Pulsed Laser Piercing Control for Thick Workpiece Cutting

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Solution Overview

Problem

Existing laser piercing methods struggle with longer piercing times and increased frequency of piercing stops when dealing with thicker workpieces, particularly those over 10 mm or 20 mm, due to inefficiencies in energy input during the piercing process.

Innovation Solution

A method and device that control the energy input of a pulsed laser beam by adjusting parameters such as average pulse power, pulse off-time, and pulse frequency based on material thickness and other process conditions to optimize the piercing process, ensuring safe piercing without stops.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the pulse frequency or average laser power is increased to minimize piercing duration, then the piercing rate improves, but the piercing process becomes unstable and piercing stops occur more frequently for thicker workpieces

Engineering Contradiction:
Improvepiercing rateVSAvoidpiercing process stability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies dynamics by making the pulse frequency variable during the piercing process. The control device adjusts the pulse frequency in real-time based on the current piercing depth and material thickness, transitioning from higher frequencies at the beginning to lower frequencies as piercing progresses. This dynamic adjustment maintains high productivity while preventing process instability and piercing stops that occur with constant high frequency.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent implements parameter changes by systematically varying the pulse frequency as a function of piercing depth and material thickness. The control device modifies this critical parameter during the process to optimize both productivity and reliability, avoiding the piercing stops that occur when parameter values are held constant at high levels throughout the entire piercing operation.

Inventive Principle:
Principle #35Parameter changes

2Speed

If higher laser powers are used to penetrate thicker materials, then the piercing speed increases, but the piercing time increases and process efficiency decreases

Engineering Contradiction:
Improvepiercing speedVSAvoidpiercing time
Core Design Contradiction:
SpeedVSLoss of time

Solution Approach 1:

The patent applies periodic action through pulsed laser irradiation with dynamically adjusted pulse frequencies. By using periodic pulses rather than continuous irradiation, the method achieves high piercing speeds while reducing total piercing time. The periodic nature of the pulses allows for efficient energy delivery that prevents heat accumulation and maintains high process efficiency throughout the piercing of thick materials.

Inventive Principle:
Principle #19Periodic action

3Use of energy by moving object

If the pulse frequency is increased to reduce piercing duration, then the energy input rate increases, but the energy distribution becomes uneven and process control deteriorates

Engineering Contradiction:
Improveenergy input rateVSAvoidprocess control
Core Design Contradiction:
Use of energy by moving objectVSEase of operation

Solution Approach 1:

The patent implements feedback control by using a control device that monitors the piercing process and adjusts the pulse frequency based on real-time conditions. This feedback mechanism ensures even energy distribution by preventing excessive energy input that would occur with constantly high pulse frequencies, thereby maintaining good process control and ease of operation throughout the piercing process.

Inventive Principle:
Principle #23Feedback

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 minimizes piercing time and maximizes piercing rate while preventing piercing stops, especially for thicker materials, by strategically reducing average pulse power and adjusting pulse parameters during the process.

Implementation Method 1

irradiating a pulsed laser beam onto a workpiece to form a piercing

Methodology Applied
Scientific EffectLaser heating: Laser

Implementation Method 2

irradiating a pulsed laser beam onto a workpiece to form a piercing

Methodology Applied
Scientific EffectAbsorption of electromagnetic radiation: Absorption (EM radiation)

Implementation Method 3

irradiating a pulsed laser beam onto a workpiece to form a piercing

Methodology Applied
Scientific EffectLaser melting: Laser

Data Source

PatentEP4117853B1Method and device for cutting into a workpiece using a laser beam
Publication Date: 2025.07.09 PRECITEC GMBH
  • EP4117853B1 patent drawingFigure 1
  • EP4117853B1 patent drawingFigure 2
  • EP4117853B1 patent drawingFigure 3A

AI summary

The invention relates to a method for cutting into a workpiece using a laser beam, having the step of: emitting a pulsed laser beam (10) onto a workpiece (1) in order to form a cut (9), wherein the average emitted pulse power (Pmittel) of the pulsed laser beam (10) decreases during the cutting process.