[Superman]

Trying to modify a T-slot cutter offset .
Logically, ( from what I understand at this point out of mastercam) mastercam uses the OD of the selected tool to follow the chain selected in the toolpath!
So fare….so good !
But….for my specific usage, I would like to have the discrepancy / the flexibility to change this “offset” of this selected tool in a manner so I can offset it from its center axis to follow this toolpath chain vs the “normal” way,.....it follows the outside cutting diam !
Make a long story….hopping this make sense !?

Now we start to see where you need guidance, it is a tool compensation query
- nothing to do with H & D offsets


- it may be best to understand the relationship between your selected geometry, what tool you want to use, & what toolpath you expect when you set the correct options, in other words, chain --> comp values --> toolpath

- it depends on what entities you select for your chain, whether they define edges of your part, or added later for "other" machining methods

- if you select geometry that form the edge of a wall, you would need the cutter to also run along that wall, we typically, would use cutter compensation. Most would use climb cut when contouring(left), ( when selecting chains, the arrows play a big part in how the tool can be controlled, large=direction of cut, small=left/right comp )

comp type is how/what numbers are needed in the control to get correct tool "offset" to the selected chains
- "WEAR" is where the toolpath is already offset to the chain, the control requires a zero offset if the tool diameter is the same as programmed, ( a +ive offset will make the path stay further away from the selected chain, where a -ive offset will move the path closer)
- "COMPUTER" is where the path is adjusted by tool diameter in Mastercam only, the toolpath cannot be adjusted by offset in the control
- "CONTROL" is where the path is the same as the chain, the control requires comp to be the cutter radius
- "OFF" is where toolpath is the chain, no comp is used

Now for the added kicker
- the toolpath for each of these methods can be "adjusted" in Mastercam by using the XY offset allowance, ie create a roughing path operation that leaves say 0.2mm on a wall, and a finishing path op set to zero,,,,, all with the same tool, no alteration to the D offset in the control.


- there are many methods to get the same toolpath
if I want a path down the centre of a slot, I can
- draw a contour that is the down the centre & select that as my chain, set comp type to OFF, XY offset=0 ( +ive number moves the path in the direction of the small arrow seen when accepting the chain, -ive moves it the other side )
- using an edge chain, comp type=WEAR, XY offset adjusted to put tool on the centre ( comment as above, D offset=0 in the control will make the tool do the same path as seen on the PC )

say I have a 16mm slot, tool is a 26mm tee-slot cutter, selected chain is on the top of the 16mm wide wall, then I would need XY offset=-5 to have the cutter travel down the centre of the 16 slot....NOTE, lead in/out must be extended to allow tool plunge/retract outside of the part, suggest you use longer tangent lines & not use arcs

PS- XY offset is on the cut parameter page of that operation, lower section, it may be labelled "Material left on walls", can be +ive or -ive
PPS - process described is by using 2D Contour strategy & by selecting wireframe entities, not a surfacing operation