Hot-Stamped Part Piercing Timing for Sheared Surface Quality

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Solution Overview

Problem

Existing hot-stamping processes face challenges with laser equipment, which have not effectively addressed issues such as increased processing time and deteriorated quality of sheared surfaces, and the need for flexible process design and quality control in hot-stamped parts manufacturing.

Innovation Solution

A method for manufacturing hot-stamped parts that includes a heating operation, transferring operation, and forming/piercing operation, with a derived maximum delay time for hot piercing based on factors like blank thickness and forming start temperature, using a correction coefficient equation to optimize the process.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If laser equipment is used for piercing, then piercing can be performed, but processing time increases

Engineering Contradiction:
Improvepiercing capabilityVSAvoidprocessing time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The blank is heated to high temperature before piercing operation. This preliminary heating action softens the material, enabling subsequent piercing to be performed quickly with press dies without increasing processing time, while maintaining good sheared surface quality

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The temperature of the blank is changed from room temperature to high temperature (Ac3 transformation point or higher) before piercing. This parameter change enables the use of press dies for piercing instead of laser equipment, resolving the contradiction between piercing capability and processing time

Inventive Principle:
Principle #35Parameter changes

2Loss of time

If press dies are used for piercing, then processing time is reduced, but quality of sheared surfaces deteriorates

Engineering Contradiction:
Improveprocessing timeVSAvoidquality of sheared surfaces
Core Design Contradiction:
Loss of timeVSManufacturing precision

Solution Approach 1:

The temperature of the blank is raised to Ac3 transformation point or higher before piercing. This parameter change softens the material, allowing press dies to produce high-quality sheared surfaces without deterioration, while maintaining short processing time

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

Heating the blank to high temperature is performed as a preliminary action before piercing. This prepares the material in advance to be more suitable for press die piercing, ensuring both quick processing and high surface quality

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If hot piercing is performed without considering delay time, then process is simple, but quality control becomes difficult

Engineering Contradiction:
Improveprocess complexityVSAvoidquality control
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent establishes feedback control by measuring the actual temperature of the blank and comparing it with the target temperature range. Based on this comparison, the piercing timing is adjusted to ensure optimal quality while maintaining relatively simple process implementation

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The piercing operation timing is made dynamic rather than fixed. The delay time from press die bottom dead center is adjusted based on actual blank temperature and thickness, enabling quality control while keeping the process adaptable rather than overly complex

Inventive Principle:
Principle #15Dynamics

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

Enables flexible process design and facilitates quality control of hot-stamped parts by optimizing the hot piercing delay time, improving the quality and efficiency of the manufacturing process.

Implementation Method 1

a heating operation of heating a blank

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

a soaking operation in which the blank may be heated to a temperature of Ac3 to 1000 °C

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Implementation Method 3

the heated blank may be air cooled at room temperature

Methodology Applied
Scientific EffectAir cooling: Convection

Implementation Method 4

in the forming and piercing operation, the transferred blank may be cooled in the press die

Methodology Applied
Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentEP4644013A1Manufacturing method for hot-stamped parts
Publication Date: 2025.11.05 HYUNDAE STEEL CO LTD
  • EP4644013A1 patent drawingFigure 1
  • EP4644013A1 patent drawingFigure 2
  • EP4644013A1 patent drawingFigure 3

AI summary

The present disclosure provides a method of manufacturing hot-stamped parts, the method including: a heating operation of heating a blank; a transferring operation of transferring the heated blank to a press die including a punch; and a forming and piercing operation of hot-forming the transferred blank into a shape of a hot-stamped part and hot-piercing the transferred blank to form a pierced portion in the hot-stamped part.