Reduce Sheet Metal Fabrication Costs With Design for Manufacturing

Design for Manufacturing (DFM) is one of the most effective ways to reduce sheet metal fabrication costs. By optimizing designs early, you can minimize material waste, simplify labor-intensive processes, and reduce the risk of production errors.

1. Optimize Material Utilization

Material often accounts for a significant portion of the total cost. Small changes in geometry can lead to large savings.

• Standardize Gauges: Design parts using standard sheet metal thicknesses. Non-standard or "off-gauge" materials are more expensive and have longer lead times.

• Nesting Efficiency: Avoid irregular or interlocking shapes that leave large gaps when cut from a sheet. Parts that nest tightly together reduce "drop" (scrap).

• Grain Direction: If your part requires heavy bending, be mindful of the material grain. Designing parts to be cut along the grain can prevent cracking and reduce the need for higher-grade, more ductile materials.

2. Simplify Bends and Geometries

Complex bends require specialized tooling and more setup time, driving up labor costs.

• Consistent Bend Radii: Use the same bend radius for every fold in a single part. This allows the fabricator to use a single setup on the press brake rather than switching out dies.

• Avoid Small Flanges: Flanges should be at least 3-4 times the material thickness. If they are too small, they cannot be gripped properly by the machine, requiring expensive manual workarounds.

• Bend Reliefs: Always include bend reliefs (small notches where a bend meets an edge). Without them, the material will tear or deform, leading to a high rejection rate.

3. Minimize Hole and Slot Complexity

While lasers and waterjets are precise, the way you place holes can impact the structural integrity and cost of the part.

• Diameter vs. Thickness: As a rule of thumb, hole diameters should be at least equal to the material thickness. Smaller holes can break punches or require slower laser speeds.

• Hole Placement: Keep holes away from bend lines. If a hole is too close to a fold, it will stretch into an oval shape during the bending process.

• Standardize Hardware: Use standard sizes for PEM nuts, standoffs, and rivets to benefit from bulk pricing and automated insertion tools.

4. Reduce Post-Processing and Assembly

Labor is often the most expensive variable. Designing to eliminate manual "touch time" is crucial.

• Tab-and-Slot Design: Use tabs and slots to make parts self-aligning. This reduces the need for expensive welding fixtures and speeds up assembly.

• Limit Welding: Welding is labor-intensive and requires secondary grinding/finishing. Whenever possible, replace welded corners with folds or mechanical fasteners.

• Finish Selection: Only specify high-end finishes (like mirror polishing or specialized plating) where strictly necessary. For internal components, an "as-fabricated" or simple powder-coated finish is much cheaper.

Cost Comparison Summary

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