Earticle

In this study, We designated the injection molded plug housing for charging electric vehicles as a research subject. And we analyzed the effect of Rib design on the quality of injection molded products. First, we used the Taguchi method to derive optimal conditions for rib design. The factors were set as the Thickness of the rib, the Height of the rib, and the Radius of the rib. Each factor consisted of 5 levels and generated conditions for a total of 125. We performed an injection molding analysis and confirmed significant factors affecting the deformation of injection molded products through ANOVA. Based on this, the 25th design detail was selected as the optimal condition. In addition, We compared the results of the molding analysis with the molded products that did not design ribs. We confirmed that the molded product designed with ribs under optimal design detail improved the deformation amount by 22.22% and the residual stress by 8.35%, compared to the molded product not designed with ribs.

For a plastic diffusion lens to uniformly diffuse light, it is important to minimize deformation that may occur during injection molding and to minimize deformation. It is essential to control the injection molding condition precisely. In addition, as the number of meshes increases, there is a limitation in that the time required for analysis increases. Therefore, We applied machine learning algorithms for faster and more precise control of molding conditions. This study attempts to predict the deformation of a plastic diffusion lens using the Decision Tree regression algorithm. As the variables of injection molding, melt temperature, packing pressure, packing time, and ram speed were set as variables, and the dependent variable was set as the deformation value. A total of 256 injection molding analyses were conducted. We evaluated the prediction model's performance after learning the Decision Tree regression model based on the result data of 256 injection molding analyses. In addition, We confirmed the prediction model's reliability by comparing the injection molding analysis results.

This paper analyzed the correlation between injection molding factors through correlation analysis. In addition, the decision-tree model, which is a white box model with excellent explanatory power, was used to obtain optimal molding conditions that satisfy multiple constraint conditions. First, 243 data to be used in the experiment were created through a full factorial design. Second, a correlation analysis was conducted to understand the correlation. Third, to verify the decision-tree model, the prediction performance was evaluated using RMSE. As a result, good prediction performance was confirmed. A decision-tree experiment analysis was conducted. As a result of the progress, the same results as the correlation analysis were derived. Based on the previous analysis results, optimal molding conditions were applied to CAE. As a result, the amount of deformation in the multi-cavity could be improved by about 1.1% and 2.72% while satisfying the constraint.

This study wanted to optimize the radiator tank's deformation assembled on the automotive engine block. Among the experimental planning methods, the Taguchi method was used to find optimal molding conditions to minimize plastic covers' deformation. The four main factors used in the Taguchi method were selected as the main factors: resin temperature, pressure time, coolant temperature, and cooling time. The number of cycles for each factor was divided into five stages, and a total of 25 experiments were conducted. The experiment used the Moldflow program, an injection molding analysis program. The maximum deformation obtained under the existing molding conditions was about 1.318mm. Still, the deformation of the mold applied with the optimal molding conditions obtained using the Taguchi method was approximately 1.273mm, which showed that the maximum deformation was reduced by 3.4% compared to the existing molding conditions.

The longest process in the injection molding process is the cooling process of the molded product. Therefore, shortening the cooling time is key to reducing the injection molding cycle time. For fast cooling time, the production of conformal cooling channels using metal 3D printing instead of the conventional linear cooling channels is continuously increasing. In this study, the cooling effect of the conventional linear cooling channel application and the conformal cooling channel application using metal 3D printing was compared in the design of the back cover molding mold of the circulator that has been widely used recently. The comparison of the cooling effect was based on the mold temperature and the molded product temperature for a certain period of time after completion of molding. It was confirmed that the time required to eject from the mold with the conformal cooling channel to the ejecting temperature of the molded product was reduced by 28.7%, and the maximum temperature of the mold was also reduced by 40%.

