• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2002.02a
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• pp.53-60
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• 2002

Recently, the development of aerospace and automobile industries brought new technological challenges, related to the growing complexity of products and new geometry models. High speed machining using 5-Axis milling machine is widely used for 3D sculptured surface parts. 5-axis milling of turbine blade generates the vibration, deflection and twisting caused from thin and cantilever shape. So, the surface roughness and the waviness of workpiece are not good. In this paper, The effects of cutter orientation and lead/tilt angle in 5-Axis high speed ball end-milling of turbine blade were investigated to improve the geometric accuracy and surface integrity. The experiments were performed at lead/tilt angle $15^{\circ}$ of workpiece with four cutter directions such as horizontal outward, horizontal inward, vertical outward, and vertical inward. Workpiece deflection, surface roughness and machined surface were measured with various cutter orientations such as cutting direction, and lead/tilt angle. The results show that when 5-axis machining of turbine blade, the best cutting strategy is horizontal inward direction with tilt angle. The results show that when 5-axis machining of turbine blade, the best cutting strategy is horizontal inward direction with tilt angle.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.10 no.5
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• pp.17-24
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• 2001

Recently, the requirements for high precision and efficiency machining are gradually increased to raise international competitiveness at the industrial fields of die and molds. This trend had made effects on the industrial fields in Korea and which needs fur studying of high precision and efficiency machining. This study is to investigate the effects of the non-out of end mill in the external cylindrical machining operated by solid carbide end mills with Al-alloy in high speed machining center relating to high spindle revolution and frost fred per minute on the dimensional precision, roundness of workpiece. From the results of experimentations followings are obtained; when Al-alloy is processed by the external cylindrical cutting of end milling through the high speed revolution, if the spindle revolution is higher relating to radial depth of cut, feed per tooth in very lower situation, finally, productivity can be raised because high precision and quality products are machined high efficiently.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2001.04a
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• pp.95-100
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• 2001

Recently, coated milling cutters are widely used for improving the productivity of cutting processes through high speed cutting and longer tool life. In metal cutting, cutting force increase rate is important factor to diagnose the cutting conditions because the amount of tool wear directly influences the cutting forces. As the cutting length increases, the worn cutter increases the cutting forces. In this study, the effect of coating process of end milling cutter on the cutting performance, especially on the cutting force increase rate, is investigated. The results acquired through the cutting test measuring cutting force increase rate show that not only the injection quantity of $N_2$ and Ar but also mean temperature influence the cutting force increase rate during the end milling process.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.34-38
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• 2000

The trend of cutting process today goes toward higher precision and higher efficiency. Many thermal/frictional troubles occur in high-speed machining of die and mold steels.In this paper, the thermal characteristics are evaluated in high sped ball end-milling of hardened steel(HRc42). Experimental work is performed on the effect of cutting environments on tool life and cutting temperature. Cutting environments involve dry, wet(20bar), compressed chilly air at -9$^{\circ}C$, compressed chilly air at -35$^{\circ}C$. The measuring technique of cutting temperature using implanted thermocouple is used. The cutting temperature is about 79$0^{\circ}C$, 35$0^{\circ}C$ and 54$0^{\circ}C$ in dry, wet and compressed chilly air at +9$^{\circ}C$, respectively. The tool life for compressed chilly air at -9$^{\circ}C$ is longer than all other cutting environments in experiment.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.18 no.3
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• pp.261-269
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• 2009

Micro end-milling process is applied to fabricate precision mechanical parts cost-effectively. It is a complex and time-consuming job to select optimal process conditions with high productivity and quality. To improve the productivity and quality of precision mechanical parts, micro end-mill wear and cutting force characteristics should be studied carefully. In this paper, high speed machining experiments are studied to construct the optimum process design as well as the mathematical modeling of tool wear and cutting force related to cutting parameters in micro ball end-milling processes. Cutting force and wear characteristics under various cutting conditions are investigated through the condition monitoring system and the design of experiment. In order to construct the cutting database, mathematical models for the flank wear and cutting force gradient are derived from the response surface method. Optimal milling conditions are extracted from the developed experimental models.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.06a
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• pp.19-27
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• 2000

