Dfmpro Cuts Costs in Sheet Metal Manufacturing

In sheet metal manufacturing, design flaws often lead to costly rework, increased quality expenses, and production delays. Drawing from DFMPro (Design for Manufacturability Pro) principles, this article outlines essential design specifications to help engineers optimize designs, prevent manufacturing challenges, and ultimately reduce costs while enhancing productivity.

Consider this common scenario: a meticulously designed sheet metal component encounters repeated production failures—tearing around holes, fractures during bending, or complete part rejection. Each rework cycle represents wasted materials, labor hours, and delayed deliveries. These hidden costs accumulate significantly, making adherence to proper design standards crucial for successful sheet metal production.

Extrusion forming uses stamping equipment to apply pressure on metal sheets, creating plastic deformation to form specific hole shapes or protrusions. While useful for connections, positioning, or ventilation, improper extruded hole designs can cause material deformation, cracking, or rejection.

During extrusion, metals endure extreme pressure with significant friction and heat generation. Insufficient edge distance may cause deformation or tearing. To ensure part integrity:

• Maintain a minimum distance of three times material thickness (3t) from hole center to part edge.

This provides adequate material support during extrusion. For tighter edge requirements, consider alternative processes like drilling or laser cutting.

Multiple extruded holes require proper spacing to prevent mutual interference during forming:

• Maintain minimum center-to-center spacing of six times material thickness (6t) between adjacent holes.

Holes serve various functions in sheet metal components, but undersized holes may break punching tools or deform parts.

• Hole diameter should equal or exceed material thickness (d ≥ t).

For smaller diameters, consider laser cutting or EDM processes.

Press-fit fasteners provide reliable connections but require precise design to prevent deformation or failure.

Precisely match hole diameters to fastener specifications—oversized holes cause looseness while undersized holes prevent proper installation.

• Maintain minimum distance of twice fastener diameter from center to part edge.

Surface embossing enhances rigidity or provides positioning references, but excessive depth causes material thinning or cracking.

• Limit depth to three times material thickness (h ≤ 3t).

Bending radius significantly affects material deformation and part strength.

• Maintain minimum inner radius equal to material thickness (R ≥ 1t).

Edge curling strengthens and protects sharp edges.

• Minimum outer curl radius should be twice material thickness (R_outer ≥ 2t).

• Maintain distance equal to curl radius plus material thickness (d ≥ R + t).

Hemmed edges improve safety and aesthetics while potentially eliminating fasteners.

• Inner diameter should equal material thickness.

• Minimum distance: 5t + bend radius + hem radius (d ≥ 5t + R_bend + R_hem).

Notches create specific shapes or facilitate bending operations.

• Minimum width: 1.5 times material thickness (W ≥ 1.5t).

Adhering to these sheet metal design specifications enhances manufacturability while reducing costs and lead times. DFMPro tools help engineers identify potential manufacturing issues during design phases, enabling collaborative optimization between design and production teams. These guidelines should be adapted based on specific materials, processes, and applications, with continuous refinement driving improved product quality and cost efficiency.