| Minimum Bend Radius (R_min) |
0.5T |
1.0T |
1.5T |
– Harder tempers (e.g., 6061-T8) require larger R_min (e.g., 1.0T).
– For stainless steel, R_min increases to 2.0T for thicknesses > 6mm. |
| Bend Line to Edge Distance |
≥1.5T |
≥1.5T |
≥2.0T |
Prevents edge buckling/tearing. For edges with sheared (not deburred) finishes, increase to 2.0T. |
| Bend Line to Hole/Cutout Distance |
≥2.0T |
≥2.0T |
≥2.5T |
Avoids hole distortion or material splitting. For holes ≤ 3mm diameter, increase to 2.5T (aluminum/CRS) or 3.0T (stainless steel). |
| Inside Bend Angle Tolerance |
±1° |
±1° |
±1.5° |
Tighter tolerances (±0.5°) are possible with precision tooling but increase cost. |
| Flat Pattern Length Tolerance |
±0.1mm + 0.005×T |
±0.1mm + 0.005×T |
±0.15mm + 0.008×T |
Accounts for bend allowance/deduction variations. Larger parts (>300mm) may have ±0.2mm tolerance. |
| Recommended Bend Sequence Priority |
1. Large outer bends
2. Small inner bends
3. Close-tolerance features |
Same as aluminum |
Same as aluminum, but allow extra tool clearance for harder material |
Avoid nesting bends (inner bends blocked by outer bends) — critical for stainless steel due to tool wear. |
| Maximum Bend Height (Per Operation) |
Up to 300mm (depends on press brake capacity) |
Up to 350mm |
Up to 300mm |
Limited by press brake tooling length and material rigidity. For taller bends, split into multiple operations. |
