Theoretical analysis and numerical modeling of the evolution mechanism of polymer melt unstable flow in two‐dimensional ultrasonic‐assisted micro‐injection molding

2021 ◽  
pp. 51853
Author(s):  
Zhongjun Qiu ◽  
Lei Wang
Keyword(s):  
Numerical Modeling ◽  
Theoretical Analysis ◽  
Injection Molding ◽  
Polymer Melt ◽  
Two Dimensional ◽  
Unstable Flow ◽  
Micro Injection Molding ◽  
Evolution Mechanism ◽  
Ultrasonic Assisted

An Investigation into the Influencing Factors for Polymer Melt at the Filling Stage in Micro Injection Molding

2013 ◽  
Vol 562-565 ◽  
pp. 1380-1386
Author(s):  
Jian Zhuang ◽  
Da Ming Wu ◽  
Ya Jun Zhang ◽  
Lin Wang ◽  
Xiong Wei Wang ◽  
...  
Keyword(s):  
Injection Molding ◽  
Influencing Factors ◽  
Polymer Melt ◽  
Theoretical Models ◽  
Injection Molding Process ◽  
Melt Flow ◽  
Molding Process ◽  
Micro Injection Molding ◽  
Filling Stage ◽  
Conventional Injection Molding

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.

Effects of Wall Slip on Filling Flow for Polymer Melt in Micro Injection Molding

2014 ◽  
Vol 609-610 ◽  
pp. 617-622 ◽  
Author(s):  
Jian Zhuang ◽  
Ya Jun Zhang ◽  
Da Ming Wu ◽  
Li Zhu Liu ◽  
Cheng Jun Sun ◽  
...  
Keyword(s):  
Injection Molding ◽  
Slip Velocity ◽  
Polymer Melt ◽  
Wall Slip ◽  
Diameter Ratio ◽  
Micro Injection Molding ◽  
Slip Mechanism ◽  
Inlet Flow Rate ◽  
Section Size ◽  
Slip Coefficients

Effect of wall slip on melt filling flow behaviors in micro injection molding are investigated based on analysis of wall slip mechanism for polymer melt flowing at filling stage. By means of comparisons, slip coefficients in different microchannels are confirmed. With finite element method, the relationship between slip velocity and inlet flow rate or length-diameter ratio is analyzed. The results indicate that the wall slip happen for polymeric melt in microchannels, and slip coefficients are related with the size characteristics of microchannels. Moreover, wall slip velocity has the size effect and increase with the decrease of the section size of microchannels, which cause melt velocity distribution to smooth. At the same time, slip velocity is proportional to length-diameter ratio of microchannel, namely when wall shear stress is uniform, the slip velocity rises with increasing length-diameter ratio of microchannel.

The Method of Improving Precision of Micro Injection Molding Machine Temperature Control

2013 ◽  
Vol 372 ◽  
pp. 354-359
Author(s):  
Sheng De Tang ◽  
Hong Xu ◽  
Da Ming Wu ◽  
Ya Jun Zhang
Keyword(s):  
Injection Molding ◽  
Temperature Control ◽  
Control Method ◽  
Polymer Melt ◽  
Molding Machine ◽  
Micro Injection Molding ◽  
Injection Molding Machine ◽  
Mathematical Algorithm ◽  
Accurate Temperature ◽  
Accurate Temperature Control

the temperature control accuracy of polymer melt is the main factor affecting quality precision of final products. In this paper, we study the method of improving the precision of temperature control based on control system of micro injection molding machine. In order to avoid big overshoot in the traditional PID control, we use gradual approximation control method based on gradual approximation mathematical algorithm to realize fast and accurate temperature control of the micro injection molding machine. Experiment results show that effective combination of the traditional PID and gradual approximation method can realize accurate temperature control of micro injection molding machine, and precision of temperature control can be improved up to±0.5°C.

Research on the Polymer Ultrasonic Plastification

2009 ◽  
Vol 87-88 ◽  
pp. 542-549 ◽  
Author(s):  
Bing Yan Jiang ◽  
Jian Liang Hu ◽  
Wang Qing Wu ◽  
Shu Ye Pan
Keyword(s):  
Theoretical Analysis ◽  
Injection Molding ◽  
Ultrasonic Vibration ◽  
Melt Flow ◽  
Flow Properties ◽  
Micro Injection Molding ◽  
Vibration Field ◽  
Micro Cavity

Melt flow properties in micro cavity play an important role in the micro injection molding (MIM). Based on the point view of improving the melting plastification quality, this study focus on solving the problem of melt filling difficulty in micro cavity of MIM by introducing the ultrasonic vibration field into the polymer plastification process. This paper studied the polymer’s ultrasonic plasitfication process by Theoretical analysis and Polymer ultrasonic plastification experiment.

Wall Slip of Linear Polymer Melts During Ultrasonic-assisted Micro-injection Molding

2018 ◽  
Vol 59 (S1) ◽  
pp. E7-E13 ◽  
Author(s):  
Shan Gao ◽  
Zhongjun Qiu ◽  
Junhao Ouyang ◽  
Yujun Yang
Keyword(s):  
Injection Molding ◽  
Polymer Melts ◽  
Wall Slip ◽  
Linear Polymer ◽  
Micro Injection Molding ◽  
Ultrasonic Assisted
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