• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.24 no.3
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• pp.334-341
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• 2015

This paper summarizes the results of an investigation into the environmental factors that have an indirect impact on parts quality, as well as those process variables and modeling information that have a direct impact. The effects of strength, surface hardness, roughness, and accuracy of shape, that is, qualities that users generally need to know, were evaluated with laminating direction experimentally. The 3D printing methods used in this experiment were fused deposition modeling (FDM), stereolithography apparatus (SLA), selective laser sintering (SLS), 3D printing (3DP) and laminated object manufacturing (LOM). The goal was to achieve a high standard of quality control and product quality by optimizing the fabrication process.

• Korean Journal of Applied Biomechanics
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• v.12 no.2
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• pp.407-415
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• 2002

Athletic products must meet the needs of athletes and the demands imposed by sports through innovative design. These needs of athletes and requirements of sports are performance, protection and comfort related. In depth knowledge of anatomy and physiology, etiology of commonly reported injuries, and lower extremity mechanics form the basis of product creation/engineering. Game analysis which entails time and frequency surveys of the skills performed during a game, interviews with athletes and coaches, and discussions with medical staffs are used to identify the skills that are critical to the needs of athletes. In lab full biomechanical analyses of these skills and/or physiological responses of the athletes lead to clear functional criterions that serve as guidelines to be met by the design team. The concepts created by the design team are in turns subjected to the same battery of biomechanical analyses. The learning gathered through this pluridisciplinary process is used to further evolve design concepts. The evolution-testing loop is repeated until biomechanical and/or physiological, mechanical and perceptual tests indicate that the design concept meets the established functional design criterions. At that time, the design concepts is ready for manufacturing research and development. Additional biomechanical and physical tests are performed through that phase to confirm that the manufacturing processes preserve the functionality of the design concept. Durability and long term performance of production samples are evaluated through a final three month long weartest program. A rigorous research/testing program is crucial to create and engineer sport products that meet the performance, protection.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.11
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• pp.63-68
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• 2019

The dimensional quality of flexible foams is often difficult to be evaluated through general machine vision inspection methods due to the free deformation of the outer shape. For the evaluation of the dimensions of flexible foams, methods of estimating the size of the product through the expansion rate of the product surface are evaluated. Specimens with various dimensions and surface gratings are prepared, and the degree of surface expansion is measured through machine vision. The correlation, between the measured surface grid size and the actual size of test specimens, is analyzed. We further analyze the correlation between the size of test specimens and the position of the surface grid. This study provides a basis for estimating the actual dimensions of specimens by measuring the surface expansion of flexible foams.

• Textile Coloration and Finishing
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• v.30 no.2
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• pp.107-116
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• 2018

Simplification of the manufacturing process in shoe making is essential to improve productivity and reduce production costs. To improve the adhesion of EVA foam used as a midsole, EVA/itaconated EPDM(EPDM-g-IA)(80/20wt%) blend was prepared using Torque Rheometer-Plasti-Corder, and 1,6-hexamethylenediamine/crosslinking agent/foaming agent/additive were mixed, followed by amidation reaction and foaming to prepare EVA/EPDM-g-IA foam for shoe midsole. In this study, we investigate the effect of the content of 1,6-hexamethylenediamine(0, 0.5, 1.0, 2.0, 3.0) on the mechanical properties, water-contact angle and adhesion of EVA/itaconated EPDM foam. As the content of 1,6-hexamethylenediamine increased, mechanical properties such as tensile strength, tear strength, tensile elastic modulus, hardness, and water-contact angle were lowered, but elongation at break and compression set(%) were increased. Both normal type and non-UV type adhesive strength increased with increasing diamine content. In particular, it was found that the adhesion strength of the non-UV type adhesion increased sharply with increasing diamine content. As a result, an adherend rupture occurs in a foam sample having a content of 1,6-hexamethylenediamine of 3phr. From this, it can be seen that the EVA/itaconated EPDM foam for shoe midsoles, which can be used for non-UV adhesion without primer and UV treatments, have been developed.

• Proceedings of the Korea Association of Information Systems Conference
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• 1996.11a
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• pp.145-155
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• 1996

This paper is to describe the development of nesting software for the materials cutting plan of footwear manufacturing processes. In shoes cutting process, almost of the materials cutting plan is dependent upon worker's experience. Thus, the pattern nesting by worker's experience for materials cutting is different from the real cutting results and also different from the error size of yield in degree of worker's skill. Recently, a few of domestic shoes' makers make use of oversee's nesting software. But the nesting software unfits for the domestic actual circumstances, and is complex to use, and is expensive, and is not to be interfaced with the auto cutting machine. Therefore, we have developed the economic nesting systems that are easier for novice to use and fit for the domestic circumstances, which can syncronize with the development of the auto cutting machine. The system comprises interrelated modules for materials information, nesting simulation, utility. The architecture of system, the functions of each module, and the information processing procedures of each function are discussed.

