Best Practices for Designing Undercuts in CNC Machined Parts

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Undercuts are essential yet challenging features in CNC machined parts, often necessary for creating interlocking components, retaining rings, or complex geometries. While our一站式零部件加工 service excels at producing them, designing with manufacturability in mind is key to ensuring costeffectiveness, quality, and faster lead times. Here are critical best practices to follow.


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First, prioritize standard tooling. Custom undercut tools increase cost and delay. Design undercuts with widths and depths achievable with standard lollipop (neck) or undercutting end mills. A common guideline is to keep the undercut depth no greater than the tool's cutting diameter. For Tslots or dovetails, ensure sufficient clearance for the tool to enter and exit without collision.

Second, incorporate adequate clearance. The tool shaft must not rub against the part wall. Always include a relief area behind the undercut's profile. This extra space is nonfunctional but crucial for machining, preventing tool deflection and ensuring a clean finish. Neglecting this leads to increased machining time and potential part damage.

Third, consider accessibility. Can the tool reach the undercut without interference? Deep, internal undercuts or those in confined areas may be impossible with a 3axis mill. Early consultation with our engineering team can determine if a 3axis, multiaxis, or even a wire EDM approach is most efficient, avoiding costly redesigns later.

Finally, optimize tolerances and finish requirements. Tight tolerances inside an undercut are difficult and expensive to achieve. Specify them only where functionally critical. Similarly, requesting a high surface finish in a hardtoreach undercut can drastically increase cycle time. Apply realistic callouts to control cost.

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By integrating these design for manufacturability (DFM) principles, you directly contribute to a smoother production process. It enables us to leverage our full CNC capabilities to deliver your precision parts faster and more economically. Partnering with us early in the design phase ensures your components with undercuts are not only innovative but also optimized for reliable and scalable manufacturing, driving your project's success and growth.