Ultrasonic Sealing for Reusable Plastic Corrugated Containers
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Solution Overview
Problem
Current methods for manufacturing reusable plastic corrugated containers fail to produce boxes with sealed edges that can return to their original shape for re-use in automated packaging lines, and existing edge sealing processes result in sharp edges that are not ergonomically safe, while also being inefficient in processing speed and prone to bowing in stacks.
Innovation Solution
A process that pre-seals and ultrasonically forms smooth, sealed edges and score lines in plastic corrugated boxes, allowing them to be reused in conventional packaging equipment, with a manufacturer's joint that adds no extra thickness and enables flaps to return to a straight position, using rotary ultrasonic welding and heating to create safe, rounded seals and memory retention in flaps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If conventional die cutting and sealing processes are used for plastic corrugated containers, then the manufacturing process is simple, but the edges become sharp and unsafe for ergonomic handling
Solution Approach 1:
The patent applies preliminary action by pre-sealing the edges of the plastic corrugated material before the container is formed and used. The sealing process is performed in advance on the blank material, creating rounded, safe edges before the container undergoes any deformation or wear during its service life. This ensures that regardless of how many times the container is folded and unfolded, the edges remain rounded and safe for handling.
2Reliability
If plastic corrugated containers are made to be reusable and cleaned, then sanitation is improved, but the flaps lose their ability to return to original alignment
Solution Approach 1:
The patent applies parameter changes by modifying the physical and chemical properties of the plastic corrugated material through controlled heating and sealing processes. By adjusting temperature, pressure, and sealing parameters, the material is transformed to have enhanced elasticity and memory properties. This allows the flaps to return to their original aligned position after being deformed during use and cleaning, enabling multiple reuse cycles while maintaining structural integrity and alignment.
3Reliability
If score lines are made with high memory to ensure flap return to straight position, then reusability is improved, but the converting equipment becomes less effective
Solution Approach 1:
The patent applies dynamics by creating score lines with optimized memory characteristics that allow the flaps to dynamically adjust during the converting process. The score lines are designed to have just enough memory to return flaps to a straight position after use, but not so much memory that they resist the folding action during manufacturing. This dynamic balance ensures compatibility with conventional converting equipment while maintaining reusability.
4Productivity
If traditional sealing methods are used, then the sealing process is simple, but the edges remain sharp and the processing speed is low
Solution Approach 1:
The patent applies mechanics substitution by replacing traditional mechanical die-cutting sealing methods with a combination of thermal sealing and ultrasonic welding processes. This substitution allows for faster processing speeds while simultaneously creating rounded, safe edges. The thermal and ultrasonic processes can be applied more quickly than conventional mechanical sealing and produce the desired rounded edge geometry as a byproduct of the sealing action itself.
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 process results in robust, reusable plastic corrugated boxes with consistent, safe edge seals, improved processing speed, and reduced bowing in stacks, enabling efficient conversion and re-use in automated systems while ensuring ergonomic safety and contamination prevention.
Implementation Method 1
rotary ultrasonic welding
Implementation Method 2
heating to create safe, rounded seals
Data Source
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AI summary
A corrugated plastic box and a method for manufacturing a corrugated plastic box from a blank are provided. The method includes the steps of forming rounded edge seals on the perimeter edges of the blank, pre-sealing portions of the blank to form a plurality of areas in which major and minor flap slots and a glue tab are desired, ultrasonically scoring the blank to form a plurality of flap score lines, and cutting the blank through the plurality of pre-sealed flap slots and glue tab, leaving a sealed edge.