Cutting Oversized Piece

[mountie1808]

I need to cut a 51" x 140" irregular shape out of a 60" x 144" piece of .125 aluminum. The challenge I face is that my table is 60" x 120". Does anyone have any suggestions as to how I can cut part of the file, reposition, rezero accurately, then continue cutting the file? The file is an outer contour which means that lines will have to meet.

Mike

[scottcox]

Mike,

In the scrap portion of your sheet, drill 1/8" holes through the aluminum and into the table, then drill through the aluminum offset by 24 inches or so. After cutting the first portion of your sheet, slide the sheet down 24" and insert dowels (or 1/8" drill bits) through the offsets in your sheet and into the table in the first holes you drilled.

Do this in four places and you should have a fairly accurate line-up. It's critical that your gantry is square for this to work well on such a large sheet.

[mountie1808]

Thanks Scott,

What I'm going to do is cut the contour into open contours. I'll reset the origin of the file to the center of the sheet which I'll set manually on the substrate once I get it on the bot. Since I already have a rail mounted along the bottom edge of the table bed to keep my plate straight on the x-axis, I only have to worry about re-zeroing the X axis once I shift. I'll use the 1/4" bit to tap a hole into the sheet at what I set as the origin. Once I shift the material, I'll re-zero to that hole and then run the rest of the file. By doing all of this, the origin in the file itself will always be on the table and readily findable with the bot.

If anyone sees any holes in my theory, I'm all ears. I'd rather hammer out the details before I cut into the sheet.

Mike