Study on the solidification kinetics of high-density polyethylene during thin-walled injection molding process

2012 ◽  
Vol 32 (6-7) ◽  
pp. 355-363 ◽  
Author(s):  
Shuang-quan Deng ◽  
Bin Yang ◽  
Ji-bin Miao ◽  
Ru Xia ◽  
Jia-sheng Qian ◽  
...  
Keyword(s):  
Injection Molding ◽  
High Density Polyethylene ◽  
Polymeric Materials ◽  
High Density ◽  
Injection Molding Process ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Molding Process ◽  
Solidification Kinetics ◽  
Thin Walled

Abstract In this work, the effect of the initial and secondary temperature differences on the solidification behaviors of high-density polyethylene (HDPE) during the thin-walled injection molding (TWIM) was intensively investigated. Simulated temperature profiles using the enthalpy transformation methodology were compared with an in situ temperature measurement, and reasonable agreement was achieved between calculations and measurements. Two-dimensional wide-angle X-ray diffraction characterization shows that the formation of oriented crystal structures was considerably affected by the thermal gradient within the injection-molded article. The present study can be practically significant to the optimization of the cooling parameters during the TWIM of crystalline polymers as well as to the further study on the relationship among “processing-structure-property” of polymeric materials.

Tribology study of hydroxyapatite (HAp) scaffold blended single based binder via rheology and mechanical properties

2017 ◽  
Vol 69 (3) ◽  
pp. 414-419
Author(s):  
Mimi Azlina Abu Bakar ◽  
Siti Norazlini Abd Aziz ◽  
Muhammad Hussain Ismail
Keyword(s):  
Mechanical Properties ◽  
Injection Molding ◽  
Palm Stearin ◽  
Polymeric Materials ◽  
High Energy ◽  
Single Step ◽  
Injection Molding Process ◽  
Plastic Behavior ◽  
Molding Process ◽  
Content Type

Purpose This paper aims to investigate the vital characteristic of an innovative ceramic injection molding (CIM) process for orthopedic application with controlled porosity and improved tribological and mechanical properties which were affected by complex tribological interactions, whether lubricated like hip implants and other artificial prostheses. The main objective is to maximize the usage of palm stearin as a single based binder as the function of flow properties during injection molding process. Design/methodology/approach The binder used in this present study consists of 100 per cent palm stearin manufactured by Kempas Oil Sdn Bhd and supplied by Vistec Technology Sdn Bhd. The feedstock was prepared by using a Z-blade mixer (Thermo Haake Rheomix OS) and Brabender mixer model R2400. The feedstock prepared was injection molded using a manually operated vertical benchtop machine with an average pressure of about 5-7 bars. The firing step included the temporary holds at intermediate temperatures to burn out organic binders. At this stage, the green molded specimen was de-bound using a single-step wick-debinding method. Findings The maximum content of ceramic material is applied to investigate the efficiencies of net formulation that can be achieved by ceramic materials. The longer the viscosity will change with shear rate, the higher the value of n obtained instead. From the slope of the curves obtained in Figure 3, the value of n for the feedstock was determined to be less than 1, which indicates a pseudoplastic behavior and suitability for the molding process. Moreover, high shear sensitivity is important in producing complex and intrinsic specimens which are leading products in the CIM industry. Originality/value The feedstock containing HAp powder and palm stearin binder was successfully prepared at very low temperature of 70°C, which promoting a required pseudo-plastic behavior during rheological test. The single binder palm stearin should be optimized in other research works carried out, as palm stearin is most preferred compared to other polymeric materials that provided high energy consumption when subjected to the sintering process. Besides the binder is widely available in Malaysia, low cost and harmless effect during debinding process.

The simulation of the warpage rule of the thin-walled part of polypropylene composite based on the coupling effect of mold deformation and injection molding process

2018 ◽  
Vol 25 (3) ◽  
pp. 593-601 ◽  
Author(s):  
Jixiang Zhang ◽  
Xiaoyi Yin ◽  
Fengzhi Liu ◽  
Pan Yang
Keyword(s):  
Injection Molding ◽  
Coupling Effect ◽  
Mold Temperature ◽  
Injection Molding Process ◽  
Plastic Part ◽  
Molding Process ◽  
Melt Temperature ◽  
Packing Pressure ◽  
Thin Walled ◽  
Packing Time

Abstract Aiming at the problem that a thin-walled plastic part easily produces warpage, an orthogonal experimental method was used for multiparameter coupling analysis, with mold structure parameters and injection molding process parameters considered synthetically. The plastic part deformation under different experiment schemes was comparatively studied, and the key factors affecting the plastic part warpage were analyzed. Then the injection molding process was optimized. The results showed that the important order of the influence factors for the plastic part warpage was packing pressure, packing time, cooling plan, mold temperature, and melt temperature. Among them, packing pressure was the most significant factor. The optimal injection molding process schemes reducing the plastic part warpage were melt temperature (260°C), mold temperature (60°C), packing pressure (150 MPa), packing time (2 s), and cooling plan 3. In this situation, the forming plate flatness was better.

