CNC Machining Tips for Design Engineers

For design engineers, transforming a brilliant concept into a functional, highquality part is the ultimate goal. CNC machining is a premier method for achieving this, offering unparalleled precision for prototypes and production runs. To fully leverage its capabilities and ensure your designs are not only innovative but also manufacturable and costeffective, consider these essential tips.


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1. Mind the Wall Thickness
One of the most common pitfalls in CNC design is specifying walls that are too thin. Thin walls are prone to vibration during machining, leading to poor surface finish, dimensional inaccuracies, and even tool breakage. For metals, a minimum wall thickness of 0.8 mm is generally advisable, while for plastics, it should be at least 1.5 mm. Reinforcing thin features with gussets or ribs can add necessary strength without drastically increasing material usage.

2. Optimize Internal Corner Radii
Designing sharp internal corners is impossible with CNC machining because cutting tools are cylindrical. Specifying a sharp corner will result in a toolradiused fillet regardless. Always design internal corners with a radius slightly larger than the intended tool size. This allows the tool to follow a smooth path, reducing machining time and cost. A standard radius recommendation is beneficial, but if possible, use the same radius for all corners to minimize tool changes.

3. Limit the Depth of Cavities and Holes

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Machining deep cavities and holes presents significant challenges. Long tools required for deep features are more susceptible to deflection (bending), vibration, and breakage, which compromises accuracy and surface quality. A good rule of thumb is to limit cavity depths to four times their diameter. For deeper holes, consider designing them as throughholes or plan for secondary operations like gun drilling.

4. Design with Standard Tooling in Mind
Custom tooling is expensive and increases lead times. You can dramatically reduce costs by designing features that can be machined with standard cutter sizes. For example, specify standard drill sizes for holes and avoid nonstandard keyways or slot widths. This simplifies the machining process and allows for faster production.



5. Choose the Right Material for the Application
Material selection is a critical balance between functionality, machinability, and cost. While highstrength alloys like titanium or 718 Inconel are excellent for extreme environments, they are difficult and timeconsuming to machine. For most applications, aluminum alloys like 6061 or 7075 offer an outstanding strengthtoweight ratio and excellent machinability, leading to faster turnaround and lower costs. Always consult with your manufacturing partner during the material selection phase.

By integrating these designformanufacturability (DFM) principles, you streamline the transition from CAD model to finished part. This collaboration minimizes costly revisions, accelerates timetomarket, and ensures you receive durable, precision components that perform as intended.

Partnering with a seasoned provider like ours for your CNC machining needs guarantees expert DFM feedback and a seamless, endtoend service from quote to delivery, driving growth for your projects through efficiency and reliability.