• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.10 no.4
• /
• pp.82-87
• /
• 2011

Lubrication has an important role to reduce frictional forces and temperature between cutting chips and the face of a tool. However, it has harmful effects to workers' health and working environment. The purpose of this thesis is to find cutting conditions through the quality analysis in boring for SM45C steel using MQL(Minimum Quantity Lubrication). Machining process is super drill, tip drill, end mill and boring in order. Experimental factors of boring and the quantity of mist air are properly selected. With the analysis of experimental data, this thesis shows that boring with MQL improves the surface roughness when spindle speed is 934rpm or feeding speed is 74mm/min.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
• /
• 2003.04a
• /
• pp.500-503
• /
• 2003

The tool geometry parameters and cutting process have complex relationships. Until now, various cutting test were needed to acquire optimal design of end mill for the purpose of high speed machining, due to the insufficient knowledge about cutting process in high speed machining. Using various tools with different geometry, relationships between tool geometry parameter (rake angle, clearance angle, length of cutter) and cutting process (cutting force, surface accuracy, surface roughness) have been studied. Acquired data can be used to design optimal tool for high speed machining

• Membrane and Water Treatment
• /
• v.9 no.5
• /
• pp.373-383
• /
• 2018

Fouling by solids and microorganisms is the major obstacle limiting the efficient use of membrane wastewater treatment. In our previous study, two stages microalgae/membrane filtration system was proposed to treat anaerobic digested palm oil mill effluent (AnPOME). This two stages microalgae/membrane filtration system had showed great potential for the treatment of AnPOME with high removal of COD, $NH_3-N$, $PO_4{^{3-}}$, TSS, turbidity, and colour. However, fouling behavior of the membrane in this two stages microalgae/membrane filtration system was still unknown. In this study, empirical models that describe permeate flux decline for dead-end filtration (pore blocking - complete, intermediate, and standard; and cake layer formation) presented by Hermia were used to fit the experimental results in identifying the fouling mechanism under different experimental conditions. Both centrifuged and non-centrifuged samples were taken from the medium with 3 days RT intervals, from day 0 to day 12 to study their influence on fouling mechanisms described by Hermia for ultrafiltration (UF), nanofiltration (NF), and reverse osmosis (RO) filtration mode. Besides, a more detailed study on the use of resistance-in-series model for deadend filtration was done to investigate the fouling mechanisms involved in membrane filtration of AnPOME collected after microalgae treatment. The results showed that fouling of UF and NF membrane was mainly caused by cake layer formation and it was also supported by the analysis for resistance-in-series model. Whereas, fouling of RO membrane was dominated by concentration polarization.

• Journal of the Korean Society for Precision Engineering
• /
• v.14 no.3
• /
• pp.66-74
• /
• 1997

In a high speed and high precision vertical machining center, chatter vibration is easily generated due to unbalanced masses in rotating parts and changtes of cutting forces. In this paper, modal test is performed to obtain modal parameters of the vertical machining center. In order to predit the cutting force of endmilling process for various cutting conditions, a mathematical model is given and this model is based on chip load, cutting geometry, and relationship between cutting forces and the chip load. Specific cutting constants of the model are obtained by averaging forces of cutting tests. The interactions between the dy- namic characteristics and cutting dynamics of the vertical machining center make the primary and the secondary feedback loops, and we make use of the equations of system to predict the chatter vibration. The chatter prediction is formulated as linear differential-differene equations, and simulated for several cases. Trends of vibration as radial and axial depths of cut are changed are shown and compared.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2000.05a
• /
• pp.944-947
• /
• 2000

Sculptured surface machining plays a vital role in the process of bring new products to the market place. A great variety of products rely on this technology for the production of the dies and moulds used in manufacturing. And, the use of CNC machines and CAD/CAM system has become a vital parts of product development process. The propose of this study is to investigate the effect of cutting parameters on the machinability such as surface roughness and cusp generated in the machining of sculptured surface on a three-axis CNC machining center using the CAD/CAM system. Experimental result showed that: In step down cutting, as the inclined angle of surface became smaller, the cusp height appeared higher. On the other hand, in step over cutting, as the inclined angle of surface became larger, the cusp height appeared higher. In the point of precision machining, step over cutting was more effective. For the minimization of cusp height, step down cutting was effective in larger inclined surface, but step over cutting in smaller inclined surface.

• Journal of the Korean Society for Precision Engineering
• /
• v.21 no.12
• /
• pp.21-28
• /
• 2004

In modem manufacturing industries such as the airplane and automobile, aluminum alloys which are remarkable in durability have been utilized effectively. High-speed machining technology for surface roughness quality of workpiece has been applied in these fields. Higher cutting speed and feedrates lead to a reduction of machining time and increase of surface quality. Furthermore, the reduction of time required for polishing or lapping of machined surfaces improves the production rate. Traditional milling process for high speed cutting can be machined with end mill tool. However, such processes are generally cost-expensive and have low material removal rate. Thus, in this paper, face milling cutter which gives high MRR has developed face milling cutter body for the high speed machining of light alloy to overcome the problems. Also vibration experiment to detect natural frequency in free state and frequency characteristics during machining are performed to escape resonance.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1995.10a
• /
• pp.131-134
• /
• 1995

The high efficiency and accuracy in machining the die material can be abtained in high speed machining, so it is necessary to analyze the mechanism of high speed cutting process : cutting force, flank wear. The tool dynomometer with high natural frequency is newly developed. With this device, the mechanism of high speed cutting process is investigated according to speed and feedate.

• Journal of the Korean Society of Safety
• /
• v.25 no.5
• /
• pp.1-6
• /
• 2010

When the ceramic material is being machined, micro crack and brittle fracture dominate the process of material removal. Generally, ceramics are very difficult-to-cut materials and machined using conventional method such as grinding and polishing. However, such processes are generally cost-expensive and have low material removal rate. Machinable ceramics used in this study contain BN powder to overcome these problem and for productivity elevation. This paper focuses on machinability evaluation during end mill process with CNC machining center in this study. Experiment for this purpose is performed for tool wear patterns and mechanism.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.12 no.5
• /
• pp.129-134
• /
• 2013

Titanium used in industry has been widely applied for aerospace important parts and automobile important parts, etc. because the titanium is higher in strength compared to the steel and light in weight compared to the steel. This study is to investigate the effect of cutting tool cooling method and cutting time on the spindle speed and feed rate of vertical machining center as a parameter to find the rough cutting time in the medium speed cutting machining of the titanium alloy. It is found that the cutting machining heat are increased as the feed rate, cutting time and spindle speed are raised.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 1997.10a
• /
• pp.19-22
• /
• 1997

The objective of this research is to use an analytical and experimental approach to develop optimal tool geometry for high speed machining. The tool geometry parameters and cutting process have complex relationships. Until now, numerous cutting tests were needed to acquire optimal design of endmill for the purpose of high speed machining, dut to the insufficient knowledge about process in high speed machining. In order to improve the cutting ability of endmill, a model for optimal cutter shape was developed to minimize resultant cutting force by combing cutting force and wear test and surface roughness test from optimized and conventional cutter with the same cutting condition. Using various tools with different geometry, relationships between the tool geometry parameter, rake angle, clearance angle, lengh of cutter have been stuied.