• 대한기계학회:학술대회논문집
• /
• 대한기계학회 2001년도 추계학술대회논문집A
• /
• pp.871-875
• /
• 2001

Laser photolithography technique is useful for fabricating micro-patterns of silicon wafers. In this work, the laser photolithography micromachining technique is optimized based on Taguchi method. Sensitivity analysis was performed using laser scanning speed and laser power level as the parameters. The results show that for the photoresist used in this work, a laser scan speed of $70{\mu}m/s$ at 50mW laser power gives the best result.

• Journal of Electrical Engineering and Technology
• /
• 제2권1호
• /
• pp.112-117
• /
• 2007

a parametric investigation was conducted to evaluate the effect of the laser beam for plastic adhesion. To determine the best condition for plastic adhesion, the $CO_2$(wavelength $10.6{\mu}m$) and nd:yag(wavelength $10.6{\mu}m$) laser were experimented with. From the experiment results obtained, the nd:yag laser was revealed to be the most suitable for plastic adhesion. In this study, three adhesion parameters such as input power level, working time of laser beam and pps(pulse per second) were systematically adjusted for suitable adhesion. From these experiments, it was observed that the target plastic melted and was evaporated by the nd:yag laser. Furthermore, the relationships between adhesive surface by laser beam and above three parameters were discovered.

• 대한용접접합학회:학술대회논문집
• /
• 대한용접접합학회 2004년도 추계학술발표대회 개요집
• /
• pp.73-75
• /
• 2004

The purpose of this study is to optimize Nd:YAG laser welding parameters to seaz a Rf source into a Ti micro capsule. Ti tube ends can be sealed as some length of ぉbe end is melted and coalesced. The exact control of the melted length is the most important to get sound sealing. The Nozzle type, tube rotating speed, tilt angle, focal position, pumping voltage, pulse frequency and pulse width were selected as the Nd:YAG laser welding Parameters. These Parameters were optimized by the Taguchi experimental method using 115 orthogonal array. Appearance and cross section of the seated tube ends were examined by SEM.

• 한국레이저가공학회지
• /
• 제12권3호
• /
• pp.14-17
• /
• 2009

The laser welding was performed for the flange joint of two overlapped coaxial circular pipes which serve as the inlet and connector pipes of STS 316L. The laser welding test finally resulted in a good penetration depth of 1.8 to 2.0 mm. On the way to get the good welding quality, two important parameters were found to be optimized. One is the focal positioning which is the offset of the laser beam focus to the exact welding seam line, which is more critical in the inner flange laser welding. When the beam spot size was deviated more than $200\;{\mu}m$ from the seam line, welding of two pipes is failed. The other is a gap size since a certain amount of gap is inevitable due to fabrication tolerance, or artificial allowances for smooth insertion of a pipe. However, it is required to restrict the gap allowance within 0.2mm to avoid undesirable undercut on a welding bead.

• 한국정밀공학회지
• /
• 제20권7호
• /
• pp.44-55
• /
• 2003

The Nd:YAG laser process is known to have high speed and deep penetration capability to become one of the most advanced welding technologies. This paper describes the machining characteristics of SM45C carbon steel welding by use of an Nd:YAG laser. In spite of its good mechanical characteristics, SM45C carbon steel has a high carbon contents and suffers a limitation in the industrial application due to the poor welding properties. The major process parameters studied in the present laser welding experiment were position of focus, travel speed and laser power. Optical microscope and SEM were used to investigate the microstructures of the welded zone. The experimental results showed that penetration depth of the welding process increases with laser power. Both the microstructural investigation and the theoretical calculations indicated that materials undergoes a very high heating and cooling cycle during welding process. It was also found that the austenite nucleation takes place at the initial stage and the completion temperature of austenite transformation is much higher than in the case of the arc welding.

