• 대한기계학회논문집A
• /
• 제26권10호
• /
• pp.1982-1988
• /
• 2002

Micro-injection molding and microfluidic devices with the help of MEMS technologies including the LIGA process are expected to play important roles in micro-system industries, in particular the bio-application industry, in the near future. Understanding fluid flows in micro-channels is important since micro-channels are typical geometry in various microfluidic devices and mold inserts for micro-injection molding. In the present study, Part 1, an experimental investigation has been carried out to understand the detailed flow phenomena in micro-channel filling process. Three sets of micro-channels of different thickness (40um,30um and 2011m) were fabricated using SU-8 on silicon wafer substrate. And a flow visualization system was developed to observe the filling flow into the micro-channels. Experimental flow observations are extensively made to find the effects of pressure, inertia force, viscous force and surface tension. A dimensional analysis for experimental results was carried out and several relationships A dimensionless parameters are obtained.

• 한국정밀공학회지
• /
• 제15권12호
• /
• pp.55-61
• /
• 1998

Recently, the needs of machining technologies of very small parts have been increasing with advent of micro-revolution. These technologies have mostly used the method applied to semi-conductor production process such as LIGA, etc. But they have serious difficulties to settle down in terms of workpiece materials, machining thickness, 3-dimensional structure. Therefore. mciro-machining technology using EDM(Electrical Discharge Machining) was proposed. It is very difficult to machine the micro-parts (microshaft, microhole) using conventional machining. Micro-machining using BDM can machine the micro-parts easily because it requires little machining force. This MEDM(Micro-EDM) need the capabilities to move a electrode and control a discharge energy precisely, and the gap control strategy to maintain the optimal discharge condition is necessary. Therefore, in this study, the new EDM machine with high precision motion stage and high-performance EDM device was developed. Using this MEDM machine, we have machined microshaft and microhole with various shapes and sizes.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2001년도 춘계학술대회 논문집
• /
• pp.934-937
• /
• 2001

It is well-known that the micro fabrication technology of micro parts are the high energy beam or silicon-based micro machining method such as LIGA Process, Laser machining, photolithography and etching technology. But, for fabricating complex 3-D structure it is better to use mechanical machining. This machining method by the mechanical machine tool with nanometer accuracy is getting attention in some field-especially micro optics machining such as grating, holographic lens, micro lens array, fresnel lens, encoder disk etc.. In this study, we survey the micro fabrication by mechanical cutting method and set up the mechanical micro machining system. And we carried out micro cutting experiments for micro parts with v-shape groove.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 추계학술대회 논문집 학회본부 C
• /
• pp.1157-1159
• /
• 1999

A new method was developed to fabricate 1-3 piezo composite, a part of ultrasonic transducer. PZT rod arrays were made by pressing PZT green sheet with LIGA mold, and were sintered. Its dielectric constant and electro-mechanical coupling coefficient showed 4000 and 55% at 1kHz, respectively. So, PZT rod arrays made by means of this process can be applied to ultrasonic transducer.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2006년도 춘계학술대회 논문집
• /
• pp.161-162
• /
• 2006

Micro-stereolithography technology is used for fabricating of 3-dimensional micro-structures. In some cases, this technology is more economical and simpler than MEMS and LIGA technologies based on semiconductor process. In this research, the micro-sterolithography apparatus that is more economical and simpler than current micro-stereolithography apparatus was developed. This apparatus uses UV lamp and optical fiber as a light source and tight delivery system, respectively.

• Design & Manufacturing
• /
• 제2권3호
• /
• pp.6-9
• /
• 2008

This paper describes the process of structure analysis and injection molding analysis to manufacture the forming injection dies for huge glass insert. Factors such as filling time, filling pressure, material temperature, shrinkage, warpage were investigated by using the analysis software, Moldflow. Runner system and cavity structure were designed and manufactured through the results of deformation analysis data for glass insert. Filling time and filling pressure were analyzed in 3.756sec and 43.37MPa.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 G
• /
• pp.3292-3294
• /
• 1999

In this paper, electrostatic scanner mirror for optical pick-up head is designed and fabricated. The mirror size is $20{\mu}m{\times}2400{\mu}m{\times}2400{\mu}m$ and torsional beam size is $10{\mu}m{\times}20{\mu}m{\times}500{\mu}m$. Static deflection angle is calculated ${\pm}0.4$ degrees when the maximum driving voltage is 20 V. Silicon mirror was fabricated using KOH etching and deep RIE. For passivation of the patterned mirror from KOH solution, parylene thin film was used and its usefulness has been verified. Driving electrode was fabricated using UV LIGA process. Mirror and electrode were bonded.

• Design & Manufacturing
• /
• 제2권5호
• /
• pp.1-4
• /
• 2008

LCD-BLU (Liquid Crystal Display - Back Light Unit) is one of kernel parts of LCD unit and it consists of several optical sheets(such as prism, diffuser and protector sheets), LCP (Light Guide Plate), light source (CCFL or LED) and mold frame. The LGP of LCD-BLU is usually manufactured by forming numerous dots with $50-200{\mu}m$ in diameter on it by erosion method. But the surface of the erosion dots of LGP is very rough due to the characteristics of the erosion process during the mold fabrication, so that its light loss is high along with the dispersion of light into the surface. Accordingly, there is a limit in raising the luminance of LCD-BLU. Especially, the negative and positive micro-lens pattern fabricated by modified LiGA with thermal reflow process was applied to the optical design of LGP.

• Design & Manufacturing
• /
• 제2권6호
• /
• pp.1-6
• /
• 2008

Recently, many researches have been done to improve optical performance of LCD-BLU(Back Light Unit). One of the most important parts in LCD-BLU is LGP(Light Guiding Plate). Micro-patterned LGP is known to have different optical characteristics depending on their shape, pattern density and size, etc. In the present study, a micro-optical patterned LGP mold was fabricated using LiGA process. The difference in the optical characteristics between positive and negative patterned LGP's was investigated by fixing the density, location and size of each pattern. It was found that the negative patterned LGP showed better optical characteristics than positive one.

• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 춘계학술대회논문집C
• /
• pp.47-52
• /
• 2001

Micro-injection molding and microfluidic devices with the help of MEMS technologies including the LIGA process are expected to play important roles in. micro-system industries, in particular the bioapplication industry, in the near future. Understanding fluid flows in micro-channels is important since micro-channels are typical geometry in various microfluidic devices and mold inserts for micro-injection molding. In the present study, both experimental and numerical studies have been carried out to understand the detailed flow phenomena in micro-channel filling process. Three sets of micro-channels of different thickness were fabricated and a flow visualization system was also developed to observe the filling flow into the micro-channels. Experimental flow observations were extensively made to find the effects of channel width and thickness, and effects of surface tension and volume flow rate and so on. And a numerical analysis system has been developed to simulate the filling flow into micro-channels with the surface tension effect taken into account. Discussed are the flow visualization experimental observations along with the predictability of the numerical analysis system.