Laser Beam Focus and Direction Interpolation for Complex Geometry Machining

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Solution Overview

Problem

Existing laser material processing devices are limited in their ability to control the beam direction on complex geometries, such as rectangular holes with straight walls, and cannot produce complex geometries with high accuracy and speed due to constraints on focus position and beam direction control.

Innovation Solution

A control method for guiding a laser beam that interpolates beam direction and focus position along a path, allowing for independent adjustment of these parameters, enabling the production of complex geometries by determining interpolation values between initial and final values, and using great circle or Euler angle interpolation to ensure precise control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the beam direction is controlled to match path geometry (e.g., constant direction for straight lines), then manufacturing precision is improved, but device complexity increases due to additional control mechanisms

Engineering Contradiction:
Improvegeometry accuracyVSAvoidcontrol mechanism complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control unit pre-calculates interpolation values for beam direction and focus position before the laser beam traverses the path segment. By determining the required beam direction at each point in advance based on the path geometry, the system achieves precise geometric control without requiring complex real-time adjustment mechanisms during beam traversal.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system dynamically adjusts beam direction and focus position continuously along the path segment using interpolation. Instead of fixed discrete adjustments, the beam direction is varied smoothly from the initial value to the final value based on the geometric requirements of each specific path segment, enabling adaptation to arbitrary geometries including lines, curves, and complex shapes.

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If the laser beam is redirected to follow complex path geometries, then manufacturing precision is improved, but processing speed decreases due to frequent beam direction changes

Engineering Contradiction:
Improvegeometry accuracyVSAvoidprocessing speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The control unit pre-calculates the complete trajectory including beam direction and focus position for the entire path segment before processing begins. This allows the laser system to traverse complex geometries at optimized speeds without real-time computational delays, as all interpolation values are determined in advance.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system uses continuous interpolation to smoothly vary beam direction and focus position along the path segment, avoiding abrupt changes that would require deceleration. This dynamic adjustment enables the laser to follow complex geometries with constant velocity, maintaining high processing speed while achieving precise geometric accuracy.

Inventive Principle:
Principle #15Dynamics

3Manufacturing precision

If the laser parameters are adjusted to maintain constant energy input along complex paths, then manufacturing precision is improved, but device complexity increases

Engineering Contradiction:
Improveenergy input consistencyVSAvoidparameter control complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The control unit pre-calculates the required laser parameters (power, pulse frequency, etc.) for each point along the path segment based on the interpolated beam direction and focus position. By determining the energy input requirements in advance, the system maintains constant energy input into the workpiece without requiring complex real-time parameter adjustment mechanisms.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP3700705B1Control method for motion control of a laser beam with interpolation of the focus position and/or beam direction
Publication Date: 2021.11.17 SCANLAB GMBH
  • EP3700705B1 patent drawingFigure 1
  • EP3700705B1 patent drawingFigure 2~3
  • EP3700705B1 patent drawingFigure 4~5

AI summary

The invention relates to a control method for motion control of a laser beam (6) of a device (1) for laser material processing, wherein a laser focus (8) of the laser beam (6) is guided along a track (18) by means of a scanning head (2) of the device (1), said track (18) comprising at least one track section (19, 20, 21), wherein a beam direction of the laser beam (6) has a starting value at a starting position (22, 23, 24) of the track section (19, 20, 21) and an end value at an end position (25, 26, 27) of the track section (19, 20, 21), which is downstream in the direction of motion. According to the invention, interpolation values for the beam direction are determined, particularly by a control unit (14) of the device (1), between the starting position (22, 23, 24) and the end position (25, 26, 27) of the track section (19, 20, 21), by interpolating the beam direction from the starting value to the end value thereof. Furthermore, the beam direction of the laser beam (6) is controlled within the track section (19, 20, 21) in consideration of the determined interpolation values.