Plastic products molded by injection molding have become an essential element of our lives. In addition, plastics can replace parts that used to be metal in the past. Plastic molded products used as a part of a mechanical system require high precision. At the same time, the appearance quality of molded products is also an important evaluation factor. The appearance quality of a molded product is affected by injection molding conditions, plastic material fluidity, and the condition of the mold surface. In this study, the cause of the short shot of the dog house, which functions to assemble the plastic tailgate parts for automobiles, was analyzed. In order to solve the short shot problem of the dog house, the root thickness of the dog house, injection molding conditions, and fluidity of plastic materials were experimented. Through the injection molding experiment, it was found that when the dog house root thickness was increased from 0.8mm to 1.2mm, the filling amount of the doghouse part increased by 43% in experiment mold. These results were verified by injection molding analysis.

The cooling process in the injection molding requires the longest time. Therefore, a lot of studies have been conducted to reduce the cooling time. In particular, studies on conformal cooling channels using 3D printing are actively being conducted. In this study, the effect of the conformal cooling channel considering the hood shape instead of the conventional linear cooling channel was investigated by injection molding analysis. In the analysis results, when the conformal cooling channel was applied, the length deformation of the molded product was reduced by about 33% and the circular deformation of the hood assembled on the lens was reduced by about 7.1㎛.

In this study, in order of to reflect the mold deformation in the injection molding process to design of mold, the mold deformation was analyzed by performing flow and structural analysis. The 5 inch LGP(light guide plate) mold, platen and tie bar were modeled and applied to the analysis. The result of melt pressure from flow analysis was extracted for use as boundary conditions acting on the mold surface in the structural analysis. In order to evaluate the accuracy of simulation analysis results, injection molding was performed under the process conditions of simulation. As a results, the mold deformation during injection molding tends to be similar that of injection pressure, and it is confirmed that it shows the behavior and properties of melt resins. Compared with the simulation and experiment, the error of the maximum mold deformation in the injection phase was 4.20%.

Smart phones are currently the most popular electronic devices with high volume production activities driven by high demand and requirements for rapid turnaround time. The changes of displacement were analyzed according to a variable of the gate size and runner system. The radial type and gate with large size were shown that better results in displacement. While the design and production of lenses, the key component of a camera, still need to be improved, the current technology has run into its limit with regard to trends in size and weight reduction. In this study, an injection molding analysis was performed on plastic lenses that are widely employed for smart phone cameras. Specifically, the displacement of lenses at the time of injection molding was studied by varying the gate size and runner system.

화장품 산업에 있어서, 용기 생산이 차지하는 비율은 상당히 높다. 금형 기술 수준 높아짐에 따라 짧은 시간에 다양한 소재의 많은 용기가 대량 생산할 수 있게 되었다. 화장품 용기는 주로 플라스틱, 유리, 금속으로 이루어져 있다. 실용성이 높으면서 이동성이 용이한 플라스틱이 전 세계 시작에서 43%를 차지하고 있다. PET 병류는 연평균 성장률이 1.7%로 지속적인 성장하고 있다. 이러한 배경에서 본 연구는 화장품 PET 용기 성형 중 인젝션 블로우 몰딩 성형조건에서 상관관계가 있는 유의미한 변수를 찾아내고자 하였다. 표본은 EJPack의 화장품 PET 용기 55건을 수집하였다. 55건의 추출 근거는 EJPack에서 현재까지 가장 많이 생산되고 있는 PET 용기로 한정하여 진행하였다. 또한 수집된 표본을 SPSS 21.0 통계 패키지를 사용하였으며, 유의 수준은 5% 수준에서 검증하였다. 총 55개의 표본의 성형조건 상관관계를 분석한 결과 제품의 용량과 냉각타임이 밀접한 관련이 있으며, 유의미한 값으로 검증되었다. 상관계수에서 유의미한 수준이 나타났으며, 회귀분석 모형 식을 알아낼 수 있었다. 본래 성형조건 내에서 제품 용량과 밀접한 상관관계를 맺는 변수들이 많이 존재한다. 하지만 본 연구에서 성형조건의 변수들 관련성을 살펴본 결과 제품의 용량과 냉각타임이 가장 많은 관련성을 가지고 있는 것을 파악하였다. 회귀모형 식까지 도출하여 차후 제품의 용량으로 냉각타임을 파악할 수 있을 것이다. 여러 변수들과의 상관관계를 파악하면서 회귀식 모형으로 나타내었으며 향후 용기 성형과정에서 도움이 되었으면 한다.

