Shape Measurement Probe Timing Sync for NC Machine Tools

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Solution Overview

Problem

Non-contact shape measuring devices for NC machine tools suffer from temporal errors and varying time discrepancies between image acquisition and coordinate acquisition, leading to low accuracy in calculated shape data due to jitter and systematic errors.

Innovation Solution

A processing system that includes a machine tool with a measuring unit, control unit, acquisition unit, estimation unit, and shape calculation unit to estimate the time of position information generation and correct for jitter, ensuring accurate shape calculation using machine coordinates and image data synchronization.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a measurement probe is inserted into a workpiece hole to measure inner circular shape, then the measurement precision can be improved, but the probe may collide with the hole bottom or fail to reach the full depth, causing measurement errors

Engineering Contradiction:
Improveinner circular shape measurement precisionVSAvoidmeasurement reliability
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The patent transitions from linear depth insertion to radial expansion by inflating the balloon probe within the hole. This dimensional change allows the measurement surface to expand outward and contact the hole walls comprehensively, ensuring full-depth measurement without collision issues.

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

Solution Approach 2:

The balloon probe acts as an intermediary between the measurement system and the hole interior. By inflating the balloon, it mediates the measurement process by adapting to the hole's geometry and transmitting deformation data to the measurement system, ensuring accurate data acquisition without direct probe-hole bottom collision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If conventional measurement probes are used to measure complex inner surfaces, then the device complexity is reduced, but the measurement precision deteriorates due to inability to adapt to varying hole geometries

Engineering Contradiction:
Improvemeasurement device complexityVSAvoidinner surface measurement precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The balloon probe transforms from a static rigid structure to a dynamic flexible structure that can adapt its shape. The inflation mechanism allows the probe to dynamically adjust its geometry to match the hole's internal shape, enabling precise measurement of varying geometries without complex device architecture.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the physical state of the measurement probe from deflated to inflated, altering its geometric parameters. This parameter change enables the probe to conform to different hole geometries, maintaining measurement precision across varied shapes while keeping the device itself relatively simple.

Inventive Principle:
Principle #35Parameter changes

3Area of stationary object

If the measurement probe is made longer to reach deep holes, then the measurement coverage is improved, but the probe stability deteriorates and collision with hole bottom increases

Engineering Contradiction:
Improvemeasurement coverageVSAvoidprobe stability
Core Design Contradiction:
Area of stationary objectVSStability of the object's composition

Solution Approach 1:

Instead of extending the probe linearly to increase coverage, the patent uses radial expansion of the balloon to achieve comprehensive measurement coverage. This dimensional shift allows the probe to measure deep holes without increasing insertion depth, maintaining stability while expanding measurement area through inflation.

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

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

The system reduces measurement errors by estimating jitter and synchronizing image and coordinate timings, thereby improving the accuracy of shape data calculation in non-contact shape measuring devices.

Implementation Method 1

a surface to be measured of the workpiece W is brought into contact with an inner circumferential surface of the balloon 4 in a state where the balloon 4 is inflated

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Data Source

PatentEP3733346B1Processing system, measurement probe, shape measuring device, and program
Publication Date: 2026.04.29 NIKON CORP
  • EP3733346B1 patent drawingFigure 1
  • EP3733346B1 patent drawingFigure 2(A)~2(E)
  • EP3733346B1 patent drawingFigure 3

AI summary

A processing system includes a machine tool including a measuring unit which outputs measurement information for calculating a shape of a processing object, a control unit which generates position information related to a position of the measuring unit at the time of measuring the processing object and outputs the generated position information and a generation time signal indicating a time at which the position information is generated, an acquisition unit which acquires the output position information and the generation time signal, an estimation unit which estimates the time at which the position information is generated on the basis of a time at which the acquisition unit acquires the generation time signal, and a shape calculation unit which calculates a shape of the processing object on the basis of the measurement information, the position information, and the time estimated by the estimation unit.