Free online calculators for press brake tonnage, bend allowance, K-factor, minimum bend radius, and plate roll blank size โ plus a complete A-Z glossary of sheet metal and CNC fabrication terms.
Enter your values and get instant results โ all calculations use metric units (mm, tonnes).
Required bending force for air bending in mild steel
Formula: T = (C ร tยฒ ร L) / V โ where C = 575 for mild steel. Material factor applied for stainless, aluminum, and high-strength steel. Add 20% safety margin before specifying press capacity. This calculator is for air bending only.
Flat blank length for sheet metal bends (K-factor method)
Bend Allowance (BA) = (ฯ / 180) ร (R + K ร t) ร A. Add BA to the sum of your flange lengths to get the total flat blank length. Bend Deduction = 2 ร (R + t) ร tan(A/2) โ BA.
Smallest inside radius without cracking the material
Minimum bend radius is the smallest inside radius that can be formed without cracking the outer surface. Bending with the grain (parallel to the rolling direction) doubles the risk of cracking โ always bend across the grain where possible. Values are typical industry guidelines; test on sample material before production.
Flat blank (developed length) for cylinders and rings
Blank length = ฯ ร (ID + t) using the neutral axis at mid-thickness. Add 5โ10mm weld seam allowance for full cylinders. Outside diameter = ID + 2t. This calculator gives the blank size before welding โ include your specific fit-up and closing allowance.
Definitions for common terms used in sheet metal fabrication, CNC press brake operation, fiber laser cutting, and plate rolling.
Rise Tek's Canadian team can help with material selection, bending calculations, and machine recommendations for your specific application.