• 한국기계가공학회지
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• 제15권4호
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• pp.101-108
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• 2016

Endmill fillet cutting at the corner was conducted with the online measurement of cutting forces and tool deflection by a tool dynamometer and an eddy current sensor system. The profile of the machined surface was also compared with the CAD profile with a Coordinate Measuring Machine (CMM) and CALYPSO software. It was found that the end mill cutter with four blades has a better surface profile than that with two blades, and the cutting forces and tool deformation were increased as the cutting speed was increased. When the tool located at the degree $45^{\circ}$ corner was found to conduct the maximum cutting force than started to the point of the workpiece. As it was compared with the CMM and ANOVA analysis result in the case that the cutting force and tool deformation was the maximum, it was found that the result was affected by the spindle speed and the number of blades.

• 센서학회지
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• 제31권1호
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• pp.57-63
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• 2022

This study describes a system that monitors the tool and cutting state of automatic beveling operation in real time. As a signal for cutting state monitoring, a motor current detected from the spindle drive system of the automatic beveling machine is used to monitor abnormal state. Because automatic beveling is processed using a face milling cutter, the cutting force mechanism is the same as the milling process. The predicted cutting torque is obtained using a cutting force model based on specific cutting resistance. Then, the predicted cutting torque is converted into the spindle motor current value, and cutting state stability is diagnosed by comparing it with the motor current value detected during beveling operation. The experimental results show that the spindle motor current can detect abnormal cutting state such as overload and tool wear during beveling operation, and can diagnose the cutting stability using the proposed equip-current line diagram.

• 한국정밀공학회지
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• 제21권4호
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• pp.39-47
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• 2004

In mold machining, there are many concave machining regions where chatter and tool deflection occur since MRR(material removal rate) increases as curvature increases even though cutting speed and depth of cut are constant. Boolean operation between stock and tool model is widely used to compute MRR in NC milling simulation. In finish cutting, the side step is reduced to about 0.3mm and tool path length is sometimes over loom, so Boolean operation takes long computation time and includes much error if the resolution of stock and tool model is larger than the side step. In this paper, curvature of CL (cutter location) surface and side step of tool path is used to compute the feedrate for constant MRR machining. The data structure of CL surface is Z-map generated from NC tool path. The algorithm to get local curvature from discrete data was developed and applied to compute local curvature of CL surface. The side step of tool path was computed by point density map which includes cutter location point density at each grid element. The feedrate computed from curvature and side step is inserted to new tool path to regulate MRR. The resultants were applied to feedrate optimization system which generates new tool path with feedrate from NC codes for finish cutting. The system was applied to the machining of speaker and cellular phone mold. The finishing time was reduced to 12.6%, tool wear was reduced from 2mm to 1.1mm and chatter marks and over cut on corner were reduced, compared to the machining by constant feedrate. The machining time was shorter to 17% and surface quality and tool was also better than the conventional federate regulation using curvature of the tool path.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 추계학술대회 논문집
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• pp.157-160
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• 1995

Pencil cutting can eliminate overload in uncut area caused by large diameter ball-end mill before finish cutting. As ball-end mill for pencil cutting is long and type, it is easily deflected by cutting force. The tool deflection when pencil cutting with thin and long ball-end mill is one of the main reason of the machining errors on a free-form surface. The purpose of the research is to find the characteristics of deflected cutter trajectory by eddy-current sensor.

• 한국기계가공학회지
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• 제11권1호
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• pp.119-124
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• 2012

The study on high speed machining was conducted for wing and rib parts of major structure in aircraft in order to investigate a optimal cutting condition and machining method using a high speed machine with 33,000rpm. Preliminary tests, such as high speed cutter test and spindle vibration test of high speed machine, were performed and the high speed machining was conducted in 3times after the preliminary test results were applied to a NC program for manufacturing.

• 한국생산제조학회지
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• 제8권3호
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• pp.83-91
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• 1999

In this paper, we suggest a virtual machining system that can simulate cutting forces of ball end milling at the stage of part design. Cutting forces, here, are estimated from the machanistic model that uses the concept of specific cutting farce coefficient. To this end, we need undeformed chip thickness which is used for calculating chip load. It is derived from the Z-map data of a CAD model. That is, chip load is the height difference between the cutting tool and the workpiece at an arbitrary position. The tool contact point is referred from the cutter location data. On the other hand, the workpiece height is acquired from the Z-map model of a CAD data. From the experimental verification, we can simulate machining process effectively to the slot and the side cutting of ball end mill.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.942-946
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• 1997

In this research,we suggest a virtual machining system that can simulate sutting forces at the stage of design. Cutting forces,here, are modeled form the machanistic model of the ball end milling. To this end, we need undeformed chip thickness which is used for calculating chip load. It is derived form the z-map data of a CAD model. That is, chip load is the height difference between the cutting tool contact point and the workpiece at arbitrary position. The tool contact point is referred from the cutter location. Form the experimental verification, we can simulate machining process effectively to the slot and the side cutting of ball end mill.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 춘계학술대회 논문집
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• pp.767-770
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• 2000

A novel process is newly developed for building RP(Rapid Prototyping) parts using a sheet lamination technique. The build process of existing sheet lamination type RP machines consists of the following steps : feeding, lamination and cutting. In this process, the laminated part of an object is often scratched by a cutter or damaged by a laser beam due to the cutting operation preceded by lamination, In addition, decubing of the unused portion from the laminated block is difficult. In the new process, cutting operation is performed before lamination. The cutting operation takes place while a paper sheet is firmly attached on the plate using electrostatic force. Then liquid glue is applied to the calculated region of the given contour for lamination. The process aims to manufacture a $2k RP machine, what we call the Freeform Mater I, that can use A4 or latter-size used papers. A prototype machine that demonstrates the design concept is built and further research issues are discussed.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.608-611
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• 2002

We developed low resistance drum that is used in sawdust machine in this research. The existent drum have two dimensional cutting form(orthogonal cutting) when see cutting pattern of saw cutter and wood, cutting resistance is big and cutting power is cost much, and also, vibration happens extremely. To improve this shortcoming, we developed helical type low cutting resistance drum for three dimensional cutting possible, decreased vibration and cutting resistance of sawdust machine, and improve productivity and sawdust ventilation. Also, a developed drum is mounting in sawdust machine, it is sold by product.

• 한국공작기계학회논문집
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• 제17권5호
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• pp.116-122
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• 2008

In order to establish automation or optimization of the machining process, predictions of the forces in machining are often needed. A new model fur farces in milling with the experimental model based on the specific cutting pressure and the Oxley's predictive machining theory has been developed and is presented in this paper. The specific cutting pressure is calculated according to the definition of the 3 dimensional cutting forces suggested by Oxley and some preliminary milling experiments. Using the model, the average cutting forces and force variation against cutter rotation in milling can be predicted. Milling experimental tests are conducted to verify the model and the predictive results agree well with the experimental results.