Hi all! I’m working on a gift for a friend’s wedding (custom engraved champagne glasses), but I’m having trouble cutting nice shapes out of polyurethane foam for packaging, even when using a brand new Exacto blade.
I’d love to be able to cut a 3D shape (to follow the curve of the glass), but at this point, I think that may be beyond my abilities, and I’ll just have to do 2D all the way through.
Any tips for cutting in a nice, professional-looking manner? I’ve attached some pictures for showing the rough edges I’ve got now.
I’d look into getting or making a foam cutter. Cut out the shadow/outline of the glass and then put a thinner layer below and above and you should be set to pack them.
I don’t have a lot of experience with our Lasers, but I feel like this would be pretty easy on one of the larger ones.
There has been talk of this on the laser front. We just need a laser instructor committed to teaching this as an advanced laser class topic as it requires changing out some hardware.
This seems like something the CNC could do well, especially if your looking for the 3d aspect.
Polyethylene foams laser well, but he’s asking about polyurethane. That may end up sticky and smelly.
Oh, I hadn’t thought of that! Two quick questions that I couldn’t find the answers to online - are there any safety concerns around CNC-ing polyurethane foam at the space? And would you need foam-specific router bits?
I have these ones, so I can play around with feeds and speeds to figure those out, but I just want to make sure I’m not doing anything risky for the machines or people in the space.
Ahh, thanks for the clarification @dannym — I’ll remember that.
Thanks, Valerie and Danny! I think I’ll stay away from lasers for this project, and maybe I’ll look into PE foam for another project.
One other tool to consider is the Shaper Origin.
How rigid is the foam? If it’s pretty squishy, it could turn into a huge PITA on the CNC, especially if you’re trying to 3D carve it. There are foam cutting bits you could try.
If you want that 3D carved look, you could get thinner sheets of foam, then stepwise cut the profile like a topo map basically. Then glue the layers back together. Sounds like that would work pretty well on the lasers with PE foam.
The o-flute would be your best bet. Sharpest new bit only.
But also look at how this is going to be held down. It’s foam, clamps will only squish it. Double sided tape may be the best option.
If you’re cutting a pocket, he basic problem at the bit is that the foam may push out of the way. Larger step over may work better than small.
I would still give the laser a try though. I know PE foam cut well for sure, just not sure of the cut quality on PU.
Polyurethane foam cuts fine. It does get sticky and smelly, but not much worse than polystyrene. I used my xTool, blue diode laser to cut some inserts for my miniatures painting kit and they turned out great, though it did have trouble getting through the 1" material.
You can get hand held foam cutters from Amazon. This is a set I got with a few different tips.