• Journal of the Korean Society of Manufacturing Process Engineers
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• v.2 no.3
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• pp.90-95
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• 2003

The W-EDM is very important In precision machining of die, punch and small parts of precision products, so this machining method is widely used in various fields of industry. In this study, machining characteristics of Hand Drum Form and surface roughness are investigated experimentally. As Hand drum form has great effect on straightness of cut-surface of workpiece, its evaluation is very important in precision cutting. As experimental material, the mold material, STD11 is used and machined by CNC wire-EDM using the 025mm wire in diameter with repeated cutting up to 6 times. The thickness of workpiece is vaned in 20, 40, 60, 80, 100mm Hand drum form and surface roughness are measured after each cutting. Experimental results show that four times-cutting is optimum in the point of hand drum form and surface roughness.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.826-830
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• 2000

Sculptured surface machining plays a vital role in the process of bring new Products to the market place. A great variety of products rely on this technology for the production of the dies and moulds used in manufacturing. And, the use or CNC machines and CAD/CAM system has become a vital parts or product development process. But, cusp is inevitable by-product in sculptured surface machining, and it is very difficult to calculate the cusp height correctly. In this study, an analytical cusp height model is proposed considering the radius of the ball end mill, radius of machined workpiece and the inclined angle of convex or concave circular surface. Experiments were performed to check the validity of this proposed model and experimental results showed that the proposed cusp model were very effective.

• International Journal of Precision Engineering and Manufacturing
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• v.5 no.1
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• pp.60-68
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• 2004

The purpose of this paper is to establish an effective inspection system by using OMM (On-Machine Measurement) system based PC-NC. This system can reduce manufacturing lead time because a workpiece is inspected at every machining process and the manufacturing system which includes inspection faculty is able to realize on-line process on CNC machining center. The proposed OMM system is composed of a few algorithms for determination of inspection parameters. It is accomplished by determining the number of measuring points, their location, measuring path using fuzzy logic, Hammersley's method, TSP (Traveling Salesperson Problem) algorithm. The inspection feature applied to this system is based on machining feature. This method is tested by simulation and experiment that are analyzed measuring data and geometry tolerance.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.660-663
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• 1997

In recent manufacturing process, the increase of productivity is required by reducing machining time with the increase of cutting force. However, the excessive increase of cutting force can cause tool breakage, and have a bad effect on both the manufacturing machine and the workpiece. Thus, it is necessary to estimate and control cutting force in real time during the process. In this study, use of disturbance observer is proposed for the indirect cutting force estimation. The estimated cutting force is used for the real time control of feedrate, making the actual cutting force follow the reference force command. Since the suggested method does not need an expensive sensor like a dynamometer, the method is expected to be used practically. By reducing the machining time resulting from making the actual cutting force follow the reference force, the increase of productivity are also expected, and the quality of cutting surface has been improved due to the adjusted feedrate. Besides, an actual constant cutting force guarantees the prevention of tool breakage. To show the effectiveness of the suggested cutting force control method, an experimental setup has been made without the force sensor, applied to several workpieces. Experiments show that the suggested method is superior to the conventional method operated by constant feedrate.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.382-386
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• 2002

The tapping is machining process that makes a female screw on the parts to be assembly together. It is used for the high-speed tapping machine with synchronizing function for the high productivity. This paper describes the development of the ultra high-speed tapping machine with 10,000rpm. The key factors in the tapping speed are the acceleration/deceleration velocity and the synchronizing errors between the spindle motor and feeding motor. To minimizing acceleration/deceleration time, the low inertia spindle with synchronous built-in servo motor is developed. To minimizing synchronizing errors, the tapping cycle algorithm under open architecture CNC environment is optimized. The developed tapping machine has 0.13sec/10,000rpm in acceleration/deceleration time and the synchronizing error below 4.0%. It has 0.55sec for cycle time of one female screw, M3 tap, 2 times depth of tap diameter.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.139-142
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• 1999

