• Transactions of Materials Processing
• /
• v.11 no.7
• /
• pp.620-627
• /
• 2002

The purpose of this paper is the development of an automated measurement system for micro spring based on the digital image processing technique. This micro spring can be used in various engineering applications such as filament, load bearing springs, hard disk suspension and many others. Main functionality of the micro spring inspection system is to measure the representative pitch of the micro spring. The derivative operators are used for edge detection in gray level image. Measurement system developed in this paper consisted of new auto feeding mechanism to take advantage of air pressure. In the process of development of the micro spring inspection system based on the image processing and analysis, strong background technology and know-how have been accumulated to measure micro mechanical parts.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2001.10a
• /
• pp.255-259
• /
• 2001

The spring constant of a micro coil spring was measured by uniaxial tensile test. The inner diameter of it is $35{\mu}m$ and the pitch size is about $23{\mu}m$. A suing constant measurement system was developed. It consists of control units, load cell units, linear stages and several specially designed jigs and fixtures. Load and displacement are measured using a commercial load cell of 1000g capacity and a magnetic scale of $0.5{\mu}m$ resolution. In this study, a method to measure the spring constant of micro coil spring is presented and the relationship between misalignment of specimen and measurement error is discussed.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2003.05a
• /
• pp.421-426
• /
• 2003

Micro-suing that used on micro mechanism should be equal to distance between pitch and correct of shape. Therefore, micro spring must make by super-precision working. But, current step of super-precision processing depends on special quality of work piece and is ineffective the aspect of cost and productivity yet. Also, to use as demandable length shearing process perform but even if make precision spring, in the aspect of quality of coil spring make difficult that produce product of good quality. Therefore, purpose of this study presented proposed process that extract the point of processing factor after perform finite element analysis applying existing sheet shearing process to suing shearing process consider cost and productivity after evaluate.

• Transactions of Materials Processing
• /
• v.17 no.8
• /
• pp.649-656
• /
• 2008

Springback is one of factors affecting precision in metal forming. Its effect is particularly prominent in bending process. In this study, bending and forging process are used in order to manufacture a micro spring with two bending region from $60{\mu}m$ diameter wire. Springback in the process lowers the precision of the micro spring. Overbending for springback compensation has wide usage in a general way. However, this method requires repeated modifications of press dies until the tolerance is allowable, which causes that production cost and time increase. In this paper, we analyzed the mechanism of springback in the forming process of the micro spring using finite element method. In addition, a simple method to control springback without modifying dies was proposed by performing numerical analysis with various parameters.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2003.11a
• /
• pp.220-225
• /
• 2003

Recent issue of optical actuator is applying to mobile device. It leads actuator to become smaller than conventional type. This paper proposes the design of micro actuator plate spring and analysis of its vibration characteristic. Considering natural frequency of spindle motor, 1st and 2nd eigenfrequency of micro actuator must avoid its natural frequency. First, magnetic circuit is designed by using fine pattern coil and magnetic force is acquired by simulation program. Then, concept design is achieved by topology optimization. From concept design, micro actuator plate spring is embodied through DOE(design of experiment). Finally, considering vibration characteristic simultaneously, optimal plate spring design is determined by RSM(response surface method).

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
• /
• v.20 no.9
• /
• pp.749-755
• /
• 2007

Recently, novel MEMS probe cards can support reliable wafer level chip test with high density probing capacity. However, manufacturing cost and process complexity are crucial weak points for low cost mass production. To overcome these limitations, we have developed micro spring structured MEMS probe card. For fabrication of micro spring module, a wire bonder and electrolytic polished gold wires are used. In this case, stringent tension force control is essential to guarantee the low level contact resistance of micro spring for reliable probing performance. For this, relation between tension force of fabricated probe card and contact resistance is characterized. Compare to conventional probe cards, developed MEMS probe card requires fewer fabrication steps and it can be manufactured with lower cost than other MEMS probe cards. Also, due to the small contact scratch patterns, we expect that it can be applied to bumping types chip test which require higher probing density.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.06a
• /
• pp.715-716
• /
• 2007

• International Journal of Precision Engineering and Manufacturing
• /
• v.6 no.4
• /
• pp.49-54
• /
• 2005

In this paper, micro structuring technique using localized electrochemical deposition (LECD) with ultra short pulses was investigated. Electric field in electrochemical cell was localized near the tool tip end region by applying pulses of a few hundreds of nano second duration, Pt-Ir tip was used as a counter electrode and copper was deposited on the copper substrate in mixed electrolyte of 0.5 M $CuSO_4$ and 0.5 M $H_2SO_4$, The effectiveness of this technique was verified by comparison with ECD using DC voltage. The deposition characteristics such as size, shape, surface, and structural density according to applied voltage and pulse duration were investigated. The proper condition was selected based on the results of the various experiments. Micro columns less than $10{\mu}m$ in diameter were fabricated using this technique. The real 3D micro structures such as micro spring and micro pattern were made by the presented method.

• Journal of the Korean Home Economics Association
• /
• v.30 no.4
• /
• pp.15-26
• /
• 1992

To investigate the seasonal effects on physiological responses of human body, clothing micro-climate, and subjective sensation, selected the cloths the most frequently dressed by men in spring and fall, and completed wearing trials in the climatic chamber. The results are as follows: 1. Rectal temp. ranged 36.8-37.1$^{\circ}C$ in either spring or fall, and no seasonal effect was found. 2. In skin temp., there was no seasonal effect in forehead, abdomen, and forearm. Skin temp. of chest was higher in spring than in fall. On the contrary, reverse was true in high and leg. Average skin temp. ranged 32.2-33.2$^{\circ}C$ in spring and 32.9-34.$0^{\circ}C$ in fall. 3. Average total sweat rate of spring, 79.4g/hr, was smaller than that of fall, 110.9g/hr. 4. Clothing temp. ranged 28.1-32.8$^{\circ}C$ in spring and 27.6-31.$0^{\circ}C$ in fall. Clothing humidity ranged 36.9-48.9% in spring and 38.2-51.1% in fall. Therefore, clothing microclimate was higher during fall than during spring. As results, skin temp. of the body core except chest did not show seasonal variation, but there was obvious seasonal variation in skin temp. of the extremities. Therefore, seasonal variation should be take into consideration in the experiments related to the cloth. In addition, standard for each season and the degree of work performance should be re-established in clothing micro-climate.

• Journal of Electrical Engineering and information Science
• /
• v.3 no.2
• /
• pp.245-250
• /
• 1998

Novel fabrication process of vertical spring for micro mirror array is proposed. The proposed fabrication process adopts a shadow evaporation process using shielding screen structure on top of the sacrificial layer. The 50${\times}$50 micro mirror arrays are fabricated using the proposed process and ceramic packaged. The static and dynamic characteristics of mirror are measured. The mirror plate touches substrate at 16V and the response time of about 16.8 ${\mu}\textrm{s}$. The resonant frequency of mirror is 16kHz. The spring thickness is calculated from static characteristic to be 1075${\AA}$.