CNC Bending Process Parameter Optimization and Springback Compensation

CNC bending is an important sheet metal forming process, but springback has always been a major factor affecting bending accuracy. This article systematically introduces methods for optimizing bending process parameters and springback compensation technology.

I. Factors Affecting Bending Accuracy

Bending accuracy is influenced by multiple factors, mainly including:

• Material properties: yield strength, elongation, thickness uniformity

• Die parameters: upper die corner radius, opening width, lower die V-groove size

• Process parameters: bending force, dwell time, bending speed

• Equipment accuracy: ram parallelism, positioning accuracy

II. Springback Mechanism and Compensation Algorithm

Springback is caused by the elastic recovery of the material. The springback amount Δθ is positively correlated with the following factors:

1. The higher the material’s yield strength, the greater the springback

2. The larger the relative bend radius R/t, the greater the springback

3. The thinner the plate, the more noticeable the springback

Modern CNC press brakes are equipped with automatic springback compensation systems. Through closed-loop control of trial bending-measurement-correction, the angle error can be controlled within ±0.5°.

III. Bending Sequence Optimization

For parts with multiple bends, a reasonable bending sequence is crucial:

Principles:

• Bend edges that do not affect subsequent positioning first

• Short edges before long edges

• Symmetric bends first

• Consider interference and clearance

IV. Quality Control Key Points

Quality inspection of bent parts should focus on:

1. Bending angle: use an angle gauge or CMM

2. Straightness: check whether the bend line is straight

3. Indentation depth: evaluate appearance quality

4. Dimensional consistency: repeatability of batch parts