Laser Cutting Separation Check Using Pulsed Beam Feedback

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Solution Overview

Problem

Existing cutting methods struggle to reliably determine if a workpiece part has been completely separated from the remaining part during cutting, leading to potential interference contours and machine damage, especially due to parameter and process errors.

Innovation Solution

Increasing the intensity of the machining beam at a test position during irradiation and terminating the beam if the workpiece part is not completely separated, using a pulsed or gradually increased power laser beam to ensure reliable detection and prevent piercing or cratering.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a processing beam is used to check workpiece separation, then detection capability is improved, but the risk of piercing or cratering the workpiece increases

Engineering Contradiction:
Improvedetection capabilityVSAvoidpiercing or cratering
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The processing beam intensity is dynamically adjusted during the checking process. The beam intensity is increased progressively in steps until a threshold is reached or separation is detected, allowing the system to adapt the detection energy level in real-time based on the workpiece response

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The intensity parameter of the processing beam is changed during the checking process. By varying the beam intensity in controlled steps, the system optimizes detection sensitivity while preventing excessive energy input that would cause piercing or cratering

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the processing beam intensity is increased during checking, then detection reliability is improved, but the risk of workpiece damage increases

Engineering Contradiction:
Improvedetection reliabilityVSAvoidworkpiece damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The processing beam is applied in periodic pulses during the checking process. The beam intensity is increased in discrete steps with pauses between increments, allowing the system to detect separation at each level while preventing continuous high-energy exposure that would cause damage

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The system continuously monitors the workpiece response to the processing beam and provides feedback to control the beam intensity. When separation is detected or damage risk is approached, the feedback mechanism adjusts or terminates beam application, ensuring reliable detection without workpiece damage

Inventive Principle:
Principle #23Feedback

3Measurement precision

If continuous beam irradiation is used for checking, then detection completeness is improved, but energy consumption and damage risk increase

Engineering Contradiction:
Improvedetection completenessVSAvoidenergy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

Instead of continuous beam irradiation, the processing beam is applied in periodic pulses. The beam is activated in steps only when needed for detection, with intervals between pulses allowing energy conservation and reducing cumulative energy input to the workpiece

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The checking process uses preliminary low-intensity beam pulses to initially detect workpiece separation. Only if separation is not detected does the system proceed to higher intensity steps, performing preliminary assessment with minimal energy consumption before committing to higher energy levels

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 allows for robust and reliable detection of workpiece separation, preventing machine damage and ensuring accurate cutting by terminating the beam when separation is incomplete, thus enhancing process reliability and safety.

Implementation Method 1

Radiating a preferably pulsed processing beam onto the workpiece at a test position within the specified cutting contour, detecting radiation generated by an interaction between the processing beam and the workpiece

Methodology Applied
Scientific EffectLaser beam interaction with material: Laser Ablation

Data Source

PatentEP3636379B1Method and device for cutting workpieces
Publication Date: 2021.03.10 TRUMPF WERKZEUGMASCHINEN GMBH & CO KG
  • EP3636379B1 patent drawingFigure 1~2
  • EP3636379B1 patent drawingFigure 3~4b
  • EP3636379B1 patent drawing

AI summary

The invention relates to a method for machining a workpiece (2) by cutting, comprising: machining the workpiece (2) along a predetermined cutting contour (18a) to separate a workpiece part (17) from a remaining part (19), and checking whether the workpiece part (17) has been completely separated from the remaining part (19) during the machining process, wherein checking whether the workpiece part (17) has been separated from the remaining part (19) comprises the following steps: shining a preferably pulsed machining beam onto the workpiece (2) at a test position (21a, 21b) within the predetermined cutting contour (18a), detecting radiation (27) generated by an interaction between the machining beam and the workpiece (2), and evaluating the detected radiation (27) to check whether the workpiece part (17) has been completely separated from the remaining part (19) during the machining process.During the application of the machining beam, the intensity of the machining beam is increased at the test position (21a, 21b) and the application of the machining beam is stopped as soon as it is determined during testing that the workpiece part (17) has not been completely separated from the remaining part (19) during the cutting process. The invention also relates to an associated machine for cutting a workpiece (2).