Cutting paper ... Scrap pieces blocking the cutting beam

I use washer shaped card stock in some of my projects and am trying to cut them with the laser.
I need a clean cut.
It works … except … the center hole cutout becomes loose (because of air assist) and will move over the material and interfere with the cutting of the stock.
So I thought that a thin sheet of glass over the card stock would hold the pieces in place while the laser is cutting them.
However the glass was etched instead.
Speed was 100 power was 20% with a 40W CO2 laser.
Any help on what I could use that the laser would go thru and cut the card stock?

I really want the air assist to keep smoke off the lens.
Perhaps if I reduce the air flow to the nozzle.

I only cut cardstock, and never use air assist.

It may not be the ideal answer, but designing into your work piece a set of tabs to keep the flying parts in check will prevent the problem you have described. Of course, the tab feature creates a non-cut area that must be popped free in post processing and may leave an undesired ragged edge. For paper and card stock, I’ve used 0.25 mm as the tab size with good results.

As you’ve discovered, you can’t have anything over the work piece. You can, however use a light tack adhesive under the work to keep the flying monkeys at bay. (Think Post-It Notes™) This implies that your bed is flat and the work is not elevated. Even if it is elevated, a sacrificial panel such as MDF or plywood with the low-tack will do the job, as it will not cut through under the lower power settings that cut the card stock.

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That has been my attempt at a solution. You hardly need any airflow through most nozzles to protect the lens from smoke getting in and messing with the lens. Less airflow often means less smoke on paper that your are cutting since there isn’t enough air to push the smoke back down on to the paper.

Doug, I hooked up a small aquarium air pump to the air assist line and it provided just enough air pressure to keep smoke from going into the nozzle. Paper stays put and cuts are clean.
Problem solved!

Depending on the wavelength of your laser there are certain colors of glass or acrylic to absorbs/stops the laser beam and other colors that will pass it through.

I think you might have been on the right track with the piece of glass, you just need to find the right color to use.

When using a cutter (the ones with a knife) with paper, we use a plastic backing sheet that is sprayed with the kind of glue that’s used by post-it notes.

You probably can do the same with a laser, just use something that doesn’t care about the laser as backing sheet. I’d try plywood or MDF first. Unless you want to run the same pattern dozens of time those should be fine at the laser power used for paper.

PS: You want to use less glue than they put into the instructions unless your air assist is very aggressive. For my cutting plotter I even take the edge off the glue by sticking on scrap paper and pulling it off again a couple of times. You want the paper to be just barely held in place and not deform when pulled of forcefully after it is cut.

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