Switching Probe Contour Checking for In-Machine Workpiece Accuracy

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Solution Overview

Problem

Existing methods for checking the dimensional accuracy of workpieces are costly, require additional resources, and are not efficient, as they often involve specialized measuring machines and complex software, and do not effectively measure deflection.

Innovation Solution

A method using a switching probe clamped in a machine tool, where a probing element is positioned relative to the workpiece, and data on target contours, distance, and deflection are stored in the control device to determine paths, generating switching signals upon contact or lack thereof, allowing for efficient contour checking without additional machines or software.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If specialized measuring machines and tactile probes are used to check dimensional accuracy, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvedimensional accuracyVSAvoidmeasuring system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The machine tool is made multi-functional by enabling it to perform both machining operations and dimensional measurements. The control device stores both machining programs and measurement programs, allowing the same machine tool to execute cutting operations and subsequently measure the workpiece without requiring separate specialized measuring equipment.

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

Solution Approach 2:

The measurement process creates a digital copy of the workpiece contour by comparing actual measurements against stored target contour data. The control device stores geometric data of the target contour and generates distance paths that represent the expected dimensions, effectively creating a digital model for comparison with physical measurements.

Inventive Principle:
Principle #26Copying

2Measurement precision

If specialized measuring machines with internal measuring ranges are used, then measurement precision is improved, but loss of time increases due to additional resources and processing

Engineering Contradiction:
Improvedimensional accuracyVSAvoidmeasurement time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The measurement function is merged with the machining function in a single integrated system. The control device combines machining program storage with measurement program storage, and the machine tool combines cutting capabilities with measurement capabilities, eliminating the need to transfer workpieces between separate machines and reducing overall measurement time.

Inventive Principle:
Principle #5Merging (Combining)

3Measurement precision

If tactile probes with deflection measurement are used, then measurement precision is improved, but device complexity and cost increase

Engineering Contradiction:
Improvecontour measurement accuracyVSAvoidprobe system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention uses simple switching probes instead of expensive tactile probes with deflection measurement capabilities. The switching probe provides binary contact information (contact/not contact) which is sufficient when combined with the pre-calculated distance paths stored in the control device, achieving accurate contour measurement without requiring complex and expensive probe hardware.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Productivity

If complete contours are traced with measuring probes, then productivity is improved, but measurement precision may be compromised with simple switching probes

Engineering Contradiction:
Improvemeasurement speedVSAvoidcontour accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The control device performs preliminary actions by pre-storing the target contour geometry and pre-calculating the distance paths before actual measurement begins. This preparation work enables the use of simple switching probes to trace complete contours efficiently, as the evaluation logic is already in place to determine dimensional compliance based on contact detection along the pre-defined paths.

Inventive Principle:
Principle #10Preliminary action

Data Source

PatentEP4443100B1Checking the dimensional stability of a workpiece with a switching measuring probe
Publication Date: 2026.02.18 SIEMENS AG
  • EP4443100B1 patent drawingFigure 1
  • EP4443100B1 patent drawingFigure 2~3
  • EP4443100B1 patent drawingFigure 4

AI summary

The invention relates to a method for checking the contour of a workpiece (16) using a machine tool (2) connected to a control unit (3), in which a tactile, switching probe (21) with a probing element (22) is clamped. The probe is preferably moved along a target contour (24) of the workpiece (16) to be checked multiple times at different distances or with different deflections of the probe (21), and it is checked whether the probe (21) generates a switching signal or loses an existing switching signal, which in each case indicates a contour deviation. The invention makes it possible to check the dimensional accuracy of workpieces (16) machined or manufactured in a machine tool (2) quickly, easily, and cost-effectively.