How to Apply the Right Sheet Metal Bend Gains to Your Design (Updated for 2026)

Let Us Help You Get Bend Data Right

Last updated on September 2nd, 2026 at 01:38 pm

When a flat sheet metal blank is bent, material on the outside of the bend is placed in tension while material toward the inside is compressed. Accounting for that deformation is necessary to develop a flat pattern that produces the intended finished dimensions after forming.

For design engineers, this is where bend allowance, bend deduction, bend gain, and K-factor come into play. These values help connect the finished formed geometry in CAD to the flat pattern that will actually be cut and formed.

Bend Allowance vs. Bend Deduction vs. Bend Gain

These terms are related, but they are not interchangeable.

During bending, the outer surface stretches and the inner surface compresses. Between those regions is the neutral axis, where the material experiences much less change in length.

The location of that neutral axis is important because it affects the developed length of the flat blank.

Why Generic Bend Values Can Cause Problems

CAD software such as SOLIDWORKS can calculate flat patterns using a K-factor, bend allowance, bend deduction, or bend table. The challenge is that the result is only as accurate as the bend data entered into the model.

A generic K-factor or bend value may be useful during early design, but it may not match the material, tooling, and forming conditions that will actually be used in production.

Actual formed results can be influenced by:

• Material type
• Alloy and temper
• Material thickness
• Inside bend radius
• Bend angle
• Press brake tooling
• Die opening
• Forming method
• Material variation
• Springback
• Grain direction where applicable

Because of these variables, a fabricator may need to adjust the flat pattern supplied by the customer if the CAD bend parameters do not match the conditions that will actually be used to form the part.

The Role of Material Type and Thickness

Material selection has a major influence on how a part behaves during forming. Strength, ductility, temper, thickness, and springback can all affect the resulting bend geometry.

How Material Affects Bending

Different materials should not automatically use the same bend data, even when the finished bend angle appears identical.

For example, 5052-H32 aluminum, 6061-T6 aluminum, cold rolled steel, and stainless steel can respond differently to the same general forming operation.

Material-related factors include:

• Ductility: More formable materials can generally tolerate tighter bend geometry than less ductile materials.
• Strength and temper: These affect forming force, springback, and practical bend radius.
• Springback: Some materials recover more after the forming load is removed, requiring the forming process to compensate for the desired final angle.
• Grain direction: Rolling direction can affect bendability in some materials. When cracking risk is a concern, bend orientation should be considered along with alloy, temper, thickness, and bend radius.

How Thickness Affects the Flat Pattern

Material thickness is another important input, but thickness alone does not determine bend radius or bend gain.

The developed flat length is influenced by the relationship between material thickness, inside radius, tooling, bend angle, and the location of the neutral axis.

This is why bend data developed for one material thickness should not automatically be applied to another thickness, even if the part geometry is otherwise identical.

Example: Aluminum vs. Stainless Steel

Consider two parts with the same finished geometry, one made from 0.063" 5052-H32 aluminum and another made from 16 ga. 304 stainless steel.

Even if both parts require the same finished bend angle, the same generic bend value should not automatically be applied to both. Differences in material properties, thickness, springback, tooling, and resulting inside radius can change the developed flat length.

The important design lesson is not that one material always requires a larger or smaller bend deduction. It is that bend data should reflect the actual material and forming process being used.

Using Bend Data in SOLIDWORKS

SOLIDWORKS sheet metal models can generate flat patterns using several different bend-calculation methods, including K-factor, bend allowance, bend deduction, and bend tables.

The best approach is to use a consistent method and, when possible, use bend data provided by the fabricator that will actually form the part.

An accurate native sheet metal model remains extremely valuable because it communicates:

• Finished geometry
• Bend direction
• Flange relationships
• Feature locations
• Interference conditions
• Assembly intent

The fabricator may simply need to adjust the bend parameters or developed flat pattern to match its actual manufacturing process.