Sealing Bar Defect Detection via Relative Displacement
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Solution Overview
Problem
Existing methods for detecting defects during the sealing of packages with film are limited, as they require direct measurement of the distance between sealing bars, which is not feasible on all packaging machines, and do not account for dynamic factors like temperature and film thickness.
Innovation Solution
A method that detects defects based on relative displacements of the sealing bars, either directly or indirectly measured, allowing for defect detection without needing to know the absolute distance between the sealing bars. This method includes calculating a unitless measure of deviation from relative displacements and rotations, which compensates for inaccuracies and dynamic behavior during sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If distance sensors are used to measure the distance between sealing bars, then defect detection capability is improved, but device complexity and adaptability worsen because the method is only suitable for packaging machines that allow direct distance measurement
Solution Approach 1:
The patent introduces sealing bar holders as intermediary elements that can be measured instead of the sealing bars themselves. The distance sensors measure the distance between sealing bar holders, which indirectly provides information about the sealing bar position. This intermediary approach allows defect detection on packaging machines where direct measurement of sealing bar distance is not feasible, thereby improving adaptability while maintaining reliability.
Solution Approach 2:
The patent replaces the direct mechanical measurement of sealing bar distance with an indirect measurement system using distance sensors on sealing bar holders. This substitution allows the system to work on packaging machines with different structures, including those where the sealing bars are not accessible for direct measurement, thus enhancing versatility without sacrificing detection capability.
2Manufacturing precision
If absolute distance measurement between sealing bars is used, then manufacturing precision is improved, but device complexity increases because it requires direct measurement capability on all packaging machines
Solution Approach 1:
The patent uses sealing bar holders as intermediary measurement targets. Instead of requiring direct measurement of the sealing bars (which would demand complex and universally applicable measurement systems), the system measures the distance between sealing bar holders, a simpler and more universally implementable approach that maintains sufficient precision for quality control without increasing device complexity.
Solution Approach 2:
The patent accepts that measuring the distance between sealing bar holders is not exactly the same as measuring the distance between sealing bars, but this partial measurement is sufficient for detecting sealing defects. The method does not require complete accuracy of sealing bar position, only enough information to detect deviations from normal sealing, thereby reducing measurement system requirements while maintaining quality control effectiveness.
3Measurement precision
If the measurement method does not account for dynamic factors like temperature and film thickness, then measurement simplicity is maintained, but measurement precision deteriorates due to inaccuracies from uncompensated variations
Solution Approach 1:
The patent incorporates feedback mechanisms that continuously monitor and adjust for dynamic factors such as temperature changes and film thickness variations. The system uses this feedback information to compensate for these variations in the measurement evaluation, thereby maintaining high measurement precision for defect detection without requiring overly complex measurement hardware, as the compensation is performed through control logic and algorithmic adjustments.
Data Source
AI summary
The present invention relates to a method for detecting defects in the sealing of a package, comprising positioning a film and another part of the package between two sealing bars and successively closing and opening the sealing bars, ‘wherein at least during the closing of the sealing bars distances are measured with the aid of distance sensors between both sealing bars or between a sealing bar and a sealing bar holder, wherein a unitless measure of deviation at a point in time T is calculated and compared with a threshold value, wherein the unitless measure of deviation is calculated from a relative measure for a distance between both sealing bars or between a sealing bar and a sealing bar holder. The invention also relates to a device and a use.