118: Crackers

Full disclosure, guys – I did not expect this week’s experiment to work.  I figured in the worst case, it would satisfy a curiosity, and I’d get to eat hand cut homemade crackers with dip.  Ryan, on the other hand, didn’t know why I was questioning it, and thought cutting cracker dough with a laser would be a low power, simple task.  The answer was somewhere in between.

Simple ingredients, simple recipe!
Food blogging, here I come!

I’ve never made crackers before, but I had everything on hand in my bare cupboard for this recipe from The Kitchn.  As suggested, I mixed up the dough, then split it in half before rolling it out.  I took advantage of the two batches to come up with two different designs (which Ryan graciously vectorized for me.  I admittedly started this project a bit late in the evening and need help.)

Rolling it as thin as possible – the dough is springy, so you can’t work it too fast. It needs to “rest”
I layered the dough on parchment paper, and on wood.

My goal for rolling out the rough was to keep it under 3mm, 1.5 ideally.  The thinner the dough, the crispier the cracker.  I rolled it out on parchment paper – food safe, and bad things wouldn’t happen to it in the laser, just a little singeing.  I then put it on some plywood for stability, and to prevent the laser from reflecting back after it hits the honeycomb bed, which might not be the cleanest.

Pro tip: I learned when rolling out the second batch of dough that it was actually easier to roll the dough between two pieces of parchment paper when it got thin.  It was easier to flip, it seemed to spring back less, and it stayed moister while I worked with it.  I did remove the top later of parchment when I put the dough in the laser.

Test cuts – third time is the charm!  Interesting thing about cutting the dough – it was a little “sparky.”  Naturally dough isn’t homogeneous, but instead a mixture of ingredients.  The laser reacts differently to this ingredients, which created tiny little light flares.

 

Less than 3mm thick, I’m thrilled!

So, I didn’t think the laser would cut the dough at all, Ryan was thinking it would be a breeze – maybe akin to paper.  It took a few tries to get though the dough, and the right answer was some there in between – we cut at 100% power, and a slow 8% speed.  I didn’t roll it perfectly evenly, so the dough was thicker in some parts, but it still all cut.  And my test measurements were all under 3mm thick!

Heart shaped vent holes – totally a pain in the butt.

The first design was this funky hexagon shape, with little 1mm hearts cut in for venting, so the crackers wouldn’t puff.  Officially, the design is too complicated.  The outer shape is fine, but the hearts took too long to cut, and didn’t come out easily.  I actually baked the hearts in place, and then Ryan popped them out after.  And the length of time tried out the dough quite a bit since we had to have the exhaust on.  with set up, test and cutting, it was in our windy laser for about 45 minutes.  The edges of the crackers were trying to curl up!

Triangles!  Classy appearance by my phone.

Second batch we went a little more simple – a nice rounded triangle with asterisks cut for venting.  They ended up delightfully mod looking, and in were in and out of the laser in under 15.

Light toasted!

Baking is pretty straight forward, but the crackers are easy to burn as you can see.  The first batch were a little extra crisp, but edible.  The second back felt under done while they were still hot, but after they cooled they were perfectly crispy.  So, watch them closely, and make sure you let them cool, unless you are going to a crispy-chewy combo.

Midnight snack.  Homemade crackers, but I totally bought the artichoke jalapeno parmesan dip, the leftovers of which had disappeared by morning.

Verdict – The recipe was tasty but be forewarned, the crackers themselves were not airy or flaky.  They were dense, and reminded me of pita chips actually.  I may have over kneaded them.  This is a fun example of too much tool for the job – a knife easily cuts the dough.  But this would be a fun recipe to perfect for fancy dinner parties, potlucks you want to impress at, or those times you want a crunchy snack and don’t want to leave the house.

117: PC Case Engraving

To ring in the new year, and celebrate the ten year anniversary of my previous build, I decided to build a new PC. Back in 2007, it was two years before we even started playing with lasers. This time around, I knew for sure I’d be laser engraving some piece or another. I’ve engraved a few macbooks and other portable devices, and I’ve even engraved a custom wood faceplate for a friend’s ATX midtower. So I’ve been pretty excited about the idea of engraving something on my own machine!

