Anybody have any luck with this? I am thinking about machining some inserts for a buddy for his gun cases and a few other cases for him. Would fit in pelican type cases. What would be the best foam to use for that? Best place to buy the material? What type of bits would be best for larger cuts and for detail cuts? Sorry for all the questions, new to the CNC router world.
Kaizan (expanded polyethylene) foam is good for that and machines great on extrusion gantry routers. Some cases use soft eggcrate polyurethane foam, which wouldn't machine well. Not sure where to buy the material, I almost never need it, but I'm guessing a super sharp/polished HSS two-flute low spiral/straight cutter would be the way to go, there may be dedicated foam cutters too. I remember Grimsmo did a video on it, I dunno if it's helpful to this specific scenario or not, but it might be a decent introduction: I don't recall if it's in the video or if he mentioned it as a followup on the podcast, but you do the reverse of machining solid materials; you machine the outside profile of the pocket first, then clear out the middle. Doing it traditionally, there isn't enough support material to get a really clean cut on the outside wall for the finishing op.
cool thanks for the video. Didnt think about machining from the outside in, but that makes a lot of sense. I figured the typical eggcrate type foam that usually comes in those types of cases would be too soft and prone to tearing. I'll have to look into the Kaizan or some other types of foam that are a little more rigid.
I have had success doing this with various foams. Kaizen not available here but I have tried various polystyrenes and those rubber matts that clip together, sold here for kids play matts. I use a Dremel (or cheaper brand) 'tile grout removal bit' which works extremely well. It looks like a corn cob of tiny teeth. The other trick is exactly as Grimsmo said, use conventional cuts. I default to climb cuts so I usually have to think about this for foam (-: I have not tried the outside cut first thing, seems interesting, though I have had good cuts doing just standard pocketing generated by SketchUcam. (note that you have to set pocket cuts to CW before you add the cuts, it cannot be changed after the cuts are added,,,, yet, thinking of changing the way direction is selected )
btw, why does Grimsmo NOT have an Ox for cutting those foam inserts? seems the obvious solution to me, keeps the big mill clean and free to make metal parts and can run at the same time to do a square meter of foam at a time.
Good call on the conventional cuts, I'd forgotten about that. Seems like that would be the way to go for any lower-rigidity material. Play mat/floor mat puzzle pieces should be EVA, which is a good option, you just have to put build them up into solid chunks with Super 77 or something. I know he's thought about it, for that exact reason- foam runs on the Mori is kinda stupid (especially now with multi-palletisation on the knife parts). They've talked about the X-Carve, I think, or one of those types of pre-built machines, but throwing together an OB machine would be a way better option. Not sure if/when that's gonna happen... I guess when it significantly impacts knife production and he has 3 people downstream standing around idle!
I need to cut a tool board soon and will try this outside cut first thing on some scrap before I do the master cut. Intrigued
