Shrinkage study of textile roller molded by conventional/microcellular injection-molding process

Hwang, Shyh‐Shin; Hsu, Peming P.; Chiang, Chi-wei

doi:10.1016/j.icheatmasstransfer.2008.02.011

Cited by 11 publications

(8 citation statements)

References 9 publications

(10 reference statements)

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“…Considering the MUCELL process, this technique reduces shrinkage with respect to CIM [101,102], and the supercritical fluid content adopted during injection stage was a critical factor [58]. In MUCELL processing, holding time, holding pressure, and mold temperature affect shrinkage [53].…”

Section: Processing Parameter Influencesmentioning

confidence: 99%

Review of Factors that Affect Shrinkage of Molded Part in Injection Molding

Annicchiarico¹,

Alcock²

2014

Materials and Manufacturing Processes

119

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Purpose: This paper reviews the factors affecting shrinkage of molded parts in injection molding. Methods: A selective screening of the papers published in the last 10 years was adopted. The review was organized according to molding scale (macro or micro) and by considering four branches of influence: material behaviors, processing parameters, mold, and specimen design. Results: Within the interval of confidence, at the macroscale, critical processing parameters were the temperatures, the packing parameters, cooling time, and injection speed; temperatures and packing parameters resulted critical factors at the microscale as well. Concerning the design aspects, the runner size and the ribs affect shrinkage at the macro and microscale, respectively. The analysis of the literature review has shown an absence of statistical approach for determining the material influences, a lack of information on shrinkage occur in powder-molded parts and the absence of data in specimen with dimensions below 10 m. Conclusions: The review collected the factors that affect shrinkage in injection molding, and identified three possible areas for further works.

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Section: Processing Parameter Influencesmentioning

confidence: 99%

Review of Factors that Affect Shrinkage of Molded Part in Injection Molding

Annicchiarico¹,

Alcock²

2014

Materials and Manufacturing Processes

119

View full text Add to dashboard Cite

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“…Among these, a promising method is the microcellular injection molding process, which allows for the production of complex, thick parts with a cellular core and a solid skin [1]. The key insight of microcellular injection molding, as developed and commercialized by Trexel Co. Ltd. as the Mucell process [2], is the application of a supercritical fluid [3]. In particular, the expansion of a physical blowing agent in the polymer melt allows for the formation of a foamed core that decreases the part weight using less raw material [4,5,6,7].…”

Section: Introductionmentioning

confidence: 99%

Lightweight High-Performance Polymer Composite for Automotive Applications

Volpe

Lanzillo²,

Affinita³

et al. 2019

Polymers

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The automotive industry needs to produce plastic products with high dimensional accuracy and reduced weight, and this need drives the research toward less conventional industrial processes. The material that was adopted in this work is a glass-fiber-reinforced polyamide 66 (PA66), a material of great interest for the automotive industry because of its excellent properties, although being limited in application because of its relatively high cost. In order to reduce the cost of the produced parts, still preserving the main properties of the material, the possibility of applying microcellular injection molding process was explored in this work. In particular, the influence of the main processing parameters on morphology and performance of PA66 + 30% glass-fiber foamed parts was investigated. An analysis of variance (ANOVA) was employed to identify the significant factors that influence the morphology of the molded parts. According to ANOVA results, in order to obtain homogeneous foamed parts with good mechanical properties, an injection temperature of 300 °C, a high gas injection pressure, and a large thickness of the parts should be adopted.

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“…In addition, the internal pressure arising from the cell foaming can significantly reduce or even eliminate sink marks, warpage and flatness defects, and hence microcellular injection molding process can improve the dimensional stability and size accuracy of the final part. 7,8 Because of these benefits, microcellular injection molding technology and microcellular injection-molded products are attracting more and more attention and are being applied in more and more areas nowadays. 9,10 Since the microcellular injection-molding process was developed and invented, substantial studies have been conducted on the cell structure in microcellular injection-molded products, especially on the cell size and cell density of the foamed core region.…”

Section: Introductionmentioning

confidence: 99%

Formation mechanism and structural characteristics of unfoamed skin layer in microcellular injection-molded parts

Dong

Zhao

Guan

et al. 2015

Journal of Cellular Plastics

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The microcellular injection-molded part usually consists of a foamed core region and two unfoamed skin layers on the cross section. This paper investigated the formation process, formation mechanism and structural characteristics of the unfoamed skin layers in microcellular injection-molded part. It is found that the unfoamed skin layers are formed in two processes namely “during filling” process and “after filling” process. The shear flow and the fountain flow behaviors of the melt in the filling stage are the main controlling factors on the formation of the unfoamed skin layer in “during filling” process, and the cooling solidification of the melt in cooling stage is the fundamental reason for the formation of the unfoamed skin layer in “after filling” process. Further studies found that the unfoamed skin layer in microcellular injection-molded part has two distinct regions, the outer region is a thin frozen layer which contains deformed and broken cells, and the inner region is a relatively thick solid-like layer which has no visible cells in. The unfoamed skin layer has a minimum thickness in the gate location. The whole thickness of the unfoamed skin layer is decreased with the increase of injection speed and mold temperature, but is slightly affected by melt temperature.

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Shrinkage study of textile roller molded by conventional/microcellular injection-molding process

Cited by 11 publications

References 9 publications

Review of Factors that Affect Shrinkage of Molded Part in Injection Molding

Review of Factors that Affect Shrinkage of Molded Part in Injection Molding

Lightweight High-Performance Polymer Composite for Automotive Applications

Formation mechanism and structural characteristics of unfoamed skin layer in microcellular injection-molded parts

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