Laser Cutting Path Correction for Sheet Metal Strips

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Solution Overview

Problem

Existing methods for cutting sheet metal blanks with predetermined contours from continuously conveyed sheet metal strips are inefficient due to reliance on costly markings, prone to damage, and slow image evaluation, as well as requiring complex and sluggish edge position correction systems.

Innovation Solution

A method utilizing laser cutting devices with movable heads and continuous distance measurement from fixed points to calculate and correct cutting paths in real-time, ensuring accurate and reliable contour cutting by continuously measuring strip edges and compensating for deviations and speed fluctuations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If markings are used on the sheet metal strip for position detection, then the cutting path can be corrected, but the cost increases and the markings can be damaged or misinterpreted causing disruptions

Engineering Contradiction:
Improvecutting path accuracyVSAvoidproduction continuity
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The patent removes the markings from the sheet metal strip entirely, extracting the problematic element that caused damage and misinterpretation. Instead, it uses an unmarked strip with a sensor system that detects the actual position of the strip edge directly, eliminating the intermediary markings that were causing reliability issues while maintaining cutting path correction capability

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces a sensor system as an intermediary between the strip position and the cutting path correction. Rather than relying on markings on the strip, the sensor acts as a mediator that continuously detects the actual strip edge position and transmits this information to the control system, which then calculates the corrected cutting path in real-time

Inventive Principle:
Principle #24Intermediary (Mediator)

2Manufacturing precision

If image evaluation is used to detect markings, then position correction is possible, but the evaluation process is time-consuming and reduces production speed

Engineering Contradiction:
Improveposition detection accuracyVSAvoidproduction speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent replaces the image evaluation system (optical/camera-based) with a direct sensor measurement system. Instead of capturing images and processing them computationally, the sensor continuously measures the actual strip edge position directly, providing real-time position data without the time-consuming image capture and evaluation process, thereby maintaining precision while increasing production speed

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

Solution Approach 2:

The patent implements continuous position measurement using the sensor system, which continuously detects the strip edge position throughout the cutting process. This continuous measurement allows for real-time cutting path correction without interrupting the production flow, eliminating the discrete, time-consuming image evaluation steps and maintaining uninterrupted productive action

Inventive Principle:
Principle #20Continuity of useful action

3Manufacturing precision

If a coiler is moved to correct strip edge position, then the position can be adjusted, but the system becomes complex and the correction is sluggish

Engineering Contradiction:
Improvestrip edge position accuracyVSAvoidcorrection system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent creates a virtual copy or model of the corrected cutting path through computational calculation rather than physically moving the coiler. The control system calculates the corrected cutting path based on the sensor-measured actual strip position, effectively copying the intended cutting geometry and adjusting it computationally to compensate for position deviations, avoiding the need for complex mechanical correction systems

Inventive Principle:
Principle #26Copying

Solution Approach 2:

The patent replaces the mechanical coiler movement system with a computational correction system. Instead of physically moving the heavy coiler to adjust strip edge position, the system uses sensors to detect actual position and employs control algorithms to calculate and adjust the cutting path accordingly, substituting mechanical complexity with computational simplicity and achieving faster, more responsive correction

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

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 enables precise and reliable cutting of sheet metal blanks with reduced errors and increased production speed by continuously measuring strip edges and adjusting cutting paths, minimizing disruptions and operational complexity.

Implementation Method 1

at least one laser cutting device with at least one laser cutting head that can be moved both in the transport direction and in a y-direction running perpendicular thereto

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

continuously measuring a first distance from a first strip edge of the sheet metal strip from a fixed first measuring point in the y-direction by means of a first distance measuring device

Methodology Applied
Scientific EffectOptical measurement: Optical Fibre

Data Source

PatentEP2828029B1Method of cutting blanks
Publication Date: 2016.04.13 SCHULER AUTOMATION
  • EP2828029B1 patent drawingFigure 1
  • EP2828029B1 patent drawingFigure 2
  • EP2828029B1 patent drawingFigure 3a~3b

AI summary

The invention relates to a method for cutting a sheet metal blank (2) having a predetermined contour (K) from a metal strip (1) that is continuously conveyed in a transport direction (x). The method comprises the following steps: providing at least one laser cutting apparatus having at least one laser cutting head (L, L1, L2, L3) that can be moved in the transport direction (x) and in a y direction perpendicular thereto, and a control device for controlling the movement of the laser cutting head (L, L1, L2, L3) along a cutting path that corresponds to the predetermined contour (K); continuously measuring a first distance (I1) of a first strip edge of the metal strip (1) from a fixed first measurement point in the y direction by means of a first distance measuring device (3) provided upstream of the laser cutting apparatus; transmitting first distance measurement values to the control device; calculating a corrected cutting path while using a predetermined cutting path and the first distance measurement values by means of a control program of the control device; and producing a cut in the metal strip (1) by moving the laser cutting head (L, L1, L2, L3) along the corrected cutting path.