Beveled Watch Stone Forming with a Sintered Flared Peripheral Face

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Solution Overview

Problem

Current machining processes are complex and inefficient for manufacturing a single stone with a partially flared peripheral wall to simplify the arrangement of guide elements and improve impact resistance in watchmaking, as they require multiple steps and can damage the stone or manufacturing system.

Innovation Solution

A method involving the production of a precursor from powdered material with a binder, pressing using dies with a protruding rib to form a green body, sintering to create a stone with a peripheral groove, and machining to create a flared peripheral face, allowing for the stone to be inserted into a bearing block for shock absorption.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional machining processes are used to create a flared peripheral wall on a single stone, then the arrangement of guide elements is simplified and impact resistance is improved, but the manufacturing process becomes complex and inefficient, causing damage to the stone or manufacturing system

Engineering Contradiction:
Improvearrangement of guide elementsVSAvoidmanufacturing process
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The flared peripheral face is formed during the sintering process itself by shaping the die cavity with a flared surface, rather than attempting to machine the flared shape after sintering. The green body is pressed in the pre-formed flared cavity, and the flared shape is preserved through sintering, eliminating the need for complex post-sintering machining operations to create the flared peripheral wall

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention replaces complex mechanical machining operations with a forming process. Instead of using cutting tools to mechanically remove material to create the flared shape, the flared geometry is formed by the die cavity shape during pressing, and this shape is maintained through the sintering process, substituting mechanical removal with formative creation

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If conventional machining processes are used to create a flared peripheral wall, then the stone structure is simplified, but the manufacturing process causes damage to the stone or manufacturing system

Engineering Contradiction:
Improvestone structureVSAvoiddamage to stone
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The flared peripheral face is formed during the green body pressing stage in the shaped die cavity, and this shape is preserved through sintering. By forming the final flared geometry before sintering rather than attempting to machine it after sintering, the stone structure is simplified without subjecting the hardened sintered stone to damaging mechanical cutting forces

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention changes the manufacturing approach from post-sintering mechanical removal to pre-sintering formative creation. The flared shape is created in the green body state using the die cavity geometry, and this shape is maintained through the sintering process, avoiding the need to machine the hard, brittle sintered stone which causes damage

Inventive Principle:
Principle #35Parameter changes

3Strength

If a single stone with flared peripheral wall is manufactured to simplify guide element arrangement, then impact resistance is improved, but current machining processes are too complex to implement

Engineering Contradiction:
Improveimpact resistanceVSAvoidmachining process
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The flared peripheral face is formed during the green body pressing operation using a die cavity with the desired flared geometry. This pre-forming approach creates the impact-resistant flared structure without requiring complex post-sintering machining, as the shape is established before sintering when the material is still in the softer green body state

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention replaces complex post-sintering mechanical machining operations with a forming process during pressing. The flared geometry is created by the die cavity shape rather than by removing material with cutting tools, and this formed shape is preserved through sintering, eliminating the need for complex machining equipment and processes

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method enables the efficient and damage-free manufacturing of a beveled stone with a flared peripheral face, simplifying the arrangement of guide elements and enhancing impact resistance by allowing the stone to absorb side impacts effectively.

Implementation Method 1

production of a precursor from a mixture of at least one powdered material with a binder

Methodology Applied
Scientific EffectBinder: Binder

Implementation Method 2

sintering said green body in order to form a body of the future stone

Methodology Applied
Scientific EffectSintering: Sintering

Data Source

PatentEP3770697B1Method for manufacturing a bevelled stone, in particular for a clock movement
Publication Date: 2023.08.30 COMADUR
  • EP3770697B1 patent drawingFigure 1~3
  • EP3770697B1 patent drawingFigure 4~7
  • EP3770697B1 patent drawingFigure 8~10

AI summary

The invention relates to a method for manufacturing a beveled stone (8), in particular for a watch part, characterized in that it comprises the following steps: - production of a precursor from a mixture of at least one powdered material with a binder; - Pressing the precursor to form a green body, using an upper die and a lower die comprising a projecting rib, - Sintering said green body to form a body (30) of the future stone (8) in said at least one material, the body (30) comprising a peripheral face (37) and a lower face (32) provided with a groove (40), and - Machining the body (30) comprising a sub-step of planing the peripheral face (37) up to the groove (40), so that an internal wall (42) of the groove forms at least one flared portion of the peripheral face of the stone (8). The invention also relates to a device for manufacturing a beveled stone implementing the process.