Over a few weeks in January I did the research, collected the parts, and then planned a small “build party” with some of my local PC enthusiast friends so we could put the machine together together. Hey, it only happens once a decade or so, that’s a pretty good excuse for a shindig, yeah?

From left to right, Brenn, Jen (<3), myself, Maul, Ray, and Mark. Also not pictured: Maul’s bro Joe! Thanks for the photography, Mark!

Together we had dinner, built the PC, played some couch games, and mulled over a few remaining questions. What should this new build be called? What part of the case will be laser engraved? What are we going to engrave on it? I was so wishy-washy on the name decision that I couldn’t even settle on it before the party was over. Furthermore, I wanted the engraving design to be related to the name, so I couldn’t really come to any decisions on that front, either. But we were able to figure out what part to engrave, and as it turned out, the answer was nothing.

Fractal Design’s Define C case is sexy, but made out of questionably engravable plastic.

The Fractal Design Define C is a sexy, sexy midtower ATX case. I love the shroud, I love the quiet, and I love the flat textured front. I like simple, unassuming case designs, and I wanted to continue down that road after my last build in an Antec P180B. But when we finally dug into the case, I learned a few laser-unfriendly things I could probably have sussed out from reviews online if I had been more thorough.

The front of the case is not an anodized aluminum plate, and it’s also not easily detached from the surrounding plastic chassis that covers the front exhaust system. It’s made out of the same plastic—it’s very pretty, with a subtle vertical brushed texture, but it’s still just the case plastic. Because the textured surface isn’t repeated anywhere on the inside (or indeed on any other external surface) I wasn’t going to be able to do an inconspicuous engraving test. So I wouldn’t be able to engrave the front plate, but what about the window?

On a quest for extreme sound dampening, my previous PC build didn’t have a window at all. But over the years I’ve kind of missed being able to peek in on my parts, so this time I bought a case with built-in acrylic window.

With a power shroud for modesty and excellent cable arrangement, who wouldn’t want to peek inside?

Unfortunately, there wasn’t going to be an easy way to test that material inconspicuously either, and with the  engraving quality difference between cast and extruded acrylics, I didn’t want to gamble.

When I looked closer at the acrylic window, I noticed there was a lip on the inside, one that would fit a secondary piece of acrylic just fine as long as the measurements were correct. So I did a couple of sizing tests with some old pieces of acrylic, got my measurements spot on, and settled on a solution: cut a separate piece of cast acrylic and snap it into the existing acrylic window. I wouldn’t technically be engraving the PC case after all, but the finished piece would still look as good. As a bonus, I’d be able to easily change out the acrylic in the future if I wanted to change the design.

Amusingly enough, it was mulling around design ideas that led me to my final decision on the name of the machine. I’ve always been a fan of the Metroid series, you can see it in some of my other projects. Most game servers I host have names based on “Maru Mari”, and you’ll be connecting to “Varia” if you try to stream content to my television. I had a feeling I’d end up going with the Metroid theme again, but it wasn’t until I thought about how much fun it would be to engrave the cold steel corridors of Tourian into acrylic that I really landed on it.

The full map is too big; I’d have to fit it in this cyan rectangle

Tourian is a big map. Well, it’s not big, but its hallways are long and the vertical shafts are all a daunting climb. I’d have to compress the map pretty significantly to make it fit the relatively tiny space I had for my acrylic window. To make matters worse, halfway through the design I realized I had laid out the template wrong and was designing for the measurements in landscape instead of portrait. But after cutting a few rooms in half (and completely excising the hallway before Mother Brain’s chamber) I was able to make it fit.

The final compressed map, corrected to a portrait aspect.

I added a few additional details (the opening text scroll and an excessively big title in the original typeface in the corner) and the design was finished. I cleaned up the acrylic, seated it in the window’s lip, and used a tiny bit of clear packing tape on the inside corners to make sure it wouldn’t somehow come loose.

A mockup of what the case might look like with the final design.

The panel looks great when it’s not connected to the computer, but as it turns out, I should look into buying some motherboard-powered LED strip lighting to brighten up this design. Most of the photography here is cleaned up to make the engraving visible, but it’s much more subtle than that when properly installed on the PC.