• 한국생산제조학회지
• /
• 제20권5호
• /
• pp.646-652
• /
• 2011

Recently, lots of automobile part manufacturers try to increase glass fiber content of their plastic parts to improve strength and impact-resistance. For this reason, injection mold requires high hardness and wear-resistant. Laser surface treatment is used to improve characteristics of wear and to enhance the fatigue resistance for injection mold. In this paper, high carbon steel (HP4MA) for injection mold material was heat-treated to harden surface by using high power diode laser (HPDL). To find the process parameters for laser surface treatment of HP4MA, many experiments are carried out as changing the parameters of surface temperature and travel speed of laser. From the results of the experiments, it has been shown that the maximum average hardness is approximately 711~739 Hv when the temperature and the travel of laser are $1,050^{\circ}C$ and 2 mm/sec.

• 한국정밀공학회지
• /
• 제32권9호
• /
• pp.773-779
• /
• 2015

The laser Powder Bed Fusion (PBF) system is currently recognized as a leading process. Due to the various materials employed such as thermoplastic, metal and ceramic composite powder, the application's use extends to machinery, automobiles, and medical devices. The PBF system's surface quality of prototypes and processing time are significantly affected by several parameters such as laser power, laser beam size, heat temperature and laminate thickness. In order to develop a more elaborate and rapid system, this study developed a new PBF system and sintering process. It contains a 3-axis dynamic focusing scanner system that maintains a uniform laser beam size throughout the system unlike the $f{\theta}$ lens. In this study, experiments were performed to evaluate the effects of various laser scanning parameters and fabricating parameters on the fusion process, in addition to fabricating various 3D objects using a PA-12 starting material.

• Advances in materials Research
• /
• 제13권1호
• /
• pp.1-18
• /
• 2024

The present experimental investigation focuses on finding optimal parametric data-set of laser micro-drilling operation with minimum taper and Heat-affected zone during laser micro-drilling of Carbon Nanotube/Epoxy-based composite materials. Experiments have been conducted as per Box-Behnken design (BBD) techniques considering cutting speed, lamp current, pulse frequency and air pressure as input process parameters. Then, the relationship between control parameters and output responses is developed using second-order nonlinear regression models. The analysis of variance test has also been performed to check the adequacy of the developed mathematical model. Using the Response Surface Methodology (RSM) and an Accelerated particle swarm optimization (APSO) technique, optimum process parameters are evaluated and compared. Moreover, confirmation tests are conducted with the optimal parameter settings obtained from RSM and APSO and improvement in performance parameter is noticed in each case. The optimal process parameter setting obtained from predictive RSM based APSO techniques are speed=150 (m/s), current=22 (amp), pulse frequency (3 kHz), Air pressure (1 kg/cm²) for Taper and speed=150 (m/s), current=22 (amp), pulse frequency (3 kHz), air pressure (3 kg/cm²) for HAZ. From the confirmatory experimental result, it is observed that the APSO metaheuristic algorithm performs efficiently for optimizing the responses during laser micro-drilling process of nanocomposites both in individual and multi-objective optimization.

• 한국레이저가공학회지
• /
• 제16권1호
• /
• pp.15-19
• /
• 2013

For numerical simulation of the deformation and residual stress development in metals during laser peening, the constitutive equations describing material behavior at various strain rates and plastic properties at high strain rate impact conditions are prerequisite. However, these parameters are often unknown for various engineering materials. In this study, the parameters of Johnson-Cook constitutive equation of duplex stainless steel were determined by comparing the residual stress profile predicted by numerical simulation using trial values and the measured residual stress profile with x-ray diffraction.

• 제어로봇시스템학회논문지
• /
• 제4권1호
• /
• pp.82-87
• /
• 1998

In this study, the theoretical resolution analysis of an active vision system using laser range finder is performed for surrounding recognition and 3D data acquisition in unknown environment. In the result, the resolution of range data in laser range finder is depend on the distance between lens center of CCD camera and light emitter, view angle, beam angle, and parameters of CCD camera. The theoretical resolutions of the laser range finders of various types which are based on parameters effected resolution are calculated and experimental results are obtained in real system.