• 한국정밀공학회지
• /
• 제17권12호
• /
• pp.163-168
• /
• 2000

Once the chip has developed a mixed mode of side-curl and up-curl, it would generally curl to strike the tool flank. The development of the bending stresses and sheat in the chip would ultimately lead to chip failure. This paper approach this problem from a mechanics-based approach, by treating the chip as a 3-D elastic curved beam, and applying appropriate constraints and forces. The expressions for bending, shear and direct stresses are developed through an energy-based criterion. The location of the maximum stresses is also identified and explained for simulated test conditions.

• 한국정밀공학회:학술대회논문집
• /
• 한국정밀공학회 2000년도 춘계학술대회 논문집
• /
• pp.730-734
• /
• 2000

Once the Chip has developed a mixed mode of side-curl and up-curl, it would generally curl to strike the too] flank. The development of the bending stresses and shear in the chip would ultimately lead to chip failure. This paper attacks this problem from a mechanics-based approach. by treating the chip as a 3-D elastic curved beam, and applying appropriate constraints and forces. The expressions for bending. shear and direct stresses are developed through an energy-based criterion. The location of the maximum stresses is also identified and explained for simulated test conditions.

• 한국생산제조학회지
• /
• 제9권2호
• /
• pp.96-101
• /
• 2000

In machining with cutting tool inserts having complex chip groove shape the flow curl and breaking pattern of the chip are different than in flat-face inserts. In the present work an effort is made to understand the three basic phe-nomena occurring in a chip since its formation in machining with groove type and pattern type inserts. These are the ini-tial chip flow the subsequent development of up and side curl and the final chip breaking due to the development of tor-sional and bending stresses. in this paper chip flow angle in a groove type and pattern type inserts. The expres-sion for chip flow angle in groove type and pattern type inserts is also verified experimentally using high speed filming techniques.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
• /
• pp.381-386
• /
• 1999

In machining with cutting tool inserts having complex chip groove shape, the flow, curl and breaking patterns of the chip are different than in flat-face type inserts. In the present work, an effort is made to understand the three basic phenomena occurring in a chip since its formation in machining with groove type and pattern type inserts. These are the initial chip flow, the subsequent development of up and side curl and the final chip breaking due to the development of torsional and banding stresses. In this paper, chip flow angle in a groove type and pattern type inserts. The expression for chip flow angle in groove type and pattern type insets is also verified experimentally using high speed filming techniques.

• 대한기계학회논문집
• /
• 제11권6호
• /
• pp.1005-1013
• /
• 1987

For the factory automation and unmanned machine operation, it is very important to manufacture highly reliable and efficient chip breakers for optimal chip control. In this research, using the CALMA CAD/CAM SYSTEM, the manufacturing process of 3-dimensional chip breakers is established. Using the results of the cutting test of the selected chip breakers with double-step grooves, the chip breaking mechanism is schematically analysed. An expression for the chip breaking relation is derived which considers chip material behavior following LUDWIK's stress-strain curve, chip breaking criterion and the shape of chip breakers. This contains the thickness of chip, the radius of chip curl, and the mechanical properties of chip materials. It is found that the expression agrees very closely with the experimental results.

• 한국공작기계학회:학술대회논문집
• /
• 한국공작기계학회 1999년도 추계학술대회 논문집 - 한국공작기계학회
• /
• pp.513-518
• /
• 1999

In this study, geometrical similarity conditions for drills of various diameters are discussed. The effect of geometrical similarity on the chip shape and forces of different sized conventional drills has been experimentally confirmed. Drilling tests are carried out for SM45C by using the conventional HSS drills. The torque and thrust forces are measured and compared with those chip forms. Chip shape in drilling are affected by three factors being flow angle, side and up curl of the chip. It is found that the feedrate and drill diameter are more affected than cutting speed on the chip form and cutting forces. The similarity conditions gives easily to estimate the chip shape, the thrust and the torque for drills of different diameters.

• 한국생산제조학회지
• /
• 제9권6호
• /
• pp.118-126
• /
• 2000

In this study, geometrical similarity conditions for drills of various diameters are discussed. The effect of geometrical similarity on the chip shape and forces of different sized conventional drills has been experimentally confirmed. Drilling tests are carried out for SM45C by using the conventional HSS drills. The torque and thrust forces are measured and compared with those chip forms. Chip shape in drilling are affected by three factors being flow angle, side and up curl of the chip. It is found that the feedrate and drill diameter are more affected than cutting speed on the chip form and cutting forces. The similarity conditions gives easily to estimate the chip shape, the thrust and the torque for drills of different diameters.

• 대한기계학회논문집
• /
• 제16권6호
• /
• pp.1121-1140
• /
• 1992

본 연구에서는 부착형 칩절단구의 경사면 대신에 원고면으로 형성한 형태 칩 절단구를 고찰하고, 재래형과 비교하여 더 효과적인 칩절단구를 개발 실용화하고자 한 다. 가공법으로서는 연속칩의 처리가 가장 곤란한 선삭을, 공작물로서는 연속칩이 가장 잘 생성되는 SM 20 C의 연강을, 공구재료로서는 P계열의 초경합금을 써서 저속에 서 고속절삭속도까지 시험하였다.

• 한국정밀공학회지
• /
• 제5권1호
• /
• pp.84-93
• /
• 1988

The on-line detection of the chip flow is one of the most important technologies in com- pletly automatic operation of machine tool, such as FMS and Unmanned Factories. This problem has been studied by many researchers, however, it is not solved as yet. For the recognition of chip flow in this study, the dynamic cutting force components due to the chip breaking were measured by dynamometer of piezo-electric type, and the frequency components of cutting force were also analyzed. From the measured results, the effect of cutting conditions and tool geometry on the dynamic cutting force component and chip formation were investigated in addition to the relationships between frequency of chip breaking (fB) and side serrated crack (fC) of chip. As a result, the following conclusions were obtaianed. 1) The chip formations have a large effect on the dynamic cutting force components. When chip breaking takes place, the dynamic cutting force component greatly increases, and the peridoic components appear, which correspond to maximum peak- frequency. 2) The crater wear of tool has a good effect on the chip control causing the chiup to be formed as upward-curl shape. In this case, the dymamic cutting force component greatly increases also 3) fB and fC of chip are closely corelated, and fC of chips has a large effect on the change of the situation of chip flow and dynamic cutting force component. 4) Under wide cutting conditions, the limit value (1.0 kgf) of dynamic cutting force component exists between the broken and continuous chips. Accordingly, this value is suitable for recognition of chip flow in on-line control of the cutting process.

• 한국정밀공학회지
• /
• 제19권12호
• /
• pp.120-126
• /
• 2002

The needs of ultra-precisely machined parts are increasing more and more. But the experimental data required to ultra precision machining of nonferrous metal is insufficient. The behavior of cutting in micro cutting area is different from that of traditional cutting because of the size effect. Copper is widely used as optical parts such as LASER reflector's mirror and multimedia instrument. In experimental, after oxygen-free copper is machined by ultra precision machine with natural mono crystal diamond tool (NCD) and synthetic poly crystal diamond tool (PCD), we compared chip formation and tool's wear according to used tool. Also, we researched optimized cutting condition with the results measured according to cutting condition such as spindle speed, feed rate and depth of cut. As a result, the optimal working condition that makes good surface roughness is obtained. The surface roughness is good when spindle speed is above 80 m/min, and feed rate is small and depth of cut is above 0.5 ${\mu}{\textrm}{m}$. In cutting of klystron anode and cavity 3.2 nmRa of surface roughness is obtained.