CNC Pocket Design: Corner Radius, Tool Access and Machining Time

Primary SEO keywords: CNC pocket design, internal corner radius, machining DFM, milling design

Deep pockets and sharp internal corners are classic examples of CAD geometry that looks easy but can be expensive to machine. Good CNC pocket design considers the cutter from the beginning.

Why Sharp Corners Are Difficult

A standard milling cutter is round. That means a perfectly sharp internal corner usually requires a special tool or another manufacturing operation.

Use a Practical Corner Radius

Adding a sensible radius can allow a standard cutter to machine the feature more efficiently. The radius should still meet the functional requirement.

Think About Depth

Deep narrow pockets can cause tool deflection, vibration and poor chip evacuation. If the geometry can be opened up or made shallower without affecting function, consider doing so.

Tool Access

Ask how the cutter enters the pocket. If the tool cannot reach the bottom surface without colliding with surrounding walls, the feature needs redesign.

DFM Lesson

Do not wait for the machinist to discover difficult geometry. A few minutes of manufacturing thinking during CAD can save a lot of machining time.


Keep learning: Explore more practical engineering articles in the GetCADFile Design Guide.

Scroll to Top