Carving detailed maps on plywood for a tabletop, but getting tear-out

I've been working on a personal project where I'm using my CNC router to carve topographic maps onto plywood for a custom tabletop. The detail is intense, with lots of fine lines for elevation contours. Problem is, I keep getting tear-out on the cross-grain sections, especially where the map has sharp angles. I've tried slowing down the spindle speed and using a down-cut bit, but it's still not perfect. Has anyone else dealt with this on similar materials? I'm curious if there's a specific bit type or holding method that works better for preventing this kind of damage. Any advice would be really helpful.

3 comments

3 Comments

the_mia17h ago

Try a compression bit with climb cuts.

jenny_kim1d ago

Oh hey, what if you sealed the plywood with a light coat of shellac before carving? @charlesm11 has a point on bits, but sometimes the wood itself just needs to be hardened a bit first.

charlesm111d ago

Down-cut bits can sometimes make tear-out worse on the top surface when you exit a cut. Try a sharp up-cut bit and use a climb cutting direction. It pulls chips up and cleanly shears the cross-grain.