Surface Roughness Measuring Unit Vibration Isolation

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Solution Overview

Problem

Existing coordinate measuring apparatuses face inefficiencies when measuring both the three-dimensional contour shape and surface roughness of a workpiece, as they require multiple steps and are prone to errors due to vibration and inaccurate positioning of contact pin units.

Innovation Solution

A surface roughness measuring unit is designed to be coupled with a coordinate measuring apparatus, featuring a contact pin unit, driver, and collision detector, which allows for precise measurement of surface roughness without relying on the moving mechanism's accuracy, enabling proper contact detection and preventing collisions with obstacles.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the contact pin unit is driven by the moving mechanism of the coordinate measuring device, then the measurement process is integrated, but the contact pin unit oscillates due to vibration from the active coordinate measuring, making it impossible to determine whether the measurement result is surface roughness or error due to oscillation

Engineering Contradiction:
Improvemeasurement efficiencyVSAvoidsurface roughness measurement accuracy
Core Design Contradiction:
ProductivityVSMeasurement precision

Solution Approach 1:

The measurement system is divided into two independent parts: the coordinate measuring apparatus for positioning and the surface roughness measuring unit for actual measurement. The contact pin unit is separated from the moving mechanism, with only the positioning function remaining coupled to the coordinate measuring apparatus while the measurement function operates independently to avoid vibration interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The contact pin unit is extracted from the moving mechanism of the coordinate measuring device. The contact pin unit is coupled to the coordinate measuring apparatus only for positioning purposes, but the actual surface roughness measurement is performed by the independent contact pin unit that is not affected by the vibration of the moving mechanism.

Inventive Principle:
Principle #2Taking out (Extraction)

2Device complexity

If the contact pin unit is attached to the tip of the Z-spindle of the coordinate measuring device, then the setup is simplified, but it is impossible to detect whether the contact pin unit has been properly set on the work piece surface, and thus the surface roughness cannot be properly measured

Engineering Contradiction:
Improvesetup complexityVSAvoidcontact detection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

A contact detector is introduced to provide feedback on whether the contact pin unit has properly contacted the work piece surface. The contact detector outputs a contact detection signal that confirms proper positioning, enabling reliable measurement by providing real-time feedback on contact status.

Inventive Principle:
Principle #23Feedback

3Measurement precision

If multiple measurement steps are used (contour shape measurement followed by surface roughness measurement with separate devices), then each measurement can be performed with specialized equipment, but the work piece must be transferred between devices, involving more steps and drastically lowering measurement efficiency

Engineering Contradiction:
Improvemeasurement accuracyVSAvoidmeasurement efficiency
Core Design Contradiction:
Measurement precisionVSProductivity

Solution Approach 1:

The coordinate measuring apparatus and surface roughness measuring unit are merged into a single integrated system. The contact pin unit allows both contour shape measurement and surface roughness measurement to be performed on the same work piece without transfer, combining the advantages of specialized equipment while eliminating the inefficiency of multiple steps.

Inventive Principle:
Principle #5Merging (Combining)

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

This solution enhances measurement efficiency by allowing accurate surface roughness detection without errors caused by the moving mechanism's vibration and ensures safe operation by preventing collisions, thus improving the overall precision and reliability of surface roughness measurement.

Implementation Method 1

a displacement detector that detects displacement of the contact pin

Methodology Applied
Scientific EffectDisplacement detection:

Implementation Method 2

a contact detector that detects contact of a measuring surface on a work piece surface

Methodology Applied
Scientific EffectContact detection:

Data Source

PatentEP2722644B1Surface roughness measuring unit and coordinate measuring apparatus
Publication Date: 2019.02.06 MITUTOYO CORP
  • EP2722644B1 patent drawingFigure 1
  • EP2722644B1 patent drawingFigure 2(a)~2(c)
  • EP2722644B1 patent drawingFigure 3

AI summary

A surface roughness measuring unit (1) according to the present invention includes a contact pin unit (3) having a contact pin (12) and a displacement detector (16), the contact pin being provided so as to project and retract through a through-hole of a skid (11) and scanning and moving along a surface of a work piece, the displacement detector (16) detecting displacement of the contact pin in a direction perpendicular to the work piece surface; a driver (4) moving the contact pin unit (3) forward and backward along the surface of the work piece; and a joint coupling the contact pin unit and the driver to a measurement head holder of a coordinate measuring system. The surface roughness measuring unit further includes a contact detector that detects contact of the skid on the surface of the work piece.