Having never used a laser cutter before, this was definitely a new and exciting challenge for me! I stuck to the beginner assignment as a result, and produced a 4 in x 4 in x 4 in box with my same and college logo (#SRRdeathfromabove).
I started by using a 1/8″ thick piece of plywood (confirmed by calipers). I vector cut a few small 0.5″ squares in the corner of the plywood to find a speed, power, and frequency combo that would cut my plywood without excessive burning. This was largely a trial and error process: I used 100% power and 10% frequency the whole time and started at 25% speed as suggested by the sticky note by the laser cutter. This did not cut through the wood. I gradually worked down to 20, 18, 15, then finally 12.5 speed when I was able to contain a clean cut through the plywood:
Then, I learned an important lesson: make sure you have a large enough piece of plywood to cut out the whole length of the box! I had already entered thickness and calculated inner box dimensions based on the plywood width, but before cutting I realized that the whole box couldn’t be cut out from the plywood I had (following measurement)! I then found another piece of plywood and adjusted my dimensions accordingly in my notebook since it was 0.2″ thick (my work for different speed documentation can also be seen here):
I determined that I would want three to four tabs on each side of the box, so based on the 4″ sides measured accordingly for the tab width of 0.5″.
I then performed the prescribed kerf test. The first time I measured with a ruler and obtained a value of 0.0125″ for kerf (average over 10 cuts):
Moral of the story? Use calipers and be very exact when measuring kerf! After setting up my design in illustrator (picture below) and using a kerf value of 0.013″ (I naively rounded up thinking I could press them together), I cut out the design. It was perfectly cut out, as I had adjusted the speed to 10% in vector cutting to account for the thicker plywood. When I tried to fit the pieces together, however, they were too big. I overcompensated for kerf! I then went back and remeasured using calipers and confirming with the ruler that the kerf was closer to 0.009″. After inputting this value and recutting (I had to get a new piece of wood to do this), I got a good output that press fit together!
Cost Analysis:
Because of my relative inexperience on the laser cutter, this project took about six hours. As an unskilled laborer, I would get paid about $10 an hour, amounting to $60 in labor costs. The machine itself costs about 15 cents per hour in power consumption, so combined with computer power consumption will result in about $1.00 for my use of the machine in machine time [1]. Most of the cost incurred in a laser cutter project comes from the machine, not the raw materials. The only essential raw material for the final product was plywood, which costs about 32 cents per square foot [2]. Including my failed attempts, I used about nine square feet of plywood, which amounts to about $3.00 of plywood raw material cost. The epilog fusion pro itself costs about $30,000, though [3]. Therefore, without incorporating the costs of the rather expensive laser cutter machine, the total price of the box is about $64.00, most of which is labor costs. With the incorporation of the machinery cost, this is almost the only thing that matters as it is magnitudes more expensive than the labor to work it or materials required for the product.
References
- Power Consumption and your laser [Internet]. Epiloglaser.com. [cited 2022 Feb 6]. Available from: http://support.epiloglaser.com/article/8205/29954/power-consumption-and-your-laser
- Askinglot.com. [cited 2022 Feb 6]. Available from: https://askinglot.com/how-much-do-plywood-sheets-cost
- Top 10 Best Laser Engravers / Laser Cutting / laser engraving systems [Internet]. Laser Cutting Lab, LLC. 2014 [cited 2022 Feb 6]. Available from: https://lasercuttinglab.com/top-10-best-laser-engravers-for-laser-cutting-laser-engraving/
