Designing parts for CNC machining requires balancing functionality, manufacturability, and cost-efficiency. At Faro Mold, we’ve compiled expert tips to help you avoid common pitfalls and ensure your designs are optimized for precision machining.

1. Mind the Wall Thickness

• Avoid Ultra-Thin Walls: Thin walls (<1mm for metals, <1.5mm for plastics) may warp or break during machining.

• Uniform Thickness: Maintain consistent wall thickness to prevent uneven stress distribution and tool deflection.

Pro Tip: For lightweight parts, use ribbing or lattice structures instead of reducing wall thickness excessively.

2. Optimize Internal Corners

• Add Radii: Sharp internal corners are impossible to machine. Design radii ≥1/3 of the cavity depth (e.g., 3mm radius for a 10mm-deep pocket).

• T-Slots & Undercuts: Avoid unless necessary. If required, specify early to plan for specialty tooling.

Pro Tip: Use fillets instead of 90° angles to reduce stress concentrations and improve part strength.

3. Simplify Complex Geometries

• Minimize Multi-Axis Requirements: 3-axis machining is cost-effective. Complex 5-axis features may increase costs.

• Avoid Deep Cavities: Deep, narrow pockets require long tools, raising vibration risks and tolerancing challenges.

Pro Tip: Split overly complex parts into multiple components for easier machining and assembly.

4. Design for Standard Tooling

• Hole Diameters: Use standard drill sizes (metric/imperial) to avoid custom tooling.

• Threads: Specify common thread types (M6, UNC) and avoid blind holes deeper than 3x diameter.

• Chamfers vs. Burrs: Add chamfers (≥0.5mm) to edges for deburring ease and safety.

Pro Tip: Include a technical drawing with tolerances and critical dimensions for clarity.

5. Material-Specific Considerations

• Metals (Aluminum, Steel): Avoid tiny features prone to tool wear; account for thermal expansion.

• Plastics (ABS, Nylon): Design thicker walls to prevent flexing; avoid sharp transitions to reduce cracking.

Pro Tip: Consult our team early for material recommendations based on your part’s load, environment, and finish needs.

6. Tolerances: Balance Precision & Cost

• Critical Features Only: Apply tight tolerances (±0.05mm) only where essential.

• Non-Critical Areas: Use standard tolerances (±0.1mm) to reduce machining time and cost.

Pro Tip: GD&T (Geometric Dimensioning and Tolerancing) ensures clarity for complex parts.

7. Optimize for Surface Finishes

• Texture & Tool Marks: Specify surface roughness requirements (e.g., Ra 1.6µm) if aesthetics matter.

Post-Processing Needs: Design features to accommodate finishes like anodizing (avoid trapped pockets) or polishing (smooth transitions).

8. Reduce Machining Time

• Minimize Tool Changes: Group similar features (e.g., holes of the same size).

• Avoid Excessive Stock Removal: Start with near-net-shape raw material when possible.

Pro Tip: Use simulations or DFM (Design for Manufacturability) software to predict machining challenges.

Collaborate with Experts

Even the best designs benefit from a manufacturing review. At Faro Mold, we offer free DFM analysis to:

• Identify cost-saving opportunities.

• Recommend design tweaks for faster production.

• Ensure your part aligns with CNC best practices.

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Ready to Optimize Your Design?

Submit your CAD files today, and let our engineers help you refine your part for seamless CNC machining.

Upload Your Design Now – and experience precision, efficiency, and cost-effectiveness from prototype to production.