• Transactions of the Korean Society of Mechanical Engineers
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• v.18 no.9
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• pp.2211-2224
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• 1994

On face milling operation a new optimal cutter, which can minimize the resultant cutting forces, was designed from the cutting force model. Cutting experiments were carried out and the cutting forces of the new and conventional cutters were analyed in time and frequency domains. The resultant cutting forces were used as the objective function and cutter angles as the variables. A new optimal cutter design model which can minimize the resultant cutting forces under the constraints of variables was developed and its usefulness was proven. The cutting forces in feed direction of the newly designed cutter are reduced in comparison with those from the conventional cutter. The magnitudes of an insert frequency component of cutting force from the newly designed cutter are reduced than those from conventional cutter and the fluctuations of cutting force are also reduced.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.10a
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• pp.28-33
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• 1992

The paper describes a new mean specific cutting pressure model in order to improve the accuracy of prediction of cutting force for face milling. The new mean specific cutting pressure model produces a mean specific cutting pressure and coefficients applied to existing cutting model not by traditional method but by considering intermittence and variation of chip width according to insert cutting position to take into cutter geometry machining condition and width of workpiece, and considering a mean measure force according to spindle eccentricity and mean measure force according to spindle eccentricity and insert initial position errors.. The simulated forces in X, Y, Z directions resulted from the simulated cutting model and the new cutting model are compared with measured forces in the time end frequency domains. The simulated forces in the time and frequency domains. The simulated forces resulted from the new cutting model have a good degreement with measured forces in comparison with these resulted from the existing cutting model

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2000.04a
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• pp.332-338
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• 2000

The high speed machining is now one of the most effective manufacturing methods to achive higher productivity. However, due to the increased cutting temperatures caused by increased cutting speed, tool wear become larger. Especially in high speed face milling, cutting tools are exposed not only to high cutting temperatures, but also to mechanical and thermal shock stresses. It is essential, therefore, to know the wear characteristics of tool materials in high speed machining. This study presents an experimental investigation of the cutting performance of CBN tools in high speed face milling of gray cast iron FC25. The effect of cutting conditions and cutting length on flank wear of CBN tools and roughness of machined surfaces is investigated. The cutting parameters involved were ; cutting speeds in the range of 600to 1800 m/min, feed of 0.1 mm/tooth, and depth of cut of 0.3mm.

• Journal of the Korean Society for Precision Engineering
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• v.13 no.6
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• pp.168-176
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• 1996

A diagnosis system which can monitor tool breakage and chipping in real time was developed using a DSP(Digital Signal Processor) board in face milling operation. AR modelling and band energy method were used to extract the feature of tool states from cutting force signals. Artificial neural network embedded on DSP board discriminates different patterns from features got after signal processing. The features extracted from AR modelling are more accurate for the malfunction of a process than those from band energy method, even though the computing speed of the former is slow. From the processed features, we can construct the real time diagnosis system which monitors malfunction by using a DSP board having a parallel processing capability.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 1996.11a
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• pp.26-30
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• 1996

This paper presents the performance of CBN tools in the machining of hardened die-materials, SKD11 and SKD61 steel with HRC 50, by high-speed face milling. Generally, grinding or EDM is being used in machining of hardened materials but the cost is very high. If those can be replaced by cutting, it will be a greatly economical advantage. CBN tool has been recognized as an effective tool in turning, but it has not been in milling. So wear and surface roughness mode of CBN tool for hardened SKD11 and SKD61 steel were investigated by high-speed face milling in this study Also the relation between cutting force and wear mode of CBN tools was investigated.

