Key Principles for Extrusion Profile Design
Adhering to proven DFM (Design for Manufacturability) guidelines during the CAD design phase prevents die breakage, reduces profile weight, eliminates surface sink marks, and lowers overall tooling and extrusion costs.
1. Maintain Uniform Wall Thickness
Abrupt transitions between thick and thin wall sections cause uneven metal flow velocity and cooling differential stresses during extrusion. If thickness changes are necessary, incorporate gradual fillets and chamfers (minimum radius R ≥ 0.5mm – 1.0mm) to ensure balanced flow.
2. Control the Die Tongue Ratio
The tongue ratio is defined as the depth of a channel divided by its width (Depth / Width). Deep, narrow slots subject the steel die tongue to excessive bending stresses. Keep the tongue ratio below 3:1 for standard solid dies; ratios exceeding 4:1 require specialized bridge dies and may increase die cost.
3. Optimize Screw Boss and Snap-Fit Geometries
Integrated screw bosses allow self-tapping assembly screws without secondary drilling. Ensure the screw boss wall thickness is approximately 70%–80% of the adjacent main profile wall to prevent visible sink marks on the exterior decorative face.
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