• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.05a
• /
• pp.24-27
• /
• 2002

The environmental problems by using coolant demanded the new cooling methods. As one of them, the studies on the finding with compressed cold air and oil mist have been done. The cooling method using compressed cold air was effective through going down the temperature of compressed air supplied below $-25^{\circ}$ and increasing the amount of compressed cold air, but had not enough cooling effect due to the low performance of lubrication. Therefore, the cooling methods using oil mist newly were suggested. This method can satisfy both cooling effect and lubrication with only small amount of coolant, also have the benefit in the point of decreasing the environmental pollution. This paper focused on analyzing the grinding characteristics of the cooling method using oil mist. The grinding test according to compressed cold air, oil mist spray pressure and oil mist supply direction were done.

• Transactions of the Korean Society of Mechanical Engineers A
• /
• v.24 no.9 s.180
• /
• pp.2159-2166
• /
• 2000

Recently, high performance machining center requires special type of sealing mechanism that prevent a leakage of oil jet or oil mist lubrication system. Sealing of oil-air mixture plays important r oles to have an enhanced lubrication for performance machining center. Current work emphasizes on investigations of the air jet effect on the protective collar type labyrinth seal. To improve sealing capabilities of conventional labyrinth seals, air jet is injected against the leakage flow. In this study, an adapted model is introduced to improve sealing capability of conventional non-contact type seals. It has a combined geometry of a protective collar type and an air jet type. Both of a numerical analysis by CFD (Computational Fluid Dynamics) and experimental measurements are carried out to verify sealing improvement. The sealing effects of the leakage clearance and the air jet magnitude aic studied in various parameters. Gas or liquid has been used as a working fluid for most of nori-contact types seals including the labyrinth seal. However, it is more reasonable to regard two-phase flows because oil mist or oil jet are used for high performance spindle's lubrication. In this study, working fluid is regarded as two phases that are mixed flow of oil and air phase. Both of turbulence and compressible flow model are also introduced in a CFD analysis to represent an isentropic process. Estimation of non-leaking property is determined by amount of pressure drop in the leakage path. Results of pressure drop in the experiment match reasonably to those of the simulation by introducing a flow coefficient. Effect of the sealing improvement is explained as decreasing of leakage clearance by air jetting. Thus, sealing effect is improved by amount of air jetting even though clearance becomes larger

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.254-257
• /
• 2002

As the large Coolant amount used of a machine holds mass serious trouble recently, an environment pollution is increased, and a machine is conquering large specific gravity in an empty cost plane. It is the stage that must reexamine the parts washing that processing is later with this current way or a problem of a liquid waste treatment back. The environmental problems by using coolant demanded the new cooling methods. As one of them, the studies on the grinding with compressed cold air and oil mist have been done. The cooling method using compressed cold air was effective through going down the temperature of compressed air supplied below -$25^{\circ}C$ and increasing the amount of compressed cold air, but had not enough cooling effect due to the low performance of lubrication. Therefore, the cooling methods using oil mist newly were suggested. This method can satisfy both cooling effect and lubrication with only small amount of coolant, also have the benefit in the point of decreasing the environmental pollution. This paper focused on analyzing the grinding characteristics of the cooling method using oil mist. The grinding test according to compressed cold air and oil mist supply direction were done.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.21 no.5
• /
• pp.98-104
• /
• 2022

When processing parts, the cutting oil can improve the cooling performance of the workpiece and tool to increase the precision of the workpiece or extend the life of the tool and facilitate chip extraction. Since such cutting oil has a harmful effect on the environment and the human body due to additives such as sulfur, research on a minimum lubrication supply method using an eco-friendly oil is recently underway. The minimum lubrication supply method minimizes the amount of cutting oil used during processing and processes it, which can reduce the amount of cutting oil used, but has a problem in that cooling performance efficiency is poor. Therefore, this study conducted a study on mist cooling of lubricants to reduce the amount of cutting oil used and maximize the cooling effect of processing heat generated during tapping processing. Spray pressure, processing speed, direction, and lubricant spray amount, which are considered to have an effect on cooling performance, were set as process conditions, and the effect on temperature was analyzed by performing an experiment using the box benquin method among experiments were analyzed. Through the experimental analysis results, the optimal conditions for mist and processing that maximize the cooling effect were derived, and the validity of the results derived through additional experiments was verified. In the case of processing by applying the mist lubrication method verified through this study, it is considered that high-precision processing is possible by improving the cooling effect.

