Spindle-Mounted Optical Sensor for Lateral Surface Measurement

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Conventional three-axial CNC machining apparatuses face difficulties in measuring the surface shape of the lateral side of a workpiece due to limited accessibility of laser light, while five-axial systems are large and expensive.

Innovation Solution

A machining apparatus with a sensor head that applies laser light in an oblique direction, allowing measurement of the lateral side of a workpiece using a non-contact sensor and a servomotor paired with an encoder for precise control, enabling measurement of the surface shape even with limited three-axial movement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If a three-axial CNC machining apparatus is used, then the apparatus is compact and cost-effective, but the laser light cannot access the lateral side of the workpiece for measurement

Engineering Contradiction:
Improvesurface shape measurement capabilityVSAvoidlaser light accessibility
Core Design Contradiction:
Measurement precisionVSAdaptability or versatility

Solution Approach 1:

The patent introduces a rotational dimension by mounting the sensor head on the spindle that can rotate around the workpiece. This allows the laser light to access the lateral side of the workpiece from multiple angles through rotation, effectively adding a fourth dimension of movement to the three-axial machining apparatus and enabling comprehensive surface measurement.

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

2Measurement precision

If a five-axial CNC machining apparatus is used, then the lateral side of the workpiece can be measured, but the apparatus becomes large and expensive

Engineering Contradiction:
Improvelateral side measurement capabilityVSAvoidapparatus structure
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The sensor head is designed to perform multiple functions: it can measure the top surface of the workpiece when the spindle is in its normal position, and measure the lateral side by rotating the spindle. This multi-functional design allows a single apparatus to perform both top surface measurement and lateral side measurement without requiring separate five-axial systems.

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

Solution Approach 2:

The patent employs dynamic rotation of the spindle to enable the sensor head to access different surfaces of the workpiece. By making the spindle rotatable, the system dynamically adapts its measurement capability to capture both top and lateral surfaces, replacing the need for complex fixed five-axial positioning mechanisms.

Inventive Principle:
Principle #15Dynamics

3Measurement precision

If the spindle is made rotatable to enable lateral side measurement, then measurement capability is improved, but control complexity increases

Engineering Contradiction:
Improvelateral side surface measurementVSAvoidspindle control system
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent incorporates an encoder to detect the rotational position of the spindle and provides feedback to the control device. This feedback mechanism enables precise control of the spindle rotation angle, allowing the system to accurately position the sensor head at any required angular position for measuring different surfaces of the workpiece.

Inventive Principle:
Principle #23Feedback

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 precise measurement of the surface shape of the lateral side of a workpiece without the need for additional axes, reducing costs and complexity while maintaining accuracy.

Implementation Method 1

a light irradiation unit that emits laser light in an oblique direction

Methodology Applied
Scientific EffectLaser: Laser

Implementation Method 2

a non-contact sensor that applies the laser light in an oblique direction to the workpiece

Methodology Applied
Scientific EffectLight reflection: Reflection

Data Source

PatentEP3693130B1Machining apparatus
Publication Date: 2023.11.29 HEXAGON METROLOGY SPA
  • EP3693130B1 patent drawingFigure 1~2
  • EP3693130B1 patent drawingFigure 3~4
  • EP3693130B1 patent drawingFigure 5

AI summary

A machining apparatus capable of measuring the surface shape of the lateral side of a workpiece is provided. A machining apparatus 1 includes a tool magazine 20 which houses a plurality of types of tools, an automatic tool changing device which picks up a tool from the tool magazine 20 and replaces the tool mounted on a spindle 26 with the tool picked up, and a non-contact sensor 110 which measures the surface shape of a workpiece. The non-contact sensor 110 is housed in the tool magazine 20. The automatic tool changing device picks up the non-contact sensor 110 from the tool magazine 20 and replaces the tool mounted on the spindle 26 with the non-contact sensor 110. The non-contact sensor 110 comprises a light irradiation unit 50 which applies a line light to the workpiece, and an imaging unit 54 which captures an image of the line light reflected from the workpiece. The light irradiation unit 50 applies the line light in an oblique direction to the workpiece. The dead zone between the sensor and the measurement unit may be monitored with a separate detector.