• 한국기계가공학회지
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• 제4권2호
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• pp.3-9
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• 2005

In this study, the chip breaking characteristics of S, PbS and BiS free machining steels have been assessed. PbS free machining steel shows the lowest value of chip thickness ($t_c$) under the same cutting conditions. SM10C steel has the largest value of the chip cross-section area ratio ($R_{CA}$). As the feed rate becomes larger the chip breaking cycle time ($T_B$) decreases and the chip breaking index ($C_B$) increases. The properly controlled-C type chip has been obtained with the value of $C_B$ between 0.05 and 0.2. Free machining steel, PbS produces the properly controlled-C type chip in a wider feed rate range than other steels.

• 한국안전학회지
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• 제9권4호
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• pp.17-28
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• 1994

Chip breaking is important in lathe work for maintaining good surface of the products and safety of operator. The purpose of this study is to investigate the performance of chip breaking and chip shape resulted from the carbide inserts with grooved type and obstruction type chip breaker. Experiments have been performed under the following cutting conditions, (1) constant cutting speed with variable depth of cut and feed rate, (2) constant depth of cut with variable cutting speed and feed rate. Also, the flying distance of chip and it's distribution have been investigated. As a results, good performance of chip breaking can be obtained for small radius of curvature and land width of grooved type chip breaker. And the thickness of chip increase with the increase of feed rate and decrease of cutting speed, and the chip breaking becomes easier with the increase of chip thickness due to the large deformation rate. Obstraction type chip breaker shows better performance of surface roughness than the grooved type. The flying distance of the chips over 90% are less than 1 meter, and the distance decreases as the feed rate decreases.

• 한국정밀공학회지
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• 제11권6호
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• pp.179-184
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• 1994

In this study a nondimensional parameter, feed/land length(F/L) was introduced, and using this parameter, cutting performance and chip breaking characteristics of the groove and the land angle type chip formers were assessed. Specific cutting energy consumed and shape of broken chip with its breaking cycle time were appraised to find out the ranges of F/L value where efficient cutting and effective chip breaking could be achieved. C type chip was found out to be the most preferable in terms of cutting efficiency.

• 한국생산제조학회지
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• 제8권4호
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• pp.45-51
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• 1999

In this study to assess chip breaking characteristics of cold-drawn free machining steels a newly developed non-dimensional parameter chip breaking index CB has been adopted. And for comparison with free machining steels chip breaking characteristics of conventional carbon steels were investigated. Properly controlled chips were produced with the CB value of 0.05-0.2 regardless of steel types. In case of cold-drawn free machining steels however cycle times of chip breaking are relatively shorter than those of conventional steels. And properly controlled chips were obtained from wider range of feed rate.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1999년도 춘계학술대회 논문집
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• pp.21-26
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• 1999

In this study, to assess chip breaking characteristics of cold-drawn free machining steels, a newly developed non-dimensional parameter, chip breaking index, C/sub B/ has been adopted. And for comparison with free machining steels, chip breaking characteristics of conventional carbon steels were investigated. Properly controlled chips were produced with the C/sub B/ value of 0.05∼0.2, regardless of steel types. In case of cold-drawn free machining steels, however, cycle times of chip breaking are relatively shorter than those of conventional steels. And properly controlled chips were obtained from wider range of feed rate.

• 대한기계학회논문집
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• 제17권12호
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• pp.2926-2935
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• 1993

Chip breaker selection analysis, only being possible through experimental process, was obtained by a applied equation which used an orthogonal cutting model and a basic chip deformation. This equation could present an analysis of the chip breaking phenomena without the use of an actual experimetal method, and it was applied to computer simulation and proved the validity of theory through actual experiments. From these results, an efficient method for finding the optimum conditions of chip breaking was found through an optimized theory being applied to basic program. A finite element model for simulating chip breaking in orthogonal cutting was developed and discussed. By simulation the animation of chip breaking is observed in process on the computer screen.

• 한국기계가공학회지
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• 제3권2호
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• pp.25-31
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• 2004

Machinability in metal cutting processes depends on cutting input conditions such as cutting velocity, feed rate, depth of cut, types of work material and tool shape factors. In this study, to assess chip breaking characteristics of a turning process, an equivalent oblique cutting system to this has been established. And the equivalent effective rake angle was determined using side rake angle, back rake angle and side cutting edge angle of the tool. A non-dimensional parameter, Chip breaking index(CB), was used to assess Chip breaking characteristics of chip in conjunction with the equivalent effective rake angle. In case of positive rake angles of the equivalent effective rake, the back rake angle has little effect on the chip breaking characteristics however, in case of negative ones, the side rake angle has some effect on Chip breaking characteristics.

• 한국정밀공학회지
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• 제16권9호
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• pp.191-199
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• 1999

In the continuous cutting process such as turning operation, chip control is thought very important to achieve the unmanned manufacturing system. The prediction of chip breakage under the given conditions is a substantial element for chip control. In this paper, a systematic approach to know the chip breaking region is represented under the concept of equivalent parameters. to Verify the suggested model, cutting experiments are executed with a commercial type and two other type chip breakers which have modified chip breaker parameters such as land width, groove width and nose radius. predicted chip breaking regions using the 3D cutting model agrees with those obtained from the experiments.

• 한국산업융합학회 논문집
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• 제2권2호
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• pp.181-186
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• 1999

For an unmanned machining system, the control and disposal of chips is one of the most serious problems at present. In order to perform chip control, feed/land length($F_L$) was introduced, and using this parameter, the cutting performance and chip breaking characteristics of groove-type and the land -angle-type chip formers were assessed. The specific cutting energy consumed and the shape of broken chips with its breaking cycle time were evaluated to find out the ranges of $F_L$ value where efficient cutting and effective chip breaking could be achieved. The C type chip was found to be the most preferable from the view point of cutting efficiency.

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