Sheet Metal Design Tips: 8 Rules for Cost-Effective Fabrication

Sheet metal fabrication is fast, scalable, and cost-effective — when parts are designed for the process. But designs that ignore bending constraints, hole-to-bend distances, or material behavior end up with higher scrap rates, longer lead times, and inflated costs. Here are eight rules to keep your sheet metal parts manufacturable and your budget intact.

1. Select Material and Gauge Thoughtfully

Your material choice cascades through every downstream decision. Cold-rolled steel (CRS/SPCC) is the default for cost-sensitive enclosures. Stainless (304, 316) handles corrosion. Aluminum (5052, 6061) saves weight. Common gauges run 0.5–3 mm — thinner bends easier but may need stiffening features; thicker stock demands bigger bend radii and heavier press tonnage.

2. Don't Fight Minimum Bend Radii

Bend too tight and the material cracks on the outside of the bend. Safe starting point: internal radius ≥ material thickness for mild steel and aluminum. Stainless steel and spring steels need 1.5–2× thickness. Orient the most critical bends perpendicular to the grain direction for maximum strength.

3. Space Holes Away from Bends

Holes too close to a bend line distort during forming — they become oval or shift position. Minimum clearance: 2.5× material thickness + bend radius, measured from hole edge to bend line. If a hole must be closer, punch it as a secondary operation after bending (at additional cost).

4. Stick to 90° Bends

Standard press brake tooling is built around 90° bends. Acute angles require specialty dies, are harder to hold tolerance on, and increase per-part cost. Obtuse bends are feasible but confirm tooling availability with your fabricator. Designing around 90° keeps tooling cost low and dimensional consistency high.

5. Include Bend Relief Notches

Where a bend line meets a part edge or another feature, the material can tear or buckle without relief cuts. These small rectangular notches at bend line endpoints let the sheet fold cleanly. Width = material thickness; length extends slightly past the bend radius. A two-minute CAD edit that prevents real fabrication problems.

6. Optimize for Nesting

Flat blanks are laser- or turret-punched from standard sheet stock (commonly 4′ × 8′ or 1000 × 2000 mm). Irregular shapes waste material between parts. Symmetrical profiles and minimized flange sizes improve nesting density. At volume, even a few percent improvement in material utilization translates to meaningful cost savings.

7. Tolerance Realistically

Sheet metal isn't machining. Standard bend-affected tolerances: ±0.25–0.5 mm. Punched hole positions: ±0.1 mm. Over-specifying tolerances forces slower production, more inspection, and higher reject rates. Apply tight tolerances only where function demands it — mating surfaces, alignment features — and let everything else float.

8. Design Hardware and Joints into the Part

PEM inserts (press-fit nuts, standoffs), spot welds, and rivet joints need to be planned from the start. Each has specific hole diameter, edge distance, and flange overlap requirements. Retrofitting fastener locations after tooling is built means redesign, re-tooling, and delays. Get it right in the first revision.

Why More Buyers Are Sourcing Sheet Metal from Vietnam

Vietnam's sheet metal fabrication sector has grown quickly over the past decade. Top facilities run fiber laser cutters, CNC press brakes with offline programming, and automated powder coating lines. Quality certifications (ISO 9001, IATF 16949) are increasingly common. With labor costs 40–60% below China and growing free trade agreements reducing tariff exposure, Vietnam is a real option for US companies looking to diversify their supply chains.