Nozzle Slot Control for Symmetrical Flat Film Thickness
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Solution Overview
Problem
Existing nozzle control systems in flat film production require manual, time-consuming adjustments of nozzle exit gaps, leading to asymmetrical and non-reproducible thickness profiles, significant material loss due to edge trimming, and unstable melt conveying behavior.
Innovation Solution
An automated control system adjusts the nozzle exit gap using actuators coupled to thermocouples, monitored by sensors, to optimize the thickness profile, including the edge region, with simultaneous and symmetrical adjustments based on material properties and production criteria, and incorporates electrostatic or pneumatic edge adhesion to stabilize the melt flow.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If manual adjustment of nozzle exit gap is performed, then the nozzle can be centered, but the adjustment is time-consuming and non-reproducible
Solution Approach 1:
The system automatically adjusts the nozzle exit gap using actuators that respond to thickness measurements, eliminating the need for manual operator intervention. The control system continuously monitors and self-adjusts the nozzle position to maintain optimal thickness profile symmetry.
Solution Approach 2:
A feedback loop is established where thickness measurements are continuously taken, compared to target values, and used to generate corrective signals to the actuators. This closed-loop control ensures reproducible and precise adjustment without manual intervention.
2Ease of operation
If manual centering of nozzle exit gap is performed, then the gap can be adjusted, but the results are asymmetrical and non-reproducible
Solution Approach 1:
The system performs self-centering automatically through actuators that adjust the nozzle position based on real-time thickness measurements, eliminating operator dependency and ensuring consistent, reproducible results.
Solution Approach 2:
Manual mechanical adjustment by operators is replaced with an automated control system that uses sensors to detect thickness variations and actuators to make precise mechanical adjustments, ensuring higher precision and repeatability.
3Manufacturing precision
If edge trimming is performed to remove thickened film edges, then quality is improved, but material loss increases
Solution Approach 1:
The system automatically compensates for edge thickening by adjusting the nozzle exit gap in real-time, preventing the formation of excessive edge thickness that would require trimming, thereby reducing material loss while maintaining quality.
Solution Approach 2:
The control system proactively adjusts the nozzle position before significant edge thickening occurs, preventing the need for subsequent trimming operations and minimizing material waste.
4Manufacturing precision
If actuators are adjusted sequentially during production breaks, then the nozzle gap can be modified, but productivity is reduced
Solution Approach 1:
The control system operates continuously during production, automatically adjusting the nozzle exit gap in real-time based on thickness measurements, eliminating the need to stop production for manual adjustments and maintaining continuous productivity.
Solution Approach 2:
A continuous feedback loop monitors thickness profile and automatically adjusts actuators during production, enabling real-time corrections without interrupting the manufacturing process, thus maintaining high productivity.
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 achieves precise, reproducible, and symmetrical thickness profiles with reduced edge trimming, enhancing process stability and product quality by optimizing melt flow distribution and eliminating manual adjustments.
Implementation Method 1
When heated, the thermocouples expand and exert mechanical pressure on the die lip via the associated actuator, causing it to deform at the corresponding point. Furthermore, the thermocouples can compress upon cooling, and via the actuators, this exerts a mechanical pull on the nozzle lip, thereby increasing the nozzle exit gap at the corresponding point.
Implementation Method 2
Thickness gauges, particularly those using ultrasonic or infrared measurements, are used to monitor the thickness profile.
Implementation Method 3
Thickness gauges, particularly those using ultrasonic or infrared measurements, are used to monitor the thickness profile.
Implementation Method 4
incorporates electrostatic or pneumatic edge adhesion to stabilize the melt flow
Data Source
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AI summary
The invention relates to a method for automatically regulating the size of a nozzle discharge slot of a nozzle assembly, wherein the nozzle assembly comprises a first and a second nozzle lip and a nozzle discharge slot arranged between the nozzle lips for setting in a controlled manner a thickness profile of a conveyable melt. A plurality of adjusting elements, in particular a plurality of adjusting pins, coupled to respective thermoelements, is arranged on the first nozzle lip, the thermoelements being controllable by the controller in such a way that the slot can be adjusted by the action of a mechanical force applied to the first nozzle lip by the corresponding adjusting element, as a result of the expansion or contraction of the thermoelements. The adjusting elements are automatically readjusted on the basis of measurement signals from at least one sensor, the sensor being designed and/or arranged on the nozzle assembly so as to allow conclusions to be drawn regarding the thickness profile of the melt. The right-hand and left-hand marginal areas of the melt are monitored by the sensor and controlled or regulated in such a way that each of the marginal areas is adjusted by readjusting the adjusting elements according to the material, in particular its viscosity and/or viscoelasticity, and/or to quality criteria and/or to a conveyance speed. The invention also relates to a control and/or regulation system.