In the cosmetics industry, the proportion of container production is quite high. As the level of mold technology increases, many containers of various materials can be mass-produced in a short time. Cosmetic containers are mainly made of plastic, glass, and metal. Plastic, which is highly practical and easy to move, accounts for 43% of the world's start-ups. PET types continue to grow at an average annual growth rate of 1.7%. Against this background, this study attempted to find a significant variable with a correlation in injection blow molding molding conditions during cosmetic PET container molding. As for the sample, 55 cosmetic PET containers of EJPack were collected. The extraction basis for 55 cases was limited to the PET containers that have been produced the most so far by EJPack. In addition, the collected samples used the SPSS 21.0 statistical package, and the significance level was verified at the 5% level. As a result of analyzing the correlation of the molding conditions of a total of 55 samples, the capacity and cooling time of the product were closely related and verified with significant values. A significant level was found in the correlation coefficient, and the regression analysis model equation could be determined. Originally, there are many variables that have a close correlation with product capacity within sexual conditions. However, in this study, as a result of examining the relationship between the variables of the molding conditions, it was found that the product capacity and cooling time had the most relevance. By deriving the regression model equation, the cooling time can be determined by the capacity of the product in the future. It is expressed as a regression model while grasping the correlation with various variables, and I hope it will be helpful in the future container molding process.

In this study, we focus on the improvement of the filling efficiency in injection molding by application of ultrasonic vibration. While studies about the filling efficiency of typical filling processes in the injection molding have been widely performed, there have been only few studies about the filling efficiency of an ultrasonic process. The effect of the ultrasonic vibration is an important process condition, which influences the flow characteristics of polymer melt. This new condition even affects well-known injection conditions such as cavity pressure, injection temperature and mold temperature. For this study, we carried out a numerical analysis by appropriate modeling and analysis of the ultrasonic process in the filling process. To verify this numerical analysis, we compared the numerical results with the experimental data. Also, we analyzed the filling process in a thin cavity using this numerical analysis. To understand the flow characteristics of polymer melt in the ultrasonic process, we substituted real and complex vibration conditions with simplified and classified conditions according to the position of vibrating cavity surfaces and the phase difference between two opposing cavity surfaces. We also introduced MFR (melt flow ratio) as a new index to estimate the filling efficiency in the ultrasonic process.

Molding conditions can be described as factors that determine the quality of a product obtained from injection molding. Many studies have been performed on the injection molding pressure, injection temperature, packing pressure and other molding conditions related to part quality. However, the most accessible factor among the adjustable molding conditions during actual injection is the injection speed. In this study, we simulated the variation of the physical quantity according to injection speed and performed experiments to understand the effect of injection speed on the actual product. A CAE analysis program (Moldflow) was used to simulate and analyze the results using PC and PBT for two models. In order to compare these results with the experimental results, an actual injection molding was performed for each injection speed, and the correlation between simulation and injection molding, especially for the shrinkage of the molded article, was discussed.

Foam reaction injection molding (FRIM) is a widely used process for manufacturing polyurethane foam with complex shapes. The modified theoretical model for polyurethane foam forming reaction during FRIM process was established in our previous work. In this study, using the modified model, parametric study for FRIM process was performed in order to optimize experimental conditions of FRIM process such as initial temperature of mold, thickness of mold, and injection amount of polymerizing mixture. In addition, we applied the modified model to real application of refrigerator cabinet to determine optimal manufacturing conditions for polyurethane FRIM process.

