Cold Press Mold Geometry for Vertical Wall Warp Suppression
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Solution Overview
Problem
Existing methods for manufacturing high-strength automotive framework members fail to effectively suppress vertical wall warping, particularly at the base end portions, due to inward warp moments, and require modifications such as beads or undulating shapes that may not be feasible in all designs.
Innovation Solution
A pressed article manufacturing method using a press mold with a punch and die that applies pressure to the base end side portion of the second wall in a first warp shape, correcting the inward warp moment by gripping it in a convex shape on the back face side, thereby reducing strain differences and preventing warping.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If high-strength sheet steel (590 MPa or greater) is used to manufacture framework members, then the strength and weight reduction goals are achieved, but vertical wall warping occurs due to inward warp moments during pressing
Solution Approach 1:
The patent applies preliminary anti-action by designing the punch and die with specific curvature radii that counteract the inward warp moment before it fully develops. The punch has a curvature radius R1 and the die has a curvature radius R2, where R2 > R1, creating a preliminary opposing moment that prevents the vertical wall from warping inward during pressing. This resolves the contradiction by maintaining both high strength and shape accuracy.
Solution Approach 2:
The patent changes the geometric parameters of the pressing tooling - specifically setting the punch curvature radius R1 to be smaller than the die curvature radius R2. This parameter difference creates a controlled stress distribution that counteracts the inward warp moment. By adjusting these curvature parameters, the patent achieves both high-strength material utilization and precise vertical wall formation without warping.
2Ease of manufacture
If conventional pressing methods are used on high-strength blanks, then manufacturing simplicity is maintained, but base end side portions warp convex on the front face side due to stress differences
Solution Approach 1:
The patent incorporates preliminary anti-action directly into the pressing process by designing the punch and die geometries to create an opposing moment. The punch with curvature radius R1 and die with curvature radius R2 (where R2 > R1) generate a counter-moment that prevents the base end side portions from warping convex on the front face side. This maintains manufacturing simplicity while achieving precise shape control.
Solution Approach 2:
The patent applies local quality by creating different curvature radii at different locations - the punch has a smaller curvature radius R1 at the contact point, while the die has a larger curvature radius R2. This localized geometric difference creates a targeted stress distribution that specifically addresses the warping issue at the base end portions without affecting other areas, maintaining overall process simplicity.
3Manufacturing precision
If additional features like beads or undulating shapes are added to suppress warping, then wall warping is reduced, but device complexity and design flexibility are reduced
Solution Approach 1:
The patent avoids adding structural features like beads or undulating shapes by instead changing the pressing parameters - specifically the curvature radii of the punch (R1) and die (R2). This parameter-based solution achieves warping suppression without increasing framework member complexity, maintaining design flexibility while achieving precise shape control.
Solution Approach 2:
The patent replaces the mechanical approach of adding structural features (beads, undulations) with a process-based approach using optimized pressing tooling geometries. By substituting the need for additional structural elements with carefully controlled punch and die curvature parameters, the patent achieves warping suppression without increasing device or product complexity.
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 method effectively suppresses wall warping in high-strength framework members with tensile strengths of 590 MPa or greater, eliminating the need for additional features like beads or undulating shapes, and maintaining structural integrity.
Implementation Method 1
portions B1, B2 of a blank B that are formed into the vertical walls 7a, 7b are subjected to bending, and bend-back, deformation by a punch 10 and a die 11 during the pressing process
Data Source
Figure 1A~1B
Figure 2
Figure 3
AI summary
A pressed article manufacturing method employing a press mold equipped with a punch and a die to manufacture a pressed article including a first wall, a second wall extending out from an end portion on at least one length direction side of the first wall toward a back face side of the first wall, and a third wall extending out from a leading end portion of the second wall toward a front face side of the second wall. The manufacturing method includes using the punch and the die to apply pressure to and grip a portion on a base end side of the second wall in a first warp shape in which the base end side portion is warped so as to be convex on a back face side of the second wall as viewed in lateral cross-section in a state prior to demolding from the press mold.