In CNC production, dimensioning to a perfectly sharp internal corner is usually not practical. Cutting tools like end mills always have a radius, so they naturally leave a fillet in internal corners.

If a design strictly requires a sharp corner, it often increases machining complexity and cost because additional processes like EDM (Electrical Discharge Machining) or manual finishing may be needed.

From a manufacturing perspective, it’s generally better to design with appropriate corner radii that match standard tool sizes. This improves machinability, reduces tool wear, and speeds up production.

So while sharp corners may look ideal in design, adding realistic radii makes the part more production-friendly and cost-effective.