Metal Sheet Crush Molding With Gap-Controlled Thickness Uniformity
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Solution Overview
Problem
Crush machining methods for metal sheets often result in uneven thickness due to varying pressing forces across different regions, leading to suboptimal quality of molded items with reduced-thickness portions.
Innovation Solution
A metal sheet molding method that uses a die with paired inclined surfaces and a flat surface, allowing the metal sheet to span both inclined surfaces and maintaining a gap between the inner end portions and the metal sheet, enabling matter to flow and distribute evenly, thus preventing uneven thickness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If crush machining is applied using a punch and die with inclined surfaces, then reduced-thickness portions can be formed in the metal sheet, but uneven thickness occurs in the surface due to varying pressing forces across different regions
Solution Approach 1:
The die machining surface is designed with different surface orientations in different regions: inclined surfaces in the width-direction end portions and a flat surface in the intermediate portion. This local variation in surface quality allows matter to flow differently in different regions, preventing uneven thickness while still forming the required reduced-thickness portions.
Solution Approach 2:
The solution introduces a new dimension to the die surface by adding a flat surface region between the inclined surfaces. This creates a three-dimensional surface structure with varying orientations, providing additional pathways for matter flow in the width direction and eliminating the thickness uniformity problem.
2Shape
If the distance between the inclined surface of the die and bottom end surface of the punch varies across regions, then reduced-thickness portions are formed, but matter flow is restricted leading to surface defects
Solution Approach 1:
The flat surface acts as an intermediary region between the inclined surfaces, providing a transition zone that facilitates matter flow. This intermediate surface allows material to redistribute evenly during pressing, preventing the accumulation that causes surface defects while maintaining the reduced-thickness geometry.
3Ease of manufacture
If pressing force is applied uniformly, then the molding process is simple, but uneven thickness occurs due to the inclined surface geometry
Solution Approach 1:
The die surface parameters are changed by introducing a flat surface region with zero inclination angle between the inclined surface regions. This parameter variation in the die geometry naturally distributes the pressing force more evenly across the metal sheet, achieving thickness uniformity without complicating the molding process.
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 effectively restricts the occurrence of uneven thickness, resulting in high-quality molded items with consistent reduced-thickness portions, suitable for applications like continuously variable transmission elements.
Implementation Method 1
flowing of matter along the surface direction of the processing surface of the die occurs in the metal sheet
Implementation Method 2
a portion (also referred to below as an 'inclined surface contact portion') sandwiched between the inclined surface of the die and the bottom end surface of the punch is pressed, thereby forming the reduced-thickness portion
Data Source
AI summary
A machining surface of a die are provided with a pair of inclined surfaces facing each other across a gap and a flat surface interposed therebetween. Each inclined surface includes an inner end portion on a side near the flat surface and an outer end portion on a side farther away from the flat surface. The molding method includes a mounting step of mounting the metal sheet on the die to span both inclined surfaces, and a pressing step of forming a reduced-thickness portion by pressing the metal sheet between the punch and the inclined surfaces of the die. The pressing step includes setting a bottom dead center of the punch to maintain a gap formed between the inner end portion and a surface of the metal sheet facing the inner end portion.