Finish = 2.3 Ra
TKM = +/- 30 Micron
One main cut technology only
Hs = .166 microns


Main cut/one trim Hs offset = .233 microns
Min cut only Hs offset = .166 microns
0.8 X (.233 - .166) = 0.8 X .067 = .0536 microns
0.0536 microns will then be the finish allowance for trimming.