Press Tool Geometry for Corrosion-Resistant Metal Cut Edges
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Solution Overview
Problem
Existing methods for manufacturing corrosion-resistant steel members with plated steel sheets result in limited plating coverage at cut edges, leading to increased work time and costs due to the need for additional plating steps to protect exposed base steel.
Innovation Solution
A press tool with specific geometries, including a punch, counter-pad, sheet holder, and die, is used to stamp a metal sheet with coating layers, employing projecting portions with defined radii of curvature to ensure plating coverage on both sides of the cut edge surface, forming recessed and sheared surfaces with improved corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If plated steel sheet is subjected to press-working process with cutting, then the metallic member is formed, but the plating layer is severed at the cut edge surface exposing base steel which reduces corrosion resistance
Solution Approach 1:
The invention applies preliminary action by providing a rounded corner with specific radius of curvature (0.05-0.50 times sheet thickness) on the cutting tool before the cutting process. This pre-configured geometry ensures that the plating layer is not severed at the cut edge during stamping, maintaining corrosion resistance without requiring subsequent corrective plating operations.
Solution Approach 2:
The invention changes the geometric parameter of the cutting tool by specifying a rounded corner radius (0.05-0.50 times the sheet thickness) instead of a sharp corner. This parameter modification alters the cutting mechanism to preserve the plating layer continuity at the cut edge, resolving the contradiction between manufacturing precision and corrosion resistance.
2Reliability
If additional plating step is applied to cut edge surface, then corrosion resistance is improved, but work time and costs increase
Solution Approach 1:
The rounded corner geometry is built into the cutting tool in advance, performing the corrosion protection function during the primary stamping operation itself. This eliminates the need for separate post-cutting plating steps, thereby maintaining high corrosion resistance while preserving productivity and reducing manufacturing time.
Solution Approach 2:
The invention merges the cutting function with the corrosion protection function into a single stamping operation. By designing the tool with a rounded corner, the plating preservation occurs simultaneously with the cutting process, combining multiple functions that would otherwise require separate steps, thus improving productivity without sacrificing corrosion resistance.
3Productivity
If conventional cutting tool with sharp corner is used, then cutting efficiency is high, but plating layer is severed exposing base steel
Solution Approach 1:
The invention modifies the geometric parameter of the cutting tool by introducing a rounded corner radius (0.05-0.50 times sheet thickness) instead of a sharp corner. This parameter change preserves the efficiency of the stamping process while simultaneously improving plating coverage at the cut edge, eliminating the need for additional plating operations.
Solution Approach 2:
The invention applies local quality by providing a rounded corner specifically at the cutting edge of the tool, while the rest of the tool maintains its conventional geometry. This localized modification targets the specific problem area (cut edge plating coverage) without affecting the overall cutting efficiency of the tool.
Data Source
AI summary
A method of manufacturing a metallic member having a cut edge surface with improved corrosion resistance is provided. The method of manufacturing a metallic member uses a press tool to stamp a metal sheet having front and back faces covered with a coating layer, thus producing a metallic member. The press tool includes a punch, a counter-pad, a sheet holder, and a die. The sheet holder includes a projecting portion at an inner circumferential edge of the face facing the metal sheet, the projecting portion of the sheet holder including a corner at its inner circumference, the corner having a radius of curvature R1, the radius of curvature R1 being not smaller than 0.10 times the thickness of the metal sheet. The manufacturing method includes: pushing the projecting portion into the metal sheet; and moving the punch and the die closer to each other to stamp the metal sheet.