for those of you who have cut XPS foam, did you find any issues with static electricity?
A friend of mine who used to mill full size boats out of foam learned the hard way that he needed to ground his machine and his vacuum system because of static built up from the foam.
if any of you have needed to do this, how did you ground the mpcnc and vacuum.
I remember a low rider post about it. I can’t remember how he fixed it. I imagine grounding the electronics case, and run a bare wire through the vac hose would fix it.
I have milled some XPS foam (Foam core wing, the largest wing I milled was 60x32x5 cm).
Before I started, I also ran a ground wire through the vacuum hose (and through the vacuum itself), because I was afraid of static electricity clogging everything up.
It was quite cumbersome when I had to remove the hose to empty the vacuum. When I built my cyclone, I decided to remove the ground wire.
I have milled the wings with the cyclone, without the ground wire, and I basically had zero issues with static electricity. The foam does cling a bit to the inside of the bucket beneath the cyclone, but MDF dust also does that. The electronics worked fine. I should note that my RAMPS board is on the left side of my MPCNC while the cyclone is on the right side. No idea whether the distance makes any difference.
When I did have the ground wire, I just used a bare wire and connected one end to the earth ground pin of an extension cord (same extension chord I used for the vacuum).
@peter I now recall seeing that post before.
thanks for the input.
I’m planning to get started cutting a fuselage next month. Maybe sooner if I can get the CAD done.
One tip for CAM: go fast. If the tool goes too slowly, it can melt the foam. If you’re unlucky the melted foam will stick to your endmill. I did 40mm/s and that worked well. Deep cuts and large stepovers were fine too.
thanks @peter fast with deep cuts and large step overs will also reduce time - I would imagine anyway.