Re: [CAD_CAM_EDM_DRO] Up and Down; Is Z- away from the part or into the part?

I do not know what a commercial machine does, but I have found that it does
not matter at all. Your frame of reference varies depending on the part
that you are milling. I prefer to have my z values go positive as I move
the tool downward, but I write all of my G-Code by hand. I start with z=0
when I touch the tool to the top surface of the part, and then I use a
z=-0.020" clearance to rapid move. All of my parts are uniform cylinders
that are rotated on a rotary table so I never have high spots on the surface
to worry about.

I change the direction of my x-axis and rotary axis by changing the polarity
of the setup file for step and direction controls. This way if I generate
the G-Code "backwards" for engraved letters, I can just switch polarity in
the setup and then it moves in the opposite direction.

If there is a standard, it is completely superfluous.

Just my uneducated opinion on reference frames.

Daniel J. Statman, Statman Designs
www.statmandesigns.com

----- Original Message -----
From: "mszollar" <mszollar@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Saturday, December 15, 2001 8:28 PM
Subject: [CAD_CAM_EDM_DRO] Up and Down; Is Z- away from the part or into the
part?


> I've noticed that depending on the CAM package I use the Z axis is
> sometime generated using + values for depth and sometimes - values
> for depth. This begs the question (as I am new in this area); is
> there a "standard" for directions? For x/Y is 0,0 in the center of
> travel or is it at the end stop so that all motion is forward? SAme
> with Z; is 0 the top of travel or is it the top of the part (I
> thought Z0 was top of material being milled)?
>
> Ken
>
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