58: Lasering Layers

Last week, Jen made some amazing costume jewelry recreations using five separate layers of acrylic. During the process, she recognized the frustration of perfectly aligning individual layers of laser-cut acrylic. Was cutting the layers first and then gluing them together the best option? Or could we stick the layers together first, and then cut out the outer shape? She explored the idea in a separate jewelry design and left it for later, but since her question piqued my interest, I decided to follow through with this week’s project.

The prototype, and the separate grey and pink templates.

The prototype, and the separate grey and pink templates.

The first thing I did was cut a pair of Jen’s new jewelry design—a two-layer chevron stud—and stuck the pieces together by hand so that I could appreciate how obnoxious the alignment can be.  Just one pair of studs wasn’t that bad, but I can imagine the tedium of assembling dozens of these tiny pieces and how annoying it would be to accidentally misalign a layer.

Pre-applied adhesive makes this a super-easy task.

Pre-applied adhesive makes this a super-easy task.

I then set up two templates. The top layer featured the internal shapes cut out first, and the bottom layer was a blank template cut to the same size so that the pieces could be stuck together before the final laser cutting pass. Thankfully, the top layer material has an adhesive backing pre-applied, so it was just a matter of peel-and-stick, making sure the templates’ edges lined up. The final piece was 1/16″ thick, so I processed it with the same laser settings I would use for a normal piece of 1/16″ thick acrylic.

Sandwiched together, the total thickness is 1/16".

Sandwiched together, the total thickness is 1/16″.

The trickiest part of the process was making sure that the final cut aligned properly with the inside cuts on the top layer. This alignment would have been automatic and impossible to mess up if I was making both the outside and inside cuts at once, but because we’re trying to avoid having to align dozens of tiny pieces, this step is necessary. Even when I used the template shape to align against the rulers, and the red laser pointer to eyeball alignment as it ran a “test” cut, my final cut was just short of a millimeter off vertically, resulting in some pieces with thicker top edges and some pieces with thinner top edges. A more modern laser with a camera registration system would alleviate this issue.

Alignment issues strike again!

Alignment issues strike again!

Beyond the slight error in registration, the cut worked exactly as I’d hoped. Each piece cut out just fine with the 1/16″ acrylic settings, and I assume the same would hold true when layering three or four pieces, as long as the adhesive layer was consistently applied and I used settings appropriate for the final thickness. In the end, having to perform one extra registration step within the cutting process is far better than having to hand-align 30+ stud earrings!

 

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