Mold surface roughness effects on cavity filling of polymer melt in micro injection molding

2007 ◽  
Vol 37 (11-12) ◽  
pp. 1105-1112 ◽  
Author(s):  
H. L. Zhang ◽  
N. S. Ong ◽  
Y. C. Lam
Keyword(s):  
Surface Roughness ◽  
Injection Molding ◽  
Polymer Melt ◽  
Mold Surface ◽  
Roughness Effects ◽  
Micro Injection Molding ◽  
Cavity Filling

Flows in Microchannels and Cavities – Visco-Elasticity, Faradaic Charging and Surface Roughness Effects

2009 ◽  
Vol 74 ◽  
pp. 73-76
Author(s):  
Yee Cheong Lam
Keyword(s):  
Surface Roughness ◽  
Injection Molding ◽  
Flow Model ◽  
Flow Instability ◽  
Polymer Melt ◽  
Injection Molding Process ◽  
Elastic Instability ◽  
Molding Process ◽  
Roughness Effects ◽  
Plastic Injection

Two phenomena for flows in microchannels, namely visco-elastic instability and Faradaic charging effects, are discussed. Aqueous solutions, which do not exhibit elastic behaviors, will behave visco-elastically with the addition of a small amount of polymers. Visco-elastic flow instability which promote mixing has been observed in the flow of these visco-elastic solutions through a constriction in microchannels. In addition, we recently show experimentally the existance of Faradaic charging in AC-electrokinetic (ACEK) flow. Lastly, surface roughness effects in micro- plastic injection molding are highlighted. The micro-injection molding process involves the flow of polymer melt in micro-cavities. Our recent investigations demonstrate that the flow model for macro-cavities could be employed satisfactorily to simulate the flow in micro-cavities if roughness effects are considered in an appropriate manner.

scholarly journals Hybrid Process Chain for the Integration of Direct Ink Writing and Polymer Injection Molding

Micromachines ◽  
2020 ◽  
Vol 11 (5) ◽  
pp. 509 ◽  
Author(s):  
Dario Loaldi ◽  
Leonardo Piccolo ◽  
Eric Brown ◽  
Guido Tosello ◽  
Corey Shemelya ◽  
...  
Keyword(s):  
Injection Molding ◽  
Polymer System ◽  
Polymer Melt ◽  
Hybrid Process ◽  
Direct Write ◽  
Mold Surface ◽  
Direct Writing ◽  
Process Chain ◽  
Polymer Injection ◽  
Functional Features

The integration of additive manufacturing direct-writing technologies with injection molding provides a novel method to combine functional features into plastic products, and could enable mass-manufacturing of custom-molded plastic parts. In this work, direct-write technology is used to deposit conductive ink traces on the surface of an injection mold. After curing on the mold surface, the printed trace is transferred into the plastic part by exploiting the high temperature and pressure of a thermoplastic polymer melt flow. The transfer of the traces is controlled by interlocking with the polymer system, which creates strong plastic/ink interfacial bonding. The hybrid process chain uses designed mold/ink surface interactions to manufacture stable ink/polymer interfaces. Here, the process chain is proposed and validated through systematic interfacial analysis including feature fidelity, mechanical properties, adhesion, mold topography, surface energy, and hot polymer contact angle.

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.

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