• Journal of the Korean Society for Precision Engineering
• /
• v.18 no.10
• /
• pp.208-213
• /
• 2001

High speed milling(HSM) is one of the emerging cutting process having tremendous potential not only in increased metal removal rates but also in improved surface finish, burr free edge, dimensional accuracy and a virtually stress free component after machining. The High efficiency and accuracy in machining of die/mold materials can be obtained in high speed machining, so it is necessary to analytic the mechanism of high speed cutting process : cutting force, acoustic emission signal.

• Proceedings of the Society of Korea Industrial and System Engineering Conference
• /
• 2002.05a
• /
• pp.439-444
• /
• 2002

Competitive power in manufacturing industries mainly depends on production time and qualify of products. The main issue for achieving this goal is to build high speed and super accuracy machine. The machine has been developed in the aspect of hardware. However, applications in high speed machining is not sufficient to give solutions to industries in machining. This research presents a method to improve surface roughness adopting experimental design. This research finds experimental factors which have great impact on surface roughness. From the experiments cutting conditions are found for better quality of machining.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.4 no.3
• /
• pp.32-38
• /
• 2005

Electrical discharge machining is the method of using thermal energy by electrical discharge. Generally, if the material of workpiece has conductivity even though very hard materials and complicated shape which are difficult to cut such as quenching steel, cemented carbide, diamond and conductive ceramics, the EDM process is favorable one of possible machining processes. But, the process is necessarily required of finish cut and heat treatment because of slow cutting speed, no mirror surface, brittleness and crack due to the residual stress for manufactured goods. In this experimental thesis, the super EDM drilling was developed for high precision semiconductor die steel and for minimization of leadframe width. It was possible to development of EDM drilling machine for high precision semiconductor die with the electrode guide and its modelling and stress analysis. The development of electrode with the copper pipe type was conducted to drill the hole from the diameter of 0.1mm to 3.0mm with the error of from 0.02mm to 0.12mm. From the SEM and EDX analysis, the entrance of the EDM drill was found the resolidification of not only the component of tungsten but also the component of copper.

• Journal of the Korean Society of Manufacturing Technology Engineers
• /
• v.19 no.1
• /
• pp.1-6
• /
• 2010

Inconel 718 alloy has been applied to high temperature, high load and corrosion resistant environments due to its superior properties. However, This alloy is a difficult-to-cut nickel-based superalloy and the chipping or notch wear is mainly generated on the cutting edge of the tool. In this study, the machinability of Inconel 718 is investigated to improve tool life under various cutting conditions with TiCN-based coated ball-end mills. The cutting conditions can be suggested to improve both the tool life and machined surface quality in Inconel 718 high speed machining.

• Tribology and Lubricants
• /
• v.27 no.1
• /
• pp.7-12
• /
• 2011

Interest in advanced machining process such as AJM(abrasive jet machining) and CMP(chemical-mechanical polishing) using micro/nano-sized abrasives has been on the increasing demand due to wide use of super alloys, composites, semiconductor and ceramics, which are difficult to or cannot be processed by traditional machining methods. In this paper, the effects of pressure, wafer moving velocity and fluid viscosity were investigated by 2-dimensional finite element analysis method considering slurry fluid flow. From the investigation, it could be found that the simulation results quite corresponded well to the Preston's equation that describes pressure/velocity dependency on material removal. The result also revealed that the stress and corresponding material removal induced by the collision of particle may decrease under relatively high wafer moving speed due to the slurry flow resistance. In addition, the increase in slurry fluid viscosity causes the reduction of material removal rate. It should be noted that the viscosity effect can vary with the shape of abrasive particle.

• Transactions of Materials Processing
• /
• v.17 no.3
• /
• pp.189-196
• /
• 2008

Alloy718 is the nickel-base super alloy well used as gas turbine components under severe operating conditions because of its high strength at high temperature and excellent creep resistance. In this study, a coupling bolt for the gas turbine component is manufactured by hot heading process instead of whole machining in order to improve the mechanical properties. Die shape for the hot heading has been designed by general design rule of hot forging and also optimal process condition has been investigated by finite element method. The initial billet temperature and the punch speed have been determined by $1150^{\circ}C$ and 600mm/s on the basis of finite element analysis, respectively. The coupling bolt has been manufactured by 200ton screw press and evaluated by experiment in order to investigate the mechanical properties. As a result of experiment, the mechanical properties such as hardness, tensile strength and creep behavior have been superior to those manufactured by machining.