Rubber Mold Hole Geometry for Void-Free Ceramic Ball CIP
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional rubber molds for cold isostatic pressing of ceramic ball materials face challenges such as residual voids, density inhomogeneity, and defects like cracks and distortions due to stress concentration and rubbing issues during the CIP process, leading to unreliable bearing balls.
Innovation Solution
A rubber mold design with approximately columnar hole sections on its surfaces, optimized ratios of hole diameter to depth, and engaging sections to prevent surface disengagement, allowing for isostatic pressure application and reducing torsional shear stress, thereby improving the yield and reliability of ceramic ball materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional rubber molds with hemispherical hole sections are used for CIP processing, then the molding process can be performed, but residual voids and density inhomogeneity occur in the green compact leading to reliability issues
Solution Approach 1:
The patent changes the geometric parameters of the hole sections from hemispherical to approximately columnar shape with specific diameter-to-depth ratios. This parameter change enables uniform pressure distribution during CIP processing, eliminating residual voids and density inhomogeneity while improving the reliability of the final bearing balls.
2Reliability
If conventional rubber molds without engaging sections are used, then the mold structure is simpler, but surface disengagement occurs leading to stress concentration and defects
Solution Approach 1:
The patent incorporates engaging sections (protrusions and recesses) on the rubber mold surfaces before the CIP processing begins. This preliminary design feature prevents surface disengagement and stress concentration during pressure application, eliminating defects in the sintered compact without significantly complicating the mold structure.
3Ease of manufacture
If uniaxial pressing is used to form green compact, then the molding process is simple, but internal voids cannot be completely eliminated
Solution Approach 1:
The patent employs cold isostatic pressing (CIP) processing that applies hydraulic pressure uniformly from all directions to the green compact. This hydraulic pressure application, combined with the optimized columnar hole section geometry, completely eliminates internal voids while maintaining process simplicity and improving manufacturing precision.
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 new rubber mold design effectively reduces voids and defects in ceramic ball materials, enhancing the reliability and quality of the sintered compacts by ensuring uniform pressure distribution and minimizing stress concentrations during the CIP process.
Implementation Method 1
performing cold isostatic pressing (CIP) processing with respect to the green compact 5 is effective. The CIP processing is a method of applying isostatic hydraulic pressure to the green compact 5 from a periphery thereof in a state where the periphery of the green compact 5 is sealed by rubber, film, or the like.
Data Source
AI summary
A rubber mold according to an embodiment is for CIP processing of a green compact with a plate shape. The rubber mold includes one or more approximately columnar hole sections are provided on at least one or more bottom surfaces. Further, when a diameter of an opening of the hole section is denoted by a and a maximum depth of the hole section is denoted by b, a/b<2.0 is satisfied.