My own currency

Before coming to Fab Academy, I had thought about creating custom reusable poker chip like coins for board games. Some board game have very lackluster coinage, so something nicer would be good.

At first I tried to make them by hand during my woodworking class, but that proved both extremely labour intensive and hard to make anything good looking. So the next step was to embrace digital manufacturing, and produce those coins with a laser cutter. Laser cutter enabled engraving, so I could create more interesting imagery on the coins.

Bought Parts

• A4 3mm laser cuttable birch plywood
• A4 3mm laser cuttable eucalyptus plywood
• A4 3mm laser cuttable oak plywood
• Osmo kirkas clear wood wax

Files

• Value 1 coins tails
• Value 1 coins heads
• Value 5 coins tails
• Value 5 coins heads
• Value 10 coins tails
• Value 110 coins heads

Steps for manufacturing

• Choose the value of coins you want
• Take the file for the tails of that coin (the numerical side), and laser cut and engrave that with your laser cutter.
• Tails side does not separate individual coins, but cuts a rectangle around all of them.
• Flip the rectangle in the laser cutter from left to right. (i.e. keep y-axis the same).
• Do not adjust the origin of the laser cutter
• Now laser cut and engrave the head side.

Diary

I drew the images with Affinity Designer, and exported them to Inkscape. Inkscape expected the files to be exported in 96 dpi (if I remember correctly), so I needed to be sure that the exported svg files from Affinity Designer matched.

In Inkscape I copied the shape with Clone -> Create Tiled Clones, and specified a tight grid that would fit in a A4 shape, as the plywood I had were cut into A4 for some reason.

I was not that exact on the positioning the coins into the grid. I started with exact measurements of 5 mm x 10 mm from the corner, but as Inkscape measures the position based on the visual edge of the line, and not the center of the line, the positions shift a bit when changing the line widths. All differences between the positions should be withing kerf, so it should be fine, even if the positions are not exact.

In order to make sure that the both sides of the coins are printed correctly, I need to be able to control the starting origin of the laser cutter. As the laser cutter that we have does not allow for such a thing, I drew a rectangle, that can be used as a guide to keep the origin in a controllable position.

After laser cutting them, I used wood wax to given them a finishing gloss and a nicer feel. As there were a lot of coins, I did not wax each coin individually. Instead, I put all of them in a plastic bag, poured the wax in it, and stirred the coins inside the bag in order to spread the was around evenly. The process worked well, but I should have used a bit more wax, as some coins were not coated properly.

I expected the wax to roughen the wood surface, which would have required me to sand them a bit, but that did not happen for some reason. Maybe plywood does react that way to wood waxes.