Hi guys, welcome to Ravi’s process of using the laser cutter and making a box. It’s been a while since I’ve last used a laser cutter back at Auburn, but I’ve only used it for etching purposes.

To create the building scheme for this box, I went over to this website – en.makercase.com. I thought a hexagon box would be cool, so that’s what I picked. The box parameters of inside diameter, inside height, and material thickness were 4”, 4”, and 1/8”, respectively. There were a few other parameters, like finger size and kerf thickness, which was ~0.5” and 0.013” (THIS WAS A MISTAKE), respectively. Here’s a quick rendering of what my box looks like:

After exporting my files into a .svg format, I was ready to start laser cutting at the OEDK. I learned all about the laser cutter in a recent training I had and I was prepared to use it:

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Here’s the MISTAKE I made – I guessed the kerf. I went through cutting a 0.5”x0.5” square to test the laser cutter settings. After tuning my settings to get the crispy, but not burnt, cuts I wanted, I cut and etched my box. I tried to assemble it but sadly it didn’t fit. I got frustrated, tried using a mallet to force it, and ended up breaking all my wood fingers.

After reflecting for a while, here’s the realization I made (pretty sure this is correct): kerf and part fit are inversely correlated. See I thought that if more was cut away (“the kerf”), the parts should fit looser by intuition, right? No – this is wrong. The box program probably slightly overcompensates box dimensions by the kerf width you specify. But if the Epilog machine’s true kerf is less than what you specified, less material is taken off than what the box program intended for leading to a tighter fit. On this next approach, I’ll actually calculate kerf using a test box. If I half the difference between the programmed and true measured width of a test box (0.5”x0.5”) after cutting, this should give me an appropriate kerf value.

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After that major disappointment, I was ready to try again. Here, I had a much better and planned approach. To calculate kerf, I programmed a 0.5”x0.5” box in Illustrator and cut it. Using calipers, I measured the distance of the width which was 0.48”. Taking half the difference between the true and measured width, I calculated my kerf to be 0.1”. Additionally, I printed an “R” on this box to test my etch settings. Here’s the test piece and the respective settings.

*units in %; freq = 50%	engrave (etch)	vector (cut)
speed	60	10
power	100	45

I tested the fit of the kerf by printing two box pieces and checking the fit – the fit was good!

After confirming I was happy with my fit, I went ahead and uploaded the .svg file into Illustrator. I added a couple of spiral patterns, a satellite, a brain, and my name. Using the same settings, I laser cut all six sides of the box – this took ~ 17 minutes.

When I started assembling my box, I was a little disappointed because my fit was a little tighter than expected. It was a struggle to put the box together and some of the wood fingers splintered a little. I truly have no idea what happened because I here I tested and tried my kerf of 0.1”. After talking to others, they used kerfs close to ~0.005” but I’m a little skeptical if that’s what they actually calculated or guessed based on others results. Our kerf values differed by a magnitude of two! Anyway, here’s the final box I made – I think it’s still pretty cool.

If I had to guess, maybe my wood wasn’t perfectly planar and so the locations where I printed my test piece and actual box changed the kerf. After all, the kerf is on such a small scale that it’s possible that it’s sensitive to other changes we wouldn’t consider.

Overall, this was a fun process – even though I failed twice, I feel like I’ve gained mastery over this machine. I do wish fabman.io would let us use the machine past 10 because I like working late.

Cost	Price	Source	Quantity	Total
0.2” planar wood	$9.5/ 288 in2	home depot	~96 in2	$3.5
operator	$15	me, the operator	2 hours	$30
overhead (running epilog laser cutter)				$25
			TOTAL:	~$58.5