Intermittent Twin-Screw Extrusion for Stronger Material Mixing
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Solution Overview
Problem
Traditional twin-screw extrusion systems lack interaction between front and rear screw grooves, limiting spatial progression and mixing performance, which adversely affects processing quality.
Innovation Solution
An intermittent extrusion system with a first screw rotating at a constant speed and a second screw rotating intermittently, featuring asymmetric left-right and front-rear screw groove configurations, allowing for continuous segmentation, stretching, shearing, and displacement of materials, enhancing mixing and homogenization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional balanced twin-screw design is used, then structural symmetry is maintained, but mixing performance and spatial progression are limited
Solution Approach 1:
The patent applies asymmetry by designing the second screw with asymmetric groove configurations where the left and right grooves have different depths. Specifically, the first screw groove has a different depth than the second screw groove, creating an asymmetric structure that enhances spatial progression and mixing performance while breaking the traditional symmetric design constraint
2Manufacturing precision
If continuous rotation of both screws is used, then material conveyance is maintained, but segmentation and mixing effectiveness are reduced
Solution Approach 1:
The patent implements periodic action by making the second screw rotate intermittently rather than continuously. The second screw rotates forward to convey material, then pauses, then rotates backward to scrape material from the first screw groove. This periodic intermittent rotation creates segmentation and enhances mixing while maintaining overall extrusion productivity
Solution Approach 2:
The patent applies dynamics by transitioning from static continuous rotation to dynamic intermittent rotation. The second screw's rotation speed is dynamically adjusted - rotating forward at a certain speed for material conveyance, then pausing, then rotating backward for material scraping. This dynamic control enhances both mixing quality and extrusion efficiency
3Manufacturing precision
If symmetric screw groove depths are used, then manufacturing simplicity is maintained, but interfacial area and dispersion are limited
Solution Approach 1:
The patent applies local quality by creating different groove depths at different locations on the second screw. The left screw groove and right screw groove have different depths, creating localized variations in the screw structure. This enhances the interfacial area between materials and improves dispersion, while the asymmetric design can be implemented using standard manufacturing techniques
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 improves material dispersion and mixing by introducing periodic changes in motion and rest, increasing interfacial area and uniform distribution, thereby accelerating plasticization and homogenization.
Implementation Method 1
The screw thread of the first screw drives the compression and extrusion of the material into the screw groove of the second screw
Implementation Method 2
the screw thread of the first screw scrapes the material out of the screw groove of the second screw
Implementation Method 3
This process subjects the material to continuous stretching, shearing, segmentation, and displacement to accelerate the plasticization of the material
Implementation Method 4
accelerate the plasticization of the material and enhance the mixing of the material
Implementation Method 5
The repeated stretching and recovery process from different directions strengthens the homogenization of the material
Data Source
AI summary
An intermittent extrusion system and an extrusion device are disclosed. The intermittent extrusion system includes a barrel and an extrusion unit. The extrusion unit includes a first screw and a second screw, both the first screw and the second screw are installed in the barrel and can rotate in the barrel, a screw thread of the first screw can mesh with a screw groove of the second screw, the first screw has at least one thread start, and the second screw has at least one thread start. The first screw rotates at a constant speed, while the second screw rotates intermittently, and a rotating direction of the first screw is opposite to that of the second screw.