Towards Optimal Flow Uniformity: Stiffener Layout Design Evaluation of Injection Moulded Plastic Part

2012 ◽  
Vol 428 ◽  
pp. 33-37
Author(s):  
Yi Min Deng ◽  
Bao Shou Sun ◽  
Hua Bo He ◽  
Fu Zhan Shangguan
Keyword(s):  
Process Conditions ◽  
Flow Uniformity ◽  
Plastic Part ◽  
Moulding Process ◽  
Manufacturing Method ◽  
Part Geometry ◽  
Stiffener Layout ◽  
Plastic Parts ◽  
Stiffener Layout Design

Injection moulding is an important manufacturing method for plastic parts. There are however many moulding quality defects caused by inappropriate setting of moulding process conditions, as well as the poorly designed plastic part geometry. Often, stiffeners are used in a plastic part to increase its strength. However, if the stiffeners are not designed properly, they will introduce one or more moulding quality problems, which in turn will worsen the part strength rather than increasing it. Although there have been quite a lot of researches on optimising moulding quality, it is often difficult to minimize multiple quality defects simultaneously. In this paper, we propose to employ flow uniformity as the optimisation objective to address this problem. A number of stiffener layout designs are evaluated in terms of this objective to determine the best design, where standard deviations of filling times and pressures at the extremities of the plastic part are used to measure the uniformity of flow. A simple case study is also presented to demonstrate the applicability of the proposed methodology.

Geometry-Based Index for Predicting Sink Mark in Plastic Parts

1991 ◽  
Author(s):  
Kurt Beiter ◽  
Kosuke Ishii ◽  
Lee Hornberger
Keyword(s):  
Process Conditions ◽  
Plastic Part ◽  
Design Rules ◽  
Packing Pressure ◽  
Molded Parts ◽  
Injection Molded ◽  
Form Features ◽  
Plastic Parts ◽  
Sink Mark

Abstract This paper describes the development of geometry-based indices that predict sink mark depth in injection molded parts. Plastic part designers need such indices to incorporate manufacturability concerns at the conceptual stage of design. These indices apply to several form features so engineers do not have to check different design rules for each geometry element. First, we propose a geometry-based sink index that can be used to predict sink mark depth as a function of process conditions such as packing pressure. Next, we explain how this relationship is identified through experiments. We also describe HyperDesign/Plastics, a Macintosh-based design aid that incorporates the sink index.

scholarly journals Computer-Aided Reengineering towards Plastic Part Failure Minimization

Materials ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6303
Author(s):  
Tiago Pinho ◽  
Tatiana Zhiltsova ◽  
Mónica Oliveira ◽  
Andreia Costa
Keyword(s):  
Injection Moulding ◽  
Original Design ◽  
Plastic Part ◽  
Load Bearing Capacity ◽  
X Ray ◽  
Moulding Process ◽  
The Core ◽  
Injection Moulding Process ◽  
History Of ◽  
Plastic Parts

The work reported here intends to identify and mitigate the causes for failure in a plastic faucet holder, a part of an integral float faucet with a well-documented history of fracture occurrence. A methodology for the identification of hidden internal defects in plastic parts and the elaboration of the required corrective actions towards quality improvement is, therefore, presented. Firstly, part defects were identified via injection moulding process numerical simulation. The latter has enabled the prediction of an excessive volumetric shrinkage at the core of the faucet holder, highlighting the presence of internal voids and, hence, the possible deterioration of the load-bearing capacity. The supposition was later confirmed by X-ray topography scans. Part reengineering, consisting of localized thickness reduction, was the option chosen for decreasing the high shrinkage at the core. For validation purposes, structural analyses were carried out, with and without accounting for the injection moulding processing history. The results obtained during part structural analysis have enabled us to conclude that, when taking into account the residual stresses generated during injection moulding, the analysis more closely reflects the experimental data and allows us to implicitly envisage the propensity to fracture. Moreover, the part modifications, undertaken during the faucet holder reengineering, led to the reduction of the cumulative (processing and imposed by load) stresses by 50%, when compared to the original design analysed.

Reduction of Injection Moulded Plastic Part Warpage Using Advanced Gas Assisted Injection Moulding

2016 ◽  
Vol 862 ◽  
pp. 200-209 ◽  
Author(s):  
Miroslav Košík ◽  
Jozef Bílik ◽  
Daynier Rolando Delgado Sobrino
Keyword(s):  
Injection Moulding ◽  
Quality Criteria ◽  
Dimensional Accuracy ◽  
Engineering Industry ◽  
Material Structure ◽  
Plastic Part ◽  
Shape Accuracy ◽  
Shape Complexity ◽  
Plastic Parts

