Rectangular Can Step Forming for Near-90° Sealing Shoulders

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Solution Overview

Problem

Conventional manufacturing methods for rectangular cans struggle to achieve an angle of 90 degrees between the step surface and the inner wall surface, which affects the sealing performance of the can.

Innovation Solution

The method involves forming steps on the inner wall surfaces of the rectangular can body using a die, mandrel, and punch system, where the punch performs multiple pressing operations to compress the sidewall, thereby forming the step and bringing the angle closer to 90 degrees.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If a conventional single pressing operation is used to form the step, then the manufacturing process is simple, but the angle between the step surface and inner wall surface cannot be brought close to 90 degrees

Engineering Contradiction:
Improveangle between step surface and inner wall surfaceVSAvoidpressing operation process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The pressing operation is divided into multiple sequential stages, with each stage forming a portion of the step. The punch presses the sidewall in successive increments, gradually shaping the step while maintaining control over the final angle between the step surface and inner wall surface, achieving near-90 degree precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The mandrel is positioned in advance to sandwich the sidewall at the bottom side before the pressing operation begins. This preliminary positioning establishes the correct geometry and support structure that enables the subsequent pressing operations to achieve the precise 90-degree angle without requiring complex real-time adjustments.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the step is formed by compressing the sidewall multiple times, then the angle closer to 90 degrees is achieved, but the manufacturing time increases

Engineering Contradiction:
Improvesealing performanceVSAvoidmanufacturing cycle time
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The multiple pressing operations are performed in continuous sequence without interrupting the molding process. The punch maintains contact with the sidewall and progresses through successive pressing stages, ensuring that the useful action of forming the step continues uninterrupted, thereby minimizing the increase in manufacturing time while achieving the required precision for sealing performance.

Inventive Principle:
Principle #20Continuity of useful action

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 approach effectively increases the sealing performance of the rectangular can by achieving a closer-to-90-degree angle between the step and the inner wall surface, enhancing the sealing efficiency when the sealing lid is placed.

Implementation Method 1

a punch for pressing a portion on a side opposite to the bottom side with respect to the portion where the step is to be formed in the inner wall surface on which the step is to be formed and compressing the sidewall between the punch and the die

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3903954B1Method for producing rectangular can
Publication Date: 2025.02.12 TOYO SEIKAN KAISHA LTD
  • EP3903954B1 patent drawingFigure 1
  • EP3903954B1 patent drawingFigure 2
  • EP3903954B1 patent drawingFigure 3

AI summary

Provided is a manufacturing method for a rectangular can according to which it is possible to bring an angle formed by a step surface of a step provided in a rectangular can body and an inner wall surface of the rectangular can body closer to 90 degrees. In a step-forming step, using a die 310 that is provided on an outer wall surface side of a sidewall on which the step is to be formed, a mandrel 410 for sandwiching the sidewall between the mandrel 410 and the die 310 on the bottom side relative to a portion where the step is to be formed in the inner wall surface on which the step is to be formed, and a punch 420 for pressing the side opposite to the bottom side relative to the portion where the step is to be formed in the inner wall surface on which the step is to be formed and compressing the sidewall between the punch 420 and the die 310, the step is formed by performing multiple instances of a pressing operation performed by the punch 420.