K-Factor Calculator

K-factor is a parameter that defines the location of the neutral axis during sheet metal bending. It represents the ratio of the distance from the inside surface to the neutral axis, divided by the material thickness. The K-factor helps predict how much material is needed for accurate bends.

K-factor is calculated using the formula: K = (180° × BA) / (π × θ × T) - Ri/T, where BA is bend allowance, θ is bend angle, T is material thickness, and Ri is inside radius. Alternatively, it can be determined through reverse engineering by measuring actual bent parts.

The main variables affecting K-factor are material type and thickness, bend radius, bend angle, and the bending method used. Material properties like ductility, grain direction, and work hardening also influence the K-factor value.

K-factor typically ranges from 0.3 to 0.5 for most materials. Soft materials like aluminum often have K-factors around 0.33-0.4, while harder materials like steel may range from 0.4-0.5. The exact value depends on specific material properties and bending conditions.

K-factor is crucial for calculating accurate flat pattern dimensions before bending. It ensures that the final bent part matches the desired dimensions, reducing material waste and improving manufacturing precision. Without proper K-factor values, parts may be too long or too short after bending.

A larger bend radius generally results in a higher K-factor because the neutral axis moves closer to the outside of the bend. Sharp bends with small radii have lower K-factors as more material compression occurs on the inside surface.

Yes, K-factor can be determined through reverse engineering by creating test bends. Measure the flat length before bending, then bend at a known angle and radius, and measure the final dimensions. This empirical method often provides the most accurate K-factor for specific materials and tooling.