Dimensional and shape accuracy are the basic quality criteria of almost every injection moulded plastic part, manufactured in the engineering industry. They are dependent on many production conditions as part and moulding tool design, material structure properties and injection parameters. Generally, it is very difficult to achieve high geometrical accuracy during injection moulding, therefore, dimensional tolerances for plastic parts are usually many times larger than in the case of metals. However, according to requirements of the engineering industry, demands for the plastic parts dimensional accuracy keep growing permanently, what also extends to the growing shape complexity of the produced parts. Due to this tendency, engineers must look for more and more advanced solutions to meet market requirements and keep the competitiveness of their product. In consonance with all this, this paper presents a case study where the progressive gas assisted injection moulding is used as a solution for the plastic part warpage reduction while any other conventional methods failed. The study is performed making use of part from the automotive industry, initially produced with unacceptable deformations. In the first step, the real manufacturing state was studied to determine the warp behaviour. Subsequently, the process parameters and cooling conditions were unsuccessfully modified while trying to reduce deformations. Nevertheless, these were effectively eliminated by the only application of internal gas support to the melt injection phase. A numerical modelling based on Finite Volume and Finite Element Method was also used in the case study in order to mathematically represent the fluid, thermal and mechanical processes during the process of injection moulding.

Simplified Version of Polymer Rotational Molding Manufacturing Method

2016 ◽  
Vol 699 ◽  
pp. 97-103 ◽  
Author(s):  
Laurenţiu Slătineanu ◽  
Oana Dodun ◽  
Margareta Coteaţă ◽  
Gheorghe Nagîţ ◽  
Irina Beşliu
Keyword(s):  
Liquid Phase ◽  
Rotation Speed ◽  
Rotational Molding ◽  
Slow Speed ◽  
Molding Process ◽  
Manufacturing Method ◽  
Polyurethane Resin ◽  
Liquid Material ◽  
Complex Equipment ◽  
Plastic Parts

Rotational molding is a manufacturing method which supposes the rotation of the mold, during the solidification of the liquid phase material, so that finally a part having a hollow could be obtained. The method could be applied in manufacturing of metallic and nonmetallic parts. Usually, the equipment for rotational molding ensures slow speed rotating of the mold around two axes placed perpendicularly each other and this fact led to relatively complex equipment for achieving rotational molding. The capacity of the liquid material to entirely cover the internal walls of the mold depends essentially on the liquid material viscosity, on the rotation speed and on the movements applied to the mold. Simplified equipment including a single rotation movement could be materialized. In order to test such a solution, a preliminary experiment was designed and materialized, by using a device adapted on universal lathe. Thus, the objective of the research presented in the paper was to study if it is possible to achieve plastic parts made by rotational molding using a single rotation movement. A polyurethane resin obtained from two liquid components was used in order to obtain the liquid material that could be introduced in the mold. The research results proved the possibility to use simplified equipment for achieving a rotational molding process, at least in certain cases and with some technological limits.

scholarly journals High-quality manufacturing method of complicated castings based on multi-material hybrid moulding process

China Foundry ◽  
2018 ◽  
Vol 15 (5) ◽  
pp. 343-350
Author(s):  
Li-min Liu ◽  
Zhong-de Shan ◽  
Feng Liu ◽  
Dun Lan
Keyword(s):  
High Quality ◽  
Moulding Process ◽  
Manufacturing Method

scholarly journals A Review of SLMed Magnesium Alloys: Processing, Properties, Alloying Elements and Postprocessing

Metals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1073
Author(s):  
Shuai Liu ◽  
Hanjie Guo
Keyword(s):  
Magnesium Alloy ◽  
Magnesium Alloys ◽  
Base Material ◽  
Alloy Design ◽  
Process Conditions ◽  
Chemical Compositions ◽  
Theoretical Understanding ◽  
Influence Of Process Parameters ◽  
Manufacturing Method ◽  
Metallurgical Defects

Selective laser melting (SLM) is an additive manufacturing method with rapid solidification properties, which is conducive to the preparation of alloys with fine microstructures and uniform chemical compositions. Magnesium alloys are lightweight materials that are widely used in the aerospace, biomedical and other fields due to their low density, high specific strength, and good biocompatibility. However, the poor laser formability of magnesium alloy restricts its application. This paper discusses the current research status both related to the theoretical understanding and technology applications. There are problems such as limited processable materials, immature process conditions and metallurgical defects on SLM processing magnesium alloys. Some efforts have been made to solve the above problems, such as adding alloy elements and applying postprocessing. However, the breakthroughs in these two areas are rarely reviewed. Due to the paucity of publications on postprocessing and alloy design of SLMed magnesium alloy powders, we review the current state of research and progress. Moreover, traditional preparation techniques of magnesium alloys are evaluated and related to the SLM process with a view to gaining useful insights, especially with respect to the postprocessing and alloy design of magnesium alloys. The paper also reviews the influence of process parameters on formability, densification and mechanical behavior of magnesium. In addition, the progress of microstructure and metallurgical defects encountered in the SLM processed parts is described. Finally, this article summarizes the research results, and with respect to materials and metallurgy, the new challenges and prospects in the SLM processing of magnesium alloy powders are proposed with respect to alloy design, base material purification, inclusion control and theoretical calculation, and the role of intermetallic compounds.

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