Interesting - Fibonacci values emerge for engraving - same results faster/slower

Beyond the Manual
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Simple and interesting observation:
I just wanted to know what the optimal settings were for the fastest single pass on an engrave for an inlay at my desired depth.

By optimal I mean “fastest way to get the depth I need for an inlay”. After messing with seemingly random values for a few hours, eventually I saw a pattern, Fibonacci values emerging, so I went with it – All tests as follows:

  • Medium Maple [solid], Proofgrade, with tape
  • All @ 450 DPI:
  • Results: all of the following yield about same engraving depth (0.016" to 0.022") my minimum requirement depth is 0.015 in my case - measured with Mitutoyo caliper
  • the last one is the fastest. (there is a little overburn at the slower settings)

Settings for tests

  • 8 / 144 - engrave - 15min [not run, too absurd]
  • 13 / 233 - engrave - 7min [good] 0.022" depth + blackened
  • 21 / 377 - engrave - 6min [good]
  • 34 / 610 - engrave - 5min [good]
  • 55 / 987 - engrave - 4min [optimal] 0.016" depth

Conclusion: those are “kinda all the same” but the last one is the fastest. This really starts to matter when doing a [13 / 233] engrave for 8 hours VS a [55 / 987] engrave in 3.75 hours

Thoughts - since woods have different hardness I wonder if there is a way to ‘ensure several woods all end up with the same engraving depth’ (this is untested as of yet)

  • 21 / 377 - Cherry [2350 hardness]
  • 34 / 610 - Maple [1450 hardness]
  • 55 / 987 - Walnut [1010 hardness]

I feel like this would all be “negligible” for PLY vs SOLID

Seemed obvious to line em up for other combos to consider:
[skip 1, 2, 3, 5, 8]
Power: 13, 21, 34, 55, 89,
Speed: 144, 233, 377, 610, 987
[nothing on GF go’s past 1597]

At the least, this I think is a good place to start when trying to figure out a method to approach custom settings where you want to use several different hardwoods and engrave all of them at the same depth for an inlay.

In my case I am using the Fibonacci sequence as a “starting point” for dialing in settings across multiple wood types and that gave me a good “reason” for why I picked the numbers I did. Could be voodoo, could be superstition, only way to find out is to keep testing.

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Depending on the wood, I would anticipate the harder Winter growth rings to stand proud of the softer Summer rings.

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I do indeed notice that when comparing lets say Maple to RedOak… when that happens I just get in there with some dentists tools and scrape it off… its brittle.

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I am having trouble seeing how this video makes any meaningful contribution to further the discussion. Which kind of reminds me why I stopped coming here… don’t get me wrong, I like comedy, but “peanut gallery time” is not the same as community.glowforge time.

So, looks like I need to turn off notifications for this post too.

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This is what happens when you think of a thread you start as “yours”, which it isn’t. You put a post out there, where the thread goes is no longer up to you.

Once I started internalizing that I had a lot more fun here. If that’s not your jam then you’ll struggle to enjoy it, as you have seen.

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@christian.zagarskas if we were all the same the world would be very boring and there would be very little innovation. Some of us like to have a little fun with things and you can always scroll past if you’re not really into that… don’t take it personally, relax and keep posting. You will get the kind of conversation you’re looking for but also there will be stuff that doesn’t resonate and you can just scroll on by.

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OK, I’m a little confused. Why not just crank the speed to fastest and adjust the power to get the result you want?

I do know that very fast and very narrow engraves are not always fastest because of the overshoot, but that doesn’t appear to be what is being tested here.

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So it sounds kind of like you found a speed/power relationship that works pretty well for you. As we know, the result is largely about energy delivery, so that’s basically where your results are coming from.

GF Engrave Speed IPM Power
144 20.182 8
233 52.91 13
377 106 21
610 191.6 34
987 330.22 55

Speed and power are pretty linear as far as cutting. For example, by cutting something at 40 watts of power and 20 inches per minute, you would end up with the same results at 20 watts of power and 10 inches per minute. Granted, Glowforge doesn’t use percents for setting these factors, but as proof of concept, I’ve built out a spreadsheet for the Trotec that finds the max cutting speed at 100% power, and then extrapolated that out down to 0.1% speed, and the formula stays true down to as far as I’ve tested (I don’t think I’ve gone below 0.5% speed because slow…).

It’s a good way to see how processing quality can be improved by changing the heat-affected area. Also, if the accel/decel rates aren’t optimized, it can be a good way to find the fastest cutting speed for the project while making sure that your cut power is correct.

I think you could fine-tune the speed/power combos a bit and end up with less than a 30% variance in engraving depth.

What I am confused by is how you plan to use this for several different types of woods and wood hardnesses. Your chart confuses me (21/377 for hardest wood on the list, 34/610 for maple, and so on). How do these base numbers you’ve set up translate to different materials when it’s really about energy delivered? Since the depth was similar, the energy delivered was similar, so 21/377, 34/610, 55/987 all deliver approximately the same amount of energy – if the engrave depth is .016" on medium solid maple, why would any of those numbers result in the same engraving depth on a harder wood?

It sounds more like you’d want to find that cherry is X% harder than maple, so I need to deposit X amount more energy to the material for a similar material removal result.

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