Stamping Tool Pressure Surface for Film Separation

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Solution Overview

Problem

Conventional punching tools struggle to reliably cut and separate tough thermoplastic-based film elements, such as PET, due to incomplete cutting lines leading to material bridges, which disrupt the processing and assembly of film elements.

Innovation Solution

The punching tool features a cutting blade with a second blade surface extending transversely to the cutting direction, allowing the pressing surface to push away the film element from the die, ensuring complete separation by stretching any remaining material bridges, thereby enhancing the reliability of processing thermoplastic films.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional cutting blades are used on thermoplastic film elements, then the cutting process can proceed, but material bridges remain uncut due to residual heat and material toughness

Engineering Contradiction:
Improvecutting completenessVSAvoidmaterial bridges
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The cutting process is divided into two distinct phases: the cutting stroke where the cutting edge severs the material, and the subsequent pressing stroke where the pressure surface acts on the top surface of the film element to push material bridges downward into the die cavity. This segmentation allows each phase to perform its specific function optimally without interference.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The pressure surface is positioned and configured to act on the top surface of the film element before the cutting edge completes its severing action. By pre-positioning the pressure surface to contact the top surface at the cutting line location, the system prepares the material bridges for immediate compression and stretching as the cutting completes, ensuring complete separation.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If sharper cutting blades are used to improve cutting quality, then material bridges are reduced, but the service life of the cutting blades decreases

Engineering Contradiction:
Improvecutting qualityVSAvoidblade service life
Core Design Contradiction:
ReliabilityVSDuration of action of moving object

Solution Approach 1:

The pressure surface acts as an intermediary mechanism between the cutting edge and the material bridges. Instead of relying solely on the cutting edge sharpness to prevent material bridges, the pressure surface provides a secondary action that compresses and stretches any remaining material bridges, ensuring complete separation even when the cutting edge has become less sharp during service.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If the pressure surface is integrated into the knife carrier, then the structure is simplified, but the ability to independently control pressing action is reduced

Engineering Contradiction:
Improvestructure simplicityVSAvoidpressing control independence
Core Design Contradiction:
Device complexityVSAdaptability or versatility

Solution Approach 1:

The pressure surface is integrated directly into the knife carrier structure, merging the support function of the knife carrier with the pressing function of the pressure surface. This integration simplifies the overall structure by eliminating separate pressing components while maintaining the ability to apply independent pressing action through the unified knife carrier assembly.

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 design ensures reliable separation of tough plastic-based film elements, extends the service life of punching knives, and maintains process integrity by preventing material bridges, even with blunter cutting blades.

Implementation Method 1

the cutting wedges of the die-cutting knives plunge into the film element to be processed in the processing position and create a cutting line in the film system along an edge length of the cutting edge

Methodology Applied
Scientific EffectShear stress: Shear Stress

Implementation Method 2

The pressure surface located downstream of the cutting edge during the cutting process causes the part of the film element being processed facing away from the die to be pushed vertically away from the part of the film element facing the die

Methodology Applied
Scientific EffectMechanical force: Mechanical Force

Data Source

PatentEP4074478B1Stamping tool
Publication Date: 2024.01.24 ROHRER TOOLS AG
  • EP4074478B1 patent drawingFigure 1
  • EP4074478B1 patent drawingFigure 2~4
  • EP4074478B1 patent drawingFigure 5

AI summary

In a die-cutting tool for cutting plastic-based film elements (12), comprising a die-cutting unit (13) having several knife carriers, each with at least one die-cutting knife (20) having a cutting wedge (24) tapering to a cutting blade (25) with a cutting edge (30), and comprising a die (14) opposite the die-cutting unit (13) for receiving the film element (12) to be processed, wherein the die-cutting unit (13) is mounted to be relatively movable relative to the die (14) during a die-cutting stroke in a cutting direction (15) between a starting position (16) and a processing position (17), wherein the cutting wedges (24) of the die-cutting knives (20) plunge into the film element (12) to be processed in the processing position (17) and create a cutting line in the film element (12) along an edge length of the cutting edge (30),The cutting blade (25) has a first blade surface (28) facing the die (14) and a second blade surface (29) aligned parallel to the first blade surface (28) and facing away from the die (14), wherein a pressure surface (33) extending transversely to the cutting direction (15) is connected to the second blade surface (29), is located downstream of the cutting edge (30) during the cutting process and can be brought into contact with a top surface (31) of the part (32) of the film element (12) facing away from the die (14).