How to Make Transparent Acrylic PCBs With a Cnc

What if a circuit board could be more than just functional—it could be a work of art? In this guide, I’ll show you how to make stunning transparent acrylic PCBs using a CNC machine with a surprisingly simple process.

Materials used

1. Transparent cast acrylic sheet
2. Only use cast acrylic, because extruded acrylic melts easily.
3. 3mm thick maximum
4. Adhesive-Backed Copper foil
5. Copper thickness of 0.06mm
6. Waterproof Adhesive
7. Double-sided tape
8. Hardboard sheet
9. 3mm thick

Software used

1. Any PCB design software that can export Gerber files
2. MakeraCam (Free) to create the toolpaths and generate the gcode

Tools used

1. Carvera Air Cnc
2. Air compressor
3. 30-degree 0.2mm V-bit
4. PCB drill bit set
5. Single flute 1/8ӯ 25mm endmill

Any PCB design software capable of generating Gerber files can be used, but I’ve designed an example circuit using Fusion.

This circuit features a 555 timer that flashes two LEDS alternately. The PCB uses through-hole components.

For the best results, PCB traces should be wider than usual. This makes the milling process easier, and the wider copper tracks look good!

The CNC machine that I used is the Carvera Air, which has a quick tool changer and height probe that are perfect for milling PCBs.

When we use a V-Bit to cut the tracks, the minimum distance between them is determined by the depth of cut. In this case, the copper layer is 0.06mm thick, and we will cut to a depth of 0.07mm. The minimum cut width is 0.238mm. Set this as the minimum distance between traces in the PCB software design rules.

Export the Gerber files from your PCB design software.

1. Stock settings:
2. Material: Plastic
3. Dimensions: 100mm x 70mm x 3mm
4. Import Gerber files:
5. Copper bottom Gerber
6. Profile Gerber
7. Drill files
8. Adjustments:
9. Delete the duplicate rectangle in the profile layer.
10. Mirror the bottom PCB design with Transform – Mirror
11. Move the design to the centre of the stock with Move – Quick Align Stock
12. Creating a toolpath to Drill Holes in the Acrylic
13. For each hole size:
14. Select the drill layer
15. Select menu 2D Path – 2D Drilling
16. Choose the correct drill size from the tool library
17. Select Plastic as the material
18. Set the drill tip end depth to 3.3mm
19. Set a different Tool number for each drill size
20. Enable peck drilling.
21. Click on calculate to create the toolpath
22. Repeat this process for each hole size.

To help with acrylic swarf build-up, create toolpaths for a small number of holes at a time. This allows us to clean the drill bit between toolpaths.

1. Creating a toolpath to Mill the Copper Traces
2. Select copper_bottom.gbr layer.
3. Select menu 2D Path – 2D Contour
4. Choose the 30-degree 0.2mm V-bit from the tool library
5. Select Copper material
6. Change the End Depth to 0.07mm
7. Change the Step down to 0.04mm
8. Select Outside Edge
9. Click on calculate to create the toolpath
10. Creating a toolpath to Cut Out the PCB Profile
11. Select the profile layer
12. Select menu 2D path – 2D Contour
13. Choose the 1/8” 25mm Single-flute endmill from the tool library
14. Select plastic material
15. Set the End Depth to 3.3mm
16. Enable Ramping for smooth entry
17. Click on calculate to create the toolpath
18. Creating a toolpath to Drill Holes in the Copper Layer
19. Select all the hole layers
20. Select menu 2D Path – 2D Drilling
21. Choose the 0.8mm drill size from the tool library
22. Select copper as the material
23. Set the drill tip end depth to 0.5mm
24. Set a Tool number
25. Enable peck drilling.
26. Click on calculate to create the toolpath
27. Export Gcode
28. Right-click on each toolpath and save the gcode

MakeraCam Project File

1. Import each gcode file into the cnc machine using the Carvera controller software

1. Prepare the acrylic sheet:
2. Cut the acrylic and hardboard to 100 x 70mm
3. Secure the acrylic to the hardboard with double-sided tape.
4. 
   
5. Clamp the acrylic and hardboard to the CNC table

1. Enable the Air supply to the Air nozzle

1. Select the 0.7mm drill gcode file
2. Set a work origin of X0, Y0 from Anchor 1
3. Enable Scan Margin
4. Enable Auto Z Probe
5. Click Run
6. Install the probe
7. Press the button to start probing
8. Install the 0.7mm drill bit
9. Press the button to start drilling
10. For the remaining drill files, repeat the process with scan margin and auto z probe disabled.

1. Remove the protective film from the acrylic sheet
2. Cut the copper sheet to 85 x 52mm
3. Smoothly apply the copper sheet to the acrylic, eliminating bubbles and creases.

1. Select the copper bottom gcode file
2. Set a work origin of X0, Y0 from Anchor 1
3. Enable Scan Margin
4. Enable Auto levelling with a 5×5 grid
5. Click Run
6. Install the probe
7. Press the button to start probing
8. Install the V-bit
9. Press the button to start milling the PCB traces

1. Select the drill copper 0.5mm gcode file
2. Set a work origin of X0, Y0 from Anchor
3. Disable Scan Margin
4. Disable Auto Z Probe
5. Disable Auto levelling
6. Click Run
7. Install the 0.8mm drill bit
8. Press the button to start drilling

1. Remove the unused copper between the tracks

1. Select the profile gcode file
2. Set a work origin of X0, Y0 from Anchor 1
3. Enable Scan Margin
4. Enable Auto Z Probe
5. Disable Auto levelling
6. Click Run
7. Install the 1/8” 25mm single flute endmill
8. Press the button to start milling the profile

1. Unclamp the board from the table
2. Remove the hardboard from the Acrylic
3. Remove the protective film from the Acrylic

Components can be soldered to the board in the normal way.

Use a fine-tipped soldering iron and work quickly.

Try to avoid any revisions.

Through-hole soldering adds strength to the tracks by clamping them to the acrylic.

This guide showcases a simple, single-sided design, but more intricate double-sided designs are easily possible.