3D Machining Mark Analysis for Fast Workpiece Surface Evaluation

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Solution Overview

Problem

Current methods for determining the surface properties of workpieces with numerous machining marks are inefficient, particularly when assessing microstructured surfaces like those found in flange connections, as they require extensive measurement time and compromise on resolution.

Innovation Solution

A method and device that acquire a 3D data set of the workpiece surface, fitting a model track representing the machining tool's theoretical path to identify individual processing tracks and determine parameters such as distance and angle between them, allowing for quick and accurate evaluation of surface properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional roughness measurement methods (stylus methods) are used to measure machining marks, then measurement precision can be achieved, but measurement time becomes very long

Engineering Contradiction:
Improvesurface property measurement precisionVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent replaces mechanical stylus methods with optical measurement methods. An optical sensor (e.g., confocal sensor, laser scanner) is used to acquire 3D surface data instead of a mechanical stylus physically contacting the surface. This substitution enables rapid acquisition of complete surface topography without the time-consuming point-by-point mechanical scanning, while maintaining measurement precision through optical resolution.

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

Solution Approach 2:

The patent transitions from traditional 1D profile measurements to 2D/3D surface mapping. By acquiring three-dimensional surface data (x, y, z coordinates of surface points), the system can analyze machining marks across the entire surface area simultaneously rather than measuring individual profiles sequentially. This dimensional expansion dramatically reduces measurement time while providing comprehensive surface property analysis.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If the distance between measuring points is increased to reduce measurement time, then productivity improves, but measurement resolution deteriorates

Engineering Contradiction:
Improvemeasurement speedVSAvoidsurface detail resolution
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The optical sensor continuously captures surface information across the entire measurement area in a single operation rather than stopping at each measurement point. The confocal sensor or laser scanner continuously scans the surface, building up a complete 3D dataset without discrete pauses, thereby maintaining high resolution while achieving high throughput through continuous data acquisition.

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The system creates a digital 3D copy (point cloud or mesh) of the entire surface geometry. This digital replica contains all surface features at full resolution, allowing subsequent analysis of machining marks, grooves, and microstructure without physically touching or physically restricting the surface. The digital copy can be processed, measured, and analyzed at any resolution level without additional measurement time.

Inventive Principle:
Principle #26Copying

3Measurement precision

If conventional profilometers are used to scan workpiece surfaces, then measurement precision is maintained, but the complexity of data acquisition and evaluation increases

Engineering Contradiction:
Improvesurface property accuracyVSAvoiddata acquisition and evaluation complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The optical measurement system (e.g., confocal sensor, laser scanner) integrated with the coordinate measuring machine performs multiple functions: it captures 3D surface geometry, identifies machining marks, determines surface parameters (roughness, waviness), and analyzes microstructure all within a single measurement operation. This multi-functionality consolidates what would otherwise require multiple specialized measurements and analysis steps into one unified process, reducing overall system complexity.

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

Solution Approach 2:

The system automatically identifies and analyzes machining marks based on the acquired 3D data without requiring manual intervention or complex pre-programming. The evaluation software automatically detects groove patterns, calculates surface parameters, and generates reports based on the raw 3D point cloud data, enabling the system to self-evaluate surface properties that would otherwise require complex manual measurement procedures.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4339556A1Method and device for determining the surface properties of a workpiece
Publication Date: 2024.03.20 CARL ZEISS INDUSTRIELLE MESSTECHNIKE GMBH
  • EP4339556A1 patent drawingFigure 1
  • EP4339556A1 patent drawingFigure 2~4
  • EP4339556A1 patent drawingFigure 5

AI summary

A workpiece surface that has been machined with a defined machining tool exhibits a multitude of individual machining marks (46, 48) resulting from the machining tool. A method for determining surface properties of the workpiece involves acquiring a first 3D data set of a defined surface section (44) of the workpiece surface, obtaining a model trace (58) representing a theoretical machining mark of the machining tool, first fitting the model trace (58) into the first 3D data set so that the model trace (58) approximates a first individual machining mark (46), and then further fitting the model trace (58) into the first 3D data set so that the model trace (58) approximates another individual machining mark.At least one parameter is determined that represents a ratio between the 3D data of the first processing track (46) and the 3D data of the subsequent processing track.