• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2003년도 추계학술대회논문집
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• pp.245-250
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• 2003

This research conducted milling tests to study effects of cutting environment conditions of ball end mills on the characteristics of hard milling process. KP4 steels and STD11 heat treated steels were used as the workpiece and WC-Co ball end mill tools with TiAIN coated were utilized in the cutting tests. Dry cutting without coolant and semi-dry cutting using botanical oil coolant were conducted and MQL (Minimum Quantity Lubricant) device was used to spray coolant. Cutting forces, tool wear and surface roughness were measured in the cutting tests. Results showed that dry cutting of KP4 and hardened STD11 specimens produced better surface quality and wear performance than MQL spray cutting did.

• 한국생산제조학회지
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• 제19권1호
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• pp.1-6
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• 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.

• 오토저널
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• 제14권6호
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• pp.105-112
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• 1992

The turning tests with sintered carbide tools have been conducted on typical high strength SSW2 railway wheel steel and its machinability were examined in terms of the cutting resistance, the roughness of turning surface, the chip disposal and others. Some results obtained in this paper are as follows: (1) The cutting resistance is not affected by the cutting speed (in this paper these were 23-78 m/min). (2) The roughness of finished surface is found to be largely dependent on cutting conditions and tool geometry. (3) There exists the explicit relates between the tool geometry cutting conditions (cutting speed, feedrate, and depth of cut) and independent variables(cutting resistance, surface roughness) are derived.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.209-214
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• 2002

Mechanical micro-engineering is an easy and cheap way to fabricate micro-structures. If the application of the conventional machining method using flat-end mill becomes available for the micro-manufacturing process, it will be advanced as an extension of the conventional machining process. In this study, micro-grooves cutting using flat-end mill(($\phi$8) was performed. The characteristics on flat-end milling was investigated to improve machinability of micro-grooves. The experiments were performed according to variations of spindle revolution, depth of cut, and feed rate. Machinability through various cutting conditions was evaluated by surface geometry, tool wear, and cutting force. The results show that micro V-grooves of width(pitch) 29${\mu}{\textrm}{m}$ were acquired by flat-end milling. The maximum and minimum roughness of the wall of grooves was 438 and 67nm, respectively

• 한국생산제조학회지
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• 제4권3호
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• pp.67-76
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• 1995

An experimental study of hot machining has performed to improve the machinability of Inconel718. This experiment used plasma are for heating materials and Whisker0reinforce aluminum oxide ceramic tool insert. An assembled plasma heating system are described and experimental results from both conventional and plasma hot machining of Inconel 718 are compared. The experiments with plasma heating demonstrated the following effectiveness. 1)The cutting force was reduced with increasing surface temperature of workpiece from 450$^{\circ}C$ up to 720$^{\circ}C$ as much as approximately from 20 to 40%. 2) Surface roughness(Ra) was improved by as much as a factor 2 in case of one pass cutting with new ceramic tool inserts.3) The depth of cut notch were at promary cutting tool was significantly reduced.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.976-979
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• 2002

This research presents the new method to fabricate small features through applying chemical mechanical micro machining(C3M) for Al5052 and single crystal silicon. To improve machinability of ductile and brittle material, reacted layer was formed on the surface before micro-drilling process by chemical reaction with $HNO_3$(10wt%) and KOH(10wt%). And then workpieces were machined to compare conventional micro-drilling process with newly suggested one. To evaluate whether or not the machinability was improved by the effect of chemical condition, surface defects such as burr, chipping and crack generation were measured. Finally, it is confirmed that C3M is one of the feasible tools for micro machining with the aid of effect of the chemical reaction.

• 한국공작기계학회논문집
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• 제11권2호
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• pp.87-94
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• 2002

In domestic industry, there is no manufacturers specialized in the production of cutting tools for the difficult cutting materials. Then, we have flew data about them. In this study, the gear driving high speed lathe on which is mounted by a tool dynamometer and high speed CCTV were used to measure the various machining characteristics. Relations among the cutting speed, feed rate per revolution, cutting depth, cutting forces and surface roughness ware graphically analyzed under 64 cutting conditions. The process of chip, i.e., generation, development and falling-off also were visualized for the characterization of chip shapes of the difficult-to-cut materials using the CCTV.

• 한국생산제조학회지
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• 제6권2호
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• pp.102-111
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• 1997

This paper deals with the machinability based on turning of WC-Co allows with the coated and the sintered diamond tools. The main conclusions obtained are as follows. (1) When machining WC-10%Co alloy, the flank wear of sintered diamond tool increases more largely with the increase of cutting speed in comparison with coated diamond tool. The tool wear decreases with the increase of the grain size and nose radius of sintered diamond tool. (2) When machining WC-20%Co alloy, the tool wear and cutting force decrease with the decrease of rake angle. Their exists a certain cutting speed range to exhibit the smallest tool wear in machining the WC-20%Co alloy, and this critical cutting speed becomes higher by 2 times in the case of coated diamond tool compared with sintered diamond tool. (3) The machinability becomes better with the increase of Co content. The effects of cutting speed and feed rate on the roughness of machined surface become smaller with the increase of Co content.

• 한국정밀공학회지
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• 제16권12호
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• pp.198-203
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• 1999

In this study, chip-tool friction and shear characteristics of cold drawn free machining steels in turning were assessed. To do this, a newly developed equivalent oblique cutting model was adopted. And for comparison with those of free machining steels, chip-tool friction and shear characteristics of conventional carbon steels were also investigated. The Pb-S free machining steel shows superior machinability to others. In case of the Bi-S free machining steel, the shear stress and the specific friction energy are relatively lower than those of conventional carbon steels, but its shear strain is relatively high, so it does not show any remarkable improvement of machinability.

• 한국정밀공학회지
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• 제16권12호
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• pp.71-77
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• 1999

In this study, Cu ferrite was machined with cermet tool to clarify the machinability. The main conclusions obtained were as follows. The tool wear becomes the smallest at the cutting speed of 90m/min with the depth of cut of 0.2mm. The surface roughness becomes larger with increasing the cutting speed and the chamfer angle. The tool with the chamfer angle of $15{\circ}$ shows the best performance. The surface roughness increases almost proportionally with the increase of the chip size. The tool wear decreases with increasing feed in the depth of cut not more than 0.2mm.