PET Food Container Weakening Using Laser Scored Connecting Edges
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Solution Overview
Problem
Existing methods for producing and filling containers made of PET are inflexible and costly due to the need for frequent replacement of cutting tools and the difficulty in creating weakened portions without significant increases in crystallinity, which is challenging for industrial productivity.
Innovation Solution
A method using high-power CO2 laser radiation to locally reduce the cross-section of PET sheets, creating weakened portions with minimal increase in crystallinity, allowing for flexible container shapes and sizes without the need for cutting tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If cutting blades or cutters are used to create weakened portions in PET sheets, then the containers can be separated into groups, but the tool life is significantly reduced and maintenance costs increase
Solution Approach 1:
The patent replaces the mechanical cutting system (blades or cutters) with a laser-based system. The laser radiation creates weakened portions by locally modifying the PET material through thermal effects, eliminating the need for mechanical contact and thereby extending tool life while maintaining the ability to separate containers into groups.
Solution Approach 2:
The patent changes the method of creating weakened portions from mechanical cutting to laser-induced thermal modification. By controlling laser parameters (power, speed, wavelength), the process creates localized changes in the PET material structure without mechanical contact, resolving the contradiction between ease of manufacture and tool durability.
2Strength
If low-power laser radiation is used to increase crystallinity in PET, then the material becomes more fragile and easier to separate, but the production time increases significantly
Solution Approach 1:
The patent changes the laser parameters from low-power/long-duration to high-power/short-duration mode. This parameter change allows the laser to rapidly heat and cool the PET material, creating localized structural modifications that increase fragility without requiring prolonged exposure, thereby maintaining high production speeds.
Solution Approach 2:
The laser radiation is applied in a periodic or pulsed manner, delivering intense energy in short bursts that create the desired crystallinity increase and material fragility. This periodic action allows for rapid processing while achieving the necessary material property changes for easy separation.
3Reliability
If mechanical cutting systems are used to create weakened portions, then the process is reliable, but the system complexity and cost increase
Solution Approach 1:
The patent replaces complex mechanical cutting systems with a simpler laser-based system. The laser delivers precise energy to create weakened portions without requiring mechanical contact, reducing system complexity while maintaining or improving separation reliability through precise control of laser parameters.
Solution Approach 2:
The patent extracts the cutting function from the mechanical domain and transfers it to the thermal/optical domain. By removing the mechanical cutting components (blades, cutters, associated mechanisms), the system complexity is reduced while the essential function of creating separable weakened portions is maintained through laser radiation.
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 method enables efficient and cost-effective production of PET containers with flexible container designs, maintaining high industrial productivity by minimizing tool wear and reducing maintenance costs.
Implementation Method 1
emission of a laser radiation at at least one portion of the connecting edge in order to provide a localized reduction of the transverse cross-section of the connecting edge
Data Source
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AI summary
A method for the production and filling of containers designed to contain food, characterized in that it comprises the steps of: - shaping a sheet (10) made of PET (polyethylene terephthalate) in order to provide a plurality of accommodation receptacles (11) provided with at least one access inlet (12), the PET sheet (10) having an initial degree of crystallinity lower than or equal to 10%; - filling, through the access inlet (12), said accommodation receptacles (11) with at least one food; - sealing the access inlet (12) by means of a closure film (13); - providing a weakened portion (21) at a connecting edge (22) between at least two adjacent accommodation receptacles (11), the provision step comprising a step of emission of laser radiation (40) at least one portion of said connecting edge (22) in order to provide a localized reduction of the transverse cross-section of the connecting edge along the weakened portion; - the final degree of crystallinity at the weakened portion (21) after the step of emission of laser radiation (40) being lower than, equal to or greater than, at most by a percentage equal to 3%, the degree of crystallinity of portions of the connecting edge (22) not affected by modifications occurring as a consequence of the step of emission of laser radiation (40) and of the sealing step.