Workpiece Machining with Triangulation Sensors for Edge Accuracy

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Solution Overview

Problem

Existing methods for machining workpieces made of wood, wood-based materials, or plastic face challenges in achieving high-quality processing results due to physical contact damage, limited scanning depth on structured surfaces, and inadequate precision with non-contact distance sensors, especially with varying degrees of gloss or roughness.

Innovation Solution

Implementing a method using high-precision non-contact distance sensors with a measurement accuracy of +/-0.01 mm or better, employing the triangulation principle, and utilizing at least two sensors measuring in different directions to enhance positioning accuracy and detect transitions like corners or edges reliably, along with a calibration and checking arrangement to maintain measurement accuracy and prevent surface damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If contactless distance sensors are used to avoid surface damage, then the risk of damage and contamination is reduced, but the measurement precision is insufficient especially with varying gloss or roughness

Engineering Contradiction:
Improvesurface damage and contaminationVSAvoiddistance measurement accuracy
Core Design Contradiction:
Object-affected harmful factorsVSMeasurement precision

Solution Approach 1:

The patent replaces contact-based mechanical probing systems with optical distance sensors that operate without physical contact. This substitution eliminates surface damage and contamination while maintaining measurement precision through optical triangulation methods that are insensitive to surface gloss or roughness variations.

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

Solution Approach 2:

The patent employs multiple distance sensors positioned at different locations and angles to measure the same workpiece surface from different perspectives. By changing the measurement parameters (sensor positions, angles, and wavelengths), the system achieves consistent and precise measurements regardless of surface optical properties like gloss or roughness.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If conventional distance sensors are used, then non-contact measurement is achieved, but the machining quality is insufficient

Engineering Contradiction:
Improvenon-contact measurement capabilityVSAvoidmachining quality
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

The patent divides the measurement task among multiple distance sensors positioned at different locations. Each sensor contributes to measuring specific features of the workpiece, and their combined data provides comprehensive and precise information for high-quality machining, overcoming the limitations of single-sensor systems.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces an intermediate processing step where the control unit receives and processes data from multiple distance sensors, filtering and integrating the measurements to determine the actual workpiece surface position. This intermediary processing ensures that machining quality is not compromised by raw sensor variations.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Measurement precision

If feeler elements are used to determine relative position, then positioning accuracy is achieved, but surface damage and marks occur

Engineering Contradiction:
Improverelative position determination accuracyVSAvoidsurface damage and marks
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces mechanical feeler elements with optical distance sensors that determine relative position without physical contact. This substitution maintains positioning accuracy through optical triangulation while completely eliminating surface damage and marks that occur with mechanical probing.

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

4Measurement precision

If structured surfaces are scanned with contact methods, then position detection is possible, but scanning is limited to certain embossing depths

Engineering Contradiction:
Improvesurface position detectionVSAvoidscanning capability on structured surfaces
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent uses multiple distance sensors positioned at different angles and locations to scan structured surfaces. By changing the measurement parameters (sensor positions, angles, and wavelengths), the system can detect surface positions regardless of embossing depth, greatly enhancing adaptability to various structured surfaces compared to contact methods.

Inventive Principle:
Principle #35Parameter changes

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 reproducible machining with reduced risk of damage, contamination, and increased processing speed, achieving high-quality results even on changing workpiece surfaces, with improved detection of discontinuities and tolerances, leading to a continuous and high-quality machining process.

Implementation Method 1

the contactless distance sensor works according to the triangulation principle

Methodology Applied
Scientific EffectTriangulation principle: Parallax

Data Source

PatentEP3851243B1Method using a device for machining a workpiece
Publication Date: 2023.08.09 HOMAG GMBH
  • EP3851243B1 patent drawingFigure 1

AI summary

Device (1) for machining a workpiece (2), which preferably consists at least partially of wood, wood-based materials, plastic or the like, comprising: at least one machining arrangement (10, 12) for machining the workpiece (2), a conveying arrangement (4) for bringing about a relative movement between at least one machining arrangement (10, 12) and the workpiece (2), at least one non-contact distance sensor (20, 22, 24, 26) configured to measure a distance to a surface of the workpiece (2), wherein the at least one non-contact distance sensor (20, 22, 24, 26) is configured to measure the distance with a measuring accuracy of +/- 0.01 mm or more precisely, and/or a triangulation sensor.