Re: [CAD_CAM_EDM_DRO] emc g92

Tom Hubin wrote:

>Hello Jon,
>
>I have seen no way to follow your procedure on a standard Sherline 5410
>(metric 5400) mill.
>
>
>

OK, I see what you are doing here. You are changing tools, and want to
manually touch-off the next tool, and then continue the program. Well, EMC
doesn't really handle stopping in the middle of a program and then
restarting. That I have to admit.

One fix for this is to set up your tooling and fixtures so you do all the
workpieces with one tool before changing. I often swap parts while
the spindle is running, and then run the program on the next part.
So, instead of changing tools, I'm changing workpieces. Yes, this is
adapting to the program, instead of the program adapting to me.

And, I usually have separate programs for each tool/step of the
process, as the restarting in the middle of a program with EMC
is cumbersome.

But, I have set up procedures for swapping tools and continuing
with EMC. In the program, it retracts the quill to the top, which
makes the drawbar accessible (on a Bridgeport). I use almost
exclusively end mill holders rather than collets, so the tool length
in the spindle will be constant. I made a replica of the Bridgeport's
R-8 spindle that can be placed on a surface plate. The tools can then
be measured with a height gauge. The first tool is often a center drill,
so I call that the "reference tool" and all other tools are measured
against that length. A zero offset is used with the reference tool, and the
difference between that and the other tools is entered in the tool
table. When the program is run, it retracts the spindle, stops it
and goes to pause. When I put the new tool in, I continue, and the
program does a select tool, then activates tool length offset, and
does a Z move, which interpolates in the tool length offset. After that,
the new tool's tip will be the correct distance from the work.

This way, I don't have to touch off the tools after each tool change.

Jon