Screw rotors are core parts of screw type air compressors, compressors in refrigerating machines and super chargers of automobiles etc. They are composed of a female and a male rotors which have complex section profiles and helically swept geometry. Screw type compressors have advantages of low noise, high efficiency, less needs in maintenance etc. Usually, machining process of screw rotors requires long machining time using CNC machine designed only for screw rotors, which increase the cost of production. In this work, the screw rotors for air-compressors were manufactured with fiber reinforced epoxy composite materials by resin transfer molding process. The mold for the RTM process was made of aluminum and silicon rubber and was designed for release of helical shape products. Composite screw rotors, manufactured by RTM process, have advantages of lightweight, less cost of production, good characteristics of vibration etc.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.6
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• pp.97-103
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• 2008

In this paper, the Post Process for the manifold complex processing using CAD/CAM Software of two and a half Dimensions(2.5D) has been developed to maximize the application of the manifold manufacturing machine. Many companies are currently making use of high price systems to improve manufacturing process using the multi-axial complex manufacturing machine. In accordance with the requirements, the utilization of CAD/CAM Software for the manifold complex manufacturing machine is earnestly demanded. However, the experts who have experience in manifold manufacturing machine are insufficient. Consequently the outcomes of the Post Process for 2.5D CAD/CAM Systems have been dealt in order to be smoothly operated by those who have basic skills and be understood in process drawings. CNC program functions can be specially used as they are, when drawn up. The Post Process for the original point designation and transformation of coordinates has been developed and applied. The results gave proof of practical manufacturing outcomes.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.18 no.10
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• pp.27-33
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• 2019

The aviation industry has grown beyond the simple processing and assembling of aircraft parts and now designs and exports finished aircraft. In this study, the vertical CNC milling rotational speed and feed rate were parameters to investigate the life of tools according to their shape: (flat, round, and ball end mill) in the rough cutting of titanium. These tools are widely used in aircraft manufacturing and assembly. The purpose of this study is to measure the cutting temperature generated during the cutting process and calculate the rate of tool wear. This will be accomplished by measuring the tool weight before and after cutting the specimen and to compare it with the results of previous studies. Our study showed that the maximum cutting temperature increased as cutting time, tool rotational speed, and feed rate increased. The highest cutting temperatures were recorded for the ball, round, and flat end mill, respectively. Tool wear for the ball, round, and flat end mill increased as the speed and feed rate increased. The flat end mill exhibited the highest rate of wear from a minimum of 0.62% to a maximum of 2.88%.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.2
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• pp.179-184
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• 2013

In this article, we introduce the study case of technology that can automatically compensate the errors of these factors of a machine during processing on the machine tool's CNC(Computerized Numerical Controller) in real time. The biggest factors that lower the machining accuracy are thermal deformation and chatter vibration. This study is related to the detection and compensation of thermal deformation and chatter vibration that can compensate for faster and produce processed goods with more precision by autonomous compensation. In addition, this study is related to the active control of vibration during machining, monitoring of cutting force and auto recognition of machining axes origin. Thus, we attempt to introduce the related contents of the development we have made in this article.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1275-1278
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• 1997

Cutting process has been automated by progress of CNC and CAD/CAM, but polishing process has been depended on only experiential knowledge of expert. To automate the polishing pricess polishing robot with 2 degrees of freedom which is attached to a machining center with 3 degrees of freedom has been developed. this automatic polishing robot is able to keep the polishing tool normal on the curved surface of die to improve a performance of polishing. Polishing task for a curved surface die demands repetitive operation and high precision, but conventional control algorithm can not cope with the problem of disturbance such as a change of load. In this research, we develop robust controller using real time sliding mode algorithm. To obtain gain parameters of sliding model control input, the signal compression method is used to identify polishing robot system. To obtain an effect of 5 degrees of freedom motion, 5 axes NC data for polishing are divided into data of two types for 3 axis machining center and 2 axis polishing are divided into data of two types for 3 axis machining center and 2 axis polishing robot. To find an efficient polishing condition to obtain high quality, various experiments are carried out.