Machine Tool Probe Calibration Without Reference Artefacts

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Solution Overview

Problem

Current methods for calibrating probes on machine tools are complex, time-consuming, and often poorly executed, leading to inaccurate measurements and poor quality workpieces due to the need for skilled personnel and manual procedures with pre-calibrated artefacts.

Innovation Solution

The calibration of probes is simplified by using relative movement between a toolsetting probe and a workpiece-sensing probe, eliminating the need for pre-calibrated artefacts, and utilizing a software program to automate the process, allowing for calibration without skilled intervention and reducing calibration time to under two minutes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If pre-calibrated artefacts and manual procedures are used for probe calibration, then measurement accuracy can be achieved, but the calibration process becomes complex and time-consuming

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidcalibration process complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the need for pre-calibrated artefacts from the calibration process. Instead of using external reference objects (spheres, ring gauges, length bars), the system uses the relationship between the toolsetting probe and workpiece-sensing probe themselves to establish calibration, thereby simplifying the process while maintaining accuracy

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The calibration system performs self-calibration by using the mutual sensing relationship between the toolsetting probe and workpiece-sensing probe. The probes calibrate each other through automated relative movement and data processing, eliminating the need for external artefacts and manual intervention

Inventive Principle:
Principle #25Self-service

2Measurement precision

If pre-calibrated artefacts and manual procedures are used for probe calibration, then measurement accuracy can be achieved, but the calibration time increases significantly

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidcalibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The calibration process maintains continuous useful action through automated relative movement between the probes. The system continuously collects measurement data during the relative movement and processes it to determine calibration values, eliminating idle time associated with manual setup and measurement of pre-calibrated artefacts

Inventive Principle:
Principle #20Continuity of useful action

Solution Approach 2:

The invention replaces manual mechanical procedures with an automated system. The calibration process is controlled by a software program that automates the relative movement, data collection, and calculation of calibration values, significantly reducing the time required while maintaining accuracy

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

3Measurement precision

If pre-calibrated artefacts are used for probe calibration, then accurate calibration can be achieved, but skilled personnel and manual setup are required

Engineering Contradiction:
Improvecalibration accuracyVSAvoidease of calibration operation
Core Design Contradiction:
Measurement precisionVSEase of operation

Solution Approach 1:

The system performs self-calibration through automated procedures. The software program controls the relative movement between probes, collects measurement data, and automatically calculates calibration values without requiring skilled personnel to manually set up pre-calibrated artefacts or interpret measurement data

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The invention replaces complex manual mechanical procedures with an automated software-controlled system. The calibration process is simplified to automated relative movement and data processing, making it easy to operate without requiring skilled personnel while maintaining high calibration accuracy

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

Data Source

PatentEP3134707B1Calibration of measurement probes
Publication Date: 2022.09.28 RENISHAW PLC
  • EP3134707B1 patent drawingFigure 1
  • EP3134707B1 patent drawingFigure 2~6
  • EP3134707B1 patent drawingFigure 7

AI summary

CALIBRATION OF MEASUREMENT PROBES A machine tool is provided with a toolsetting probe(14)mounted on a bed or table (10), and a workpiece-sensing probe (16) which can be mounted in a movable spindle(12). Both probes are calibrated by using them to make measurements against each other. The arbitrary length of the workpiece-sensing probe (16) is used to calibrate the toolsetting probe, rather than using a pre-calibrated artefact of known length mounted in the spindle. A stylus disc (26) of the toolsetting probe (14) has a pre-calibrated size or dimension, and the workpiece-sensing probe is calibrated with respect to that. This obviates the need for skilful manual calibration procedures using pre-calibrated artefacts and manual measurement tools.