한국공작기계학회:학술대회논문집 (Proceedings of the Korean Society of Machine Tool Engineers Conference) (Proceedings of the Korean Society of Machine Tool Engineers Conference)
한국생산제조학회 (The Korean Society of Manufacturing Technology Engineers)
- 기타
한국공작기계학회 1996년도 춘계학술대회 논문집
-
The Job of Milling in the Local Skill Contest in 1996 was to assemble parts into a complete whole of the parts number 1, 3, 4 worded by Milling Machine and the parts number 2 worked by Machining Center. In the parts of Milling Machine, the Job was to work 45
$^{\circ}$ angle working, T-slot, dovetail, the correct position drilling, rimming, boring, etc. In the Machining Center, there were the way of calculation of point of contact of 'R' contour curved line and lots of working elements. So, it was possible to work the parts and assemble them within the time limit only through the program to be made out in the way to shorten working hours. -
The seniconductor, which is precision product, requires many inspection processes. The surface conditions of the semiconductor chip effect on the functions of the semiconductors. The defects of the chip surface is crack or void. Because general inspection method requires many inspection processes, the inspection system which searches immediately and preciselythe defects of the semiconductor chip surface. We propose the inspection method by using the computer vision system. This study presents an image processing algorithm for inspecting the surface defects(crack, void)of the semiconductor test samples. The proposed image processing algorithm aims to reduce inspection time, and to analyze those experienced operator. This paper regards the chip surface as random texture, and deals with the image modeling of randon texture image for searching the surface defects. For texture modeling, we consider the relation of a pixel and neighborhood pixels as noncasul model and extract the statistical characteristics from the radom texture field by using the 2D AR model(Aut oregressive). This paper regards on image as the output of linear system, and considers the fidelity or intelligibility criteria for measuring the quality of an image or the performance of the processing techinque. This study utilizes the variance of prediction error which is computed by substituting the gary level of pixel of another texture field into the two dimensional AR(autoregressive model)model fitted to the texture field, estimate the parameter us-ing the PAA(parameter adaptation algorithm) and design the defect detection filter. Later, we next try to study the defect detection search algorithm.
-
In this study, unsintered and pre-sintered low purity alumina ceramics were machined with various tools to clarify the machinability, optimum tool materials and optimum cutting conditions. The main conclusions obtained were as follows. (1)In the case of dry cutting, the sintered diamond and natural diamond tools exhibit better performance in machining of the ceramic pre-sintered at lower temperature, and the tool lives of both tools in machining the ceramics pre-sintered at high temperature becomes extremely short. (2)The performance of CBN tool becomes better in dry machining of the ceramics pre-sintered at higher temperature. (3)When the pre-sintered ceramics were wet machined with sintered diamond, the tool life becomes considerably long, and higher cutting speed can be used than in the case of the CBN and ceramic tools, the tool lives becomes shorter at wet cutting than at dry cutting, especially exhibiting extremely short tool life in wet cutting with ceramic tool.
-
Unsteady-state temperature distributions and thermal deformations of a spindle system are studied in this paper. Three dimensional model is built for analysis, and the amount of heat generation of bearing and the thermal characteristic values including heat transfer coefficient are estimated. Temperature distributions and thermal deformations of a model are analyzed using the finite element method and the termal boundary values. Numerical results are compared with the measured data. The results show that thermal deformations and temperature distributions of a high precision spindle system can be reasonably estimated using the three dimensional model and the finite element method.
-
Though the increment of using computer vision system in modern industry, there are lots of difficulties to measure precisely because of measurement error distortion phenomenon. Between these reasons, the distortion of edge is dominant reason which is occured by the blurred image. The blurred image is happened when camera can not discriminate its precise focus. To correct and generalize distortion phenomenon is imprrtant. Thus we must fix the discrimination criteria which is collected by image recognition of precise focus. The edge of image means discontinuous point of intensity, and the component of edge is discribed as high frequency component at special domain specturm of image. The good condition of focus means there are much high frequency energy in image. The method of discribing high frequency energy is gradient operater which determines the condition of focus.
