• Transactions of Materials Processing
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• v.11 no.6
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• pp.513-518
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• 2002

The equivalent boundary conditions have been applied to the front door panel forming process, in order to demonstrate its reliability and validity. The elongation in the bead forming process is applied to the binder wrap process as the equivalent displacement boundary condition and the restraining force in the drawing process is applied to stamping process as the equivalent force boundary condition. The result calculated with the equivalent boundary conditions shows closer coincidence with the experimental result than simulation with different boundary conditions. The numerical result fully demonstrates that drawbead forming simulation for calculation of equivalent boundary conditions is necessary and effective.

• Design & Manufacturing
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• v.17 no.3
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• pp.34-40
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• 2023

In this study, real-time collection of mold vibration signals during injection molding processes was achieved through IoT devices installed on the mold surface. To analyze changes in the collected vibration signals, injection molding was performed under six different process conditions. Analysis of the mold vibration signals according to process conditions revealed distinct trends and patterns. Based on this result, cosine similarity was applied to compare pattern changes in the mold vibration signals. The similarity in time and acceleration vector space between the collected data was analyzed. The results showed that under identical conditions for all six process settings, the cosine similarity remained around 0.92±0.07. However, when different process conditions were applied, the cosine similarity decreased to the range of 0.47±0.07. Based on these results, a cosine similarity threshold of 0.60~0.70 was established. When applied to the analysis of mold vibration signals, it was possible to determine whether the molding process was stable or whether variations had occurred due to changes in process conditions. This establishes the potential use of cosine similarity based on mold vibration signals in future applications for real-time monitoring of molding process changes and anomaly detection.

• Journal of the Korean Institute of Intelligent Systems
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• v.11 no.6
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• pp.465-469
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• 2001

In injection molding short shot is one of the frequent and fatal defects. Experts of Injection molding usually adjust process conditions such as injection time, mold temperature, and melt temperature because it is most economic way in time and cost. However, it is difficult task to find appropriate process conditions for troubleshooting of short shot as injection molding process is a highly nonlinear system and process conditions are coupled. In this paper, a modular fuzzy neural network (MFNN) has been applied to injection molding process to shorten troubleshooting time of short shot. Based on melt temperature and fill time, a reasonable initial mo이 temperature is recommenced by the NFNN, and then the mold temperature is inputted to injection molding process. Depending on injection molding result, specifically the insufficient quantity of an injection molded part. and appropriate mold temperature is recommend repeatedly through the NFNN.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.12
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• pp.33-37
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• 2002

A short shot is a molded part that is incomplete because insufficient material was injected into the mold. Remedial actions to control the process conditions can be taken by the injection molding experts based on their knowledge and experience. However, it is very difficult for the non-experts to avoid short shot by finding the proper process conditions such as mold temperature, melt temperature and filling time. In this paper, an intelligent generator of the optimal process conditions based upon fuzzy logic algorithm is proposed so that trial and error can be minimized and the non-experts as well as the experts can also find the optimal process conditions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.402-405
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• 2001

A short shot is a molded part that is incomplete because insufficient material was injected into the mold. Remedial actions to control the process conditions can be taken by the injection molding experts based on their knowledge and experience. However, it is very difficult for the non-experts to avoid short shot by finding the proper process conditions such as mold temperature, melt temperature and filling time. In this paper, an intelligent generator of the optimal process conditions based upon fuzzy logic algorithm is proposed so that trial and error can be minimized and the non-experts as well as the experts can also find the optimal process conditions.

