Personalized Pi Acrylic Nightlight Using a Diode Laser Engraver

I created a personalized Pi nightlight for my daughter who loves math and has memorized the first 100 digits of Pi. I made it from a blank piece of 4mm thick circular clear acrylic and a LED base. I used my xTool S1 laser engraver with a 40W diode laser and xTool Creative Space design software.

I will talk through all my steps including design and machine setup but my focus will be on the process I use to etch acrylic. You cannot cut clear acrylic with a diode laser, but you can etch it. You will need to use some type of substrate that will absorb the light energy and transfer it to the acrylic. I have used black craft paint and card stock in the past. Both work well but require a lot clean up and usually result in scratches on the acrylic. I have started using a piece of dark anodized aluminum flashing and have been very impressed with the results. 

Supplies

circular clear acrylic blank with LED base

brown anodized aluminum roll flashing

xTool S1 laser engraver with a 40W diode laser

xTool Honeycomb

magnets

lens cleaning cloth or towelette

Step 1: Graphic Design (symbol)

Launch Creative Space and import a vector file of a Pi symbol. I already had an svg from a previous project but you should be able to find one easily. Worse case, you can import and image and trace it. I like to draw a boundary to give me an idea of the size material that I will be working with. My blank acrylics are 5” diameter so I added a 5” circle to the canvas. I sized the Pi to approximately 3.5” and centered it in the 5” circle. I gave it a 0.05” outline and used the “Subtract at overlap” tool to combine it into one object. 

Step 2: Graphic Design (text)

Add a line of text. I used the default typeface (Lato) with a 95 pt. font and centered it on the symbol. I gave it a 0.05” outline, but I did not combine this time.

I wanted the name to appear in front of the symbol. I use the text outline as a boundary and the “Subtract” tool to trim out the portion of the symbol needed to be removed. In this process, the text outline will be deleted as well, so you will need to add another one. I combined the new text outline with the text using the “subtract at overlap” tool.

Step 3: Laser Settings

I’ve had the most consistent results on clear acrylic using the “Score” process type. I will usually score at 10% and speeds of 80-120 mm/s. I will run it a second time if it is not quite as defined as I like. These setting work well for my machine but performing a test grid is recommended.

Note: I have attempted to “Engrave” in the past with mixed results. If your power or process speed settings are a little off, it will likely burn the acrylic. 

Step 4: Machine Setup

I keep my xTool S1 in my home office and haven’t had any problems with smoke or odors, but it is a fully enclosed system with automatic ventilation. If you are using an “open frame” style, it is recommended to be in a well-ventilated area.

The acrylic blanks come with a protective film on both sides that will need to be removed. I try (although not always successfully) to only touch the acrylic on the edges once the film is removed. Fingerprints and smudges show up very well and are difficult to remove without scratching the surface.

I use my honeycomb when etching acrylic to have a clean flat surface for the aluminum flashing and acrylic. I cut a 12” piece of the flashing and place it dark side up on the honeycomb securing it with magnets. Make sure the flashing is clean and flat before the placement of the acrylic. I like to secure it with magnets as well.

Make sure you set your focal distance and framing area prior to processing!

Step 5: Process

“Process” the project. Once it is finish, look closely at your acrylic before touching it. If it doesn’t have the detail you are looking for, an additional pass may help. I have found that shining a flashlight from the edge will give you a good idea of the final outcome. 

Step 6: Finish

Carefully remove the acrylic from the laser engraver. You will likely need to clean some residue off from the engraving process. I like to clean by running warm water over the surface and pat dry with a soft cloth. Avoid rubbing it with anything like a paper towel as this will scratch it. I have had good luck with moist lens cleaning towelettes. Once clean you can insert the acrylic in the LED base.

The LED base that I purchased came with a USB power cord but can also operate on batteries. It also has a remote that will change the color and mode.