Press Brake Force Sensing for Precise Bending Control

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Solution Overview

Problem

Existing bending press technologies are limited in their ability to provide optimized control of the bending process, relying on pressure measurements that are not suitable for detailed control and are often used only to prevent exceeding predetermined limits, lacking the capability to adapt to various workpiece types and ensuring reliable, reproducible information.

Innovation Solution

A bending press equipped with a pressure sensor arranged in the main force flow, interacting with tool holders, and a data processing device that uses algorithms to determine workpiece properties and bending press deformations from sensor data, allowing for precise control of the bending process by calculating output variables such as bending angle and deformation, and utilizing piezoelectric sensors for accurate and cost-effective measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pressure sensors are arranged laterally in the longitudinal direction of the table to measure hydraulic pressure, then pressure values can be determined, but the information obtained is not meaningful for optimized control of the bending process

Engineering Contradiction:
Improvepressure measurementVSAvoidbending process information
Core Design Contradiction:
Measurement precisionVSLoss of information

Solution Approach 1:

The patent transitions from lateral pressure measurement to longitudinal force measurement by arranging sensors in the main force flow direction. This dimensional change enables direct measurement of bending forces and moments, providing meaningful information for process control rather than just hydraulic pressure values.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent introduces calculation means that act as an intermediary between the force sensors and the control system. This intermediary processes raw sensor data to extract meaningful bending parameters such as bending moment, force distribution, and workpiece properties, transforming unusable data into actionable process information.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If multiple sensors are arranged to provide detailed bending process information, then control precision is improved, but device complexity increases

Engineering Contradiction:
Improvebending angle precisionVSAvoidsensor arrangement complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent divides the bending press into multiple measurement sections with force sensors arranged at different longitudinal positions. Each sensor segment measures local forces, and the calculation means integrates these segmented measurements to determine overall bending parameters, achieving precise control through modular measurement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The force sensors serve multiple functions: they measure bending forces, determine workpiece thickness, calculate bending moments, and monitor process safety. This multi-functionality reduces the need for separate measurement systems, maintaining precision while limiting complexity growth.

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

3Device complexity

If pressure sensors are used to determine bending parameters, then the construction remains simple, but reliable and reproducible information about the bending process cannot be ensured

Engineering Contradiction:
Improvesensor arrangement simplicityVSAvoidbending process information reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent replaces hydraulic pressure sensing with direct mechanical force sensing in the main force flow. This substitution provides more reliable and reproducible measurements because force sensors directly measure the mechanical actions on the workpiece, eliminating the indirect and unreliable pressure-transmission path through hydraulic fluid.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Loss of information

If force measuring devices are mounted on machine frame or machine table, then bending process information can be detected, but the structure becomes more complex and expensive

Engineering Contradiction:
Improvebending process informationVSAvoidmachine structure complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent merges the force measurement function with the existing tool holder structure. By integrating force sensors into the tool holder that is already part of the bending mechanism, the system obtains bending process information without adding separate measurement structures, thereby maintaining simplicity while improving information quality.

Inventive Principle:
Principle #5Merging (Combining)

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

Enables precise and reliable control of the bending process, allowing for optimized force application and adaptation to different workpieces, ensuring accurate bending angles and deformations, which improves the efficiency and quality of bending operations.

Implementation Method 1

the use of a piezoelectric sensor is particularly preferred

Methodology Applied
Scientific EffectPiezoelectric effect: Piezoelectric Effect

Data Source

PatentEP3191236B1Press brake and a method for bending a workpiece with the bending press
Publication Date: 2023.06.28 TRUMPF MASCHEN AUSTRIA
  • EP3191236B1 patent drawingFigure 1
  • EP3191236B1 patent drawingFigure 2~3
  • EP3191236B1 patent drawingFigure 4~6

AI summary

The invention relates to a brake press (1) for bending a workpiece (2), said brake press comprising: two platforms (3) which can be moved relative to one another and each of which supports a tool holder (4) that holds a tool (5); a control device (7); and a sensor (6) connected to the control device (7). The invention is characterized in that the at least one sensor (6) is a force or pressure sensor, which sensor cooperates with one of the tool holders (4), and in that the control device (7) comprises a data processing device (8) that is designed to determine at least one characteristic of the workpiece (2) and/or the deformation of the brake press (1) effected by the bending process from the sensor data of the force or pressure sensor (6).