Offset Perforation Lines for Plastic Bag Opening
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Solution Overview
Problem
Users face difficulties in opening plastic bags made from tubular blown film due to slick surfaces and sticking issues, making it hard to distinguish the opening from the sealed end, especially when the edges are not offset.
Innovation Solution
A process involving forming tubular blown film with offset perforation lines on both sides and connecting them with seal lines, allowing for easier separation and identification of bag openings by creating non-straight edges that facilitate grasping and opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the tubular blown film is collapsed and perforated to form a roll of plastic bags, then the manufacturing efficiency is improved, but the edges of the bags become straight and parallel, making it difficult for users to distinguish the opening from the sealed end and difficult to grasp
Solution Approach 1:
The patent applies asymmetry by offsetting the perforation lines on the first side and second side of the collapsed tubular blown film. Instead of having perforation lines directly aligned, the second perforation line is offset relative to the first perforation line, creating non-parallel, non-straight edges at the bag openings. This asymmetric edge configuration makes it easier for users to distinguish the opening from the sealed end and provides better grasping surfaces, while still maintaining the manufacturing efficiency of the collapsed tubular blown film process.
2Strength
If the plastic bag surface is made slick for ease of cleaning and durability, then the bag strength is improved, but the user cannot easily grasp the bag lips to open the bag
Solution Approach 1:
The patent applies local quality by creating localized edge features through offset perforation lines at specific locations (the bag openings), while the rest of the bag surface maintains its slick, durable properties. The offset perforation creates non-straight edges with increased surface area and irregular geometry at the grasping location, providing better friction and grip for users, while the bulk of the bag surface remains smooth and slick for its intended durability and cleaning properties.
3Ease of manufacture
If the perforation lines on both sides are aligned to create straight edges, then the manufacturing process is simpler, but the bag edges become indistinguishable and difficult to open
Solution Approach 1:
The patent resolves this contradiction by introducing a controlled offset between the first perforation line on the first side and the second perforation line on the second side. This offset creates asymmetric, non-straight edges that are easily distinguishable and provide better grasping surfaces, while still maintaining relative process simplicity by using standard perforation equipment on both sides of the collapsed tubular blown film during manufacturing.
Data Source
AI summary
A process of manufacturing a roll of plastic bags. The process includes forming a tubular blown film, and collapsing the tubular blown film so that the tubular blown film includes a first side, a second side, a first edge, and a second edge. Openings are cut in the collapsed tubular blown film, and sealing closure mechanisms are inserted through the openings into the collapsed tubular blown film. The sealing closure mechanisms are then fixed to the collapsed tubular blown film.