High speed machining (HSM), specifically end milling and ball end cutting, is attracting interest in the die/mold or aerospace industries for the machining of complex 3D surfaces. HSM of difficult-to-cut materials such as die/mold steels, titanium alloys or nickel based superalloys generates the concentrated thermal/frictional damage at the cutting edge of the tool and rapidly decreases the tool life. Following a brief introduction on HSM and reated aerospace or die/mold work, the paper reviews published data on the effect of cutter/workpiece orientation and cutting environments on tool performance. First, experimental work is detailed on the effect of cutter orientation on tool life, cutting forces, chip formation, specific force and workpiece surface roughness. Cutting was performed using 8 mm diameter PVD coated solid carbide cutters with the workpiece mounted at an angle of 45 degree from the cutter axis. A horizontal downwards cutting orientation proveded the best tool life with cut lengths ∼50% longer than for all other directions (horizontal upwards, vertical downwards, vertical upwards). Second, the cutting environments were investigated for dry, flood coolant, and compressed chilly air coolant cutting. The experiments were performed for various hardened materials and various coated tools. The results show that the cutting environment using compressed cilly air coolant provided better tool life than the flood coolant or the dry.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.15 no.5
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• pp.1-7
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• 2016

In the present study, a plastic surface end-milling was implemented to investigate the effects of processing parameters on surface quality. The end milling can be considered an efficient method for rapid prototyping of thermoplastic bio-systems since it exhibits several beneficial functions including short fabrication time and high dimensional accuracy. In this regard, putative biocompatible thermoplastic materials, such as PMMA, PET, and PC, were chosen as workpiece materials. Among the relevant processing parameters influencing the surface quality of the final product, depth of cut, feed rate, and spindle speed were considered in the present study. The roughness of surfaces machined under various conditions was measured to elucidate the effect of each parameter. We found that the cut depth was the most significant factor. Heat generation during machining also had a remarkable effect. From these investigations, an appropriate combination of processing conditions specific to each type of use and end-product could be found. This optimization can be useful in end-milling of thermoplastic bio-systems.

• Journal of the Korean Ceramic Society
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• v.45 no.1
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• pp.75-81
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• 2008

In this study, machining characteristics of AIN-hBN composites were evaluated in end-milling process. As a first step, AIN-hBN composite specimens with various hBN contents were prepared using hot press method. Material properties of the composites, such as relative density, Young's modulus and fracture toughness, were measured and compared. Then, a series of end-milling experinients were performed under various cutting conditions by changing cutting speed, depth-of-cut and feed rate. Cutting force variations were measured using a tool dynamometer during the cutting experiments. Machined surfaces of the specimens were observed using SEM and a surface pro filer to investigate the surface integrity changes. The cutting force decreased with an increases of hBN content. The cutting process was almost impossible for monolithic AIN, owing to severe chipping. In contrast, at high content of hBN, surface damage and chipping decreased, and better surface roughness can be obtained.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.8 no.2
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• pp.137-143
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• 1999

The study of the high speed machining of inclined plane using ball end mill is performed. The use of ball end mill is rapidly growing in die and mold manufacturing. The cutting characteristics, such as cuttin g force, surface roughness and surface profile, are varied according to the variation of cutting directions. Free surface is cut using ball end mill, the surface profile is greatly varied depending upon the cutting direction. So this study will deal with the characteristics of cutting such as cutting efficiency according to the inclined plane of the workpiece, the cutting force according to tool path, surface profile and the roughness of surface. The optimal cutting direction to be applied the cutting for 3-D sculptured surfaces can be show through the results of this study.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2005.06a
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• pp.199-202
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• 2005

High speed milling process is emerging as an important fabrication process benefits include the ability to fabricate micro and meso-scale parts out of a greater range of materials and with more varied geometry. It also enables the creation of micro and meso-scale molds for injection molding. Factors affecting surface roughness have not been studied in depth for this process. A series of experiments has been conducted in order to begin to characterize the factors affecting surface roughness and determine the range of attainable surface roughness values for the high speed milling process. It has previously been shown that run-out creates a greater problem for the dimensional accuracy of parts created by high speed milling process. And run-out also has a more significant effect on the surface quality of milled parts. The surface roughness traces reveal large peak to valley variations. This run-out is generated by spindle dynamics and tool geometry. In order to investigate the relationship between tool setting errors and surface roughness end tilted mills were used to cut aluminum samples. The results indicate that tool setting errors have significant effects on surface roughness and cutting forces.