Study of Ultrasonic-Assisted High Light Seamless Injection Molding Process and Technology

Author(s):  
Jibin Li ◽  
Keke Xu ◽  
Haixiong Wang ◽  
Haijun Liu

This paper rebuilt a set of melt flow rate instrument which is loaded a power adjustable ultrasonic device. The melt flow rate (viscosity curve) is studied on three kinds of plastic materials, PC, ABS, and PMMA, at different temperatures. The variation of melt flow rate is analyzed under the ultrasonic field. In addition, the practicability of ultrasonic-assisted high light seamless injection molding process and technology is tested and discussed.

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

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.


Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 965 ◽  
Author(s):  
Nguyen Truong Giang ◽  
Pham Son Minh ◽  
Tran Anh Son ◽  
Tran Minh The Uyen ◽  
Thanh-Hai Nguyen ◽  
...  

In the injection molding field, the flow of plastic material is one of the most important issues, especially regarding the ability of melted plastic to fill the thin walls of products. To improve the melt flow length, a high mold temperature was applied with pre-heating of the cavity surface. In this paper, we present our research on the injection molding process with pre-heating by external gas-assisted mold temperature control. After this, we observed an improvement in the melt flow length into thin-walled products due to the high mold temperature during the filling step. In addition, to develop the heating efficiency, a flow focusing device (FFD) was applied and verified. The simulations and experiments were carried out within an air temperature of 400 °C and heating time of 20 s to investigate a flow focusing device to assist with external gas-assisted mold temperature control (Ex-GMTC), with the application of various FFD types for the temperature distribution of the insert plate. The heating process was applied for a simple insert model with dimensions of 50 mm × 50 mm × 2 mm, in order to verify the influence of the FFD geometry on the heating result. After that, Ex-GMTC with the assistance of FFD was carried out for a mold-reading process, and the FFD influence was estimated by the mold heating result and the improvement of the melt flow length using acrylonitrile butadiene styrene (ABS). The results show that the air sprue gap (h) significantly affects the temperature of the insert and an air sprue gap of 3 mm gives the best heating rate, with the highest temperature being 321.2 °C. Likewise, the actual results show that the height of the flow focusing device (V) also influences the temperature of the insert plate and that a 5 mm high FFD gives the best results with a maximum temperature of 332.3 °C. Moreover, the heating efficiency when using FFD is always higher than without FFD. After examining the effect of FFD, its application was considered, in order to improve the melt flow length in injection molding, which increased from 38.6 to 170 mm, while the balance of the melt filling was also clearly improved.


Author(s):  
Ali Keshavarz Panahi ◽  
Hossein Khoshkish

In this article, the fabrication steps of copper parts, using the powder injection molding method have been investigated. For the purpose of this study, first, several feedstocks were prepared by mixing copper powder (in volume percentages of 60, 64, 68, and 72%) and a thermoplastic binder. Due to the sensitivity of the mixing stage in the powder injection molding process, the Extrumixing method was utilized to appropriately mix the copper powder with the binder. Rheological characteristics of the different feedstocks were analyzed by means of a capillary rheometer. Based on this analysis, the feedstock having a 68 vol. % copper powder was selected as the optimum powder, out of which, samples shaped like tensile test specimens were successfully molded. These samples were later debinded by the solvent debinding method. Sintering of the pieces was carried out at different temperatures. Research showed that raising the sintering temperature leads to an increase of density and tensile strength of the specimens.


2019 ◽  
Vol 971 ◽  
pp. 15-20
Author(s):  
The Nhan Phan ◽  
Trung Do Thanh ◽  
Son Minh Pham

Improving the melt flow length by increasing the mold temperature has been an issue encountered in the injection molding processes for composite products. In this study, an injection molding process was applied to a melt flow length model having a part thickness of 1.0 mm. The mold temperature varied from 30 °C to 110 °C. Six types of composite materials of polycaprolactam 6 (PA6) and glass fiber (GF) were selected to study the influence of mold temperature on the material filling in the injection molding process. The simulation results denoted that the mold temperature considerably influenced the flowability during the injection molding process, especially using 30% GF; further, the melt flow length was increased by 25.5% when the mold temperature was increased from 30 °C to 110 °C. In accordance with the simulation, our experiments demonstrated that we could achieve a mold temperature of 110 °C using all types of composite materials. Therefore, in this study, we denoted that both the simulation and experimental results of the melt flow length were comparable, thereby indicating a good agreement.


