Recycled Polymer Granulate for Additive Manufacturing
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Solution Overview
Problem
Mechanical recycling of thermoplastics and thermoplastic composites results in degradation of thermomechanical properties with each recycle, making them less suitable for cost-effective and widespread use in applications, and current methods are more expensive than thermoset materials.
Innovation Solution
A method involving shredding and granulating of fiber reinforced polymer composite articles without using a twin screw extruder, followed by additive manufacturing or compression molding using the recycled granulate, which bypasses the compounding and pelletizing steps to maintain excellent thermomechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional mechanical recycling methods (sorting, shredding, granulating, recompounding, repelletizing) are used, then recycling pathways are established, but the reinforcing fiber is shortened and molecular weight decreases, adversely impacting thermomechanical properties
Solution Approach 1:
The invention extracts and eliminates the harmful compounding and pelletizing steps from the traditional recycling process. By removing these mechanical processing steps that cause fiber shortening and molecular weight degradation, the patent preserves the thermomechanical properties of recycled composites while maintaining effective recycling pathways.
Solution Approach 2:
Instead of following the traditional sequence of shredding → granulating → compounding → pelletizing, the invention inverts the approach by skipping the compounding and pelletizing steps entirely. The recycled granulate is used directly as feedstock for compression molding or injection molding, reversing the conventional wisdom that these steps are necessary for recycling.
2Reliability
If thermoplastic composites are used as feedstock for big area additive manufacturing of molds, then recyclable alternative to thermoset materials is achieved, but the cost is more expensive than thermoset materials
Solution Approach 1:
The invention removes the expensive compounding and pelletizing steps from the recycling process. By eliminating these energy-intensive mechanical processing steps and associated equipment requirements, the cost of producing recycled thermoplastic composite feedstock is reduced to levels comparable to thermoset materials, making the recyclable alternative economically viable.
3Ease of manufacture
If compounding and pelletizing steps are included in the recycling process, then traditional industrial methods are followed, but fiber reinforcement is shortened and thermomechanical properties deteriorate
Solution Approach 1:
The patent extracts and eliminates the compounding and pelletizing steps from the traditional recycling methodology. This removal prevents the mechanical shearing and degradation that occur during these processes, thereby preserving fiber length and molecular weight while still establishing an effective recycling pathway that adheres to practical industrial constraints.
Data Source
AI summary
A improved method of additive manufacturing of a recycled granulate is provided. The method comprises providing a starting article. A shredder shreds the starting article to give a shredded product. A granulator shreds the shredded product to give a recycled granulate. The recycled granulate is fed into an additive manufacturing machine. The additive manufacturing machine prints a printed article using the recycled granulate. The method does not comprise a step of compounding the recycled granulate using a twin screw extruder. The starting article, the shredded product, and the recycle granulate each comprise a fiber reinforced polymer composite.