Ultra-short Pulse Laser Machine Tool Speed Profile Control

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Solution Overview

Problem

Classic machining methods, such as turning, often result in burr formation and require long process times, while existing machine tools with ultra-short pulse lasers struggle to efficiently adjust to varying workpiece geometries for optimal material removal.

Innovation Solution

A machine tool with a rotation unit and ultra-short pulse laser that adjusts speed profiles based on geometry data, combined with a galvanometer scanner for precise pulse overlap control, and a lens for focal point management, enables efficient material removal without burr formation by setting pulse overlap along both rotation and scanning axes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If classic machining methods like turning are used, then material removal is achieved, but burr formation occurs and process time increases

Engineering Contradiction:
Improveprocess timeVSAvoidburr formation
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent replaces mechanical machining methods (turning) with a laser-based system consisting of an ultra-short pulse laser and rotation unit. This substitution eliminates mechanical contact that causes burrs while achieving efficient material removal through laser ablation, simultaneously improving productivity and eliminating harmful burr formation.

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

Solution Approach 2:

The ultra-short pulse laser induces phase transition of material from solid directly to vapor through ablation. This phase transition mechanism enables clean material removal without the mechanical deformation that causes burrs, while the controlled pulse duration optimizes processing speed and productivity.

Inventive Principle:
Principle #36Phase transitions

2Productivity

If pulse overlap is increased to improve material removal efficiency, then productivity increases, but surface quality deteriorates

Engineering Contradiction:
Improvematerial removal rateVSAvoidsurface quality
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The system dynamically adjusts the speed profile of the rotation unit based on real-time parameters to optimize pulse overlap. By making the rotational speed variable rather than fixed, the system can increase productivity through higher overlap while maintaining surface quality through adaptive control, resolving the trade-off between these two parameters.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The control unit receives geometry data about the workpiece and automatically adjusts the speed profile to achieve optimal pulse overlap for different sections. This feedback mechanism ensures that productivity and surface quality are simultaneously optimized by adapting processing parameters to the specific geometric requirements of each workpiece section.

Inventive Principle:
Principle #23Feedback

3Manufacturing precision

If speed profile is adjusted to control pulse overlap, then surface quality improves, but device complexity increases

Engineering Contradiction:
Improvesurface qualityVSAvoidspeed profile control system
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control unit serves multiple functions: it receives geometry data, calculates optimal speed profiles, controls the rotation unit speed, and monitors pulse overlap. By consolidating these functions into a single multi-functional control system rather than separate dedicated devices for each function, the system achieves precise surface quality control without proportionally increasing overall device complexity.

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

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 solution allows for precise control of surface quality and geometry, achieving efficient material removal with reduced burr formation and adaptable processing times, enabling the production of smooth or rough surfaces as needed.

Implementation Method 1

When the laser pulses hit the workpiece, cold material is removed, in which the material to be removed changes directly from a solid state to a gaseous state

Methodology Applied
Scientific EffectLaser ablation: Laser Ablation

Implementation Method 2

a galvanometer scanner which is arranged between the ultrashort pulse laser and the workpiece and which is designed to shift a point of impact of the respective laser pulse on the surface of the workpiece

Methodology Applied
Scientific EffectGalvanometer deflection: Galvanometer

Implementation Method 3

an objective, which is arranged between the galvanometer scanner and the workpiece, for bundling the laser pulses in a respective focal point

Methodology Applied
Scientific EffectOptical focusing: Lens

Data Source

PatentEP2969367B1Machine tool with a device for operating the machine tool
Publication Date: 2019.01.30 CONTINENTAL AUTOMOTIVE GMBH
  • EP2969367B1 patent drawingFigure 1~2

AI summary

A device is provide for operating a machine tool. The machine tool includes a rotation unit designed to rotate a workpiece about an axis of rotation with an adjustable rotational speed progression, and an ultra-short pulse laser for generating laser pulses, the laser being arranged such that material of the workpiece is removed by means of the laser pulses. The device is configured to adjust the rotational speed progression based on geometry data of a specified geometry and/or a specified surface quality characteristic value representative of a corresponding surface quality.