Punch-Die Shearing Geometry for Corrosion-Resistant Cut Edges
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Solution Overview
Problem
Existing methods for manufacturing steel members with corrosion resistance at cut edges are inefficient, as they either produce excessive fracture surfaces or limit the plating layer, leading to potential corrosion issues.
Innovation Solution
A processing apparatus with a punch and die arrangement where the side faces include inclined portions to form an edge surface with a plating layer, ensuring at least 60% of the edge surface is covered, thereby enhancing corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional clearance (1-20% of sheet thickness) is used between die and punch, then the plating layer coverage is improved, but the fracture surface area increases leading to poor corrosion resistance
Solution Approach 1:
The invention changes the geometric parameters of the die by providing an inclined portion with a specific angle (15° or more) and height (60% or more of sheet thickness). This parameter modification allows the formation of an inclined surface that extends the plating layer coverage while controlling fracture surface area, thereby improving corrosion resistance without requiring additional plating processes.
2Manufacturing precision
If small clearance (≤1.0% of sheet thickness) is used between die and punch, then the shear surface length increases, but the plating layer coverage remains limited and fracture surface is reduced
Solution Approach 1:
The invention introduces a new dimensional element by adding an inclined portion to the die with a height of 60% or more of the sheet thickness. This creates an inclined surface that extends in the thickness direction, thereby increasing plating layer coverage area without compromising shear surface length or requiring reduced clearance.
3Reliability
If additional plating process is applied to cut edge surface, then corrosion resistance is improved, but work time and manufacturing costs increase
Solution Approach 1:
The invention performs the plating layer preservation action during the cutting process itself by using the die with an inclined portion. This preliminary action ensures that the plating layer covers at least 60% of the edge surface area during shearing, eliminating the need for subsequent plating processes and reducing total work time.
Solution Approach 2:
The invention merges the cutting function with the plating layer preservation function into a single die structure. The inclined portion of the die simultaneously performs material separation and plating layer protection, combining multiple functions into one operation and eliminating the need for separate plating processes.
Data Source
AI summary
A processing apparatus capable of manufacturing a metallic member with improved corrosion resistance at its cut edge surface is provided. A processing apparatus (20) includes a punch (21) and a die (22) to be positioned on one side and the other side of a workpiece constituted by a metal sheet (10), the one and the other sides being arranged in the sheet-thickness direction, each of the punch (21) and the die (22) includes an end face (211), (221) and a side face (212), (222), the punch (21) and the die (22) are positioned such that the end face (211) of the punch (21) and the end face (221) of the die (22) do not overlap in plan view, at least one of the side face (212) of the punch (21) and the side face (222) of the die (22) includes an inclined portion (212a) providing a surface inclined to face the metal sheet (10) and shaped to overlap the other one of the punch (21) and the die (22) in plan view, and the surface provided by the inclined portion (212a) and the sheet-thickness direction form an angle θ not smaller than 15°.