Influence of Mold Temperature on Mold Filling Behavior and Part Properties in Micro Injection Molding

2013 ◽  
Vol 28 (5) ◽  
pp. 550-557 ◽  
Author(s):  
S. Meister ◽  
D. Drummer
Keyword(s):  
Injection Molding ◽  
Mold Temperature ◽  
Mold Filling ◽  
Micro Injection Molding

Study on Optical Properties of Microstructure of Lightguiding Plate for Micro Injection Molding and Micro Injection-Compression Molding

2006 ◽  
Vol 505-507 ◽  
pp. 229-234 ◽  
Author(s):  
Yung Kang Shen ◽  
H.J. Chang ◽  
C.T. Lin
Keyword(s):  
Optical Properties ◽  
Injection Molding ◽  
Digital Camera ◽  
Mold Temperature ◽  
Compression Molding ◽  
Micro Injection Molding ◽  
Melt Temperature ◽  
Packing Pressure ◽  
Injection Compression Molding ◽  
Better Than

The purpose of this paper presents the optical properties of microstructure of lightguiding plate for micro injection molding (MIM) and micro injection-compression molding (MICM). The lightguiding plate is applied on LCD of two inch of digital camera. Its radius of microstructure is from 100μm to 300μm by linearity expansion. The material of lightguiding plate uses the PMMA plastic. This paper uses the luminance distribution to make a comparison between MIM and MICM for the optical properties of lightguiding plate. The important parameters of process for optical properties are the mold temperature, melt temperature and packing pressure in micro injection molding. The important parameters of process for optical properties are the compression distance, mold temperature and compression speed in micro injection-compression molding. The process of micro injection-compression molding is better than micro injection molding for optical properties.

scholarly journals Characterization of Stereolithography Printed Soft Tooling for Micro Injection Molding

Micromachines ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 819 ◽  
Author(s):  
Daniel Dempsey ◽  
Sean McDonald ◽  
Davide Masato ◽  
Carol Barry
Keyword(s):  
Aspect Ratio ◽  
Injection Molding ◽  
Raw Materials ◽  
Tool Material ◽  
Mold Temperature ◽  
Micro Injection Molding ◽  
Digital Light Processing ◽  
Electron Microscopies ◽  
Aspect Ratios ◽  
The Impact

The use of microfeature-enabled devices, such as microfluidic platforms and anti-fouling surfaces, has grown in both potential and application in recent years. Injection molding is an attractive method of manufacturing these devices due to its excellent process throughput and commodity-priced raw materials. Still, the manufacture of micro-structured tooling remains a slow and expensive endeavor. This work investigated the feasibility of utilizing additive manufacturing, specifically a Digital Light Processing (DLP)-based inverted stereolithography process, to produce thermoset polymer-based tooling for micro injection molding. Inserts were created with an array of 100-μm wide micro-features, having different heights and thus aspect ratios. These inserts were molded with high flow polypropylene to investigate print process resolution capabilities, channel replication abilities, and insert wear and longevity. Samples were characterized using contact profilometry as well as optical and scanning electron microscopies. Overall, the inserts exhibited a maximum lifetime of 78 molding cycles and failed by cracking of the entire insert. Damage was observed for the higher aspect ratio features but not the lower aspect ratio features. The effect of the tool material on mold temperature distribution was modeled to analyze the impact of processing and mold design.

Warpage Measurement of a Micro Electrical Fan on Micro-Injection Molding

2012 ◽  
Vol 184-185 ◽  
pp. 1651-1654
Author(s):  
Jeou Long Lee ◽  
Y. Lin ◽  
Y.K. Shen
Keyword(s):  
Injection Molding ◽  
Injection Pressure ◽  
Acrylonitrile Butadiene Styrene ◽  
Mold Temperature ◽  
Micro Injection Molding ◽  
Optimum Result ◽  
Suitable Material ◽  
Packing Pressure ◽  
Injection Molded ◽  
Packing Time

This study characterizes warpage of a micro-injection molded micro electrical fan using the Michelson interference method. This study conducts experiments to analyze different polymers-polypropylene (PP), polyamide (PA), acrylonitrile-butadiene styrene (ABS), ABS+ polycarbonate (PC), and polyoxymethylene (POM)-process parameters, such as mold temperature, injection temperature, injection pressure, injection time, packing time, and packing pressure, for a micro electrical fan. To obtain the optimum result (minimum warpage), this study assesses the effect (warpage) of each material on micro-injection molding. PA plastic is the very suitable material for micro electrical fan with Michelson interference analysis on micro-injection molding.

