scholarly journals Polypropylene/talc foams with high weight-reduction and improved surface quality molded by mold-opening microcellular injection molding

2021 ◽  
Author(s):  
Junji Hou ◽  
Guoqun Zhao ◽  
Guilong Wang
Keyword(s):  
Injection Molding ◽  
Surface Quality ◽  
Weight Reduction ◽  
High Weight ◽  
Microcellular Injection Molding

Applications of Core Retraction in Manufacturing Low-Density Polypropylene Foams with Microcellular Injection Molding

2018 ◽  
Vol 37 (1) ◽  
pp. 1-20
Author(s):  
Hrishikesh Kharbas ◽  
Thomas Ellingham ◽  
Lih-Sheng Turng
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Tensile Properties ◽  
Weight Reduction ◽  
Low Density ◽  
Cavity Volume ◽  
The Core ◽  
Process Use ◽  
Incomplete Filling ◽  
Microcellular Injection Molding

Without modifying existing part and mold designs, the conventional microcellular injection molding (MIM) process can typically save about 5–10% material without encountering problems such as incomplete filling, excessive shrinkage, or deteriorating microstructure and mechanical properties. In this study core retraction was used in combination with the MIM process to produce thick polypropylene (PP) parts (up to 7.6 mm thick) with high density reductions of 30% and 55%. The cavity volume was modified by changing the retraction distance, which enabled control of density reductions. The lowest densities were achieved with this core retraction-aided microcellular injection molding (CR-MIM) process, the results of which could not have been achieved by the conventional MIM process alone. The effects of delay time in core retraction and weight reduction on the microstructure of the core and skin layers were investigated. It was shown that the CR-MIM process yielded better microstructure and tensile properties than the conventional MIM process. Use of core retraction also yielded more consistent densities and tensile properties throughout the length of the foamed parts.

scholarly journals Investigation on Foamed PP/Nano-CaCO3 Composites in a Combined in-Mold Decoration and Microcellular Injection Molding Process

Polymers ◽  
2020 ◽  
Vol 12 (2) ◽  
pp. 363 ◽  
Author(s):  
Kui Yan ◽  
Wei Guo ◽  
Huajie Mao ◽  
Qing Yang ◽  
Zhenghua Meng
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Surface Quality ◽  
Transition Layer ◽  
Cellular Structure ◽  
Vertical Section ◽  
Injection Molding Process ◽  
Caco3 Content ◽  
Microcellular Injection Molding ◽  
Film Side

A combined in-mold decoration and microcellular injection molding (IMD/MIM) method has been used in this paper. The foamed PP/nano-CaCO3 composites were prepared to investigate their mechanical properties, cellular structure, and surface quality. The content of nano-CaCO3 varied from 0 to 10 wt %. The results showed that nano-CaCO3 acted as a reinforcing phase and nucleating agent, which help to improve the mechanical properties of foamed composites. The cellular structure and mechanical properties were optimum when the nano-CaCO3 content was 6 wt %. In the vertical section, the cell size and density of transition layer on the film side was bigger than that on the non-film side. In the parallel section, the cell ratio of length to diameter of transition layer on the film side was smaller than that on the non-film side, and the cell tile angle was larger than that on the non-film side. With nano-CaCO3 content increasing, the surface quality showed a trend of decreasing first and then increasing.

Microcellular Injection Molding

2005 ◽  
Vol 20 (2) ◽  
pp. 202-214 ◽  
Author(s):  
S. Gong ◽  
M. Yuan ◽  
A. Chandra ◽  
H. Kharbas ◽  
A. Osorio ◽  
...  
Keyword(s):  
Injection Molding ◽  
Microcellular Injection Molding

Effect of Processing Conditions on the Shrinkage and Warpage of Glass Fiber Reinforced PP Using Microcellular Injection Molding

2012 ◽  
Vol 501 ◽  
pp. 294-299 ◽  
Author(s):  
Zhi Bian ◽  
Peng Cheng Xie ◽  
Yu Mei Ding ◽  
Wei Min Yang
Keyword(s):  
Injection Molding ◽  
Glass Fiber ◽  
Injection Pressure ◽  
Mold Temperature ◽  
Process Conditions ◽  
Fiber Reinforced ◽  
Injection Speed ◽  
Glass Fiber Reinforced ◽  
Microcellular Injection Molding ◽  
Molded Parts

This study was aimed at understanding how the process conditions affected the dimensional stability of glass fiber reinforced PP by microcellular injection molding. A design of experiments (DOE) was performed and plane test specimens were produced for the shrinkage and warpage analysis. Injection molding trials were performed by systematically adjusting six process parameters (i.e., Injection speed, Injection pressure, Shot temperature, SCF level, Mold temperature, and Cooling time). By analyzing the statistically significant main and two-factor interaction effects, the results showed that the supercritical fluid (SCF) level and the injection speed affected the shrinkage and warpage of microcellular injection molded parts the most.

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