Multi-Step Press Forming for Controlled Material Inflow

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Solution Overview

Problem

Existing methods struggle to form component shapes that require significant drawing without causing defects like cracks and wrinkles, especially when the final shape's line length exceeds the initial shape's uniform elongation.

Innovation Solution

A method involving multiple press steps with cross-sectional analysis to determine and distribute material inflow amounts, using a die shape designing device to set cross sections and calculate line lengths, ensuring proper material flow and distribution to prevent defects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a single press step is used to form the final component shape, then the manufacturing process is simple, but the component cannot be formed without excessive drawing which causes defects like cracks and wrinkles

Engineering Contradiction:

Improvemanufacturing process simplicityVSAvoidcomponent quality without defects

Core Design Contradiction:

Ease of manufactureVSReliability

Solution Approach 1:

The manufacturing process is divided into multiple press steps (first press step, second press step, etc.) where each step performs a specific forming operation. The first press step performs initial drawing to create an intermediate shape, and the second press step performs final forming. This segmentation allows the total drawing to be distributed across steps, preventing excessive drawing in any single step and avoiding defects while maintaining manufacturing feasibility.

Inventive Principle:

Principle #1Segmentation

2Reliability

If multiple press steps are used to form the final component shape, then the component quality improves by preventing defects, but the manufacturing process complexity increases

Engineering Contradiction:

Improvecomponent quality without defectsVSAvoidmanufacturing process complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The first press step performs preliminary drawing to create an intermediate pressed component shape before the final forming operation. By pre-forming the blank to a specific intermediate shape with controlled dimensions and material distribution, the subsequent second press step can complete the forming without excessive drawing. This preliminary action simplifies the overall multi-step process by optimizing the intermediate state, reducing the complexity of controlling the final forming step.

Inventive Principle:

Principle #10Preliminary action

3Shape

If the final component shape has a line length increase exceeding uniform elongation, then the component achieves the required complex shape, but material defects occur due to excessive drawing

Engineering Contradiction:

Improvefinal component shape complexityVSAvoidmaterial integrity without defects

Core Design Contradiction:

ShapeVSManufacturing precision

Solution Approach 1:

The total line length increase required to achieve the complex final shape is segmented across multiple press steps. The first press step achieves a partial line length increase to create an intermediate shape, and the second press step achieves the remaining increase. This segmentation ensures that the drawing in each step remains within the material's uniform elongation capacity, preventing defects while achieving the required complex final shape.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The process changes the forming parameters by introducing an intermediate pressed component shape with specific dimensional parameters between the initial blank and final component. By controlling the intermediate shape's line length, surface area, and material distribution parameters, the process ensures that the drawing ratio in each step remains within acceptable limits, maintaining material integrity while achieving the required shape complexity.

Inventive Principle:

Principle #35Parameter changes

4Ease of operation

If material inflow is not properly controlled in multi-step pressing, then the process is easier to control, but defects like wrinkles and cracks occur

Engineering Contradiction:

Improveprocess control simplicityVSAvoidmaterial flow control accuracy

Core Design Contradiction:

Ease of operationVSManufacturing precision

Solution Approach 1:

The first press step performs preliminary forming to create an intermediate shape that pre-determines the material distribution and flow characteristics for the second press step. By controlling the intermediate shape's geometry and material inflow in the first step, the process simplifies the control requirements for the second step, as the material is already positioned and distributed optimally. This preliminary action ensures accurate material flow control without requiring complex real-time adjustments.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12472548B2Pressed component manufacturing method, die designing method, die shape designing device, and die

Publication Date: 2025.11.18 JFE STEEL CORP

AI summary

A pressed component manufacturing method wherein, in press forming a metal sheet into a final component shape through two or more press steps, the inflow amount of the required material is determined based on the increase in the cross-sectional line length of the shape with respect to the line length before forming when the metal sheet is press formed by a single press step, the determined amount is distributed to each step, and a preformed shape after press forming based on the distributed inflow amount. As the cross section, a line orthogonal to a direction in which the material flows when the metal sheet is drawn is set, and a plurality of cross sections is set which is individually cut by each of planes orthogonal to the line and extending in a direction along the sheet thickness direction of the metal sheet before forming.