Machining Jig With Compressive Clamping to Reduce Workpiece Chipping

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Solution Overview

Problem

Machining processes under severe conditions, such as high machining speed, often result in chipping of molded bodies before sintering, compromising the quality of the final sintered components due to tensile stress applied during machining.

Innovation Solution

A machining jig that applies compressive stress to the workpiece using a sliding mechanism with inclined sections, ensuring the inner peripheral surface of the jig matches the workpiece contour, thereby reducing chipping and maintaining product quality even under severe machining conditions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If machining is performed under severe conditions (high machining speed) to improve productivity, then productivity is improved, but chipping occurs due to tensile stress applied during machining

Engineering Contradiction:
Improvemachining speedVSAvoidchipping
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The invention applies compressive stress to the workpiece before machining to counteract the tensile stress that occurs during machining. The jig exerts compressive force on the outer peripheral surface of the workpiece at the position to be machined, creating a preliminary opposing action that prevents chipping even when high-speed machining is performed

Inventive Principle:
Principle #9Preliminary anti-action

2Manufacturing precision

If compressive stress is applied to prevent chipping, then manufacturing precision is improved, but device complexity increases due to additional jig components

Engineering Contradiction:
Improvechipping reductionVSAvoidjig structure
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention combines the clamping function and the compressive stress application function into a single jig structure. The jig includes both a clamping portion that holds the workpiece and a compression portion that applies compressive stress, merging multiple functions into one integrated device rather than using separate components

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The jig is designed with multi-functionality, serving both as a clamping device and as a device to apply compressive stress during machining. The compression portion can be integrated with the clamping mechanism, allowing the same device to perform multiple functions: holding the workpiece and applying compressive stress to prevent chipping

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

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 application of compressive stress significantly reduces chipping during machining, allowing for efficient production of high-quality machined products, including those with complex shapes like undercut features, while maintaining or improving machining speed.

Implementation Method 1

The sliding mechanism causes the small-diameter portion of the second inclined section to press the large-diameter portion of the first inclined section so that compressive stress is applied to the outer peripheral surface of the workpiece at a position near a portion to be removed by the tool

Methodology Applied
Scientific EffectCompressive stress: Compression

Data Source

PatentEP3486030B1Machining jig and machining method
Publication Date: 2021.04.21 SUMITOMO ELECTRIC INDUSTRIES LTD
  • EP3486030B1 patent drawingFigure 1
  • EP3486030B1 patent drawingFigure 2
  • EP3486030B1 patent drawingFigure 3

AI summary

A machining jig holds a workpiece with respect to a tool that partially removes an outer peripheral surface of the workpiece. The machining jig includes a first jig including an inner peripheral surface having a shape similar to a contour of the workpiece and an outer peripheral surface including a first inclined section inclined with respect to an axial direction of the workpiece; a second jig including an inner peripheral surface including a second inclined section configured to be fitted to the first inclined section; a base to which the second jig is coaxially fixed; and a sliding mechanism that enables a large-diameter portion of the first inclined section and a small-diameter portion of the second inclined section to move toward and away from each other. The sliding mechanism of the machining jig causes the small-diameter portion of the second inclined section to press the large-diameter portion of the first inclined section so that compressive stress is applied to the outer peripheral surface of the workpiece at a position near a portion to be removed by the tool.