How to Design for CNC Machining

In the competitive world of custom part manufacturing, designing for manufacturability (DFM) is not just a best practice—it's a critical factor in determining cost, lead time, and final part quality. For businesses seeking reliable, highprecision components, understanding the core principles of designing for CNC machining is essential. As a leading onestopshop for CNC machining services, we've compiled key design strategies to help you optimize your parts and accelerate your time to market.


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1. Prioritize Internal Corner Radii
One of the most fundamental rules in CNC design is to avoid sharp internal corners. Cutting tools are cylindrical, so they naturally create radii. Always design internal pockets and vertical edges with a corner radius. Specifying a standard radius, slightly larger than the tool used, eliminates the need for specialized tools and reduces machining time and cost.

2. Optimize Wall Thickness
Excessively thin walls are prone to vibration during machining, leading to poor surface finish and potential part failure. Conversely, overly thick walls waste material and increase cycle times. Aim for a uniform and adequate wall thickness. A general guideline is to maintain a minimum wall thickness of 1mm for metals and 1.5mm for plastics to ensure stability and integrity.

3. Limit the Depth of Cavities and Holes

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Deep cavities require longreach tools, which can deflect (bend) during cutting, causing inaccuracies and tool breakage. A good rule is to limit cavity depths to four times their diameter. For deeper holes, consider designing them as throughholes or using specialized techniques like gun drilling, but be aware this adds cost.

4. Design for Standard Tooling
Customizing your design to use standard drill and tool sizes can drastically reduce costs. For example, specify thread sizes that are readily available. Designing holes with standard diameters avoids the need for nonstandard tooling, streamlining the machining process.



5. Consider Undercuts and Complex Geometries
While CNC machining is versatile, features like undercuts (internal recesses) often require special tooling and multiple setups. If an undercut is necessary, communicate this early. Our engineering team can advise on the most efficient way to machine it or suggest alternative designs that achieve the same function without the complexity.

Partner with Experts for Optimal Results
Adhering to these design principles will significantly enhance the manufacturability of your parts. However, the most effective strategy is to collaborate with your manufacturing partner from the initial design stage. Our engineering team provides free DFM analysis, offering expert feedback to refine your designs for performance, costefficiency, and rapid production.

By designing with CNC machining in mind, you unlock the full potential of this technology, ensuring you receive highquality, precision parts that drive your projects forward. Let us be your trusted partner in turning your innovative designs into reality.