Yeah I’m sure I don’t need to tell you that EVA shrinks a bit with heat.
Maybe it’s like a kerf setting to keep in mind, I’d imagine the shrinkage is pretty predictable?
I did get an error about the assist fan not running at the right speed, and then, like you did, moved my magnets to the front. I can see how it might stress the assist fan motor if you drive over those powerful things repeatedly. Maybe I should design seatbelts for the foam that doesn’t require magnets… hmm.
I’ve been cutting stencils using magnets too, but the stencil film is not thick, so the magnets are not as close to the fans. I might use weaker magnets for that, since I don’t need the mega scary ones to hold that thin plastic down.
What does “Back to the mothership” cost you other than time? I don’t suppose you could replace that fan yourself if need be?
They did a warranty replacement, thank goodness, so I’m not sure what it would have cost!
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Have you met my new friend?
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Glue a magnet to the handle and the stamp(s) so you can use multiple images.
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I did see that. It’s fab. How sucky is it? would it hold down this thick foam?
I’m worried about the close the chord in the door part, as I’m not up for cutting a hole in my machine at the moment. I have a Plus. You tried it, yes? Does the glowforge think it’s closed?
This would be exceptionally helpful making detailed stencils. The little bits pop out and fuse onto the stencil. I have to more or less scrape and poke them out after. I’d love to skip that step.
Sort of? The laser goes back and forth when engraving, and edges that are more parallel to the engraving direction seem to shrink back a little more than edges orthogonal to the passes. Or at least it is somewhat nonuniform having to do with the direction the laser is passing.
That said, the stamp came out pretty dang circular. These foam stamps are not high precision anyway. You’d want to use a harder material like rubber or wood for block printing if you wanted precision.
I was thinking velcro, but yeah, good idea.
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It is easy to imagine what a moving object using electrical connections feels when passing through a strong magnetic field, The fan is moving faster with more amps so shows it more but any material that can transmit electrons will be perturbed some.
if you can loosely hold a screwdriver at a location the head might pass and can feel the pull then it is too much.
Better to make bed pins and hold things down that way. If you need to hold down an area you can hold down some scrap that covers the area needed.
Ohhhh … something new to play with! I appreciate you sharing your process. Thank you!
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Awesome technique and share!
Not sure if you have seen the holdown pins before, but if not, these might be the magic seatbelts you’ve been looking for! They’re pretty friggin’ amazing. There’s been several updated version and the ones with only one handle are my favorite.
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I have some 3D printed ones. Do you just jam them into the waffle? is there a direction they fit nicely? I had trouble because the head/handle bit stuck up too far when holding down the foam (it’s pretty thick). I’m going to print some with a flat top bit.
Are the ones you like in the free designs folder?
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Search for “honeycomb hold down pins” and it’ll pop right up.
There’s usually one angle where they’re loose, and one where they’re tight - but two spots next to each other can be opposite angles.
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Yes, it’s @primal_healer version and here’s the link to them. I used to break the other ones trying to get them out and I don’t have issues with these at all. And they’re pretty intuitive because they only fit in my tray one way. I wonder if you could flatter the head a bit to get them under the head? 
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Thanks, that is different from the one I’m using.
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In his thread he says you can run it in the front, with the lid closed, but that you need a thin cord for the power. Not sure what thin is, but I’ve seen some pretty thin cords on power supplies that I would expect to work.
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just so i understand, how big is the piece of foam you are cutting out the disk? and the magnets go on the edges (front?) to keep it in place and avoid the air assist, right?
in the cnc world they use masking tape and super glue. a layer of tape, super glue down the middle, then the second tape stuck to the board and sprayed with accelerator for quick curing. I have started using masking and double sided tape. less mess and easier to remove. maybe that would work.
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I have used painters’ tape on the edge of stuff like the foam, then put a strip of scrap on the side of the tape that’s on the honeycomb tray, and pin the scrap down with honeycomb pins.
If I ever cleaned my tray, the tape would probably just stick to it and I wouldn’t have to go to all the extra trouble. 
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I don’t know why I felt the need to put on my weenie hat for this reply. But now I’ve written it, seems a shame to delete it. So here it is FWIW. 
The motor is brushless, so the armature (wire windings) don’t rotate, the magnets do. The magnets inside the motor are the same rare-earth Neodymium as the magnets on the crumb tray. They’re smaller for sure, but they’re a lot closer to the windings and that matters more. So the current induced in the motor by its own magnets is going to be much greater than the contribution from magnets on the crumb tray. IMO, I don’t think the crumb tray magnets can be inducing much if any current in the motor windings.
The problem I think, is that the fan uses a speed-regulated DC motor. I don’t think that there’s anything particularly special about it. Just a typical brushless DC fan. But it’s a motor, and motor operation depends on magnetism, and external magnetic fields will affect the field inside the motor, which will negatively impact the motor’s performance. And if the motor’s speed is regulated, the motor controller will have to push the motor harder to maintain speed. That’ll make the motor run hotter and heat accelerates failure.
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Actual experience tells a different story, A strong Magnet on the crumb tray will halt the motor when in range of the field and slow it down when in some distance. It took me a year and a dead Glowforge to figure that out, but once I did a whole lot of things made sense that had not before.