Tag Archives: acrylic

112: Three-Ply Acrylic

It’s kind of amazing that it’s taken me this long to get to this project; when 52 Lasers was first conceived, using three-ply acrylic was on the first draft of our potential projects list. Now, more than two and a half years later, I finally have a project that requires this unique material!

Rowmark's convenient visual representation.
Rowmark’s convenient visual representation.

Three-ply acrylic is similar to the two-ply acrylic I use very often, except the thin cap layer is applied to both sides of the main acrylic substrate. While most of the badges, magnets, and other pieces I make only need one side to be engraved, certain items like medallions or coins might need both sides engraved, and this is when you’d use a three-ply option. This month’s project is a great example.

 

A bunch of SCA tokens celebrating an elevation.
A bunch of SCA tokens celebrating an elevation.

A couple of dear friends of ours are part of a group called the Society for Creative Anachronism. While I’d like to explain what that is for you, I couldn’t possibly do better than the SCA’s excellent portal for curious newcomers. Dave got in touch and explained that his husband Jim was going to be recognized for his accomplishments in the Society, in a ceremony called an elevation. For the event, they wanted to distribute small tokens, in SCA appropriate colors, featuring Jim’s moniker in Chinese (凱曾, Kai Tseng) and the triple rapier logo of the Order of the Masters of Defense. I’ve always used wood for tokens that need both sides engraved up to this point, but it was far easier to get the colors Dave and Jim wanted by using the three-ply LaserMax acrylic from Rowmark.

When you’re engraving two-ply material, you don’t really have to worry too much about the back face; people aren’t going to be scrutinizing a blank back surface, so imperfections caused by the manufacturing process aren’t a big deal. That’s why two-ply materials only ship with mask on the front surface. Three-ply material has mask on both cap layers, and while you want to remove the mask from the side you’re engraving first, you definitely want to leave the mask on the bottom side. That’s because those vector cutting scars—plastic residue, honeycomb table impressions—are going to damage that side if you don’t. It’s okay to engrave the reverse side with the original side unmasked because you won’t be doing any high power vector cutting in that final step; it’s just surface engraving, which doesn’t cause those kinds of issues.

Red tokens placed upside down in the makeshift jig.
Red tokens placed upside down in the makeshift jig.

Conveniently enough, just cutting the shapes out in the first pass automatically creates a makeshift jig—or template—out of the leftover material. As long as you send the second half of the engraving data in the same exact positions as the first, all you have to do is flip the shape over and engrave again. Now, this requires a symmetrical shape, or else you’ll have to take flipping into consideration and cut extra pieces out of the material that will form the jig. You also want to remember to take the mask off of the flipped token’s new front side before engraving; firing the laser through that thin plastic layer will usually create a sticky mess.

With all of that in mind, it’s fairly simple to process three-ply material in a clean manner. You’ll still have to wipe down the edges with a light alcohol or a solvent similar to Goo Gone, but that’s usually the case with two-or-more-ply acrylics anyway. For how simple the whole process is, I still managed to muck things up, and I lost a whole set of twenty yellow tokens on the first pass due to a technical issue with the laser that I still haven’t figured out.

Unexpected markings ruined a whole batch of tokens.
Unexpected markings ruined a whole batch of tokens.

Once in a while, when raster engraving, the field I’m engraving will be speckled with tiny additional engraved dots. I can never predict when it happens, and just rebooting the system fixes it, but it always loses me a piece or two.

Token stacks.
Token stacks.

I also noticed with this project that my laser alignment isn’t perfectly perpendicular to the engraving surface currently; if you look a the picture of the token stacks above, you’ll notice the slight skew in the 1/8″ thickness of the tokens. I think this is due to a misaligned mirror #3, but it’s difficult to know for sure and I might end up having to replace the mirror #3 assembly with a factory-calibrated one.

If any of you have any tips for cleaning the laser-cut edges of a two-or-three-ply piece, any ideas on what might cause the rare engraving field speckling, or any suggestions on how to realign the beam path across the surface, let me know in the comments below!

109: Edge-Lit Acrylic

I’ve been playing a lot lately with a new toy I picked up from Inventables: a powered LED strip for edge lighting acrylic. It’s made in particular to work in tandem with specially made acrylics that transmit light efficiently, but I’ve found it works really well with simpler transparent and fluorescent acrylics.

The first dual-layer design.
The first dual-layer design.

My first test was with transparent orange material sourced at the Aurora Public Library’s Makerspace—check it out if you’re local!—and it seemed appropriate to design a little sign for the space as the test. Because the LED strip is designed to snap to the edge of a 1/4″ piece of acrylic and I only had 1/8″ material available, I decided to split the design across two layers of acrylic. The front layer included all of the vector engraving and the back layer was just the main title text filled. The resulting look is striking, but using two transparent layers means you have to be extra careful not to let any fingerprints or dust get in between.

The short sign lit up easily.
The short sign lit up easily. Please ignore the Macbook!

Around the same time, I was working with a local artist to create some wall décor based on the classic Pac-Man maze. We agreed pretty quickly that the lit effect would look great and settled on some fluorescent blue acrylic. The first several tests confirmed that the two layer effect would be excellent; dividing the pellets, ghosts and other objects from the maze walls might not be very visible in the photography, but it’s a really neat trick when you’re examining the piece up close.

