PET Preform Inspection via Rotational Camera Scanning
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Solution Overview
Problem
Current PET bottle preform inspection systems fail to provide a cost-effective, high-speed, and all-round inspection method for detecting defects, leading to incomplete sorting of unsuitable preforms.
Innovation Solution
A modular, optical inspection system with integrated sorting capabilities that includes preform conveyors, inspection modules, and peripherals, capable of checking geometric features, material defects, and color deviations, allowing for comprehensive evaluation and precise sorting of PET bottle preforms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If PET bottle preforms are inspected from three or more sides simultaneously using multiple cameras, then all-round inspection capability is improved, but the distance between preforms must be increased to allow camera capture, which reduces processing speed
Solution Approach 1:
The patent transitions from simultaneous multi-side inspection (requiring spatial separation) to sequential inspection by rotating the preform 360 degrees in front of a single camera. This dimensional change from parallel to sequential inspection eliminates the need for increased preform spacing while maintaining all-round inspection capability.
Solution Approach 2:
The patent introduces dynamic rotation of the preform during inspection, allowing a single camera to capture images from all sides sequentially. This dynamic approach replaces the static multi-camera arrangement, enabling high-speed inspection without requiring fixed spatial separation between inspection points.
2Measurement precision
If a lateral recording of the PET bottle preform is included in the inspection system, then inspection coverage is improved, but there is no true all-round inspection capability
Solution Approach 1:
The patent implements dynamic rotation of the preform to achieve true all-round inspection. By rotating the preform 360 degrees in front of the camera, the system captures images from all sides including top, bottom, and lateral surfaces, providing complete inspection coverage and enabling reliable detection of defects anywhere on the preform.
3Measurement precision
If a modular optical inspection system with integrated sorting capabilities is implemented, then detection accuracy and sorting precision are improved, but system complexity increases
Solution Approach 1:
The patent combines the inspection module with the sorting mechanism into an integrated system. The sorting device is positioned to receive preforms directly from the inspection module, and the control unit coordinates both functions. This merging reduces overall system complexity while maintaining high detection and sorting precision.
Solution Approach 2:
The patent extracts the sorting function as a separate but integrated module that works in conjunction with the inspection system. The sorting device can be independently controlled and adjusted, allowing for precise sorting based on inspection results while maintaining modularity for easier maintenance and adjustment.
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 system enables efficient detection of defects in PET bottle preforms, increasing processing speed and ensuring accurate sorting, with the ability to handle high-speed applications up to 100,000 preforms per hour, while maintaining compactness and gentle handling.
Implementation Method 1
Rotating the centered preforms so that a view from all sides is possible
Implementation Method 2
a suction disk ring (8), which rotates about an axis (9) and thereby sequentially presents centered preforms (10) in front of the high-speed cameras (23.1 to 23.3)
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
The invention relates to a method for the quality control of PET bottle preforms, characterized by the following steps: synchronized intake of the preforms by suctioning a front region; dynamic self-centering of the preforms by rotation and centering conveyors; rotation of the preforms about the longitudinal axis thereof; guiding of the rotating preforms on one side by at least one high-speed camera for controlling a longitudinal region of the preforms and on another side by an illuminating station; encompassing the preforms by suctioning the longitudinal region; and guiding the preforms by at least one further high-speed camera for controlling the front face region of the preforms.