Specifically, anyone got settings for cutting the blue foam camping pad from Walmart? There’s an instructable that mentions it’s a safe type of foam to cut with laser and it’s cheap ($8 for a 2’x6’ piece), but the instructable writer wasn’t using a Glowforge.
I’ve played with it a bunch and while I’ve found settings that seem reasonable for cutting out a small square (2x3" or so), what doesn’t work is cutting smaller holes in it, especially if they’re close to one another. It’s definitely that there’s just too much heat in a small area and it melts the foam, particularly the middle of the hole. That’s not horrible except it always melts back to the first side it cut and thus is hard to remove. It also “wallows” out the hole on the bottom badly…that is to say the top looks dimensionally correct, but the bottom of the hole is often much larger than the top. I kind of need a uniform hole.
I’m almost thinking I need to separate my drawing into several sets of lines…the holes are rectangular, so I could probably make the top of all rectangles one cut, then the bottom, then the right side, then the left side, so that the heat isn’t all in that one spot for as long at one time.
Any other suggestions? The baseline that seems to cut fine for longer cuts is a speed of 200 and a power of about 85-90. But I’ve tried higher speeds, lower speeds, lower power with two passes, etc. Nothing seems to help much but I can definitely melt it a lot worse!
I’m going to shift this to the Beyond the Manual section for you, since Glowforge won’t comment or give settings information for products they don’t sell.
Some other customers might have cut it though and they can discuss it with you there.
Oh that’s not a problem, everyone misses it the first time.
You might find something similar in here already if you click on the little magnifying glass up in the right top corner and do a search for “foam settings”. This is the section we keep them in.
Thanks for the nudge there. I actually did do that in two other forums, but didn’t realize this was “the one”, so I hadn’t done that here. But I just did and still didn’t find what I’m looking for…learned a little generic knowledge that might help, but nothing concrete. Big problem is it seems while we can say “foam”, there are a TON of different foams out there that have different properties entirely. Ugh.
Well, the one cut that I did on foam was a different kind entirely, so I don’t have any helpful suggestions other than be extremely careful with it - foam can catch fire and toast your machine. Very easily. Never leave it unattended for even a minute.
i like the idea of breaking up the cuts into batches…like all vertical cuts then all horizontal cuts…that might work. If you set the lines to be different colors, you can do them that way, and leave a minute or two for the foam to cool between batches.
Yeah. Maybe do two passes at higher speed, lower power. The problem is not that the foam is tough to cut through, it’s that the beam is becoming more dispersed the further away from the focal point that you get. (And that foam melts rather badly.)
If you cut the top half of the foam at a much higher speed (300) you will not go as deep. Then on the second pass, lower the focal point to the middle of the foam sheet at 0.23" with a manual override. Do not touch the foam on the bed between the passes, and the second pass will land exactly where the first one was.
And do watch it very closely…the likelihood that foam will catch on the bottom is kind of high.
Part of your problem here likely is: when cutting the larger pieces, the head has time to come up to speed. When cutting small circles, it doesn’t have time to accelerate to those speeds but the power output is the same, so the total energy delivered to the material is greater (due to the slower speeds).
I would agree that is part of the issue. When cutting finicky things I have found that going slowly, like 100-150, helps to keep the true head speed more constant across various sizes of cuts.
From what I have seen of thinner EPS foam, multiple passes will help a lot too.