This door is all that’s left of a completely deleted room. Don’t tell the purists!

The end result may be disappointingly dim, but I still had a blast manipulating the Tourian map in a way that wouldn’t compromise the basic layout, and I will definitely be using what I’ve learned on this project to make some more “window inserts” for this case in the future. Once it’s lit up, the design itself should really shine, but for now it still makes for some pretty fun close up photography!

The engraving fights with the inner bits just a little more than I’d hoped.
I love that the escape shaft coincidentally has its own murky yellow and green lighting.
This example clearly shows how dim the engraving is compared to the LED-lit components inside.
A two character 8 segment LED readout hides in Tourian’s O.
One Metroid, permanently frozen.

116: Laser Foil

Years ago, I purchased a roll of a foil material when I was first getting creative with the laser. I didn’t really know how it worked, and most instructions required a process I was wholly uncomfortable with: touching the material in-between passes. Most of my experiences touching anything between engraving and cutting meant engravings that fell out of alignment, so my poor roll of black laser foil was left mostly unused for several years.

The metallic foil shines bright red from most angles.

This year, for a New Years Party happening in just a few days, we were asked to design name badges for the attendees. For part of the design, Jen and I wanted to use a thin sticker on top the base badge acrylic, but since our normal supply of paper-thin acrylic didn’t come in red, we had to find alternatives. At some point I was reminded of the laser foil, so I ran a quick test with the black roll I’ve had on hand and quickly realized that would be the way to go.

Laser foil in rolls; one black roll from years ago and the red roll bought for this project.

The foil would have to be red, though, because of the design chosen. The badge design for this event features two small dogs sipping their drinks (art by 957thedog.com!) next to a large dumpster fire—complete with a burning “2016” sign inside—the symbolism of which I’ll leave to you to interpret. That fire wouldn’t really stand out if it was just engraved onto the same smooth silver surface the badge is made from, so red foil it would be!

There are a few different ways to use laser foil effectively, but the way I settled on is described below, and it requires a few different steps that have to be done in order.

Black fills are raster engravings, blue and red are vector cuts of varying depths.

Make sure you only run your raster engraving first—the black and grey fills will convert to halftone and result in the surface engraving seen in the photography, while (in this configuration) the blue and red lines are score and cut respectively and will be done next.

Engraving done, now to carefully apply the foil.

With raster engraving done, very carefully apply a portion of laser foil to the surface, overlapping where your blue and red lines will do the dirty work. Since the fire design element is completely enclosed, you don’t have to worry about aligning the foil too much. Just make absolutely certain you do not nudge the material out of alignment during this step. I use an old iron bookbinding bar to keep my material in place.

The foil is applied; it doesn’t need to be perfectly aligned.

Set your software up to cut the blue lines next, and then the red lines after. You don’t need to stop the process in-between unless you want to turn on air assist for the cutting portion. Once all three processing steps are completed, you’ll have a finished badge with a bunch of extra foil on it.

Peeling foil back isn’t as troublesome as peeling vinyl; not nearly as stretchy!

Carefully remove the foil. It’s not as bad as weeding vinyl, thankfully, as the foil doesn’t easily get bent out of shape. Once you’re done, a light cleaning with some denatured or isopropyl alcohol and the badge is done!

From certain angles the reflection looks even more firey.

Because of its reflective nature, the foil fire will catch reflections and create a high contrast black and red look, while the smooth silver below will be bright in low light and aid in badge visibility. I did consider for a brief time going with a classic “dumpster green”, but the back color (white) didn’t work with the design well and, frankly, the results were too ugly to even consider photographing.

Happy new year!

115: Rounded Edges

One of the first limitations of laser engraving I learned about was the right angle. On most (if not all? let me know!) laser engravers, the laser can only fire in one direction: straight down, perpendicular to the surface plane. This means that you can’t easily get beveled edges, rounded corners, or other nice depth effects you can get using a rotary engraving system like a CNC mill.

There are ways around this limitation, of course: a patron I spoke to at the Aurora Public Library‘s Makerspace suggested rigging smaller pieces of material at their own angles, allowing the laser to fire directly down at a skewed surface, creating the angled edge desired. I considered this process, but it only works if you are cutting a single straight line—any shift in the direction will pull the head out of focus with the section of material you’re cutting.

