Segmented Disk Profile Adjustment in Blown Film Extrusion
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Solution Overview
Problem
The blown extrusion technology for producing plastic films lacks precision in adjusting the transverse profile, leading to localized thickness defects known as 'cords' which are difficult to correct, especially in multipurpose lines, and existing solutions like oscillating drives have limitations with sticky or rigid films and cannot completely eliminate profile defects.
Innovation Solution
A method using a sine wave with adjustable amplitude and frequency, generated by a segmented disk with metal sectors, to actively adjust the film profile, allowing for the creation of a 'virtual skidding' effect that masks defects, eliminating the need for oscillating drives and improving profile uniformity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If blown extrusion technology is used to produce plastic films, then production flexibility and low waste percentage are improved, but manufacturing precision of the film profile deteriorates
Solution Approach 1:
The patent implements dynamic adjustment of cooling air flow rates through a programmable control unit that modifies the operational parameters of blowing fans and cooling systems in real-time during the extrusion process. This allows the system to adapt cooling conditions dynamically to compensate for profile deviations and achieve precise film thickness control while maintaining production flexibility
Solution Approach 2:
The patent changes physical parameters of the cooling process, specifically the temperature and flow rate of cooling air, to control film profile. By adjusting these thermal parameters dynamically during extrusion, the system achieves precise thickness control without sacrificing the inherent flexibility of blown extrusion technology
2Device complexity
If traditional profile adjustment methods are used in blown extrusion, then device complexity is reduced, but manufacturing precision of local thickness defects deteriorates
Solution Approach 1:
The patent divides the cooling system into multiple independently controllable zones along the film width, with separate cooling channels and adjustable air flow rates for different segments. This segmentation allows local adjustment of thickness defects without requiring complex mechanical adjustment of the entire die system
Solution Approach 2:
The patent replaces complex mechanical adjustment systems with a programmable control system that uses sensors and automated feedback to regulate cooling air flow. This substitution reduces mechanical complexity while achieving superior local thickness control through electronic control and real-time parameter modification
3Manufacturing precision
If oscillating drives are used to distribute thickness defects, then profile uniformity is improved, but reliability deteriorates due to limitations with sticky or rigid films
Solution Approach 1:
The patent eliminates mechanical oscillating drives by implementing a programmable control system that uses variable frequency drives and automated cooling regulation to achieve profile uniformity. This non-contact control method avoids the reliability issues associated with mechanical systems handling sticky or rigid films
Solution Approach 2:
The patent achieves profile uniformity by dynamically changing the operational parameters of the cooling system, specifically the air flow rate and temperature distribution, rather than relying on mechanical oscillation. This parameter-based control is more reliable and adaptable to different film types including sticky and rigid materials
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 method significantly improves the profile uniformity of films produced with blown technology, reducing thickness tolerance by up to 30% and enabling the production of high-quality reels without the limitations of traditional oscillating drives, particularly beneficial for films with low thickness and unidirectional stretching applications.
Implementation Method 1
a disk with "n" segments, physically divided by metal sectors or any other compatible material, which regulate the quantity or temperature, or both parameters, of a flow of cooling air
Implementation Method 2
a sine wave with adjustable amplitude and frequency, generated by a segmented disk with metal sectors, to actively adjust the film profile, allowing for the creation of a 'virtual skidding' effect that masks defects
Data Source
Figure 1~1D
Figure 2
Figure 3
AI summary
The present invention relates to a method for the active adjustment of the profile of a film produced by means of the blown extrusion technology, the film obtained with said method and the reel resulting from the winding of the film.