Here’s another relatively artistic project. I made this clock as a gift for someone:

Laser cut clock with a 12-point mandala face

The build was pretty straightforward. First, I searched online for mandala designs, and I started with one that I liked. The hardest part of this stage was finding designs that were 12-pointed; most mandalas have a 2^n number of points.

Next, I used Inkscape to vectorize the mandala and modified it to be appropriate for laser cutting. This included selecting parts to be engraved and cut as well as some tweaks to the design. I like making renderings to give me an idea of what the final project will look like, so I added some additional layers and a woodgrain bitmap to produce this preview.

This image gives a picture as to what the mandala would look like before laser cutting; I could use the same technique to visualize other designs cut and etched in cherry wood.

Satisfied with the design, I purchased some 1/4″ cherry wood and lasered it out.

Before cutting, I covered the piece in masking tape to protect the finish. It was a pain to remove the masking tape from all the little regions, but the result looks good. You can still see a piece of tape on the piece in this picture.

I think settings on laser cutters always take some tuning, so, for reference, I used these settings on a 30W laser cutter.

• Cutting power: 100%
• Cutting speed 32%
• Cutting frequency: 2500Hz
• Raster power: 25%
• Raster speed: 100%
• Raster resolution: 500dpi

Next, I applied linseed oil to the result. I bought a small clock movement with brass parts, which I inserted into the hole in the face.

My favorite part is how the color changes depending on whether you’re looking at it along the grain or against the grain. One way, it looks golden, and the other way, it looks reddish in color.

A few days ago I made a low-profile fan for my window out of computer fans. I wanted to mount the fans in a laser-cut frame, so I started by taking measurements and drafting the design in SolidWorks.

This row of fans takes up only a few vertical inches of window real estate.

Often, when I make a design in SolidWorks, I include a file for storing global variables for my project. I liken this to defining global variables or constants at the beginning of a software project. I use this technique frequently to great utility in SolidWorks, but I don’t see very many colleagues use it, so let me elaborate on it.

First, I make a text file called “dimensions.txt” or similar, and, in it, I list all the global variables I’d like to use in my project, like the example below. These include values that I’d like to be the same across parts files. I also include values that I think will have to be changed by the end of the project.

For example, for this project, I thought I might change what computer fan I used and how many I used, so I included mounting dimensions for the fan as well as the quantity of fans.

However, I knew the width of the window wouldn’t change, and was only used in one or two parts, so I didn’t include that constant in my list of project-wide constants.

"dimensions.txt"

1 "depth" = 0.98
2 "side" = 2.36
3 "hole spacing" = 1.97 'horizontal or vertical distance between two holes
4 "fan diameter" = 2.52
5 "fan count" = 6
6

There are some tricks to this text file–for SolidWorks to understand it, all variables must be enclosed in quotes ( ” ” ), comments must be preceded by a single quote ( ‘ ), and the file must end with a newline. Note that in the box above, the numbers on the left mark the lines but are not in the actual text file.

I save dimensions.txt in the root directory of my SolidWorks project. Then, whenever I make a new part, I first use the Equations dialogue in SolidWorks to import this file into the list of parameters for that part; the screenshot below shows the Equations dialogue after importing dimensions.txt. For a parametric modeling software, I think SW sure has this parameter dialogue tucked away, so I have it hotkeyed to Q, the same as the default in Autodesk Inventor, if I recall correctly.

In addition to the globals imported from dimensions.txt, I added a few values specific to this part, the front panel. These values in particular were derived from the globals in dimensions.txt, but they weren’t necessary to be known by every part in the assembly.

Then, whenever I dimension a sketch or feature in the part, I link those values to the global variables imported in dimensions.txt, as shown below.

I linked the values of the dimensions here to my global variables, as indicated by the red chainlink symbol.

This allows me to change parameters after I’ve finished the basic CAD. Whenever the part or assembly is rebuilt, SolidWorks automatically refreshes the values in dimensions.txt. Consequently, I can change one value with my text editor, rebuild the top-level assembly in SolidWorks (ctrl+b), and all files update their parameters from dimensions.txt.

This actually ended up being relevant for this project because I found an extra fan of the same size as my earlier ones, and I wanted to add it to the array. Due to this technique, this change required an order of magnitude fewer operations–my panel and assembly were updated immediately and automatically, as demonstrated below.

Changing from five fans to six required about two clicks instead of a dozen.

Anyway, after I made this design, I laser cut the front panel.

I’m a huge fan of how fast laser cutters are.

Then, I screwed it all together and ran it off of a 5V couple-Amp power supply.

I covered the rest of the fan box with a sheet of cardboard.

Here’s another thing I made using a laser cutter!

Poi Holder

I cut a sock poi holder out of acrylic. It’s a slot with a curved, tapered opening, so it’s easy for poi to slide in to hang and slide out. First, I made a holder out of cardboard, but then I cut some out of acrylic, which resulted in a slot that is a much smoother and less likely to catch.

Here are the acrylic pieces. I set the design a few thou large to account for the laser kerf as noted in Charles’s guide.

Here are the pieces prior to assembly.

The holes in the back are for screwing mounting the holder.

Then, I assembled them and fused them with cyanoacrylate glue.

Wood screws secure this piece against a 2×4.

The color is great.

Other Stuff

I also prototyped a mount for an optical quadrature encoder and a mount for a robotic radiator dial controller, but I’ll post about those later.

Laser cutters are really sweet! You just put your material in, and then you wait a few seconds, and you’ve machined this really complicated part. Here’s some stuff I made using a laser cutter over the past year.

Stencil for Bleaching a Shirt

My friend Kirsten L. gave me this idea and helped me make stencils for making bleached T-shirts. Here from Make and here from Stencilry are instructions for making T-shirts with cool graphic effects using bleach and a stencil. However, instead of making a stencil by hand, I used a laser cutter, which was really easy. I didn’t use very complex designs, but a laser cutter would be way preferable compared to hand cutting for very intricate stencils.

This stencil was cut from cardboard using a laser cutter.

I mixed and sprayed bleach using a spray bottle.

Here’s one with a fire nation symbol. whooo fire.

Here’s my shirt!

I also made another shirt. In my next post I’ll tell you about something else I made with a laser cutter.