New challenge

[John Lifer]

I've a new customer that wants me to cut out shapes. The trick is this is a 2'x4' sheet with several hundred printed images on the sheet and I'll be cutting out around them.
The printer is actually printing on a 4ft x 8ft sheet and then router cutting into smaller sheet. So sheets won't be able to be registered once and then lasered.
(at least I expect there to be some difference in size of sheet after routing and hence registration won't match sheet to sheet.)

Any tricks to help here?

I'm having him print some registration marks on each small sheet that I'll work to use to line up sheet, but I was hoping not to spend 5 minutes per sheet to register.

thoughts?

[Gary Hair]

I would use a piece of thin acrylic and tape it to the laser bed. Laser the registration marks on it and then align the piece to be cut to the acrylic. It should take you no more than about 10 seconds per sheet to align.

[John Lifer]

Great Idea. I though about some sort of template, but the acrylic would work well.
And DUUHHH, I can see through the sheet I'm cutting.
Heck, I've got plenty of 'scrap' (odd color rowmark) that would work great for that.

[Kev Williams]

Does your 1390 have a working, accurate red pointer? Just use that. Since the prints will vary, you'll need to locate 3 corners. I would use top left, bottom left, bottom right. Redlight each registration mark, make note of the XY coordiates. Repeat with the BL and BR. In Corel, put guidelines at the coordinates, then line up the image's reg marks in Corel to the guidelines...

At this point, one of two things will be true: Your laser will match the image, or it won't. Chances are high that it won't. But the fix is easy: Just stretch the image in Corel until the reg marks line up perfectly. Now, your laser, the cut job you're sending and the part you're cutting are all in sync, and you're ready to cut.

For subsequent pieces, with the laser aligned to the job, you'll only need to align to 2 diagonal marks.

So to speed up the process, I'd make a couple of alignment pointers and stops for them. I'd cut out a couple of corner L's for the stops, an inch wide, 6 to 8" long one side, 1" long the other. Then make some 'mobile' pointers...

Tried to draw this in corel in hope it makes sense, colors are just reference for each piece :) - first, I'll assume the work is 1/4" thick for this example. The corners and pointers will be made from scrap rowmark. this shows the work table, the work, and the pointer setup... the blue L's need to be held, screwed or taped to the table so they won't move.
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the corners would be 1/16" thick, 8x2" overall, leaving a 1" pocket.
The green piece is 1" x 4", and would need to be the same thickness as the work. 1/4" plex or any combination of glued together shims works for me.
Then, just make an arrow- this one I drew 3/4" x 2". Clear plex with a marker engraved on it to place over the reg marke would work good too.
Tape it to the green shim once alignment is verified...

below, a close-up, rotated 90-
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directly above is a side shot of the L-corner, the green shim, and the pointer. Note I've left some free between the pointer setup and the work to allow for any variances in the work piece..

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-above, just shows pointers move out of the way for engraving...

Hope this makes sense! The process would be: Align the first work piece dead center on the table-- align/sync the job, laser and workpiece, when satisfied, affix the corners, make the pointers, and while the green shims are parked in each corner, align the pointer to reg mark on the work and tape it to shims-- remove the pointers, run the job...

If all is well, then from here on all you have to do is place the next piece on, park the pointers in the corners, and move the work until the reg marks match the pointers...

Should work-- make up any tweaks as you see fit that works for you... I do variations of this with the fiber lasers all the time :)

[Trey Tull]

If they are using a CNC router to cut the sheets, have them put three registration holes in the wood. Build a template w/ three posts (same size as holes) and secure it to your bed. Then all you have to do is put their parts on top of your fixture and away you go.

[AL Ursich]

Love the Pin Hole idea. I ran into a similar problem. I uses a crude registration sheet to line up my work piece on a carrier jig. I cut it on my Hobby Grade CarveWright.

[John Lifer]

Thanks Kev, I'll see what transpires. I'm waiting on next trial. First one went well, cut parts to his satisfaction. The printer had used 'his' material instead of the customer's acrylic, but I ran a group on clear acrylic also.
The Printer's material appeared to be acrylic, but it sure wasn't. I think an acetate as it stank to high heaven. Way worse than acrylic.

Trey, good idea, I'll have to check if it is cnc and they would do that for him. easy enough if it is.
Kind of what I was first thinking of, but how could I do it? Let them...

And Al, good use of two machines.