Maximize efficiency and reduce manufacturing costs by applying core Design for Manufacturability principles in your next sheet metal project.
1. Maintain Minimum Bend Radius
The inside bend radius should never be less than the material thickness. Going below this threshold causes cracking on the outer surface, especially with harder alloys like stainless steel. For aluminum, a 1:1 ratio (radius = thickness) is standard. For mild steel, 1.5× thickness provides a safer margin.
2. Keep Features Away from Bend Lines
Holes, slots, and tabs placed too close to a bend zone will deform during the bending process. The general rule is to maintain a clearance of at least 2× the material thickness plus the bend radius from any feature edge to the nearest bend line.
- Holes near bends become oval-shaped and lose positional accuracy
- Tabs near bends can tear or curl unpredictably
- Notches near bends create stress concentrators that lead to cracks
3. Design for Uniform Thickness
Mixing material thicknesses in a single part dramatically increases tooling costs and complicates nesting on the sheet. Wherever possible, consolidate your design into a single gauge. If different thicknesses are structurally necessary, consider breaking the assembly into separate parts joined by fasteners or spot welds.
4. Standardize Hardware and Fasteners
Using industry-standard PEM inserts, clinch nuts, and self-clinching standoffs eliminates secondary machining operations. Design your hole patterns to match standard hardware catalogs — this reduces lead times and inventory costs across your entire product line.
5. Optimize Flat Pattern Nesting
Consider how your flat pattern will nest on a standard sheet size (typically 48" × 120" or 1220mm × 3050mm). Designs that nest efficiently can reduce material waste by 15–30%, which compounds into significant savings on high-volume production runs.
- Avoid odd angles that prevent tight nesting
- Use rectangular profiles where possible
- Coordinate with your fabricator on their standard sheet sizes early in the design phase
The Bottom Line
Applying these five DFM principles at the CAD stage prevents costly surprises during manufacturing. A few hours of design optimization upfront can save weeks of rework and thousands in scrap costs downstream.