CNC wood machining requires understanding how fibers behave under cutting load.
Unlike metal, wood has a grain direction — cut it wrong and you’ll get tear-out, fuzz, and chatter.
Compression and Upcut Tools
Use compression bits when cutting plywood or laminates. Their dual-direction flutes pull up on the bottom and down on the top, compressing the layers to avoid breakout.
For solid hardwood, upcut bits clear chips faster but can lift fibers — climb cutting minimizes this.
Feeds, Speeds, and Chip Load
For MDF, aim for:
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¼" bit: 18 000 RPM @ 200 IPM feed
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⅜" bit: 16 000 RPM @ 250 IPM feed
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½" bit: 14 000 RPM @ 300 IPM feed
Always watch chip size — dust means you’re rubbing, not cutting.
The Onion-Skin Technique
Cut 95% through on the first pass, leaving a 0.010–0.015" skin to hold the part.
On the final pass, remove the skin in a full-depth cut. This prevents small parts from vibrating or shifting.
Toolpath Direction
Always climb-cut on the final contour for a cleaner edge.
If tear-out persists, reverse the direction and test a conventional pass — each species reacts differently.
Vacuum Hold-Down & Fixturing
Leaks kill precision. Use MDF spoilboards with gasket channels and ensure a fresh surfacing every few days.
Add onion-skins or tabs for small parts that might lift.
Takeaway
Programming wood successfully isn’t just about speed — it’s about grain awareness, sharp tools, and clean chip evacuation.
A properly dialed program leaves a sand-free edge that’s ready for finish straight off the table.
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