Hey everyone! I'm working on a small box using a laser cutter to make pieces from 3mm plywood with finger joints for easy assembly. I've run into some warping issues with the plywood; some sheets are not completely flat. I'm wondering if there's a way to fix this warping or if I should consider switching to a different material that's flatter, like MDF. The box will eventually be covered, so I'm mostly focused on it being precise and as flat as possible. Any advice is greatly appreciated!
2 Answers
Thin materials like plywood are often prone to warping. You mentioned MDF, which is a great alternative as it's generally flatter. Another tip is to secure your workpiece with tape or even cut it down to size to minimize warping. At the maker space I go to, we have clips designed to fit in the laser bed grid which helps keep the edges down—might be worth trying!
What’s the size of your finished box? This thin plywood should press flat when you assemble it. If you're careful during assembly and apply some pressure, it might just straighten out. You could also use cauls and clamps to help keep everything square and flat.

It's about the size of a DVD case. I’m using a 20lb weight to glue it down this time, so hopefully that helps! But I might still grab some MDF or another flat material just in case.