Bag Welding Process Using Intermediary Barrier

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Solution Overview

Problem

Existing processes for manufacturing plastic bags, such as T-shirt bags, fail to minimize production costs and material consumption, particularly in the folding and welding stages, often requiring additional non-stick coatings or barriers to prevent unintended layer joining.

Innovation Solution

The process involves folding tubular film over a longitudinal axis into 2×4 layers and interposing a barrier to prevent unintended welding, allowing for V-folding and heat sealing without additional materials, using a non-stick tape or electrostatic treatment to prevent layer connection during welding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If additional non-stick coatings or barriers are used to prevent unintended layer joining during welding, then welding reliability is improved, but production cost and material consumption increase

Engineering Contradiction:
Improvewelding reliabilityVSAvoidmaterial consumption
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent introduces a release agent layer as an intermediary substance between the tubular film layers that need to remain separated during welding. This release agent prevents unintended adhesion of the film layers to each other and to the welding tool, allowing reliable welding of the bag structure without requiring the film layers to stick together. The release agent is applied in a controlled manner and can be removed or remains as a minimal residue, thus improving welding reliability while minimizing additional material consumption compared to permanent coatings.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If additional non-stick coatings or barriers are used to prevent unintended layer joining, then manufacturing process reliability is improved, but device complexity increases

Engineering Contradiction:
Improvemanufacturing process reliabilityVSAvoidprocess complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The release agent serves as a temporary intermediary that simplifies the manufacturing process by preventing unwanted adhesion during critical welding operations. Rather than requiring complex mechanical separation systems or permanent non-stick coatings on welding tools, the release agent chemically prevents adhesion at the film interface, reducing the complexity of the overall manufacturing system while maintaining high process reliability.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Ease of manufacture

If conventional folding and welding processes are used without barriers, then production cost is reduced, but unintended layer joining occurs reducing manufacturing precision

Engineering Contradiction:
Improveproduction costVSAvoidfolding and welding precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The release agent acts as a precise control mechanism that allows the folding and welding operations to proceed with high precision without unintended layer joining. By applying the release agent only where needed between specific film layers, the process achieves precise control over which layers adhere and which remain separated, maintaining manufacturing precision while avoiding the need for expensive permanent coatings or complex barrier systems throughout the entire production line.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 reduces production costs by eliminating the need for additional materials and simplifies the folding and welding process, ensuring reliable and inexpensive production of plastic bags with minimized material consumption.

Implementation Method 1

a barrier such that a transverse weld obtained through the welding does not connect the four layers of film on the first side of the barrier with the other four layers of film on the second side of the barrier

Methodology Applied
Scientific EffectThermal insulation: Thermal Insulation

Implementation Method 2

using a non-stick tape or electrostatic treatment to prevent layer connection during welding

Methodology Applied
Scientific EffectElectrostatic repulsion: Electrostatics

Data Source

PatentEP2411203B1A process of making bags
Publication Date: 2016.01.06 ROLL O MATIC AS
  • EP2411203B1 patent drawingFigure 1
  • EP2411203B1 patent drawingFigure 2~6
  • EP2411203B1 patent drawingFigure 7

AI summary

A process of making bags from tubular film (1) by means of passing tubular film through a plurality of stations performing the steps of providing the tubular film with side gussets (8), V-folding the film, providing a perforation which in a final product outlines the neckline (2) of a T-shirt, providing a perforation, forming a severance line (3) of a bag, providing a transverse weld (4), constituting a top end weld, ahead of the perforation, and providing the film with a transverse weld (5), constituting a bottom end weld, behind of said perforation, wherein the process further comprise a step of, prior to providing the tubular film with a weld, interpose between the 2x4 layers of film, a barrier (6) such that four layers of film are disposed on a first side of the barrier and four layers of film are disposed an a second side of the barrier, whereby welding of the 2x4 layers of film, separated by the barrier, in the subsequent steps extends through four respective contiguous layers of film.