• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.27 no.6
• /
• pp.1007-1013
• /
• 2003

As environmental restriction kas continuously become more strict, machining technology has emphasized on development of environment-friendly technology. In cutting technology, it has been well recognized that cutting fluids might have undesirable effects on workers health and working environment. In this study, compressed cold air was used as a replacement for conventional cutting fluids. The cooling effect on cutting tool was analyzed using the finite element method and the computational fluid dynamics. This study focused on the temperature simulation of cutting tool by real flow analysis of cold air. The maximum flow rate and the minimum temperature of compressed cold air are 300ι/min and -30$^{\circ}C$ respectively. To compare the simulation and experimental results, inner temperature of the cutting tool was measured with the thermocouple embedded in the insert. The results show that the analysis of cutting temperature using FEM and CFD is resonable, and the replacement of cutting fluid with cold air is available.

• Design & Manufacturing
• /
• v.10 no.3
• /
• pp.1-7
• /
• 2016

In the semiconductor industry the memory and chip were developed to high density memory and high performance chip, so circuit design was also high integrated and the test bed was needed to be thin and fine pitch socket. LGA(Land Grid Array) IC socket with thin wall thickness was designed to satisfy this requirement. The LGA IC socket plastic part was manufacture by injection molding process, it was needed accuracy, stiffness and suit resin with high flowability. After injection molding process the side gates were needed to remove for further assembly process. ln this study, the cold press cutting process was applied to remove the gates. For design of punch and die, the cold press cutting analysis was implemented by$DEFORM-2D^{TM}$ ln consideration of the simulation results, an adequate punch and die was designed and made for the cutting unit. In order to verify the performance of cutting process, the roughness of cutting section of the part was measured and was satisfied in requirement.

• Journal of Welding and Joining
• /
• v.13 no.4
• /
• pp.113-121
• /
• 1995

This study deals with the quality and the optimum range of laser cutting process. Cold rolled steel sheets for automobile application were cut by a high power CO$_{2}$ laser system with beam quality of TEM$_{\infty}$ mode. Both process parameters such as travel speed and assist gas pressure, and quality factors were considered to optimize the laser cutting. It was revealed that the thinner the sheet thickness, the less effect of oxidation energy for contributing the cutting process. High speed photographs demonstrated that molten spot on the cut surface moved in a random and vigorous manner according to its viscosity and the flowing direction of assist gas, which resulted in so called striation. Laser cutting produced a very smooth surface of average roughness(Ra) about less than 1.5.mu.m at the optimum range. It was also shown that the characteristics of dross formation was influenced by the flowing durection of assist gas and the fluidity of molten metal drop..

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2009.05a
• /
• pp.135-138
• /
• 2009

In this study we investigate the machining characteristics of tool material for cold forging by using the machining center. The test was in the SKD62 cold forging material by 2-edge endmill with cutting fluid. The coating conditions are depth of cut 1,2,3mm. WC-endmill, federate 20mm/min, cutting velocity 20m/min. The surface roughness increase as the depth of cut increase. Also cutting force increase whiles the depth of cut increase.

• Journal of Welding and Joining
• /
• v.14 no.5
• /
• pp.59-68
• /
• 1996

This study was aimed to characterize the laser cutting process for the cold rolled stainless steel sheet. The principal process parameters of the cutting process were applied to both the continuous wave form and the pulsed wave form for the laser output mode. The laser-oxygen cutting process and the laser-nitrogen cutting process were also considered to characterize the quality and efficiency of the cutting process. The laser-oxygen cutting process revealed the better productivity than the laser-nitrogen cutting process, since the laser energy and the exothermic oxidation energy exerted on the laser-oxygen cutting process simultaneously during the entire cutting process. However, the straightness of the cutting section, which was considered as the most important factors, was inferior to that of the laser-nitrogen cutting process due to the formation of chromum oxide on the cutting surface. Frequency and duration of the pulsed wave form act as the main factors for the better quality, When the frequency increased from 100 Hz to 200 Hz and the duty increased from 20% to 40%, the quality factors such as the height of dross and the surface roughness were improved remarkably. The increase in the frequency from 200 Hz to 300 Hz, on the other hand, revealed the less effective in the cutting quality.

• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.9
• /
• pp.31-36
• /
• 2001

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.968-973
• /
• 2003

As environmental restrictions have continuously become more strict, it has emphasized development of environment-friendly technologies. In cutting technology, it has been well recognized that cutting fluids might have undesirable effects on worker's health and working environment and, hence, recently there have been numerous attempts to minimize harmful effects of cutting fluids on environments. To minimize the use of cutting fluids in machining, conventional cutting fluids have been replaced with the technologies of pressurized cold air and minimum quantity lubrication(MQL). Compared with milling, turning is a continuous cutting process, where tools are continuously heated up and lack of lubricity could lead to tool wear and deteriorated surface roughness. In this study, it has been investigated how tool wear and surface roughness could be affected by cutting conditions, supply and cooling methods. The experimental results show that MQL technology is able to minimize harmful effects of conventional cutting fluids.

• Nuclear Engineering and Technology
• /
• v.55 no.11
• /
• pp.4181-4190
• /
• 2023

Nuclear power plants are subjected to various processes during decommissioning, including cutting, decontamination, disposal, and treatment. The cutting of massive bio-shields is a significant step in the decommissioning process. Cutting is performed near the target structure, and during this process, workers are exposed to potential radioactive elements. However, studies considering worker exposure management during such cutting operations are limited. Furthermore, dismantling a nuclear power plant under certain circumstances may result in the unnecessary radiation exposure of workers and an increase in secondary waste generation. In this study, a cutting scenario was formulated considering the bio-shield as a representative structure. The specifications of a standard South Korean radioactive waste disposal drum were used as the basic conditions. Additionally, we explored the hot-to-cold and cold-to-hot methods, with and without the application of polishing during decontamination. For evaluating various scenarios, different cutting time points up to 30 years after permanent shutdown were considered, and cutting speeds of 1-10nullm²/h were applied to account for the variability and uncertainty attributable to the design output and specifications. The obtained results provide fundamental guidelines for establishing cutting methods suitable for large structures.

• Journal of the Korean Society for Precision Engineering
• /
• v.19 no.10
• /
• pp.221-226
• /
• 2002

As environmental restriction has continuously become more strict, machining technology has emphasized on development of environment-friendly technologies. In cutting technology, it has been well recognized that cutting fluids might have undesirable effects on workers health and working environment and, hence, recently there have been numerous attempts to minimize harmful effects of cutting fluids on environments. To minimize the use of cutting fluids in machining, conventional cutting fluids have been replaced with the technologies of pressurized cold air and minimum quantity lubrication (MQL). Compared with milling, turning is continuous cutting process, where tools are continuously heated up and lack of lubricity could lead to tool wear and deteriorated surface roughness. In this work, it has been investigated how tool wear and surface roughness could be affected by cutting conditions, supply and cooling methods. The experimental results show that MQL technology is able to minimize conventional cutting fluids.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2004.08a
• /
• pp.101-108
• /
• 2004

It is very important to diagnose state of knife and strip cutting face in real time in the side trimming process due to improvement of quality of trimming face. In this study, diagnosis system for knife and strip cutting face was developed. CCD camera was installed at the both side of strip in the entry of burr masher roll. This system offer to operator the diagnosis result that was analyzed image obtained from CCD camera. As a result, bad quality of trimming face is decreased below 1/10 and knife breakage is detected $100\%$.