Focus matters, though, as I found out several months ago while cutting some badges for an event. I accidentally left the laser bed way out of focus when cutting one of these badges, and you can see how the laser didn’t cut through, and instead just created a rounded channel in the surface of the material, in the shape of the badge I’d intended to cut. It made me realize I could cut a shape normally, and then cut it again out of focus, to give the edge a soft curve.

The mistake that taught me how to round corners via unfocused engraving.
The mistake that taught me how to round corners via unfocused engraving.

So this month, I got around to testing that some more! I opted for some snowflake designs (sourced from freepik.com; thank you!) to give me plenty of edges to smooth and for general holiday goodness. The first step is to cut the piece normally, which results in the traditional sharp 90 degree edges you see in most lasered pieces.

Sharp 90 degree edges, standard for laser cutting.
Sharp 90 degree edges, standard for laser cutting.

Leave the leftover material in the laser bed, and do your absolute best not to disrupt its place. In fact, I suggest not touching the piece at all at this point and just telling the laser to fire again with new settings. Specifically, I threw the laser out of focus by telling it I was engraving on a 1.125″ thick material rather than a .125″ thick material. I’ve experimented with different unfocused settings, and can probably dial that in a little better, but 1″ is a nice easy number to get a decently rounded corner on a 2″ lens. I also sped up the laser a little bit because I didn’t want to overpower the edges when rounding them (while my speed settings won’t match yours exactly for a multitude of reasons, I cut the snowflake at 5.5% speed and then rounded the edges at 15% speed.)

The top side is now rounded; it's an imperfect process and looks a little rough up close.
The top side is now rounded; it’s an imperfect process and looks a little rough up close.

Since the rounding only happens on one side, you’ll have to flip the piece and round the edges again if you want to give both surfaces the same treatment. This is only possible if your piece has an axis of symmetry, and this is where you have to be very careful not to move your temporary jig. Once you’re done, you might have to clean the piece as firing a laser out of focus can produce a fair bit more detritus than firing it in focus.

Make sure to clean your honeycomb first, and wipe down any residue between each step. Oh, and use a clean cloth! Trust me!
Make sure to clean your honeycomb first, and wipe down any residue between each step. Oh, and use a clean cloth! Trust me!

As it turns out, even if you don’t move the makeshift jig at all, your second pass might be slightly out of alignment to the first. Why is this? Kerf—the width of the laser—means that your freshly cut snowflake might shift a fraction of a millimeter inside the jig. There’s a tiny, tiny little bit of give and it can sometimes be enough that the alignment is visually off. You can solve this by rounding one side before cutting, but you’ll still have to contend with this on the back half, and kerf didn’t affect my alignment nearly as much as another issue:

Much more alarmingly, I discovered while doing this project that pulling my laser out of focus by about an inch noticeably moves the laser’s aim. It’s not enough to ruin the project, but it is enough that I had to correct for it after several prototypes to get a nice even rounding. This aim issue as the laser focus changes is due to incorrectly calibrated mirrors somewhere along the laser’s path (totally my fault, as I foolishly adjusted them once upon a time and have been tweaking them here and there ever since) so if your mirrors are factory aligned like they should be you shouldn’t run into this issue.

Even if you don't move the piece at all between steps, kerf or poorly calibrated mirrors might cause your rounded edges to be misaligned.
Even if you don’t move the piece at all between steps, kerf or poorly calibrated mirrors might cause your rounded edges to be misaligned.

In the end, the rounded edges are a little rough looking, but if you get your settings dialed in (or would it be dialed out in this case?) you can get a nice smoothed edge that will catch light in a novel way for a laser cut item. I used opaque and translucent acrylic for this project, but I know this effect would look great in transparent and fluorescent acrylic as well. I can’t imagine it working as well with natural materials or microsurfaced plastic, but maybe I should experiment with that in the future!

If you have any unfocused laser tricks, or tips for keeping materials clean while processing pieces in multiple steps, let us know in the comments below! Happy holidays!

One laser, fifty-two weeks