Ribbed Thermoplastic Bag Manufacturing Process
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Solution Overview
Problem
The challenge is to create a thermoplastic bag designed for trash receptacle liners that reduces material cost while maintaining strength and toughness, suitable for high-speed manufacturing and minimizing the risk of tearing or rupture.
Innovation Solution
A thermoplastic bag with a ribbed pattern is formed using a high-speed manufacturing process involving cylindrical rollers with intermeshing circular ridges, which imparts a corrugated shape to the material, increasing its resilience and allowing for cost savings by using less material while maintaining strength and toughness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the amount or quality of thermoplastic material is reduced to lower production cost, then material cost decreases, but bag strength and toughness are compromised making the bag susceptible to tearing or rupture
Solution Approach 1:
The patent applies composite material principles by combining thermoplastic material with a foamed layer to create a multi-layer structure. The foamed layer provides insulation and structural support, allowing the thermoplastic layer to be thinner while maintaining overall bag strength and toughness. This composite approach enables cost reduction through material optimization without sacrificing performance.
Solution Approach 2:
The patent implements local quality by varying the thickness and material properties of different regions of the bag. The foamed layer is strategically positioned in specific areas to provide enhanced insulation and structural support where needed, while other areas use thinner thermoplastic material. This localized optimization reduces overall material usage and cost while maintaining necessary strength and toughness in critical regions.
2Loss of substance
If thermoplastic material is reduced to save cost, then production cost decreases, but the bag becomes more susceptible to tearing or rupture
Solution Approach 1:
The composite structure of thermoplastic material combined with a foamed layer provides enhanced reliability. The foamed layer acts as a reinforcing element that distributes stress and prevents tear propagation, allowing the thermoplastic material quantity to be reduced while maintaining or improving resistance to tearing and rupture.
Solution Approach 2:
The foamed layer serves as a pre-positioned cushioning and reinforcement layer that prevents tearing and rupture before they can occur. This layer absorbs and distributes mechanical stresses, providing beforehand protection against tearing that would otherwise compromise the bag's reliability with reduced thermoplastic material.
3Productivity
If high-speed manufacturing is implemented to reduce production cost, then productivity increases, but manufacturing precision and quality control become more challenging
Solution Approach 1:
The patent applies preliminary action by pre-forming the foamed layer and thermoplastic layers in a controlled manner before final bag assembly. The extrusion process is designed to create consistently layered structures with predetermined thicknesses and properties, ensuring manufacturing precision is maintained even at high production speeds. The co-extrusion or lamination process is optimized to deliver consistent quality without requiring complex post-processing.
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
The ribbed pattern enhances the bag's tensile energy to yield and ultimate tensile strength, providing increased toughness and tear resistance while allowing for larger bags to be made with less material, thus achieving cost savings and improved performance.
Implementation Method 1
reducing the thickness of the web between the rollers may stretch and may compress some of the web material longitudinally and perpendicularly of a machine direction in which the web is proceeding
Implementation Method 2
the web material may be worked. Thus, the resulting ribbed pattern may have more permanence and resilience when subsequently distorted
Data Source
AI summary
The plastic bag may include flexible thermoplastic sidewalls that have a pattern imparted onto them. The wrinkle pattern may be a plurality of linear ribs formed into the sidewall that may be arranged adjacent and parallel to one another. To impart the pattern to the sidewall, a thermoplastic web used to make the sidewall may be directed between a first cylindrical roller and a second cylindrical roller, each of which may have a plurality of spaced ridges extending about their peripheries. When the web is directed between the first and second rollers, the meshing of the ridges may form ribs into the web.