2018 ◽  
Vol 145 ◽  
pp. 02006
Author(s):  
Margarita Natova ◽  
Ivan Ivanov ◽  
Sabina Cherneva ◽  
Maria Datcheva ◽  
Roumen Iankov

During conventional polymer injection molding, flow- and weld lines can arise at the molded parts caused by disturbed polymer melt flow when it crosses different parts of the equipment. Such processed plastic goods have discrete zones of inhomogeneities of very small dimensions. In order to stabilize the melt flow and to equalize dimensions of such defective products, an approach for pulse injection molding is applied during production of polymer packagings. Testing methods used for evaluation of macromechanical performance of processed polymer products are not readily applicable to estimate the changes in visual surface obtained during pulse injecting. To overcome this testing inconvenience the performance of processed packagings is evaluated by nanoindentation. Using this method, a quantitative assessment of the polymer properties is obtained from different parts of technological products.


2013 ◽  
Vol 562-565 ◽  
pp. 1380-1386
Author(s):  
Jian Zhuang ◽  
Da Ming Wu ◽  
Ya Jun Zhang ◽  
Lin Wang ◽  
Xiong Wei Wang ◽  
...  

The flow behaviors for polymer melt at the filling stage in micro injection molding are different from those in conventional injection molding due to the miniaturization of plastic parts. This paper focuses on the study of the effects of three main influencing factors, including the microscale viscosity and wall slip, on melt filling flow in microscale neglected those in conventional injection molding process. The theoretical models and the interrelation of these factors in microscale channels were constructed by means of the model correction method. Then, the micro melt flow behaviors were investigated with comparisons of the available experimental data. The results indicate that the dimensions affect the shear rates and viscous dissipation, which in turn affects the apparent viscosity. Finally, the conclusion is that the melt flow behaviors in microchannels are different from those in macrochannels owing to these significant influencing factors.


2019 ◽  
Vol 2019 ◽  
pp. 1-17 ◽  
Author(s):  
Phan The Nhan ◽  
Thanh Trung Do ◽  
Tran Anh Son ◽  
Pham Son Minh

In the injection molding process, mold temperature control is one of the most efficient methods for improving product quality. In this research, an external gas-assisted mold temperature control (Ex-GMTC) with gas temperature variation from 200°C to 400°C was applied to thin wall injection molding at melt thicknesses from 0.2 to 0.6 mm. The melt flow length was evaluated through the application of this system to the mold of a thin rib product. The results show that the heating process achieves high efficiency in the initial 20 s, with a maximum heating rate of 6.4°C/s. In this case, the mold surface reached 158.4°C. By applying Ex-GMTC to a 0.2 mm flow thickness, the flow length increased from 37.85 to 41.32 mm with polypropylene (PP) material and from 14.54 to 15.8 mm with acrylonitrile butadiene styrene (ABS) material. With the thin rib mold and use of Ex-GMTC, the mold temperature varied from 112.0°C to 140.8°C and the thin rib height reached 7.0 mm.


AIChE Journal ◽  
1996 ◽  
Vol 42 (6) ◽  
pp. 1706-1714 ◽  
Author(s):  
S. C. Chen ◽  
N. T. Chen ◽  
K. S. Hsu ◽  
K. F. Hsu

2019 ◽  
Vol 299 ◽  
pp. 06001
Author(s):  
Jozef Dobránsky ◽  
Zigmund Doboš

The aim of this paper is to monitor the melt volume index of thermoplastic materials and other rheological properties such as shear rate and viscosity. The aim is to compare and assess whether several times ground and subsequently re-melted samples of pure polymer granulate will have the same or similar rheology properties and whether adjustment of the injection molding machine will be required or willneed to reduce or increase production times. Thermo Scientific with HAAKE Meltflow MT software was used to determine the melt flow rate index (MVR) of thermoplastic materials. Based on the melt flow rate (MVR), shear rate and viscosity evaluation, it has been found that, although the selected materials have undergone multiple changes in the rheology of the polymeric materials, there is no problem in the molding process, and MVR does not change significantly. In this case, no changes in the settings of theinjection molding machines and reduction or increase in production times will be necessary. When re-melting the granulate samples, no excess waste was generated, which would then need to be disposed of and the samples could be re-used for further measurement after grinding.


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