• Transactions of Materials Processing
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• v.9 no.5
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• pp.512-525
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• 2000

Designers are frequently faced with multiple quality issues in injection molded parts. These issues are usually In conflict with each other, and thus tradeoff needs to be made to reach a final compromised solutions. The objective of this study is to develop an automated injection molding design methodology, whereby part defects such as warpage and weld line are optimized. The features of the proposed methodology are as follows: first, Utility Function approach is applied to transform the original multiple objective problem into single objective problem. Second is an implementation of a direct search-based Injection molding optimization procedure with automated consideration of process variation. The Space Reduction Method based on Taguchi's DOE(Design Of Experiment) is used as a general optimization tool in this study. The computational experimental verification of the methodology was partially carried out for a can model of Cavallero Plastics Incorporation, U. S. A. Applied to production, this study will be of immense value to companies in reducing the product development time and enhancing the product quality.

• Transactions of Materials Processing
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• v.8 no.1
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• pp.22-28
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• 1999

The explicit and implicit time integration methods are applied effectively to analyze sheet metal stamping processes, which include the forming stage and the springback stage consecutively. The explicit time integration method has better merits in the forming stage including highly complicated three-dimensional contact conditions. By contrary, the implicit time integration method is better for analyzing springback since the complicated contact conditions are removed and the computing time to get the final static state is short. In this work, brief descriptions of the formulation and the factor study for springack simulations are presented. Further, the simulated results for the S-rail and the roof panel stamping processes are shown and discussed.

• Journal of Korean Society for Quality Management
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• v.45 no.4
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• pp.1003-1020
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• 2017

Purpose: The purpose of this study is to find the optimum working conditions for spot welding of wire Cu alloys to achieve high-level quality. The parts subject to spot welding are brush card assemblies, which are the main module of the electric movement method of the car seat. Methods: In this study, the signal-to-noise ratio(SN ratio) and the loss function [L(y)] are used as Taguchi method for dynamic characteristics. Results: The results of the study are as follows. First, the analysis of variance using SN ratio showed 6 significant factors(p = 0.1% or less) among 7 factors except press force. Second, the optimal design of the dynamic characteristics is the tip exchange cycle: 50,000 ea., the welding time is 110 ms, the pressing force is 11 kgf/cm2, the rise time is 40 ms, and the tip dressing is 3,000 ea., Tip angle is 12o and electric current is 1,800 A. Conclusion: The validity of the spot welding process of the manufacturer's brush card assembly was verified and proved to be consistent with the study results. The results of this study are expected to standardize the welding conditions and guarantee the quality level required by the customers.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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• pp.195-198
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• 2009

In this study, in order to get the forming limit of AHSS sheet in the negative minor strain region, the shapes of die corner and drawbead are redesigned by employing the Taguchi's design of experiment method and the FEM forming simulation. With the redesigned FLD tool, the forming limit tests of automotive multi-phase(Dual Phase and Complex Phase) steel sheets which induce the normal fractures on the blank are performed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.10a
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• pp.345-348
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• 2008

Metallic bipolar plate for molten carbonate fuel cell(MCFC) is composed of the shielded slot plate and the center plate. Among these, the center plate plays an important role in gas sealing. Therefore, manufacturing of the center plate is considered one of the key issues in MCFC. The center plate is manufactured by bending process. In bending process, springback and recoiling are two main problems. The aim of this article is to optimize the bending process of the center plate regardless of springback and recoiling. To achieve this goal, we proposed the punch having step to reduce springback and recoiling. Using finite element method and $L_9$ orthogonal array, we determined the main factors in the center plate bending process. And we found the optimal bending process condition for the MCFC center plate.

• KIEE International Transaction on Electrical Machinery and Energy Conversion Systems
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• v.3B no.2
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• pp.84-89
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• 2003

The finite element method (FEM) is typically used in the process of motor design. However, the FEM requires computation time, Therefore, decreasing the number of FEM simulations may also decrease the simulation cost. Several optimal design methods overcoming this problem have been recently studied. This paper investigates the optimal design of the magnet pole of a BLDC motor through reducing simulation cost. The optimization minimizes the magnet volume and limits the average and cogging torques to certain values. In this paper, the response surface methodology and Taguchi's table for reducing the number of FEM simulations are used to approximate two constraints. The optimization result shows that the presented strategy is satisfactorily performed.

• Transactions of Materials Processing
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• v.19 no.5
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• pp.305-310
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• 2010

Recently industry of motor vehicle is making a gradual progress of automotive electric components. According to this step, wire harness equipped at motor vehicle is also increased. The most important component at the wire harness is electric connector. At the manufacturing process of electric connector, exactly at the crimping process, design variables, such as clamping-height, clamping-width and clamping die shape are critical parameters to assure satisfactory harness shape in clamping process of electric connector. In this study we have performed FEM simulation for clamping process and clarified the effect of design variables on compression rate of wire.

• Proceedings of the KIEE Conference
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• 1998.07f
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• pp.2060-2063
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• 1998

The proper placement of work-coil is needed for heating the interior of an IH rice cooker uniformly. It is possible that the flavor of rice is better by heating it through the optimal placement of the work-coil of the IH rice cooker. This paper describes the procedure and the result of finding the optimal placement of the work-coil by analyzing the properties of the rising temperatures of the interior through Taguchi Method.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.39 no.9
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• pp.923-928
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• 2015

In this paper, we propose an ultrasonic magnetic abrasive polishing (US-MAP) technique to effectively machine a high-strength material, and we prove the efficiency of hybrid finishing. We use Taguchi's experimental method to determine the influence of each parameter. Based on the results, US-MAP exhibited a higher polishing efficiency than traditional MAP, and a suitable frequency for hybrid finishing was 28 kHz. When investigating the effect of the parameters on the surface roughness, the ultrasonic amplitude had the greatest effect. However, when machining with $55-{\mu}m$ amplitude, the machining efficiency decreased as the magnetic flux density varied.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.657-663
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• 2018

In this study, shape optimization was performed to improve the vibration isolation capability of an anti-vibration rubber assembly, which is used in the field option cabin of agricultural tractors. A uniaxial tension test and biaxial tension test were performed to characterize the hyper-elastic material properties of rubber, and the data were used to calibrate the material model used in the finite element analyses. A field test was performed to quantify the input excitation from the tractor and the output response at the cabin frame. To account for the nonlinear behavior of rubber, static analyses were performed and the load-displacement curve of rubber was derived. The stiffness of the rubber was calculated from this curve and input to the harmonic analyses of the cabin. The results were verified using the test data. Taguchi's parameter design method was used to find the optimal shape of the anti-vibration rubber assembly, which indicated a shape with reduced stiffness. The vibration of the cabin frame was reduced by the optimization by as much as 35% compared to the initial design.