• Journal of the Korean Society for Precision Engineering
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• v.14 no.1
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• pp.185-193
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• 1997

This paper presents the on-line monitoring of the surface roughness in a face milling operation. The cut- ting force was used to monitor the surface roughness, since the insert run-outs not only deteriorate surface roughness but also change cutting force. AR model and band energy method were taken to extract the fea- tures from the cutting force. The features extracted from AR modelling are more accurate about the moni- toring than those from band energy method, whereas, the computing speed of the former is slow. An artifi- cal neural network discriminated the level of the surface roughness by using the features extracted via signal processing.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.1
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• pp.71-79
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• 2004

The deformed layers generated in face milling works were comparatively investigated to type 316L and nitrogen(N)-added type 316LN stainless steels. In order to characterize mechanical properties between type 316L and type 316LN, high-temperature tensile tests were conducted with different temperatures: R.T to $700^{\circ}C$. The cutting forces of three components, Fx, Fy and Fz were measured using a tool dynamometer through the face milling cutting tests. The deformed layers were measured by micro-hardness tests along deformed layers. The results of mechanical properties showed that type 316LN was superior to type 316L. The deformed layers of two steels were generated in the 1501m-3001m ranges, and type 316L was higher than type 316LN. The reason for this is due to the high strength properties by nitrogen effect. It was found that deformed structures were well observed for type 316L, but were minutely observed for type 316LN in this cutting conditions.

• Journal of the Korean Wood Science and Technology
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• v.16 no.4
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• pp.61-69
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• 1988

Recently the automization of wood manufacturing and the development of CNC machine tools becomes the center of interest. Cutting mechanism, tool wear and the roughness of machined surface have been studied. In the studies about wood for special uses, concrete data of cutting is desired. While Pinus densiflora is characterized that heartwood develops as age increases, Chunyang District has the characteristic of strength, red color, relatively regular chap and high heartwood - percentage. But there is no data about cutting this wood, Chunyang District. In this study face milling by sintered carbide tool was excuted to Chunyang District. Cutting force, Surface roughness and states were investigated with regard to cutting speed. Example results were as follows; 1) Mean cutting resistance against lateral component force and longitudinal component force decreased rapidly up to cutting speed of 155 m/min, and remains constant above this speed. 2) The surface roughness of cutting surface lowered as cutting speed increased, regardless of fiber formation. Radial rougness of fiber is larger than lineal surface roughness. 3) Increase in Cutting speed made machining mark restrained. Down-milling showed larger marks than up-milling.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.9 no.6
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• pp.57-64
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• 2000

In order to regulate cutting torque in milling, monitoring system should be set to a certain threshold. Radial immersion ratio is an important factor to determine the threshold and should be estimated in process for automatic regulation. In this paper, on-line estimation of the radial immersion ratio using spindle motor current in face milling is presented. When a tooth finishes sweeping, a sudden drop of cutting torque occurs. This torque drop is equal to the cutting torque acting on a single tooth at the swept angle of cut and can be acquired from cutting torque signals. Average cutting torque per revolution can also be calculated from cutting torque signals. The ratio of cutting torque acting on a single tooth at the swept angle of cut to the average cutting torque per revolution is a function of the swept angle of cut and the number of teeth. Using the magnitude of this ratio, the radial immersion ratio is estimated. Identical algorithm is adopted to estimate the immersion ratio based on the spindle motor current measurement. The experiments performed under different cutting conditions show that the radial immersion ratio can be estimated within 10% error range by the proposed method using spindle motor current. Varying immersion ratio is also estimated well using the presented algorithm.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.28 no.2
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• pp.196-205
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• 2004

The cutting characteristics and the deformed layer of nitrogen(N)-added type 316LN stainless steel were comparatively investigated to type 316L stainless steel. The cutting force, the surface roughness(Ra) and the tool wear in face milling works were measured with cutting conditions, and the deformed layers were obtained from micro-hardness testing method. The cutting resistance of type 316LN was similar to type 316L in spite of its high strength. The surface roughness of type 316LN was superior to type 316L for all the cutting conditions. In particular, in the high cutting speed above 345m/min, the surface roughness of the two stainless steels was closely same. The deformed layer thickness of the two stainless steels was generated in the 150$\mu\textrm{m}$-300$\mu\textrm{m}$ ranges, and its value of type 316LN was lower than that of type 316L. This is due to the high strength properties by nitrogen effect. It was found that type 316LN was higher in the tool wear than that type 316L, and flank wear was dominant to crater wear. In face milling works of type 316LN steel, tool wear is regarded as a important problem.