High Speed Blow Forming Process for Complex Shapes

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Solution Overview

Problem

Superplastic forming is a slow process, making it impractical for mass production scenarios such as in the auto manufacturing industry, where complex shapes with significant curvatures are required, as it involves low strain rates and long processing times.

Innovation Solution

Combining hot crash forming with high-speed blow forming, where a heated metal blank is clamped between a mold and a sealing counterpart, and pressurized gas is used to form the part, followed by vacuum application to hold the part against the mold, allowing for rapid and efficient shaping with significant elongation, and sequenced ejection to facilitate part removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Shape

If superplastic forming is used to form complex shapes with significant curvatures, then the desired shape can be achieved, but the processing time becomes excessively long making it impractical for mass production

Engineering Contradiction:
Improvecomplex shape with significant curvaturesVSAvoidprocessing time
Core Design Contradiction:
ShapeVSLoss of time

Solution Approach 1:

The forming process is divided into two distinct stages: first, hot crash forming to create a preform with minimal elongation, and second, high-speed blow forming to achieve the final complex shape. This segmentation allows each stage to optimize for its specific function, reducing total processing time while achieving the desired complex geometry.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hot crash forming step performs preliminary shaping of the blank into a preform before the final blow forming operation. This preliminary action prepares the material in an optimal state for the subsequent high-speed forming, enabling faster processing of the final complex shape.

Inventive Principle:
Principle #10Preliminary action

2Productivity

If high-speed blow forming is used to reduce processing time, then productivity increases, but achieving complex shapes with significant curvatures becomes difficult

Engineering Contradiction:
Improveprocessing speedVSAvoidcomplex shape with significant curvatures
Core Design Contradiction:
ProductivityVSShape

Solution Approach 1:

The process segments the forming operations so that high-speed blow forming handles the final complex shape achievement, while hot crash forming handles the preliminary shaping. This allows the blow forming stage to operate at high speed without being constrained by the need to perform both preliminary and final shaping.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hot crash forming step performs preliminary shaping to create a preform that is optimally positioned and shaped for the subsequent high-speed blow forming. This preliminary preparation enables the blow forming operation to achieve complex shapes more efficiently at high speed.

Inventive Principle:
Principle #10Preliminary action

3Strength

If hot crash forming is used to consume minimal elongation, then material elongation is preserved for subsequent forming, but additional process steps are required

Engineering Contradiction:
Improvematerial elongation capacityVSAvoidnumber of process steps
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent combines hot crash forming and high-speed blow forming into a single integrated die system that performs both operations sequentially without removing the workpiece. This merging of operations into one setup reduces overall process complexity despite adding a forming stage, as it eliminates the need for separate setups and repositioning.

Inventive Principle:
Principle #5Merging (Combining)

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

This method significantly reduces processing time, achieving part formation in less than 15 seconds with elongations greater than 200%, enabling the production of complex shapes that were previously unattainable with other techniques, thus enhancing manufacturing throughput and efficiency.

Implementation Method 1

applying first pressure on the blank from the sealing counterpart so the blank is pressed upward to form a shaped part corresponding to the mold, the first pressure applied through a diffuser on the sealing counterpart

Methodology Applied
Scientific EffectPressure: Pressure Increase

Implementation Method 2

applying a vacuum to the shaped part to hold it against the mold also after separating the mold and the sealing counterpart

Methodology Applied
Scientific EffectVacuum: Vacuum

Implementation Method 3

Clamping the blank comprises a hot crash forming that consumes only minimal available elongation from the blank

Methodology Applied
Scientific EffectPlasticity: Plasticity

Implementation Method 4

applying the first pressure comprises a high speed blow forming operation that generates the shaped part

Methodology Applied
Scientific EffectPressure: Pressure Increase

Data Source

PatentEP3352925B1High speed blow forming processes
Publication Date: 2020.11.04 TESLA INC
  • EP3352925B1 patent drawingFigure 1
  • EP3352925B1 patent drawingFigure 2
  • EP3352925B1 patent drawingFigure 3

AI summary

A method of forming a part includes: inserting a blank into a die, the die comprising a mold mounted above a sealing counterpart; clamping the blank between the mold and the sealing counterpart; applying first pressure on the blank from the sealing counterpart so the blank is pressed upward to form a shaped part corresponding to the mold; applying a vacuum to the shaped part to hold it against the mold also after separating the mold and the sealing counterpart, the vacuum applied through at least one opening in the mold located in a corner of the mold that the blank does not reach when the first pressure is applied; and discontinuing the vacuum to allow the shaped part to be released from the mold.