Plastic Molded Article Manufacturing via Gravity Separation of Decorative Particles
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Solution Overview
Problem
Existing methods for manufacturing plastic molded articles from waste materials, such as automobile bumpers, increase the number of manufacturing steps and degrade the aesthetic appearance due to separation of granular plastic bases and paints using specific gravity separation.
Innovation Solution
A method involving fine pulverization of waste materials with decorative layers, mixing with virgin thermoplastic, melting, and maintaining the molten mixture in a mold to allow decorative particles to precipitate by gravity, reducing their presence in the final product's decorative surface region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If specific gravity separation is used to separate granular plastic base and paint, then aesthetic appearance is improved, but number of manufacturing steps increases
Solution Approach 1:
The patent extracts and removes paint particles from the granular waste material through specific gravity separation before molding. By separating the paint granules from the plastic base granules, the method ensures that the decorative surface of the molded article does not contain excessive paint particles, thereby improving aesthetic appearance while maintaining a manageable number of process steps
Solution Approach 2:
The patent changes the physical state of the material from granular to molten by heating to melting point or higher. This phase change allows the material to be injected into the mold cavity and subsequently cooled to form the final product. This parameter change enables the production of high-quality molded articles with controlled particle distribution in the decorative surface region
2Manufacturing precision
If two-stage pulverization is used to produce granular waste material, then particle size uniformity is improved, but manufacturing time increases
Solution Approach 1:
The patent divides the pulverization process into two stages: first pulverization to produce coarse granular material, and second fine pulverization to achieve uniform fine granular waste material. This segmentation of the size reduction process ensures that the waste material reaches the required particle size uniformity for high-quality molding while managing the overall manufacturing time through efficient process design
Solution Approach 2:
The patent performs preliminary pulverization to produce granular material before the fine pulverization and separation steps. By preparing the material in advance through coarse grinding, the subsequent fine pulverization and separation processes can proceed more efficiently, reducing the total manufacturing time while maintaining particle size uniformity
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 approach reduces the number of manufacturing steps and minimizes aesthetic degradation by controlling the distribution of decorative particles, enhancing the appearance and mechanical strength of the plastic molded articles.
Implementation Method 1
producing a molten waste material by melting the granular waste material
Implementation Method 2
molding the plastic molded article by cooling the molten waste material that is maintained in the molten state
Implementation Method 3
Since the granular plastic base and the granular paint included in the granular waste material have different specific gravities, the granular plastic base and the granular paint are separated from each other by a known specific gravity separation
Data Source
AI summary
A method for manufacturing a plastic molded article includes producing a granular waste material by finely pulverizing a waste material that includes a base made of a thermoplastic and a decorative layer provided on a surface of the base, producing a molten waste material by melting the granular waste material, injecting the molten waste material into a cavity of a mold and maintaining the molten waste material in a molten state in the cavity, and molding the plastic molded article by cooling the molten waste material that is maintained in the molten state.