Foam reaction injection molding (FRIM) is a widely used process for manufacturing polyurethane foam with complex shapes. Numerical model for polyurethane foam forming reaction during FRIM process has been intensively investigated by a number of researchers to precisely predict final shapes of polyurethane foams. In this study, we have identified a problem related with a previous theoretical model for polyurethane foam forming reaction. Thus, previous theoretical model was modified based on experimental and computational results.

The wavelike flow mark phenomenon is one of the surface defects that can arise during the injection stage of the injection molding process. We have performed a numerical analysis using a finite element method for the injection molding to verify the validity of 'Go-over' hypothesis. Also, we have compared the results of numerical analysis with available experimental data. Numerical analysis results of the flow marks are qualitatively in good agreement with experimental data of reference, but are quantitatively deviated from experimental data in a consistent manner. A parametric study has been performed to examine the correlative effects of various injection molding processing parameters and material properties on the flow mark size.

A computer code was developed to simulate both the thermal stresses introduced during the post-filling stage and the in-plane deformation after ejection process by finite element method based on the plane stress theory. The computer simulation was applied to the mold design of a 2 inch light guide plate (LGP) for thin film transistor (TFT)-liquid crystal displays (LCD). With injection molding experiments based on the design of experiments (DOE) technique, the influences of the processing conditions in injection molding on brightness and uniformity of the LGP were investigated, and the optimal processing parameters were selected to increase the brightness and uniformity. The verification experiment showed that the brightness and uniformity of the LGP were increased dramatically under the selected optimal processing conditions.

We studied the flow characteristics of the polymer melt in the injection molding process with ultrasonic vibration by using the numerical analysis. To minimize the error between the experimental data and numerical result, we presented a methodology using the design of experiments and the response surface method for reverse engineering. This methodology can be applied to various fields to obtain a valid and accurate numerical analysis. Ultrasonic vibration is generally applied between an extruder and the entrance of a mold for improvement the flow rate in injection molding. In comparison with the general ultrasonic process, the mode shape of the mold must be also considered when the ultrasonic vibration is applied on the mold. The mode shape is defined as the periodic and spatial deformation of the structure owing to the effect of the vibration, and it varies greatly according to vibration conditions such as the forcing frequency. Therefore, we considered new index and found the forcing frequency for obtaining the highest flow rate within the range from 20 to 60 kHz on the basis of the index. Ultimately, we presented the methodology for not only obtaining a valid and accurate numerical analysis, but also for finding the forcing frequency to obtain the highest flow rate in injection molding using ultrasonic vibration.

In injection molding, the quality of an injection molded product varies greatly depending on the molding conditions. Many researche studies have been conducted on the quality analysis of molded parts according to the molding conditions such as injection pressure, injection temperature, and packing pressure. However, there have not been many studies on the V/P switchover timing. It is known that when a large pressure is applied to a cavity in the packing phase, the cavity pressure is most affected by the packing pressure. In addition, depending on the position (timing) of the packing pressure, it can have a direct influence on quality based on the shrinkage and dimensions of the molded parts. In this study, the change in pressure profile in the cavity according to the V/P switchover position is confirmed. A CAE analysis program (Moldflow) was used to simulate and analyze two models using the PC and PBT materials. In order to compare these results with the actual injection molding results, injection molding was performed for each V/P switchover position, and the correlation between simulation and experiment, especially for the shrinkage of molded parts, was evaluated.

Housing and insulation of electrical connectors are made of plastic resin by injection molding process. The metallic inner tube is easily deformed by high pressure during the injection process. In order to prevent deformation of the inner tube, it is desirable to simulate it by structural CAE analysis. However, it takes a long time to calculate the stress- of the part by commercially available injection molding CAE software with sufficient accuracy. In this study, structural analysis in conjunction with injection molding analysis is proposed to improve accuracy of the structural analysis. Pressure distribution on the inner tube is predicted by the injection molding CAE analysis, and then mapped onto the mesh of structural analysis by a mapping algorithm developed in this study. As a result reliable result is obtained in shorter time than the conventional method. The predicted deformation of the inner tube is compared with the actual part after experiment.