Effect of Micro-Injection Molding Processing Conditions on the Replication and Consistency of a Dense Network of High Aspect Ratio Microstructures

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
John W. Rodgers ◽  
Meghan E. Casey ◽  
Sabrina S. Jedlicka ◽  
John P. Coulter
Keyword(s):  
Injection Molding ◽  
Flow Rate ◽  
Mold Temperature ◽  
Processing Parameters ◽  
Molding Process ◽  
Micro Injection Molding ◽  
Fluid Behavior ◽  
Replication Quality ◽  
Average Standard Error ◽  
Experimental Trials

When molding macroscale polymer parts with a high density of microfeatures (>1 × 106/cm2), a concern that presents itself is the ability to achieve uniform replication across the entire domain. In the given study, micro-injection molding was used to manufacture microfeatured polymer substrates containing over 10 × 106 microfeatures per cm2. Polystyrene (PS) plates containing microtopography were molded using different processing parameters to study the effect of flow rate and mold temperature on replication quality and uniformity. Flow rate was found to significantly affect replication at mold temperatures above the glass transition temperature (Tg) of PS while having no significant effect on filling at mold temperatures below Tg. Moreover, replication was dependent on distance from the main cavity entrance, with increased flow rate facilitating higher replication differentials and higher replication near the gate. Simulation of the molding process was used to corroborate experimental trials. A deeper understanding of polymer fluid behavior associated with micro-injection molding is vital to reliably manufacture parts containing consistent microtopography (Note: Values are expressed in average ± standard error).

Design and Fabrication of a Polymeric Microfilter for Medical Applications

2015 ◽  
Vol 4 (1) ◽  
Author(s):  
Rossella Surace ◽  
Vincenzo Bellantone ◽  
Gianluca Trotta ◽  
Vito Basile ◽  
Francesco Modica ◽  
...  
Keyword(s):  
Injection Molding ◽  
Electrical Discharge Machining ◽  
Mold Temperature ◽  
Machining Process ◽  
Injection Velocity ◽  
Injection Molding Process ◽  
Molding Process ◽  
Micro Injection Molding ◽  
Melt Temperature ◽  
Steel Mold

This paper reports on design, fabrication, and characterization of a microfilter to be used in biomedical applications. The microfilter, with mesh of 80 μm, is fabricated by micro-injection molding process in polymeric material (polyoxymethylene (POM)) using a steel mold manufactured by micro-electrical discharge machining process. The characteristics of the filter are investigated by numerical simulation in order to define a suitable geometry for micro-injection molding. Then, different process configurations of parameters (melt temperature, injection velocity, mold temperature, holding pressure and time, cooling time, pressure limit) are tested in order to obtain the complete part filling via micro-injection molding process preventing any defects. Finally, the component is dimensionally characterized and the process parameters optimized to obtain the maximum filtration capacity.

Study on Micro-Feature of Backlight Module for Micro Injection Molding Technology

2007 ◽  
Vol 364-366 ◽  
pp. 53-57 ◽  
Author(s):  
Yung Kang Shen ◽  
Yi Lin ◽  
Jeou Long Lee ◽  
Fwu Hsing Liu ◽  
Chih Wei Wu ◽  
...  
Keyword(s):  
Injection Molding ◽  
Injection Pressure ◽  
Mold Insert ◽  
Mold Temperature ◽  
Processing Parameters ◽  
High Viscosity ◽  
Injection Velocity ◽  
Parameter Method ◽  
Micro Injection Molding ◽  
Melt Temperature

This research first indicates the melt front delay of wedge-shaped lightguiding plate of backlight module on micro injection molding. This research fabricated the patterns of mold insert of lightguiding plate by photo etching process. The micro-facture of lightguiding plate was manufactured by micro injection molding. The lightguiding plate of backlight module was used for the PMMA material. The single parameter method was used to discuss the flatness and replication properties for different processing parameters (mold temperature, melt temperature, packing pressure, packing time and injection pressure). The results show that there are melt front delays due to the slow injection velocity, the low temperature induced by the little effect of shear heating, the high viscosity, the large flow resistance and the slow flow velocity. The mold temperature is the most important factor for the flatness and the replication of micro-feature of liughtguiding plate. Lower mold temperature induces better flatness properties. The surface roughness of micro-facture of lightguiding plate is 8.8 nm on micro injection molding for this work.

