Metal Cylinder Grain Gradient for Smooth Impact Pressing
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Solution Overview
Problem
Existing methods for producing metal cylinders through impact pressing often result in surface roughness and recesses on the outer peripheral surface, leading to dot defects in images formed by electrophotographic photoreceptors due to uneven crystal grain sizes, which affect the quality and consistency of the cylinders produced.
Innovation Solution
A method involving shot peening to adjust the crystal grain diameter at specific depths of the metal slug surface, ensuring it is smaller at 10 μm than at 100 μm, with a range of 30 μm to 120 μm, to reduce surface roughness and suppress recess formation during impact pressing, thereby enhancing the surface quality of the cylinders.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If impact pressing is used to mass-produce metal cylinders, then productivity is improved and cost is reduced, but surface roughness and recesses occur on the outer peripheral surface
Solution Approach 1:
The patent applies preliminary action by adjusting the crystal grain structure of the metal slug before impact pressing. Specifically, the crystal grain diameter at the surface (10 μm depth) is controlled to be smaller than at deeper layers (100 μm depth), with the surface crystal grain diameter maintained between 30-120 μm. This pre-adjustment of material structure prevents surface defects during the subsequent impact pressing process, enabling mass production of cylinders with smooth surfaces and minimal recesses.
2Manufacturing precision
If crystal grain diameter at surface is reduced to minimize recesses, then surface quality is improved, but material strength may be affected
Solution Approach 1:
The patent applies local quality by creating a gradient crystal grain structure where different depths have different crystal grain diameters. The surface layer (10 μm depth) has smaller crystal grains (30-120 μm) to ensure smooth surface quality and minimize recesses, while deeper layers (100 μm depth) maintain larger crystal grains to preserve overall material strength. This localized differentiation of crystal grain sizes allows simultaneous optimization of surface quality and bulk mechanical properties.
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 approach effectively minimizes recesses on the outer peripheral surface, producing cylinders with higher hardness and reduced surface roughness, resulting in improved image quality and consistency, equivalent to or surpassing cutting methods, while enabling mass production with reduced need for automatic surface testing.
Implementation Method 1
A method involving shot peening to adjust the crystal grain diameter at specific depths of the metal slug surface
Implementation Method 2
forming a cylinder by impact pressing of the metal slug having the surface as a bottom
Data Source
AI summary
A method for producing a metal cylinder includes preparing a metal slug having a surface adjusted so that the crystal grain diameter at a depth of 10 μm from the surface is smaller than that at a depth of 100 μm from the surface, and the crystal grain diameter at a depth of 10 μm from the surface is 30 μm or more and 120 μm or less; and forming a cylinder by impact pressing of the metal slug having the surface as a bottom.