• Management Science and Financial Engineering
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• v.18 no.1
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• pp.39-48
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• 2012

This article presents a way of tackling a special class of space optimization problems that arise in a number of practical applications in industry and elsewhere. It presents an elegant solution to a problem that was considered by (Das, 2005) in optimizing storage space in warehouse of a footwear manufacturing company. In (Das, 2005), the problem was formulated as a nonlinear programming problem. In this article, it is shown that the problem can be formulated as a generalized transportation problem which is a special case of generalized network flow problems. Further, an elegant scheme is devised to handle the dynamic situation of warehousing problem which can be easily translated into a decision support system for the warehouse management system. Also, the article points out certain obscurities and gaps in (Das, 2005).

• Journal of Korea Society of Industrial Information Systems
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• v.1 no.1
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• pp.203-217
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• 1996

This paper is to describe the development of nesting software for the materials cutting plan of footwear manufacturing processes. In shoes cutting process, almost of the materials cutting plan is dependent upon worker's experience. Thus, thepattern nesting by worker's experience for materials cutting is different form the real cutting results and also different form the error size of yield in degree of worker's skill. Recently, a few of domestic shoes' makers make use of oversee's nesting software.But the nesting software unfits for the domestic actual circumstances , and is complex to use , and is expensive , and is not to be interfaced with the auto cutting machine. Therefore , we have developed the economic nesting systems that are easier for novice to use and fit for the domestic circumstances, which can synchronize with the development of the auto cutting machine. The system comprises interrelated modules for materials information, nesting simulation, utility. The architecture of system, the function of each module, and the information processing proceduresof each function are discussed.

• Fibers and Polymers
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• v.3 no.2
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• pp.80-84
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• 2002

Tension control is an important factor in producing high quality knitted products and in maintaining good processing condition. Yarn tension during knitting is subject to be affected from many elements of the machine and process parameters. Several factors including yam feeding speed, feeding angle, and needle gauge that are considered to influence on the tension variation were investigated. Yam feeding speed did not show high contribution to the tension variation but feeding angle of yam did show high correlation with the tension. No or negative correlation of the tension with needle gauge was found from the results. In order to keep well-determined process condition in the knitting manufacturing, it is strongly suggested that all knitting elements and parameters should be in the integrated control circumstance.

• 제어로봇시스템학회:학술대회논문집
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• 2004.08a
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• pp.1469-1473
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• 2004

We suggest how to program off-line robot path along shoes' outsole shape in the footwear buffing process by a 5-axis microscribe system like robot arms. This microscribe system developed consists a 5-axis robot link with a turn table, signal processing circuit, PC and an application software program. It makes a robot path on the shoe's upper through the movement of a microscribe with many joints. To do this, first it reads 5-encoder's pulse values while a robot arm points a shoes' outsole shape from the initial status. This system developed calculates the encoder pulse values for the robot arm's rotation and transmits the angle pulse values to the PC through a circuit. Then, Denavit-Hartenberg's(D-H) direct kinematics is used to make the global coordinate from robot joint one. The determinant is obtained with kinematics equation and D-H variable representation. To drive the kinematics equation, we have to set up the standard coordinates first. The many links and the more complicated structure cause the difficult kinematics problem to solve in the geometrical way. Thus, we can solve the robot's kinematics problems efficiently and systematically by Denavit-Hartenberg's representation. Finally, with the coordinate values calculated above, it can draw a buffing gauge-line on the upper. Also, it can program off-line robot path on the shoes' upper. We are subjected to obtaining shoes' outline points, which are 2 outlines coupled with the points and the normal vector based on the points. These data is supposed to be transformed into .dxf file to be used for data of automatic buffing robot. This system developed is simulated by using spline curves coupled with each point from dxf file in Autocad. As a result of applying this system to the buffing robot in the flexible footwear manufacturing system, it can be used effectively to program the path of a real buffing robot.

• Fashion & Textile Research Journal
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• v.23 no.2
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• pp.290-296
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• 2021

The effect of draw ratio (8, 10, 12, 14 times) and additive CaCO₃ content (0, 0.5, 1.0, 1.5, 2.0, and 3.0 wt%) on the properties of high-performance PE monofilament was investigated in this study. As the draw ratio increased (8-14 times), the melting enthalpy (ΔHf), crystallinity, specific gravity, and tensile strength increased significantly. However, the draw ratio had little effect on the melting temperature (Tm) and crystallization temperature (Tc). The seawater fastness (stain and fade) of the hydrophobic PE monofilament prepared in this study showed an excellent grade of 4-5 in all draw ratios. To investigate the effect of the additive CaCO₃ content on the properties of high-performance PE monofilament, the draw ratio was fixed at 14 times. It was found that the tensile strength of the PE monofilament sample containing 0.5 wt% of CaCO₃ was much greater compared to the sample without CaCO₃, but the elongation of the sample containing 0.5 wt% of CaCO₃ was much less than the sample with 0 wt% CaCO₃. However, in the case of the sample containing more than 0.5 wt% CaCO₃, the tensile strength slightly decreased and the elongation slightly increased as the CaCO₃ content increased. The seawater fastness (stain and fade) of the hydrophobic PE monofilament showed excellent grades of 4-5, regardless of the amount of additives. From the above results, it was found that the maximum draw ratio of 14 times with an additive of 0.5 wt% CaCO₃ are the optimal conditions for manufacturing high-performance marine fusion materials with various fineness (denier) with high strength and low elongation.