Clearance / Feed plane - Absolute/Incremental

[jcnewbie]

Trying to understand this concept

Let say I have a rectangle and using a contour toolpath. I place 5 inches for clearance plane in absolute and 3 inches for feed plane in incremental. I am thinking that would not matter what I use absolute or incremental because I have only one rectangele. However, it would matter if I have one or more chain in the toolpath, correct ?

[Superman]

No,
It would depend upon where( in the Z plane ) the shape was drawn

Absolute Z values are in respect to the WCS origin

Inremental is in respect of the shape

Eg. 1 rectangle at Z2. and 1 rectangle at Z-2.

Clearance = 5" (Abs)
Retract = 3" (Abs)
Feed plane = 0.2 (Inc)
Top os Stock = 0 (Abs)
Depth = -1. (Abs)
your paths are to start feeding into the shapes at Z0.2 and finish at Z-1.
Both rectangles will start / finish at the same Z plane

But
Clearance = 5" (Abs)
Retract = 3" (Abs)
Feed plane = 0.2 (Inc)
Top os Stock = 0 (Inc)
Depth = -1. (Inc)
your paths are to start feeding into the #1 shape at Z2.2 and finish at Z1.
and #2 shape feed in at Z-1.8, bottom will be Z-3

[jcnewbie]

Sorry for my ignorance but I'm trying to understand the second example. How do you get a value of Z-3 ?

#2 shape feed in at Z-1.8, bottom will be Z-3

[Superman]

Because you told mastercam that the final cut-depth is to be 1" below the shape ( Depth = -1 increm )

Remember, the shape you select controls the Zplane when incremental is used

Try using incremental, and regen a toolpath, then lift only 1 of the chains.
Your toolpath will go dirty, regen it again and only the toolpath on the moved chain will be modified.

[jcnewbie]

Thanks for the response.

Feel like an idiot, its all starting to make sense !!

[Superman]

Be prepared to feel that way for a long time,
There's a lot to learn