• Design & Manufacturing
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• v.6 no.1
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• pp.90-94
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• 2012

Recently, injection molding process became more popular than ever to produce large quantities of high precision products. Extensive studies have been conducted for reducing the residual stresses and birefringence in injection-molded optical products. Flow-induced and thermally-induced stresses and birefringence have been found as two main sources during injection molding process. Generally, quantitative value of birefringence can be measured with polarizing microscope using the compensator. However, it is difficult to measure low order retardation with microscope, so developing a measurement system for low order optical path difference is in need. In the present paper, a system using Photo Elastic Modulator (PEM) is demonstrated to measure low phase retardation in injection-molded products.

• Journal of Power System Engineering
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• v.13 no.4
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• pp.38-42
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• 2009

The Injection molding is used more than 70% of total production in plastic products. The injection molding process has 4 processes such as filling, packing, cooling and ejecting. now then, cooling process spends the most of times in Injection molding cycle time. Therefore, it is important to control the mold temperature in producing plastic products. The cooling system and time affect the product's quality and productivity. Especially, cooling time has about 60% of total injection cycle time. Therefore, we can improve a productivity by shortening cooling time. In this study, the rapid cooling system was developed and performed a efficiency test. This system could refrigerate coolant to $1^{\circ}C$ and had to need 10 minutes for normal operating.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.357-360
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• 2009

The cooling stage greatly affects the product quality in the injection molding process. The cooling system that minimizes temperature variance in the product surface will improve the quality and the productivity of products. In this research, we tried the back-propagation algorithm of artificial neural network to find an optimum solution in the cooling system design of injection mold. The cooling system optimization problem that was once solved by a response surface method with 4 design variables was solved by applying the back-propagation algorithm, resulting in a solution with a sufficient accuracy. Furthermore the number of training points was much reduced by applying the fractional factorial design without losing solution accuracy.

• Journal of the Korean Society for Precision Engineering
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• v.12 no.10
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• pp.32-39
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• 1995

The design of injection molded polymeric parts has been done empirically, since it requires profound knowledge about the moldability and causal effects on the properties of the part, which are not available to designers through current CAD systems. An interactive computer-based design system is developed in order to realize the concept of rational design for the productivity and quality of mold making. The knowledge-based CAD system is constructed by adding the knowledge -base module for mold feature synthesis and appropriate CAE programs for mold design analysis in order to provide designers, at the initial design stage, with comprehensive process knowledge for feature synthesis, performance analysis and feature-based geometric modeling. A knowledge-based CAD system is a new tool which enables the concurrent design with integrated and balanced design decisions at the initial design stage of injection molding.

• Design & Manufacturing
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• v.14 no.2
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• pp.34-41
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• 2020

Typical characteristics of medical device parts are that they can not be reused and there are many disposable products. Therefore, there is a need for an injection molding machine having excellent repeatability of molding conditions and a precision injection mold for mass production. Recently, the performance of an injection machine has made a remarkable evolution compared to the past. However, defects such as short-shot, flash, weld line, gas burning, warpage, and deformation, which are typical defects, still do not disappear at all. This is due to the lack of gas ventilation from the product cavities, even if the gas is smoothly vented from the sprue and runner of the mold. For this reason, the internal pressure of the cavity rises and is directly connected to the quality defects. In this study, an active gas vent system was designed to prevent defects due to trapped gas in the cavity. Since it can be easily adjustable in response to the molding conditions and the mold temperature changes, it is expected to improve productivity due to the reduction of the defective ratio.

• Journal of Electrical Engineering and Technology
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• v.10 no.3
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• pp.1383-1388
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• 2015

Proportional integral derivative (PID) control is one of the conventional control strategies. Industrial PID control has many options, tools, and parameters for dealing with the wide spectrum of difficulties and opportunities in manufacturing plants. It has a simple control structure that is easy to understand and relatively easy to tune. Injection mold is warming up to the idea of cycling the tool surface temperature during the molding cycle rather than keeping it constant. This “heating and cooling” process has rapidly gained popularity abroad. However, it has discovered that raising the mold wall temperature above the resin’s glass-transition or crystalline melting temperature during the filling stage is followed by rapid cooling and improved product performance in applications from automotive to packaging to optics. In previous studies, optimization methods were mainly selected on the basis of the subjective experience. Appropriate techniques are necessary to optimize the cooling channels for the injection mold. In this study, a digital signal processor (DSP)-based PID control system is applied to injection molding machines. The main aim of this study is to optimize the control of the proposed structure, including a digital PID control method with a DSP chip in the injection molding machine.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.2587-2593
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• 2014

Ceramic Injection Molding (CIM) is one of wide used processes in industry field and the applications are gradually being expanded to parts of medical and electric devices. In this study, the CIM process were analyzed with FEM and process parameters were studied and analyzed the effect on product quality. The shape of simple flat plate was compared to the shapes with the hole, with the round corner portion or with the side wall portion. If there are holes then the hole around the uneven density distribution and the defects such as weld lines could be occurred. The Large radius of the corners of the product give good formability and fluidity. Not only the shape parameters of product but also the process parameters during CIM are studied. The simulation results showed that the process parameters of temperature, initial fractions and velocity are important design parameters to improve the quality of products.

• 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.

• Korean Journal of Computational Design and Engineering
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• v.16 no.5
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• pp.344-350
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• 2011

In injection molding industries, CAE analyses are generally used to find out problems predicted during the process of manufacturing. The results of CAE analyses consist of much in formation such as meshes and stress, so that the size of data is pretty large. To reduce the size of the data and to make it easy to share, the CAE result to JT translator is proposed in this paper. The translator consists of three modules to translate CAE result to JT format; Extracting module gets ASCII data of product shape and the result values of CAE analysis. Sorting module and mapping module make an element data set and JT file with the data extracted from Extracting module respectively. To the JT files, engineers are able to append product properties and their comments, so that they can share the whole history of the analysis process. In addition, our case study shows that the size of JT format is reduced by almost 90% of its original data format.

• Design & Manufacturing
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• v.8 no.2
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• pp.7-11
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• 2014

The Core-Shift is often generated on injection mold which have thin and long core. And Core-Shift brings out problems for thickness variation and product ejecting process. In this study, analysis of Core-Shift was performed according to change of materials of core(steel P-20, Be-Cu) and various polymers(PP, PC) by using MoldFolw MPI 6.1 which is commercial injection molding analysis program. As the results of analysis, the magnitude of Core-Shift was increased as being use polymer had lower fluidity and lower rigidity core. In the future, we will study the relationship between amount of Core-Shift and ejecting force.