scholarly journals An Assessment of Thermoset Injection Molding for Thin-Walled Conformal Encapsulation of Board-Level Electronic Packages

2019 ◽  
Vol 3 (1) ◽  
pp. 18 ◽  
Author(s):  
Romit Kulkarni ◽  
Peter Wappler ◽  
Mahdi Soltani ◽  
Mehmet Haybat ◽  
Thomas Guenther ◽  
...  
Keyword(s):  
Injection Molding ◽  
Manufacturing Industry ◽  
Mechanical Stability ◽  
Flow Simulation ◽  
Dust Particles ◽  
Injection Molding Process ◽  
Market Demand ◽  
Molding Process ◽  
Thin Walled ◽  
Board Level

An ever-growing market demand for board (second) level packages (e.g., embedded systems, system-on-a-chip, etc.) poses newer challenges for its manufacturing industry in terms of competitive pricing, higher reliability, and overall dimensions. Such packages are encapsulated for various reasons including thermal management, protection from environmental conditions and dust particles, and enhancing the mechanical stability. In the due course of reducing overall sizes and material saving, an encapsulation as thin as possible imposes its own significance. Such a thin-walled conformal encapsulation serves as an added advantage by reducing the thermo-mechanical stresses occurring due to thermal-cyclic loading, compared to block-sized or thicker encapsulations. This paper assesses the encapsulation process of a board-level package by means of thermoset injection molding. Various aspects reviewed in this paper include the conception of a demonstrator, investigation of the flow simulation of the injection molding process, execution of molding trials with different encapsulation thicknesses, and characterization of the packages. The process shows a high dependence on the substrate properties, injection molding process parameters, device mounting tolerances, and device geometry tolerances. Nevertheless, the thermoset injection molding process is suitable for the encapsulation of board-level packages limiting itself only with respect to the thickness of the encapsulation material, which depends on other external aforementioned factors.

Rice Husk/High Density Polyethylene Bio-Composite: Effect of Rice Husk Filler Size and Composition on Injection Molding Processability with Respect to Impact Property

2009 ◽  
Vol 83-86 ◽  
pp. 367-374 ◽  
Author(s):  
Wan Aizan Wan Abd. Rahman ◽  
N.M. Isa ◽  
A.R. Rahmat ◽  
N. Adenan ◽  
R.R. Ali
Keyword(s):  
Impact Strength ◽  
Injection Molding ◽  
Rice Husk ◽  
High Density Polyethylene ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Molding Process ◽  
Melt Flow Rate ◽  
Filler Size ◽  
The Impact

The compounding of rice husk and high density polyethylene (HDPE) was undertaken on a Sino PSM 30 co-rotating twin screw extruder. Four sizes of rice husk were studied at various compositions. The size ranged from 500 μm and below (coded A, B, C and D) while the content of rice husk in the composite varies from 30, 40 and 50 percent of weight. A fixed amount of Ultra-Plast TP10 as a compatibilizer and Ultra-Plast TP 01 as lubricant, were added into the bio-composite compound. The injection molding process ability of the bio-composite was studied through flow behavior on melt flow indexer and analyzed on JSW N100 B11 Injection Molding. Size A which has the largest particle is the most appropriate size as the bio-composite filler based on thermal stability test. The melt flow rate of rice husk/HDPE (RHPE) decreases with the increased in rice husk compositions and apparent viscosity also increases with composition for all filler size. Melt flow rate above 4g/10 min was found to be the lower limit for injection molding process. The smaller the filler size, the lower is the impact strength and the increased in the filler composition lowers the impact strength. A bio-composite at 30 weight percent rice husk size A (RH30PEA) was found to have optimum rheological properties with respect to impact strength.

scholarly journals Effect of Organic Cage Nucleating Agent Structure on Nucleating Efficiency and the Structure-Property Relationship

Polymers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 1975
Author(s):  
Yuhui Zhou ◽  
Li He ◽  
Wei Gong
Keyword(s):  
Injection Molding ◽  
Nucleating Agent ◽  
Nucleation Theory ◽  
Classical Nucleation Theory ◽  
Injection Molding Process ◽  
Structure Property ◽  
Molding Process ◽  
Cage Compounds ◽  
Cavity Structure ◽  
Nucleation Agents

Three types of organic cage compounds, namely, cucurbit[6]uril (Q[6]), hemicucurbit[6]uril (HQ[6]), and β-cyclodextrin (BC), with different cavity structures as heterogeneous nucleation agents were selected for a polypropylene (PP) foaming injection molding process. The experimental results showed that Q[6] with a “natural” cavity structure possessed the best nucleation efficiency of these three cage compounds. The nucleation mechanism of organic cage compounds was explored through classical nucleation theory, molecular structure, and in situ visual injection molding analysis.

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