• Transactions of the Society of Information Storage Systems
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• v.1 no.2
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• pp.192-196
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• 2005

In this paper, we investigated the possibility of replicating patterned media by nano-injection molding process with a metallic nano-stamper. The original nano-master was fabricated by E-beam lithography and ICP etching process. The metallic nano-stamper was fabricated using a nanoimprint lithography and nano-electroforming process. The nano-patterned substrate was replicated using a nano-injection molding process without additional etching process. In nano-injection molding process, since the solidified layer, generated during the polymer filling, deteriorates transcribability of nano patterns by preventing the polymer melt from filling the nano cavities, an injection-mold system was constructed to actively control the stamper surface temperature using MEMS heater and sensors. The replicated polymeric patterns using nano-injection molding process were as small as 50 nm in diameter, 150 nm in pitch, and 50 nm in depth. The replicated polymeric patterns can be applied to high density patterned media.

• Design & Manufacturing
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• v.11 no.3
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• pp.29-34
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• 2017

Increased demand for parts with micro-pattern structure made of metals, ceramics, and composites in various fields such as medical ultrasonic sensors, CT collimators, and ultra-small actuator parts. Micro powder injection molding (PIM) is a technology for manufacturing micro size, high volume, complex, precision, net-shape components from either metal or ceramic powder. In the present study, a standard mold with a variable insert core capable of producing various micro patterns was investigated. An injection molding test was performed on a standard mold using a line type micro-pattern core having an aspect ratio of 2, a slenderness ratio of 70, a pattern size of $200{\mu}m$, and a pattern spacing of $150{\mu}m$. During the filling process, the deformation of the mold with large aspect ratio and slenderness ratio was analyzed by the experiment and the numerical simulation according to the position of the gate. We proposed a mold structure that minimizes mold deformation by gate modification and enables uniform pattern filling behavior.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09a
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• pp.45-46
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• 2006

In recent years, micro powder injection molding $(\mu-PIM)$ is being explored as an economical fabrication method for microcomponents in microsystems technology (MST). Technical and economic comparison was performed for $\mu-PIM$ processes. Molding experiment and simulation during the filling process were performed to evaluate several different geometries and processing conditions. The influence of material parameters and process conditions on mold filling were examined as a function of features size using microchannels as an example. It was found that the heat conductivity and viscosity of feedstock, geometry and mold temperature were the most critical parameters for complete filling of micro features.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 1995.10a
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• pp.64-67
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• 1995

Transfer Molding is currently the most widely used process for encapsulation integrated circuits(;IC). Although the process has been introduced over 20 years ago, generating billions of parts each year, it is far from being optimized. With each new mold, epoxy mold, epoxy mold compound, and lead-frame, lengthy period and expensive qualification runs have to be performed to minimized defects ranging from wire sweep, incomplete fill, and internal voids etc. This studies describes how simulation can be applied to transfer molding to yield acceptable design and processing parameter. The non-isothermal filling of non-newtonian reactive epoxy molding compound(;EMC) in a multi-cavity mold is analyzed. Sensitivity analysis is conducted to investigate the influence of process deviations on the final molded profile. This study trend is carried out by following some heuristic process guidelines.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1993.04b
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• pp.323-327
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• 1993

Mold-making industry demands currently to reduce the tooling costs and time in mold making, and to improve the productivity and quality in injection molding process. These problems can be easily removed by laminated injection mold which is made with metal sheets prepared by laser cutting and bonded by brazing. Comparing withthe conventional mold making technology which mainly depends on the machining, this new technologyenables an arbitary design of cooling circuit without anyrestrictions of geometry. So it brings about high production rates of the injection molding processes. This paper estimate the conventional and laminated injection mold making process with a simple molding, and also the cooling efficiencyof thoes two kinds of mold with the filling and cooling analysis. The results show that the laminated injectionmold has much shorter tooling time, uniform mold temperature, and shorter cooling time in injection molding process.

