Extrudate Puller Speed Control via Laser Proximity Sensors
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Solution Overview
Problem
The challenge lies in controlling the dimensional variation of extruded synthetic cellulose/plastic wood compositions with low melt strength, which makes consistent volume output from an extrusion device impossible, leading to deformation and inconsistency in the extrudate due to variations in volume output and expansion rates.
Innovation Solution
A puller speed control device using non-contact optical sensors and a real-time processor to detect and respond to changes in volume output by adjusting the speed of the extrudate puller device, ensuring continuous and precise control of the extrudate dimensions, allowing for downstream sizing and coating or reinforcement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a puller device is used to maintain consistent shape and size of extrudate, then manufacturing precision is improved, but device complexity increases due to the need for real-time monitoring and speed adjustment mechanisms
Solution Approach 1:
The patent implements a feedback control system where optical sensors continuously monitor the dimensions of the extruded cellulosic composite and send signals to a microprocessor. The microprocessor adjusts the puller speed in real-time based on the measured dimensional variations, creating a closed-loop control system that maintains manufacturing precision despite variations in volume output.
Solution Approach 2:
The patent replaces mechanical measurement and control methods with optical sensing and electronic control. Instead of using mechanical gauges or manual measurement, optical sensors non-contactingly measure extrudate dimensions, and a microprocessor electronically controls the puller motor speed, reducing mechanical complexity while improving precision.
2Manufacturing precision
If the puller speed is adjusted to compensate for volume output variations, then manufacturing precision is improved, but response time must be reduced to effectively correct dimensional variations
Solution Approach 1:
The patent implements continuous monitoring and continuous adjustment of puller speed. The optical sensors continuously measure extrudate dimensions, the microprocessor continuously processes this data, and the puller speed is continuously adjusted without interruption. This continuous action eliminates delays that would occur with periodic or discrete adjustments, maintaining both precision and rapid response.
Solution Approach 2:
The real-time feedback loop immediately detects dimensional variations and triggers speed adjustments without delay. The optical sensors provide instantaneous measurement data to the microprocessor, which immediately calculates the required speed correction and implements it, minimizing the response time between detection and correction.
3Measurement precision
If non-contact optical sensors are used to detect changes in volume output, then measurement precision is improved, but device complexity increases due to the integration of sensing and control systems
Solution Approach 1:
The patent replaces contact-based mechanical measurement systems with non-contact optical sensors. This substitution improves measurement precision by eliminating mechanical interference and wear, while the electronic integration of sensors and microprocessor, though adding complexity, enables more accurate and maintenance-free measurement compared to mechanical alternatives.
Solution Approach 2:
The microprocessor serves multiple functions: it processes optical sensor signals, calculates dimensional variations, determines required speed adjustments, controls the puller motor, and potentially interfaces with other system components. This multi-functionality consolidates what could be multiple separate devices into a single integrated control unit, managing complexity through functional consolidation.
4Productivity
If the extrusion process operates at high productivity rates, then output volume increases, but dimensional control becomes more difficult due to variations in volume output and expansion rates
Solution Approach 1:
The patent implements a dynamic control system where puller speed is not fixed but continuously adjusted based on real-time measurements of extrudate dimensions. This dynamic adjustment allows the system to maintain dimensional precision even at high productivity rates, where variations in volume output and expansion rates would otherwise cause significant dimensional inconsistencies.
Solution Approach 2:
The feedback control system operates continuously at high extrusion speeds, with optical sensors measuring dimensions, the microprocessor calculating deviations from target dimensions, and the puller speed being adjusted in real-time. This rapid feedback loop enables precise dimensional control to be maintained even as productivity increases and process variations become more pronounced.
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 solution enables precise control of the extrudate dimensions, preventing deformation and allowing for finer detailing and closer tolerance, enabling the production of high-quality cellulosic composite lumber with improved dimensional accuracy and the ability to incorporate coatings or reinforcing fibers in a single step process.
Implementation Method 1
a non-contact measuring device consisting of at least one pair of optical sensors
Data Source
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AI summary
A system (l0) for controlling the dimensions of an extrudate (16) exiting an extruder (14) and for compensating for the variations in the extrusion rate of the extruder, expansion rate and rate of travel of the extrudate through sizing devices by changing the speed of an extrudate puller device (30), includes an extruder which extrudes the extrudate; a conveyor system comprising rollers and a series of sizing devices; a puller device for pulling the extrudate through the sizing devices; and a laser proximity measuring device (50) to assist the system in keeping the desired shape of the extrudate. The laser proximity measuring device includes at least one pair of optical non-contact displacement transducers, a real time processor (40), and an interactive touch screen display (60). The transducers emit a laser beam which provides a laser point on the side of the extrudate.