> I had a program that drilled a grid of holes in a plate. The plate was
> bigger than my machine's travel limits, so I set up the program to do as
> much as the machine could reach in one run. Then I moved the plate and
> tried to use the same program to do another section of the plate, but
> the tail end of the program would have exceeded the travel limits. I
> planned to stop the program when it had finished enough of the holes. I
> have done things like this in the past, and the first dialog box with
> the "run anyway" button implies that EMC2 can do this. A quick fix was
> to put an M02 in the program at the appropriate spot.
>
> Yes, after moving the plate, I had to center over the last row of holes
> and "touch off" the coordinates based on that position.
>
> Jon
>
I used to program Sheet Metal punch presses for a large air conditioning
manufacturer. Our 45 ton machine had the capability for "Automatic
Sheet Repositioning" which would punch all of the sheet that was
possible with the work holders holding the original position. Then
1. The piece would be brought back to X-zero
2. two pneumatic sheet holders would come down to hold the sheet in place
3. the work holders would open up
4. the X axis would move to a value of zero plus some known amount
5. the work holders would grab the sheet again
6. the sheet holders would retract, and the machine would be ready to
punch out the other half of the sheet.
It's a technique that might let us use a bigger blank than our axis can
handle in one bite. for the bolt hole pattern, for example, consider a
group of 20 holes grouped as 2 by 10 holes 2 inches apart on a blank 24
inches long by 6 inches wide. Now suppose we have a machine with an X
limit of 15 inches and a Y limit of 8 inches. The X axis would need
repositioning. We could...
1. Program a pattern of 5 by 2 holes followed by the reposition move.
2. Cut the holes at 2, 4, 6, 8, and 10 inches
3. Move the cutter to the first hole at the 12 inch mark
4. Drill in and shut off the spindle
5. Prompt the operator to open the clamps and pause
6. With the clamps open and the spindle still stopped, slowly move
the spindle (and the blank) to the 2" position (may need to
retract spindle a few thousandths). The operator may have to
carry or suspend a part of the blank.
7. Pause and prompt the operator to re-clamp the blank.
8. Start the spindle
9. Then remove the spindle from the blank
10. Now repeat the cutting of the first 10 holes and stop.
Of course this must be done cautiously, and keeping the final position
of the blank parallel to the original position may require special
fixturing, but the spindle doing the moving can keep the X-axis
positioning pretty accurate.
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