• Journal of Practical Engineering Education
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• v.9 no.2
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• pp.119-124
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• 2017

In injection molding process, the runner system of the mold is a flow path for filling the cavity of the molded part during the advance of the screw by the force of the hydraulic cylinder, which involves the filling and packing process of the molten resin. Thus, the sprue, runner and gate greatly affect the appearance of the molded part, the physical properties of the resin, the dimensional accuracy and the molding cycle etc. Feed systems with incorrect runner and gate designs cause various molding defects, So it is important to maintain the optimum runner balance to prevent these defects. In order to improve the knowledge of practical mold technology, which is applied to the manufacturers of injection molds, a training model of the mold technology process is presented based on the technical guidance on the technical difficulties.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.7
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• pp.167-173
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• 2001

The simulated die-casting process in which the traditional plaster casting process is combined with Rapid Prototyping technology is being used to produce AI, Mg, and Zn die-casting prototypes. Unlike in the die-casting process, molten metal in the conventional plaster casting process is fed via a gravity pour into a mold and the mold does not cool as quickly as a die-casting mold. The plaster castings have much larger and grosser grain structure as compared with the normal die-castings and the thin walls of the plaster mold cavity may not be completely filled. Because of lower mechanical properties induced by the large grain structure and incomplete filling, the conventional plaster casting process is not suitable for the trial die-casting process to obtain quality prototypes. In this work, an enhanced trial die-casting process has been developed in which molten metal in the plaster mold cavity is vibrated and pressurized simultaneously. Patterns for the casting are made by Rapid Prototyping technologies and then plaster molds, which have a runner system, are made using these patterns. Pressurized vibration to imparted molten metal has made grain structure of castings much finer and improved fluidity of the molten enough to obtain complete filling at thin walls which may not be filled in the conventional plaster casting process..

• Design & Manufacturing
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• v.2 no.6
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• pp.49-55
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• 2008

Double-injection molding can inject two different materials or two colors in the same mold and process. If this injection process use, product has ability because the base part maintain strength and specified part can inject soft-material. It makes the cost down by single operation automatically for saving wages. In this paper, we designed double-injection mold for automobile remote control to inject secondary using this part as insert after inject external appearance of product. CAE analysis was progressed gate location and runner size as variable and analysis result is reflected in mold design process. As a result, it could solved badness that is generated at the conventional mold. Additionally, cost is downed by reducing loss of runner as well as could omit painting process because surface of finished product is improved through new mold.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.40 no.1
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• pp.35-40
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• 2017

A most important progress in civilization was the introduction of mass production. One of main methods for mass production is die-casting molds. Due to the high velocity of the liquid metal, aluminum die-casting is so complex where flow momentum is critical matter in the mold filling process. Actually in complex parts, it is almost impossible to calculate the exact mold filling performance with using experimental knowledge. To manufacture the lightweight automobile bodies, aluminum die-castings play a definitive role in the automotive part industry. Due to this condition in the design procedure, the simulation is becoming more important. Simulation can make a casting system optimal and also elevate the casting quality with less experiment. The most advantage of using simulation programs is the time and cost saving of the casting layout design. For a die casting mold, generally, the casting layout design should be considered based on the relation among injection system, casting condition, gate system, and cooling system. Also, the extent or the location of product defects was differentiated according to the various relations of the above conditions. In this research, in order to optimize the casting layout design of an automotive Oil Pan_BR2E, Computer Aided Engineering (CAE) simulation was performed with three layout designs by using the simulation software (AnyCasting). The simulation results were analyzed and compared carefully in order to apply them into the production die-casting mold. During the filling process with three models, internal porosities caused by air entrapments were predicted and also compared with the modification of the gate system and overflows. With the solidification analysis, internal porosities occurring during the solidification process were predicted and also compared with the modified gate system.

• Journal of the Korean Society for Precision Engineering
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• v.16 no.8
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• pp.71-78
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• 1999

The application range of injection molded parts is expanding by the development of engineering plastics with good mechanical properties. Plastic gears are specially used as automotive parts due to an excellent performance in the characteristics of a strength vs. weight, and the study of injection molding process of plastic gear using Nylon66 is performed in this study. Filling, packing and cooling analyses were done by using the simulation software like Moldflow, and a mold was designed by following the simulation results. Pin-point gates with three points were taken to satisfy the design guides like a full-shot, and lower clamping force and uniform shrinkage. Characteristics of shrinkage of molded gear and temperature difference between cavity and core sides of a mold were shown.