Green Compact Press Tool for Multi-Part Interference Fitting

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Solution Overview

Problem

Current methods for producing green compacts often result in sintered components that are prone to cracking due to density inhomogeneities and axial/radial stresses, and require separate compaction and assembly of parts, which is time-consuming and may lead to fitting inaccuracies.

Innovation Solution

A method where at least two partial green compacts are pressed and joined in a single operation using a press tool with separate working spaces, allowing for independent compaction and interference fitting without disruptive stresses, and optionally post-compacting the joined body in the same tool.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If separate compaction and assembly of parts is performed, then manufacturing flexibility is improved, but production time increases and fitting accuracy deteriorates

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidproduction time
Core Design Contradiction:
Ease of manufactureVSProductivity

Solution Approach 1:

The patent combines separate compaction and assembly operations into a single integrated process. Multiple partial green compacts are compacted and assembled simultaneously in one press operation, eliminating the need for separate compaction and assembly steps. This merging of operations reduces production time while maintaining manufacturing flexibility through the modular tooling design.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The press tool is divided into separate working spaces that can independently compact different subsets of powdered material. This segmentation allows each working space to form partial green compacts simultaneously, which are then assembled within the same tool. The segmented approach enables parallel processing of multiple components, improving productivity without sacrificing manufacturing flexibility.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If separate compaction and assembly of parts is performed, then ease of assembly is improved, but manufacturing precision deteriorates due to fitting inaccuracies

Engineering Contradiction:
Improveease of assemblyVSAvoidfitting accuracy
Core Design Contradiction:
Ease of operationVSManufacturing precision

Solution Approach 1:

By combining compaction and assembly in a single operation within the same press tool, the invention eliminates dimensional tolerances that would arise from separate operations. The partial green compacts are assembled while still in the green state, allowing for precise interference fitting without the accumulation of tolerances that would occur with separate compaction and assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The partial green compacts are prepared in advance within the same tool that will perform the final assembly. This preliminary action within the integrated tooling system ensures that all components are positioned and fitted with high precision before the final compaction, eliminating fitting inaccuracies that would result from separate operations.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If conventional compaction methods are used, then process simplicity is improved, but reliability deteriorates due to cracking from density inhomogeneities and stresses

Engineering Contradiction:
Improveprocess simplicityVSAvoidcracking resistance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention segments the powdered material into multiple subsets that are compacted independently in separate working spaces. This segmentation allows each subset to be compacted to uniform density without the density inhomogeneities that occur in conventional single-piece compaction. The resulting partial green compacts have more homogeneous density distributions, reducing internal stresses and cracking risk.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

By merging the compaction of multiple subsets with their assembly into a single integrated operation, the invention eliminates the disruptive stresses that would arise from separate handling and assembly operations. The partial green compacts are assembled while in the green state, allowing for stress-free interference fitting that maintains structural integrity and prevents cracking.

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 method reduces the risk of cracking, achieves a high degree of fitting accuracy, and allows for faster production with a firm mechanical clamping force sufficient for transport to a sintering furnace, resulting in a green compact with strength comparable to the final sintered structure.

Implementation Method 1

the first and second subsets are compressed at least in the first working chamber to form a first partial green part and in the second working chamber to form a second partial green part

Methodology Applied
Scientific EffectMechanical compaction: Compression

Implementation Method 2

the at least two partial green parts are pressed and joined in a single operation... allowing for independent compaction and interference fitting without disruptive stresses

Methodology Applied
Scientific EffectInterference fitting: Mechanical Force

Data Source

PatentEP2480359B1Method for producing a green compact apparatus for the manufacture thereof and computer programm
Publication Date: 2021.12.22 GNK SINTER METALS GMBH & CO KG
  • EP2480359B1 patent drawingFigure 1A~2F
  • EP2480359B1 patent drawingFigure 3A~4

AI summary

The invention relates to a method for producing a green compact, said green compact comprising at least two partial green compacts, each partial green compact being compacted and joined from at least one powdery material in one working cycle. Particularly, two, three, four or more than four partial green compacts can be compacted and joined in one working cycle.