Extrusion Head Die Adjustment for Polymer Flow Control
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Solution Overview
Problem
In tyre manufacturing, the extrusion speed of polymeric materials needs to be dynamically regulated to maintain quality, as constant speeds can lead to scorching, clots, stagnation zones, and uneven material distribution, affecting the uniformity and homogeneity of extruded elements, especially when reinforced with thread-like elements.
Innovation Solution
The extrusion head's conveying channel cross-sectional area is adjusted in response to extrusion speed variations by displacing the female die relative to the male die, using a resilient element or servo-device to counteract pressure changes, ensuring optimal flow rates and preventing scorching or mechanical damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the extrusion speed is increased to improve productivity, then the output increases, but the polymeric material may scorch or overheat due to extended residence time in the extrusion head
Solution Approach 1:
The patent applies the dynamics principle by making the conveying channel cross-sectional area variable rather than fixed. The cross-sectional area is dynamically adjusted based on the extrusion speed to maintain optimal flow conditions. When extrusion speed increases, the cross-sectional area increases proportionally, preventing material stagnation and overheating while maintaining high productivity. This is achieved through a movable female die that can change its position relative to the male die, thereby varying the conveying channel area.
Solution Approach 2:
The patent applies parameter changes by varying the geometric parameter of the conveying channel cross-sectional area in response to changes in extrusion speed. The relationship is defined such that the cross-sectional area S varies as a function of extrusion speed v according to the formula S = k·v, where k is a constant. This parameter adjustment ensures that material residence time and flow velocity remain within optimal ranges regardless of the extrusion speed setting.
2Object-affected harmful factors
If the extrusion speed is decreased to prevent scorching, then material quality is maintained, but productivity and output are reduced
Solution Approach 1:
The dynamics principle enables the system to adapt to different productivity requirements without compromising material quality. When lower extrusion speeds are used to prevent scorching, the conveying channel cross-sectional area automatically decreases, maintaining optimal flow velocity and residence time. This allows the system to operate at reduced speeds when quality is the priority while still achieving acceptable productivity levels.
Solution Approach 2:
The parameter changes principle allows the conveying channel cross-sectional area to be adjusted according to the desired extrusion speed. By reducing the cross-sectional area when extrusion speed is lowered, the system maintains appropriate flow conditions that prevent scorching while still producing output. The mathematical relationship S = k·v ensures that the parameters are coordinated to achieve both quality and productivity goals.
3Object-affected harmful factors
If the conveying channel cross-sectional area is increased to maintain flow rate at high extrusion speeds, then scorching is prevented, but the extrusion head geometry becomes more complex
Solution Approach 1:
The dynamics principle resolves the geometric complexity issue by using a simple mechanical adjustment mechanism - a movable female die that can slide along the extrusion head axis. This single degree of freedom adjustment allows the conveying channel cross-sectional area to be varied continuously from a minimum to a maximum value, covering the full range of conditions needed for different extrusion speeds, without requiring complex multi-dimensional adjustments or sophisticated control systems.
Solution Approach 2:
The movable female die mechanism serves multiple functions: it adjusts the conveying channel cross-sectional area, controls the extrusion rate, and maintains material flow uniformity. This single component performs what would otherwise require multiple separate adjustment mechanisms, thereby reducing overall device complexity while achieving the desired material uniformity across a wide range of operating conditions.
4Stability of the object's composition
If the extrusion speed is dynamically regulated to maintain quality, then material homogeneity is improved, but the control system complexity increases
Solution Approach 1:
The system applies the self-service principle by using the extrusion speed itself as the control input for adjusting the conveying channel cross-sectional area. The relationship S = k·v creates a self-regulating system where the extrusion speed automatically determines the appropriate channel area, eliminating the need for external sensors, controllers, or complex feedback loops. The system serves itself by using its own operating parameter (extrusion speed) to control its geometric parameter (channel area).
Solution Approach 2:
The parameter changes principle simplifies control by establishing a direct mathematical relationship between two key parameters: extrusion speed v and conveying channel cross-sectional area S. The formula S = k·v provides a predetermined, easily implementable control law that requires only one adjustable parameter (the constant k) to maintain material homogeneity across all extrusion speeds, greatly simplifying the control system compared to multi-parameter control approaches.
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 adjustment allows for a wider range of extrusion speed variation, reducing waste and maintaining material quality by controlling pressure and residence time, preventing scorching and stagnation, and ensuring consistent extrusion thickness.
Implementation Method 1
using a resilient element or servo-device to counteract pressure changes
Implementation Method 2
adjustment means comprising a resilient element acting on at least one die and partially counteracting the force exerted on said at least one die by the polymeric material flowing in the conveying channel
Data Source
AI summary
A method for extruding a polymeric material includes the steps of: a) feeding the polymeric material to an extrusion apparatus including an extrusion head, the extrusion head including: a male die; a female die coaxially arranged with respect to the male die; a conveying channel, at least one portion of which is defined between the male die and the female die; and b) adjusting a cross-sectional area of the at least one portion of the conveying channel by reciprocally displacing the female die with respect to the male die in response to an extrusion speed variation of the polymeric material. An extrusion apparatus and a process for manufacturing a tire which uses the extrusion apparatus, are also disclosed.