scholarly journals Low‐stress over‐molding of media‐tight electronics using thermoplastic foam injection molding

2021 ◽  
Author(s):  
Constantin Ott ◽  
Dietmar Drummer
Keyword(s):  
Injection Molding ◽  
Foam Injection Molding ◽  
Thermoplastic Foam

Interaction Between Foam Injection Molding and Welding Process

2020 ◽  
pp. 233-246
Author(s):  
Karoline Hofmann ◽  
Christian Brütting ◽  
Michael Gehde ◽  
Volker Altstädt
Keyword(s):  
Injection Molding ◽  
Welding Process ◽  
Foam Injection Molding

Process comparison on the microstructure and mechanical properties of fiber-reinforced polyphenylene sulfide using MuCell technology

2018 ◽  
Vol 37 (15) ◽  
pp. 1020-1034 ◽  
Author(s):  
Christoph Lohr ◽  
Björn Beck ◽  
Frank Henning ◽  
Kay André Weidenmann ◽  
Peter Elsner
Keyword(s):  
Mechanical Properties ◽  
High Pressure ◽  
Injection Molding ◽  
Fiber Orientation ◽  
Polyphenylene Sulfide ◽  
Injection Molding Process ◽  
Fiber Reinforced ◽  
Molding Process ◽  
Glass Fiber Reinforced ◽  
Foam Injection Molding

The MuCell process is a special injection molding process which utilizes supercritical gas (nitrogen) to create integral foam sandwiches. The advantages are lower weight, higher specific properties and shorter cycle times. In this study, a series of glass fiber-reinforced polyphenylene sulfide foam blanks are manufactured using the MuCell injection molding process. The different variations of the process (low-pressure also known as structural foam injection molding) and high-pressure foam injection molding (also known as “core back expansion,” “breathing mold,” “precision opening,” decompression molding) are used. The sandwich structure and mechanical properties (tensile strength, bending strength, and impact behavior) of the microcellular and glass fiber-reinforced polyphenylene sulfide foams are systematically investigated and compared to compact material. The results showed that the injection parameters (injection speed, foaming mechanism) played an important role in the relative density of microcellular polyphenylene sulfide foams and the mechanical properties. It could be shown that the specific tensile strength decreased while increasing the degree of foaming which can be explained by the increased number of cells and the resulting cell size. This leads to stress peaks which lower the mechanical properties. The Charpy impact strength shows a significant dependence on the fiber orientation. The specific bending modulus of the high-pressure foaming process, however, surpasses the values of the other two processes showing the potential of this manufacturing variation especially with regard to bending loads. Furthermore, a high dependence of the mechanical properties on the fiber orientation of the tested specimens can be found.

scholarly journals Effect of Cellulose Nanofiber (CNF) Surface Treatment on Cellular Structures and Mechanical Properties of Polypropylene/CNF Nanocomposite Foams via Core-Back Foam Injection Molding

Polymers ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 249 ◽  
Author(s):  
Long Wang ◽  
Kiyomi Okada ◽  
Yuta Hikima ◽  
Masahiro Ohshima ◽  
Takafumi Sekiguchi ◽  
...  
Keyword(s):  
Injection Molding ◽  
Mechanical Performance ◽  
Tensile Modulus ◽  
Cellulose Nanofiber ◽  
Cellular Structures ◽  
Test Results ◽  
Nanocomposite Foams ◽  
Composite Foams ◽  
Reinforcing Agent ◽  
Foam Injection Molding

Herein, lightweight nanocomposite foams with expansion ratios ranging from 2–10-fold were fabricated using an isotactic polypropylene (iPP) matrix and cellulose nanofiber (CNF) as the reinforcing agent via core-back foam injection molding (FIM). Both the native and modified CNFs, including the different degrees of substitution (DS) of 0.2 and 0.4, were melt-prepared and used for producing the polypropylene (PP)/CNF composites. Foaming results revealed that the addition of CNF greatly improved the foamability of PP, reaching 2–3 orders of magnitude increases in cell density, in comparison to those of the neat iPP foams. Moreover, tensile test results showed that the incorporation of CNF increased the tensile modulus and yield stress of both solid and 2-fold foamed PP, and a greater reinforcing effect was achieved in composites containing modified CNF. In the compression test, PP/CNF composite foams prepared with a DS of 0.4 exhibited dramatic improvements in mechanical performance for 10-fold foams, in comparison to iPP, with increases in the elastic modulus and collapse stress of PP foams of 486% and 468%, respectively. These results demonstrate that CNF is extraordinarily helpful in enhancing the foamability of PP and reinforcing PP foams, which has importance for the development of lightweight polymer composite foams containing a natural nanofiber.

scholarly journals Study on Foam Injection Molding of Thermoplastic Elastomer by Supercritical Fluid

Seikei-Kakou ◽  
2013 ◽  
Vol 25 (12) ◽  
pp. 585-591
Author(s):  
Hironori Kakishima ◽  
Masahiro Seto ◽  
Masashi Yamabe
Keyword(s):  
Injection Molding ◽  
Supercritical Fluid ◽  
Thermoplastic Elastomer ◽  
Foam Injection Molding

Theoretical and visual study of bubble dynamics in foam injection molding

2009 ◽  
Vol 50 (3) ◽  
pp. 561-569 ◽  
Author(s):  
Mehdi Mahmoodi ◽  
Amir Hossein Behravesh ◽  
Seyyed Abdol Mohammad Rezavand ◽  
Mohammad Golzar
Keyword(s):  
Injection Molding ◽  
Bubble Dynamics ◽  
Visual Study ◽  
Foam Injection Molding
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