A small cross-section of the Pac-Man design in two layers.
A small cross-section of the Pac-Man design in two layers.

One concern I continue to have is whether a single LED strip will be able to illuminate the entire flourescent blue acrylic sheet—this piece is 16 inches tall, towering compared to the 4″ makerspace sign. A quick test on some scrap acrylic shows that the light visibly dims near the top, but I won’t be able to know for sure how the final piece will look until a last-minute shipment of materials arrives. Speaking of that, here’s a pro tip: don’t assume you’ve got all the materials you need until the day you’re scheduled to cut! Always check, even if it’s something you always keep in stock, like the black cast acrylic that was supposed to be the backing layer for the finished Pac-Man piece.

A later single layer test cut with rounded vector engraved maze walls.
A later single layer test cut with rounded vector engraved maze walls.

Edge lit acrylic is a great look, and I’m might have to investigate the “EndLighten” brand or similar substrates to maximize light transmission. I know I’m also going to be looking into portable equivalents; this hardware has to plug into a wall. I’m sure that’ll be a post in the future; until then, look forward to an update on this post with additional pictures of the finished Pac-Man piece!

This crazy square panorama shows how the lighting falls off near the top. We'll see how it looks in the finished piece!
This crazy square panorama shows how the lighting falls off near the top. We’ll see how it looks in the finished piece!

107: Thick Acrylic

A few months ago, my friend Arty got in touch with me and said he had “some thick acrylic” left over from a recent storefront revamp at a mobile phone store. Not really knowing what I was getting into, I said “hey any scrap material that I can laser is good with me!”

This stuff is so clear it's almost hard to see.
This stuff is so clear it’s almost hard to see.

Much more recently, I went to pick up the acrylic that he’d been graciously holding onto for me. As it turned out, the acrylic wasn’t just thick. It was far thicker than I could process with the laser, with 7/8″ as the thinnest edge. But there were several chunks of uniformly cut acrylic, and every surface was smooth enough that you could see clear through to the other side. This was material worth experimenting on!

The first engraving test confirmed that it was cast acrylic.
The first engraving test confirmed that it was cast acrylic.

I first determined whether it was cast or extruded acrylic by doing a surface engraving featuring some art deco frame stock. The surface engraving was powdery and white, which was perfect—cast acrylic engraves in a much more visible manner than extruded acrylic.

The second design didn't really convey the "frosted ice" look I was going for.
The second design didn’t really convey the “frosted ice” look I was going for.

The second design I tried was based on a “frosted ice” theme I developed while working with a client a couple of years ago. While it looked great on the snowflake shapes I used originally, the effect was lost on the square chunk of acrylic, and the “FROSTY” text I added didn’t really come out clearly.

Two different sizes of blocks "comprised" of tetriminos.
Two different sizes of blocks “comprised” of tetriminos.

I revisited some tetrimino patterns from a very early 52LASERS post. Using three different engraving techniques, I created a pattern that highlighted certain shapes with fills and deeper cuts. The result not only looks awesome from straight on, it created some really stunning effects when looking through the unengraved side of the acrylic.

Looking through the clean edge shows off each "deep cut" tetrimino.
Looking through the clean edge shows off each “deep cut” tetrimino.
Any fan of Tetris will recognize these shapes!
Any fan of Tetris will recognize these shapes!

I still have plenty of stock of these blocks left, so if you can think of any more creative ways to jazz up the acrylic’s surface, let me know in the comments!

Quite a supply of material too thick to cut through!
Quite a supply of material too thick to cut through!

97: Utilitarian Fridge Shelf

The empty fridge, absent a long lost shelf.
The empty fridge, absent a long lost shelf.

As I’ve written about before, even when there’s not much creativity involved, the laser platform allows for all sorts of functional usefulness. In this case, local friend Brenn once again provides a fun project: replacing a lost wire shelf in his mini fridge.

We measured the space and cut a prototype out of cardboard. It’s a good thing we did; we overlooked a small gap of extra space on the left side where a key on the shelf would slot in, so the second cardboard prototype (pictured) had the key built into the side.

The second cardboard prototype added a small key on the end to fit the space better.
The second cardboard prototype added a small key on the end to fit the space better.

The cardboard also helped Brenn and I realize that the initial material we’d chosen wouldn’t be thick enough for the space. Thankfully, I do keep some 1/4″ thick acrylic around, but unfortunately the only color I had on hand was black.

A snug fit, allowing Brenn to better utilize what little space is inside.
A snug fit, allowing Brenn to better utilize what little space is inside.

Still, with the shape measured twice and cut thrice, the final black shelf fit in just fine! We discussed cutting out a “grill” of holes in the center of the acrylic to make it look a little more at home, but the extra time spent cutting that entirely decorative element would have increased the price too much for such a simple project.

Brenn hasn’t had the fridge set back up long enough for us to know whether the frigid temperature is going to be an issue with the acrylic, but I don’t foresee any issues!

A close up of the keyed shelf edge.
A close up of the keyed shelf edge.