Adaptive Laser Cutting for Thermoformed Packages
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Solution Overview
Problem
Thermoform packaging machines with high performance rates face issues in cutting packages from composite films, resulting in variations in sealed seam widths due to chain elongation, which require wider seams to maintain minimum width tolerance, leading to increased pressure and sealing time.
Innovation Solution
A method that involves detecting the position of sealed seams using a vision system to precisely orient a cutting unit, such as a laser cutting unit, along the outer contour of the seams, eliminating the need for wider seams and allowing for adaptive cutting patterns without tool adjustments, using a reference element like a punched hole for precise alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the sealed seam width is increased to compensate for chain elongation variations, then the minimum seam width tolerance is maintained, but the sealing pressure and sealing time increase
Solution Approach 1:
The patent applies preliminary action by detecting the position of sealed seams upstream of or in the cutting station before the actual cutting operation. The vision system captures the actual seam positions, and the controller pre-calculates the cutting pattern adjustments needed to compensate for chain elongation variations. This allows the cutting unit to be precisely oriented to match the actual seam locations, eliminating the need to increase seam width as a preventive measure against tolerance violations.
2Manufacturing precision
If the sealed seam width is increased to compensate for chain elongation variations, then the minimum seam width tolerance is maintained, but the machine length and tool design space requirements increase
Solution Approach 1:
The patent implements dynamics by making the cutting pattern adaptive rather than fixed. The vision system dynamically detects the actual sealed seam positions, and the controller dynamically adjusts the cutting pattern coordinates based on the detected positions and chain elongation measurements. This dynamic adjustment allows precise cutting along the actual seam contours regardless of variations in seam width or position, eliminating the need for increased seam widths to accommodate tolerance ranges.
3Productivity
If a fixed cutting pattern is used without adaptation, then the cutting process is simple, but it cannot compensate for chain elongation variations causing seam width variations
Solution Approach 1:
The patent applies feedback by using the vision system to detect the actual positions of sealed seams and feeding this information back to the controller. The controller compares the detected positions with the expected positions, calculates the deviations caused by chain elongation, and adjusts the cutting pattern accordingly. This closed-loop feedback system ensures that the cutting unit precisely follows the actual seam contours, maintaining uniform seam widths despite variations in film advancement.
4Manufacturing precision
If the cutting unit is physically repositioned for format changes, then cutting accuracy is maintained, but setup time increases
Solution Approach 1:
The patent replaces the mechanical repositioning system with an optical-digital system. Instead of physically moving or adjusting the cutting unit for different formats, the vision system optically detects the sealed seam positions, and the controller digitally recalculates the cutting pattern coordinates. The cutting unit remains in the same physical position, but the cutting path is dynamically adjusted through software-based pattern generation, eliminating time-consuming mechanical setup operations while maintaining cutting accuracy.
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 approach ensures that packages are cut with the minimum required seam width, reducing unnecessary seam width variations and minimizing setup times, while maintaining precise cutting without the need for frequent tool adaptations, thus optimizing the cutting process in thermoform packaging machines.
Implementation Method 1
the sealed seams are detected by means of a vision system and the position of a cutting pattern is determined
Implementation Method 2
the cutting unit is a laser cutting unit for separating the packages from one another by cutting them out of the composite film along the sealed seams
Data Source
AI summary
A method is provided for cutting packages out of a composite film in a thermoform packaging machine by previously detecting the position of the sealed seams and by suitably adapting the position of a cutting pattern. Additionally, a thermoform packaging machine is provided for executing the above-mentioned method.