Machine Tool Optical Roughness Measurement Without Touch Probes

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Solution Overview

Problem

Existing machine tools that measure surface roughness using contact-type touch probes face issues such as damage to the workpiece and limited size of the R chamfering of the leading end of the touch probe.

Innovation Solution

A machine tool equipped with a non-contact light sensor system that includes a frequency-swept light emitter, a light splitter, a sensor head, a light interferometer, an analog-to-digital converter, distance information calculating circuitry, and roughness measuring circuitry to measure surface roughness without physical contact.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a contact-type touch probe is used to measure surface roughness, then measurement precision is improved, but the workpiece surface gets damaged

Engineering Contradiction:

Improvesurface roughness measurement precisionVSAvoidworkpiece surface damage

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical contact-type touch probe with a non-contact optical measurement system. The optical measurement unit uses light to measure surface roughness without physical contact, thereby eliminating the damage caused by mechanical contact while maintaining measurement precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces light as an intermediary medium between the measurement system and the workpiece surface. Instead of direct mechanical contact, light serves as the mediator to carry measurement information, avoiding workpiece damage while enabling precise surface roughness measurement.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a contact-type touch probe is used to measure surface roughness, then measurement precision is improved, but the R chamfering size of the probe leading end is limited

Engineering Contradiction:

Improvesurface roughness measurement precisionVSAvoidR chamfering size of probe leading end

Core Design Contradiction:

Measurement precisionVSLength of moving object

Solution Approach 1:

The patent replaces the mechanical touch probe with an optical measurement system, eliminating the physical probe leading end and its R chamfering limitations. The optical system uses light interaction with the surface to measure roughness without being constrained by probe geometry.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent creates an optical copy or representation of the surface topography through light reflection and interference patterns. Instead of physically touching the surface with a constrained probe, the system captures optical information that replicates surface characteristics for measurement.

Inventive Principle:

Principle #26Copying

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

Enables accurate non-contact measurement of surface roughness, preventing workpiece damage and overcoming the limitations of contact-type probes.

Implementation Method 1

a light interferometer to generate interference light of the reference light obtained by the light splitter and the reflection light received by the sensor head on the basis of the reference light and the reflection light

Methodology Applied

Scientific EffectLight interference: Interference

Implementation Method 2

a frequency-swept light emitter to output frequency-swept light

Methodology Applied

Scientific EffectFrequency-swept light:

Implementation Method 3

a light splitter to split the frequency-swept light output by the frequency-swept light emitter into reference light and irradiation light

Methodology Applied

Scientific EffectLight splitting:

Implementation Method 4

a sensor head to cause the machining surface of the workpiece after the machining by the machining mechanism to be irradiated with the irradiation light obtained by the light splitter, and receive reflection light from the machining surface

Methodology Applied

Scientific EffectLight reflection: Reflection

Implementation Method 5

an analog-to-digital converter to convert the electric signal obtained by the light interferometer, which is an analog signal, into a digital signal

Methodology Applied

Scientific EffectAnalog-to-digital conversion:

Data Source

PatentUS20250035435A1Machine tool

Publication Date: 2025.01.30 MITSUBISHI ELECTRIC CORP

AI summary

A frequency-swept light output unit to output frequency-swept light; a light splitting unit to split the frequency-swept light into reference light and irradiation light; a sensor head unit to cause a machining surface of a workpiece after the machining to be irradiated with the irradiation light, and receive reflection light from the machining surface; a light interference unit to generate interference light of the reference light and the reflection light, and convert the interference light into an electric signal; an A/D converter to convert the electric signal into a digital signal; a distance information calculating unit to calculate information about the distance from the leading end of the sensor head unit to the machining surface on the basis of the digital signal; and a roughness measuring unit to measure the surface roughness of the machining surface on the basis of a result of the calculation are included.