Bending Machine Control for Time-Dependent Springback Compensation

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Solution Overview

Problem

Existing bending machines struggle to accurately maintain a desired bending angle over time due to material springback, which can lead to deviations during subsequent machining operations, especially when there is a delay between bending and further processing.

Innovation Solution

A bending machine equipped with a controller that calculates an adapted bending angle based on time-dependent springback data, allowing the workpiece to be overbent to compensate for springback during storage, ensuring the correct bending angle is maintained at the time of subsequent machining.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the workpiece is bent to the desired bending angle during the bending operation, then the bending angle is correct immediately after bending, but the bending angle deviates during storage due to springback before subsequent machining

Engineering Contradiction:
Improvebending angle accuracyVSAvoidbending angle stability over time
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The controller calculates and applies a preliminary compensation for springback by determining an adapted bending angle that accounts for the expected springback during storage. This preliminary action ensures that the workpiece achieves the desired bending angle at the time of subsequent machining, not just immediately after bending.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system applies an opposite action to counteract the anticipated springback effect. By calculating the expected springback based on storage time and material properties, the controller bends the workpiece beyond the desired angle initially, creating a compensating overbend that results in the correct angle after springback occurs during storage.

Inventive Principle:
Principle #9Preliminary anti-action

2Manufacturing precision

If the bending machine compensates for springback by overbending the workpiece, then the correct bending angle is achieved at the time of subsequent machining, but the bending operation becomes more complex

Engineering Contradiction:
Improvebending angle accuracy at machining timeVSAvoidcontroller calculation complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The controller uses feedback from stored springback data, material properties, and storage time information to automatically calculate the adapted bending angle. This feedback mechanism enables the system to adjust the bending operation dynamically based on specific workpiece conditions and storage durations, maintaining precision without manual intervention.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The bending machine performs the springback compensation calculation and adjustment automatically through its controller, which accesses stored springback data and material properties. The system serves itself by eliminating the need for manual springback compensation calculations or adjustments, reducing operational complexity while maintaining high precision.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If the bending machine stores springback data for different materials and conditions, then the springback compensation becomes more accurate, but the data management system becomes more complex

Engineering Contradiction:
Improvespringback measurement accuracyVSAvoiddatabase and interface complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The database system is designed to store and manage springback data for multiple materials, thicknesses, and bending conditions using a unified structure. This universal approach allows the same database and interface to handle diverse data types and queries, reducing the need for separate management systems for each material or condition type.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

Springback data for different materials and conditions is pre-stored in the database before actual bending operations. This preliminary preparation of data allows the controller to quickly retrieve and use appropriate springback values during bending operations, eliminating the need for real-time data collection and analysis, thereby reducing operational complexity.

Inventive Principle:
Principle #10Preliminary action

4Manufacturing precision

If the workpiece is bent beyond the desired angle to compensate for springback, then the correct angle is maintained during storage, but the bending operation requires additional adjustment of the die and/or stamp

Engineering Contradiction:
Improvebending angle stability during storageVSAvoiddie and stamp adjustment requirement
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The controller uses feedback from stored springback data and storage time information to automatically calculate the required die and stamp adjustments for overbending operations. This feedback mechanism enables the system to determine the precise adjustment needed based on the specific workpiece and storage conditions, reducing manual trial-and-error adjustments.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The required die and stamp adjustments for overbending are calculated and determined in advance by the controller before the actual bending operation. This preliminary determination of adjustment parameters allows the operator to make the necessary adjustments once, before bending, rather than requiring additional adjustments after the bending operation.

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach ensures precise bending angles during subsequent machining operations by accounting for both immediate and future springback, enabling accurate and tailored machining processes such as automatic welding.

Implementation Method 1

the inherent springback of the material during or immediately after the bending operation

Methodology Applied
Scientific EffectSpringback: Elastic Recovery

Implementation Method 2

The bending machine according to the invention takes into account that the bending angle reached after the bending operation, for example, depending on the bending speed and material, undergoes an additional provision during storage of the part after the completed bending operation

Methodology Applied
Scientific EffectStress relief: Stress Relaxation

Data Source

PatentEP3898021B1Bending machine, machining line and method for bending
Publication Date: 2022.08.03 BYSTRONIC LASER AG
  • EP3898021B1 patent drawingFigure 1
  • EP3898021B1 patent drawingFigure 2
  • EP3898021B1 patent drawingFigure 3~4

AI summary

The invention relates to a bending machine (100) configured to bend a metallic workpiece (200), having a controller (130) configured to control a bending operation, wherein the controller (130) has at least one interface (340) configured to obtain information about a time-dependent springback of the workpiece (200) to be bent and to obtain a time indication of a subsequent further machining of the workpiece (200) to be bent, wherein the controller (130) is configured to calculate an adapted bending angle (α) based on the springback and the time indication, and wherein the bending machine (100) is configured to bend the bending operation beyond a bending angle (β) to be bent up to the adapted bending angle (α). Due to the adapted bending angle, the workpiece (300) has the correct bending angle (β) to be bent at the time of subsequent further machining.