• Journal of Power System Engineering
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• v.14 no.6
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• pp.35-40
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• 2010

This article deals with the numerical analysis results of stiffness of diaphragm spring used in the clutch of a manual transmission. In order to investigate the relationship of the force and displacement in a diaphragm spring, we have established a numerical model of diaphragm spring using a well-known analytic model of Belleville spring and a cantilever beam model for the finger part of diaphragm spring. Using the stress and strain relations of Belleville spring and cantilever beam, we propose the analytic equation of motion of diaphragm spring for the use of a clutch automated actuator in an automated manual transmission. The proposed analytic model represents the typical dynamic characteristics of diaphragm spring along with the release bearing travel. And it is characterized in a closed-form equation, therefore it can be used for the further study of development of actuator and control law of clutch automating mechanism.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2003.05a
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• pp.985-990
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• 2003

With the rotational speed of the hard disk drive (HDD) increased, the low frequency structural vibration induced by the unbalance force gives rise to the structure home noise of the personal computer, and finally degrades the noise quality. As the unbalance of the hard disk drive is decided by the mechanical assembly allowance between clamping and platter disk, there is limit to control this unbalance by the improved assembly method. To improve the noise and vibration performance of PC, basically the unbalance of HDD needs to be measured absolutely and reduced during the stage of the disk assembly. This study introduces the HDD unbalance measurement methods of the absolute magnitude based on the mobility concept, and the unbalance location information with the acceleration orbit.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.5
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• pp.462-468
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• 2009

In this study, a workpiece-chucking device that generates a chucking force from a shape memory alloy is introduced. This paper first presents train procedure to transform a commercial one-way shape memory alloy into a two-way shape memory alloy, which makes unclamping mechanism of the chucking device simpler than that using the one-way shape memory alloy Second, it describes a conceptual design of the workpiece-chucking device using the two-way type shape memory alloy. Third, it presents a prototype and its chucking characteristics, such as time-response of clamping/unclamping operations and a relationship between temperatures and chucking forces. Finally, it describes a mill-machining test conducted with the prototype. The results confirm that the proposed workpiece-chucking device is feasible for micro machine-tools.

• Design & Manufacturing
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• v.11 no.2
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• pp.9-14
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• 2017

The design and manufacturing tehcnology of IC sockets beyond 0.3mm pitch were presented. We compared the developed IC socket with the conventional one especially on the core metal-insulation part. Advanced machining techniques were employed to provide high precision. Our wire electrodischarge machining and high speed machining centers were able to maintain the micro-scale precision. We performed an injection molding analysis using a commercial analysis tool to predict the performance of the developed IC socket. We found that the solidification of the plastic resin and the high level of the clamping force are responsible for the defects such as incomplete filling and short shot. From these results, we modified the IC socket and successfully remove the defects. We were also able to find out that the new design socket needs less maintenance cost.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2007.06a
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• pp.44-44
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• 2007

New inchworm type piezoelectric actuator design, which can reduce the number of the piezoelectric body for manufacturing inchworm type actuator, is suggested in this work. Inchworm type actuator consists of three or more piezoelectric bodies, on the other hand the new-designed inchworm type actuator has only one piezoelectric body. The one piezoelectric body that size is $2\;{\times}\;2\;{\times}\;4\;[mm^2]$ (DWL) has 2 clamping part and 1 extending part. The size of the new-designed actuator with one piezoelectric body is $5\;{\times}\;6\;{\times}\;9\;[mm^2]$ (DWL). The new-designed inchworm type actuator performed the operation at a cycle (6 steps) of $0.3{\mu}m$ per $33.3{\mu}s$ and a generated force of 0.6N.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2005.09a
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• pp.17-22
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• 2005

The residual birefringence in molded plastic parts can be divided into two kinds of residual birefringence, i.e., the flow induced residual birefringence produced in flowing stages and the thermally induced residual birefringence produced in cooling stage. In this paper, the effect of new injection-press molding process with normal injection mold, i.e. I) injection-compression mode, ii) injection-press mode, on the distribution of birefringence was studied. It was found that the values of the birefringence was reduced at i) low clamping force and ii) longer mold opening length by injection-press molding.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.10a
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• pp.781-785
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• 2005

Cutting forces and tool deflection in end milling are represented as the closed form of tool rotational angle and cutting conditions. The discrete cutting forces caused by tool entry and exit are continued using the Fourier series expansion. Tool deflection is predicted by direct integration of the distributed loads on cutting edges. Cutting conditions, tool geometry, run-outs and the stiffness of tool clamping pan are considered for cutting forces and tool deflection estimation. Compared to numerical methods, the presented method has advantages in short prediction time and the effects of feeding and run-outs on cutting forces and tool deflection can be analyzed quantitatively. This research can be effectively used in real time machining error estimation and cutting condition selection for error minimization since the ferm accuracy is easily predicted by tool deflect ion curve.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.9
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• pp.119-126
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• 2004

In this paper, we design a wedge type rail clamp which can protect container crane from a sudden strong blast with constant clamping force regardless of the operating period. When we design wedge type rail clamp, it is important to determine the angle of wedge and analyze a contact condition of roller and wedge so that we might develop a wedge type rail clamp for parking devices of port cargo working system with variable capacity. Therefore, this paper suggests a process to decide wedge angles within feasible range which could be obtained using load analysis and FEA of wedge type rail clamp

• Current Applied Physics
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• v.18 no.11
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• pp.1451-1457
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• 2018

Injection compression molding (ICM) is an advantageous processing method for producing thin and large polymeric parts in a robust manner. In the current study, we employed the ICM process for an energy-related application, i.e., thin and large polymeric battery case. A mold for manufacturing the battery case was fabricated using injection molding. The filling behavior of molten polymer in the mold cavity was investigated experimentally. To provide an in-depth understanding of the ICM process, ICM and normal injection molding processes were compared numerically. It was found that the ICM had a relatively low filling pressure, which resulted in reduced shrinkage and warpage of the final products. Effect of the parting line gap on the ICM characteristics, such as filling pressure, clamping force, filling time, volumetric shrinkage, and warpage, was analyzed via numerical simulation. The smaller gap in the ICM parting line led to the better dimensional stability in the finished product. The ICM sample using a 0.1 mm gap showed a 76% reduction in the dimensional deflection compared with the normal injection molded part.

• Journal of the Korea institute for structural maintenance and inspection
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• v.15 no.2
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• pp.136-143
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• 2011

The oversized and slotted holes are frequently required for the built-up in construction sites. The foreign provisions specify the reduction of the slip load subjected to the size of bolt holes and the direction of load. There are no domestic building codes and researches on the bolt holes. Therefore, it is necessary to evaluate a change of joint strength quantitatively according to the bolt-hole size and surface condition by means of experiment. This study was conducted to evaluate the slip load subjected to the size of bolt holes, and measured on a change of clamping force of high strength bolts during 168 and 800 hours to analyze the trend of relaxation after fastening bolts. Torque shear bolts defined on KS B 2819 was used for the specimen. Test results exhibit that the variation on the slip load of the others was below 10% by contrast with the standard hole and the highest rate of relaxation was 2.66% of the initial clamping force at the case of the long-slotted hole of 2.5D.