• KSTLE International Journal
• /
• v.3 no.2
• /
• pp.79-83
• /
• 2002

Sealing an oil-air mixture plays important roles to have an enhanced lubrication for high speed spindle. High speed spindle requires non-contact type of sealing mechanism. Current work emphases on the investigation of the air jet effect on the protective collar type labyrinth seal. To improve the sealing capability of conventional labyrinth seal, air jet was injected against through the leakage flow, It has a combined geometry of a protective collar type and an air jet type. Both of a numerical analysis by CFD (Computational Fluid Dynamics) and experimental measurements are carried out to verify sealing improvement The sealing effects of the leakage clearance and the air jet magnitude are studied in various parameters. The results of pressure drop in the experiment match reasonably to those of the simulation by introducing a flow coefficient Effect of sealing improvement is explained as decreasing of leakage clearance by air jetting. Thus, sealing effect is improved by amount of air jetting even though clearance becomes larger.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2002.04a
• /
• pp.32-37
• /
• 2002

High speed machining is one of most effective technologies to improve productivity. It can give great advantage for manufacture of die and Moulds. However, when the high speed machining of materials, especially in machining of micro groove, a severely thermal demage was generated on workpiece and tool. Generally, the cutting fluid is used to improve penetration, lubrication, and cooling effect. In order to rise the performance of lubrication, it contains extreme pressure agents (Cl, S, P). But the environment of work room go bad by those additive Therefore, the compressed chilly air with Oil mist system was developed to replace the conventional cutting fluid system. This paper carried out the tests to evaluate the machinability by the cutting environment in high speed micro groove machining of NAK80 (HRC40). Compressed chilly air with oil mist was ejected on the contact area between cutting edge and workpiece. The effectiveness of this developed compressed chilly air with oil mist system was evaluated in terms of tool life. The results showed that the tool life of carbide tool coated TiAIN with compressed chilly air mist cooling was much longer than with dry and flood coolant when cutting the material.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2002.10a
• /
• pp.172-175
• /
• 2002

High speed machining is one of the most effective technologies to improve productivity. It can give great advantage for manufacture of die and Moulds. However, when machining of micro groove in high speed machining a severely thermal damage was generated on workpiece and cutting tool. Generally, the cutting fluid is used to improve penetration. lubrication. and cooling effect. In order to rise the performance of lubrication. it contains extreme pressure agents (Cl, S, P). But the environment of work room go bad by those additive. Therefore, the compressed chilly air with oil mist system was developed to replace the conventional cutting fluid system. This paper carried out the tests to evaluate the machinability by the cutting environment in high speed micro groove machining of NAK80 (HrC40). Compressed chilly air with oil mist was ejected on the contact area between cutting edge and workpiece. The effect of this developed compressed chilly air with oil mist system was evaluated in terms of tool life. The results showed that the tool lift of carbide tool coated TiAlN with compressed chilly air mist cooling was much longer than that of the dry and flood coolant when cutting the material.

• Proceedings of the KSME Conference
• /
• 2008.11b
• /
• pp.3026-3031
• /
• 2008

In conventional closed-loop crankcase ventilation systems, the lubrication oil had to be re-circulated to the intake manifold, in the form of oil mist mixed with the blow-by gas. This blow-by gas containing the engine lubricant oil affects on the engine problems and the exhaust emissions. A high-efficient oil separator is required to minimize consumption of engine oil and reduce harmful emissions. In the conventional oil separator of CI engines, it has good oil separation performance even though separator design is simple, due to lots of the blow-by gas. As the emission regulation becomes severe, the oil separator for SI engines is also required. But in SI engines, separator design should be optimized, due to small size of oil particles and little amount of blow-by gas. In this study, oil separation performance classified by diameter of oil mist in cylinder head cover internal model which has three cyclones and two baffle plates for SI engine is calculated with CFD methodology.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.04a
• /
• pp.625-629
• /
• 1997

Sealing an oil-air mixture plays important roles to have an enhanced lubrication for high speed spindele. Current work was emphased on the investigation of air jet effect on the protective collar type labyrinth seal. To improve the sealing capability of conventional labyrinth seal,ari jet was injected against through the leakage flow. It has a combined geometry of a protective collar type and an air jet type. In this study, both of a numerical analysis by CFD (Computational Fluid Dynamics) and experimental measureements are carried out of verify sealing improvement. But of the turbulence and the compressible flow model were introduced in CFD analysis. The sealing effect of the leakage clearance and the air jet magnitude were studied for variousparameter in the experiment. The results of pressure drop in the experiment match reasonably to those of the simulation by introducing a flow coefficient. Effects of sealing improvement are explained as decreasing of effective leckage clearance by air jetting. Thus, sealing effect is improved by amount of air jetting even though clearance become larger.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2004.10a
• /
• pp.428-432
• /
• 2004

The important problem in the high speed spindles is to reduce and minimize the thermal effect by the motor and ball bearings. Thermal characteristics according to the bearing preload and hollow shaft cooling are studied for the test spindle with the oil mist lubrication and high frequency motor. Bearings and motor e main heat generation, and heat generation by ball bearings as a function of load, viscosity and gyroscopic moment effect are considered. Temperature distribution and thermal displacement according to the speed of spindle are measured by thermocouple and gap sensor. The results show that the fitting preload and hollow haft cooling are very effective to minimize the thermal effect by the motor and ball bearings.