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Fiber Orientation Analysis of Overflow Water-Assisted Injection Molding with Short Glass Fiber Reinforced Polypropylene. ADVANCES IN POLYMER TECHNOLOGY 2022. [DOI: 10.1155/2022/9968902] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The fiber orientation is playing an important performance indexed for glass fiber reinforced polypropylene for water-assisted injection molding. Based on the viscoelastic constitutive equation (White-Metzner) and the fiber orientation model (iARD-RPR), the effects of fiber mass content, water injection delay time, water injection pressure, and melt temperature, which are on the fiber orientation along the flow direction and shear rate distribution of the melt, were investigated. Studies found that the orientation degree of the fiber along the flow direction was reduced with the increase of the fiber mass content, the extension of the water injection delay time, and the improvement of the melt temperature and that the orientation degree of the fiber along the flow direction was raised with the increase of the water injection pressure flow in the laminar flow state, but it was reduced with the increase in the turbulent state. It can be further learned from the shear rate distribution that decreasing fiber mass content, reducing the water injection delay time, lower melt temperature, and increasing water injection pressure in laminar flow conditions will increase the shear rate in the channel layer and the shear rate gradient along the thickness direction of the melt, while the water injection pressure in the turbulent state is on the contrary.
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Zhang W, Kuang TQ, Liu HS, Lai JM, Han JK, Jiang QS, Wan ZH. Improved process moldability and part quality of short-glass–fiber-reinforced polypropylene via overflow short-shot water-assisted injection molding. JOURNAL OF POLYMER ENGINEERING 2022. [DOI: 10.1515/polyeng-2021-0217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
Water-assisted injection molding (WAIM) is a promising molding process developed based on conventional injection molding (CIM). It has been a research hotspot in recent years and is still receiving extensive attention from many scholars and industries because of its significant potential advantages in practical applications. However, compared with CIM, since the additional water-related parameters are involved, the process moldability of thermoplastics is significantly reduced, especially for fiber-reinforced thermoplastics, which stunts the development of WAIM process. In this work, short-shot WAIM with an overflow cavity (OSSWAIM) was developed to address the problems and broaden the application scope of WAIMs. The results showed that compared with overflow WAIM (OWAIM) and short-shot WAIM (SSWAIM), OSSWAIM could significantly improve the process moldability and part quality of fiber-reinforced thermoplastics, especially for thermoplastic composites with a high fiber weight fraction. Besides, it was also found that water penetration had a slight influence on the fiber orientation near the water inlet, but had a significant influence on the fiber orientation near the end of mold cavity. Finally, three processing parameters affecting the water penetration, i.e., water pressure, melt temperature, and water injection delay time were investigated in terms of their influences on the fiber orientation within OSSWAIM.
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Affiliation(s)
- Wei Zhang
- Jiangxi Key Laboratory of High-Performance Precision Molding, Polymer Processing Research Laboratory, Nanchang University , Nanchang 330031 , China
| | - Tang-qing Kuang
- School of Mechatronics and Vehicle Engineering, East China Jiao Tong University , Nanchang 330013 , China
| | - He-sheng Liu
- Jiangxi Key Laboratory of High-Performance Precision Molding, Polymer Processing Research Laboratory, Nanchang University , Nanchang 330031 , China
- School of Mechatronics and Vehicle Engineering, East China Jiao Tong University , Nanchang 330013 , China
- School of Mechanical and Electronic Engineering, Jiangxi Province Key Laboratory of Polymer Micro/Nanomanufacturing and Devices, East China University of Technology , Nanchang 330013 , China
| | - Jia-mei Lai
- Jiangxi Key Laboratory of High-Performance Precision Molding, Polymer Processing Research Laboratory, Nanchang University , Nanchang 330031 , China
| | - Ji-kai Han
- Qingdao Campus of Naval Aviation University , Qingdao 266041 , China
| | - Qing-song Jiang
- School of Mechanical and Electronic Engineering, Jiangxi Province Key Laboratory of Polymer Micro/Nanomanufacturing and Devices, East China University of Technology , Nanchang 330013 , China
| | - Zhi-hui Wan
- School of Mechanical and Electronic Engineering, Jiangxi Province Key Laboratory of Polymer Micro/Nanomanufacturing and Devices, East China University of Technology , Nanchang 330013 , China
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