scholarly journals Optimized Micro-Pattern Design and Fabrication of a Light Guide Plate Using Micro-Injection Molding

Polymers ◽  
2021 ◽  
Vol 13 (23) ◽  
pp. 4244
Author(s):  
Fang-Yu Fan ◽  
Hsin-Hua Chou ◽  
Wei-Chun Lin ◽  
Chiung-Fang Huang ◽  
Yi Lin ◽  
...  
Keyword(s):  
Optimal Design ◽  
Injection Molding ◽  
Light Guide ◽  
Field Measurements ◽  
Mold Temperature ◽  
Optimized Design ◽  
Processing Parameter ◽  
Micro Injection Molding ◽  
Field Distributions ◽  
Micro Pattern

This study examined the uniformity of illuminance field distributions of light guide plates (LGPs). First, the authors designed microstructural patterns on the surface of an LGP. Then, a mold of the LGP with the optimal microstructural design was fabricated by a photolithography method. Micro-injection molding (μIM) was used to manufacture the molded LGPs. μIM technology can simultaneously manufacture large-sized wedge-shaped LGPs and micro-scale microstructures. Finally, illuminance values of the field distributions of the LGPs with various microstructures were obtained through optical field measurements. This study compared the illuminance field distributions of LGPs with various designs and structures, which included LGPs without and those with microstructure on the primary design and the optimal design. The average illuminance of the LGP with microstructures and the optimal design was roughly 196.1 cd/m2. Its average illuminance was 1.3 times that of the LGP without microstructures. This study also discusses illuminance field distributions of LGPs with microstructures that were influenced by various μIM process parameters. The mold temperature was found to be the most important processing parameter affecting the illuminance field distribution of molded LGPs fabricated by μIM. The molded LGP with microstructures and the optimal design had better uniformity than that with microstructures and the primary design and that without microstructures. The uniformity of the LGP with microstructures and the optimal design was roughly 86.4%. Its uniformity was nearly 1.65 times that of the LGP without microstructures. The optimized design and fabrication of LGPs with microstructure exhibited good uniformity of illuminance field distributions.

Injection Molding

2006 ◽  
Author(s):  
Chang Dae Han
Keyword(s):  
Injection Molding ◽  
Cooling Water ◽  
Polymer Melt ◽  
Mold Temperature ◽  
Mold Filling ◽  
Injection Rate ◽  
Mold Cavity ◽  
Complex Nature ◽  
Almost All ◽  
Cavity Cooling

Injection molding is one of the oldest polymer processing operations used to produce goods from thermoplastic polymers. Today, almost all commercial injection molding machines have a reciprocating single screw for softening (or melting) under heat a thermoplastic polymer, and polymer melt is then injected into an empty mold cavity, as schematically shown in Figure 8.1. In the injection molding operation, the mold is first closed and then a predetermined amount of polymer melt from the screw section is injected into an empty mold cavity. Pressure is maintained for some time after the mold cavity has been filled to permit the build-up of adequate pressure in the mold cavity. Cooling water is circulated through channels in the mold so as to keep the mold cavity walls at a temperature usually between room temperature and the softening (or melting) temperature of the polymer. Thus, the hot polymer begins to cool as it enters the mold cavity. When it is cooled to a state of sufficient rigidity, the mold is opened and the part is removed. Some of the important variables in the operation of an injection molding machine are: (1) pressure applied by the screw, (2) temperature profile of the screw section, (3) mold temperature, (4) the screw forward time, (5) the mold closed time, and (6) the mold open time. Relationships between these variables are very complicated. In general, one would like to know the pressure, temperature, and density of the polymer in the mold cavity as functions of time during and after the mold is filled. In principle, these quantities can be calculated, via a mathematical model, during the entire period of mold filling and subsequent cooling when information on the geometry of the mold cavity, the rheological properties of the polymer, the temperature at which the polymer enters the mold cavity, and the mold temperature is available. However, in practice it is not easy to develop a rigorous theory because of the geometrically complex shapes of mold cavities, the complex nature of mold filling patterns (i.e., jetting) at normal injection speeds of industrial practice, and the highly viscoelastic nature of polymer melts, which varies with temperature, pressure, and injection rate (i.e., shear rate in the runner).

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