Sheet Metal Tolerance Design Guide
Standard tolerance bands for punching, bending, and welding with annotation guidance you can apply directly.
Sheet metal tolerances vary by operation: punched holes ±0.1 mm, bend angle ±1°, welding distortion ±0.5 mm are common references.
1Punching tolerances
Hole diameter: ±0.05–0.1 mm (standard punch), ±0.02 mm (precision). Hole-to-hole: ±0.1 mm. Minimum hole diameter ≥ 1× sheet thickness for 0.5–6 mm stock.
2Bending tolerances
Bend angle: ±0.5–1° standard, ±0.3° precision. Flange length: ±0.2–0.5 mm. Minimum inside radius ≥ 1× thickness (mild steel), ≥ 1.5× for stainless.
3Welding tolerances
Distortion: ±0.5–1 mm on thin sheet (<3 mm), ±1–2 mm on thicker plate. Weld width: +2/−0 mm. Allow for stress relief distortion in assemblies.
4Stack-up
Use RSS (root sum square) for multi-step stack-up. Critical mating faces may need secondary machining after forming.
Key points
- Minimum hole ≥ sheet thickness
- Use k-factor for flat pattern development
- Baseline hole pitch ±0.1 mm
- Allow heat distortion on welded parts
- Add machining after bend for precision fits
Want the best process recommended for your part?
AI Quote Chat