Re: [CAD_CAM_EDM_DRO] emc g92

John Dammeyer wrote:

>Thanks Jon,
>
>Good link. But I didn't see anything in those programs for
>stopping EMC, moving the work out of the way to change a tool
>bit, and then moving the work back.
>

You can put that code in your G-code program with an editor. I do
this all the time, if I will be making several parts. Retract the quill,
move the workpiece back or to the side, stop spindle and pause.

>
>Or for EMC based systems is it better to make each a separate
>program? Ie. When first operation is complete. (in my example
>the first slot) move to home position and stop. Then Operator
>can install new tool bit into existing mill holder and start the
>new program?
>
>

I have found that it is often much faster to do all the processes with one
tool on multiple workpieces, then change the tool and run the next
processing
step with a different program.

I don't change the tool in the mill holder, I swap out the whole end
mill holder.
That way, the tool can be relocated to the same position with minimal
variation
by just putting the holder back in.

>But how under EMC does the operator tell the system where the 0
>point is for the new tool bit?
>
>

By entering the tool length in the tool table and using a G43 command to
select
the tool length from the tool table. I made a replica of the R-8
spindle taper
and can measure my tool length with a surface plate and vernier height
gauge.

This allows repeatable tool length in the spindle, and repeatable
positioning
over the work. I have to touch off the first tool to the work, and
everything
is automatically compensated after that.

You cannot do this with collets, as the tool will not come to the same
length
every time. EMC does not allow you to change anything while paused in
the middle
of a program. You cannot change the G92 or G10 L2 Pn work offsets or
do anything like that while in the middle of a part program. This is a
limitation
of EMC. There are reasons for it, but they are limitations, and they do get
in the way sometimes.

Jon