• Journal of the Semiconductor & Display Technology
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• v.16 no.3
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• pp.41-46
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• 2017

This study aims to select suitable co-solvents and to obtain optimal process conditions in order to improve process efficiency and productivity through experimental results obtained under various experimental conditions for the etching and rinsing process using liquid carbon dioxide and supercritical carbon dioxide. Acetone was confirmed to be effective through basic experiments and used as the etching solution for MEMS-wafer etching in this study. In the case of using liquid carbon dioxide as the solvent and acetone as the etching solution, these two components were not mixed well and showed a phase separation. Liquid carbon dioxide in the lower layer interfered with contact between acetone and Mems-wafer during etching, and the results after rinsing and drying were not good. Based on the results obtained under various experimental conditions, the optimum process for treating MEMS-wafer using supercritical CO2 as the solvent, acetone as the etching solution, and methanol as the rinsing solution was set up, and MEMS-wafer without stiction can be obtained by continuous etching, rinsing and drying process. In addition, the amount of the etching solution (acetone) and the cleaning liquid (methanol) compared to the initial experimental values can be greatly reduced through optimization of process conditions.

• Proceedings of the KSME Conference
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• 2007.05a
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• pp.642-647
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• 2007

Determination of loading conditions for tube hydroforming(THF) process that implies an amount of the increment in axial feeding and internal pressure for each step is one of the most important constituents at the process design level. On account of the fact that those design factors mentioned above are imposed simultaneously during the process, suitable loading conditions are required to obtain robust products without any failure such as buckling, necking, bursting and so on. In which, especially, bursting is well known as the most frequently occurred failure in general THF process. In this study, therefore, determination of the loading condition based on the adaptive method was carried out to obtain safe loading paths. In addition, forming limit curves are applied to evaluate the derived loading conditions by using the simulation results. Consequently, it is found that described method in this study for THF process design is useful and has a feasibility.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.30 no.4 s.247
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• pp.381-388
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• 2006

The objective of this study is to predict the etching characteristics using spray characteristics for the optimization on the etching process of Lead-Frame. The etching characteristics such as etching factor, uniformity were investigated on the actual operating conditions. The correlation between the etching characteristics and the spray ones obtained by measurement were analyzed to simulate the etching characteristics according to actual conditions of lead-frame etching process. These conditions of lead-frame process were spray pressure, distance from nozzle tip to substrate, pipe pitch, and nozzle pitch. To improve the etching characteristics in the lead-frame process, effects of the various operating conditions should be understood in detail. The spray characteristics obtained by experiment using PDA system were simulated by the Monte-Carlo method. The etching process model was coded by Java language. It was found that simulation results generally agreed well with the measured results of etching characteristics in lead-frame etching process. The optimal operating parameters were successfully found under variable conditions.

• Proceedings of the Korean Operations and Management Science Society Conference
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• 2003.05a
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• pp.76-80
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• 2003

The procedure of finding operating conditions minimizing qualify loss is proposed with a real industry example. The procedure consists or major two parts - the selection or process variables critical to the response and He determination or operating conditions. The coefficients or ridge regression and the and stores or partial least squares are applied to select important process variables. Functional approach and Non-functional approach are used to find proper operating conditions of important process variables.

• International Journal of Korean Welding Society
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• v.3 no.2
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• pp.24-28
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• 2003

This study was aimed to evaluate the quality of flash welded joints and optimize the welding process for flash butt welding of 780MPa grade high strength steel. And then the relationship between the welding process variables and the joint quality would be established. The effect of process variables between flashing and upsetting process was elucidated. Microstructure observation of the joint indicated that the decarburized band was mainly changed with upsetting process. Width of HAZ was also related to the upsetting conditions rather than the flashing conditions. Generally maximum hardness at HAZ was correlated with Ceq of steel and the empirical relationship was obtained to estimate the HAZ properties. Tensile elongation at the joint was usually decreased with increasing the initial clamping distance. Investigation of fracture surface after tensile and bending tests reveal that the origin of cracking at the joint was oxide inclusions composed of $SiO_2$, MnO, $Al_2O_3$, and/or FeO. The amount of inclusions was dependent on the composition ratio of Mn/Si in steel. If this ratio was above 4, the amount of inclusions was low and then the resistance to cracking at the joint was enough to maintain the joint performance. It was obtained that the flashing process influenced the conditions for the energy input to establish uniform or non­uniform molten layer, while the upsetting conditions influenced the joint strength. Heat input variable during flashing process was also discussed with the joint properties.