Deep-Drawing Die Wave Indentations for Wrinkle Control

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Solution Overview

Problem

The deep-drawing process often results in undesirable wrinkles and crease failures due to the inclination of the frame in deep-drawn parts, leading to surface defects and increased reject rates, as existing methods to counteract these issues, such as increasing sheet holding force, are insufficient and can lead to other failures like bottom tears.

Innovation Solution

A deep-drawing device with means for controlled wrinkle generation, such as wave-like indentations or elongated depressions on the drawing die, which influence the formation and arrangement of folds in the frame area, ensuring regular distribution and minimizing crease failures by integrating wave disturbances specific to the part geometry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the sheet holding force is increased to prevent type 2 wrinkles in the frame area, then wrinkle formation is reduced, but sheet thinning increases which leads to bottom cracks

Engineering Contradiction:
Improvewrinkle preventionVSAvoidsheet thickness
Core Design Contradiction:
Manufacturing precisionVSStrength

Solution Approach 1:

The invention applies local quality by introducing wave-like indentations only in specific zones where type 2 wrinkles occur (frame areas with inclined walls), rather than uniformly increasing sheet holding force across the entire blank. This localized geometric modification redirects material flow and compressive stresses precisely where needed, preventing wrinkles without causing excessive sheet thinning that would lead to bottom cracks.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The invention changes the geometric parameters of the drawing die by incorporating wave-like indentations with specific wavelengths and amplitudes. These parameter changes modify the material flow pattern and stress distribution during deep-drawing, transforming the harmful compressive stresses that cause type 2 wrinkles into controlled material redirection, thereby preventing wrinkles without requiring increased sheet holding force that would thin the sheet.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If the wall inclination angle is increased to enable part stacking, then space utilization improves, but type 2 wrinkle formation increases

Engineering Contradiction:
Improvestacking efficiencyVSAvoidsurface quality
Core Design Contradiction:
Volume of moving objectVSManufacturing precision

Solution Approach 1:

The invention applies preliminary action by pre-shaping the drawing die with wave-like indentations before the deep-drawing process begins. These pre-configured geometric features proactively guide material flow and prevent type 2 wrinkle formation during forming, enabling the use of larger wall inclination angles (5-15 degrees) for better stacking efficiency without sacrificing surface quality. The wave patterns are built into the tooling in advance to counteract the wrinkle-prone conditions created by inclined walls.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If conventional deep-drawing tools are used without wave disturbances, then device complexity is low, but crease failures and scrap rates increase

Engineering Contradiction:
Improvetool design simplicityVSAvoidproduct quality
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention applies curvature by replacing the conventional flat or simple curved drawing die surface with a die featuring wave-like indentations. These sinusoidal or undulating geometric patterns on the die surface create controlled material flow patterns during deep-drawing, preventing type 2 wrinkles and crease failures in the frame areas. The curved wave patterns are integrated into the die geometry, maintaining relative simplicity while dramatically improving product quality and reducing scrap rates.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Data Source

PatentEP4434651A1Deep drawing device for preventing the occurrence of wrinkle suppression in the production of thin-walled deep-drawn parts
Publication Date: 2024.09.25 DATWYLER SCHWEIZ AG
  • EP4434651A1 patent drawingFigure 1~2(b)
  • EP4434651A1 patent drawingFigure 3~3(A)
  • EP4434651A1 patent drawingFigure 4~4(A)

AI summary

In a deep-drawing device for producing a thin-walled deep-drawn part (1) from a sheet blank (2), comprising a drawing die (2) with a drawing edge (5) and a sheet holder (4), which together form a flanged infeed zone of the deep-drawing device, and a drawing punch (3); wherein the deep-drawn part (1) has a flange (12) inclined relative to a working direction (A); it is provided that the deep-drawing device has at least sectional means for controlled fold generation (6, 6a) in the flanged infeed zone.