-
An overall feature to simulate composite behavior and to predict closed solution has been performed for the application to the stress analysis in a discontinuous composite solid. To obtain the internal field quantities of composite, the micromechanics analysis and finite element analysis (FEA) were implemented. For the numerical illustration, an aligned axisymmetric single fiber model has been employed to assess field quantities. Further, a micromechanics model to describe the elastic behavior of fiber or whisker reinforced metal matrix composites has been developed and the stress concentrations between reinforcements were investigated using the modified shear lag model with the comparions between reinforcements were investigated using the modified shear lag model with the comparison of finite element analysis (FEA). The rationale is based on the replacement of the matrix between fiber ends with the fictitious fiber to maintain the compatibility of displacement and traction. It was found that the new model gives a good agreement with FEA results in the small fiber aspect ratio regime as well as that in the large fiber aspect ratio regime. It was found that the proposed simulation methodology for stress analysis is applicable to the complicated inhomogeneous solid for the investigation of micromechanical behavior.
-
The dynamic equation is built by the mathematical modelling. The modelling is composed of various components used for the automatic transmission of tracked vehicles. When the transmission is shifting, the shock occurs in the drivetrain. The transient torques affect the durability and reliability of the vehicle. The factor and design point are analyzed for the transmission.
-
Based on experimental analysis, the characteristics of pulsating pressure wave propagation is clarified by testing of 4-stroke gasoline engine. The pulsating pressure wave in exhaust system is generated gyulsating gas flow due the working of exhaust valve. The pulsating pressure wave is closely concerned to the loss of engine power according to back pressure and exhaust noise. It is difficult to exactly calculate pulsating pressure wave nonlinear effect. Therefore, in the first step for solving these problems, this paper contains experimental model and analysis method which are applied two-port network analysis. Also, it shows coherence function, frequency response function. back pressure, and gradient of temperature in exhaust system.
-
This paper presents a new approach to the design of adaptive control system using DSPs(TMS320C31) for robotic manipulators to achieve trajectory tracking by the joint angles. Digital signal processors are used in implementing real time adaptive control algorithms to provide an enhanced motion control for robotic manipulators. In the proposed control scheme, adaptation laws are derived from the improved Lyapunov second stability analysis method based on the adaptive model reference control theory. The adaptive controller consists of an adaptive feedforward controller, feedback controller, and PID type time-varying auxillary control elements. The proposed adaptive control scheme is simple in structure, fast in computation, and suitable for implementation of real-time control. Moreover, this scheme does not require an accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the adaptive controller is illustrated by simulation and experimental results for a SCARA robot.
-
In the word, there is varied types of vibration, and these affect the mechanical industry. In this paper is plates with two parallel sides fixed. Electronic speckle pattern interferometry (ESPI) is one of the optical nondestructive testing technique. By using the ESPI, vibration modes for excitation point, a/b(ratio of longuitudinal and lateral length), and kind of specimen are measured and compared qualitatively with theoritical analysis that Warburton proposed.
-
Conventionally, grinding of stainless steel, aluminium alloy, copper alloy, and titanum alloy is difficult due to the mechanical properties such as low hardness, high toughness which result in the loading of wheel and the poor surface finish. In order to grind this sort of materials easily, discontinuous grinding wheel with multi-porous grooves was newly developed. The multi-porous grooves were formed during wheel production. This discontinuous grinding wheel drastically increases the grinding performance. It is desirable to use the discontinuous grinding wheel when grinding materials with high efficiency and accuracy which is impossible by conventional wheels. In this paper, the construction and manufacturing method of grinding wheel with multi-porous grooves are explained. The grinding charateristics of discontinuous grinding wheel was also illustrated.
-
This paper proposes a new technique to the design of adaptive control system using DSPs(TMS320C50) for Digital signal processors are used in implementing real time adaptive control algorithms to provide motion for robotic manipulators. In the proposed scheme, adaptation laws are derived from the improved second stability analysis based on the indirect adaptive control theory. The proposed control scheme is simple in structure, fast in computation. an suitable for implementation of real-time control. Moreover, this scheme does not requre an accurate dynamic modeling, nor values of manipulator parameters and payload. Performance of the adaptive controller is illustrated by exeperimental reults for a SCARA robot.
-
The demands for robotic and automatic system are continually increasing in manufacturing fields. There were so many studies to monitor and predict system, but it were mainly relied upon measuring of cutting force, current of motor spindle and using acoustic sensor, etc. In this study digital image of time series sequence was acquired taking advantage of optical technique. Then, mean square error was obtained from it and was available for useful observation data. The parameter was estimated using PAA(parameter adaptation algorithm) from observation data. AR model was selected for system model, fifth order was decided according to parameter estimation. Uncorrelation test was also carried out to verify convergence of parameter. Through the proceedings, we found there was a system stability.
-
The use of small hemispherical high-speed precision bearing has increased drastically these days in the field of computer disk driver, highteech devices as well as communication and electronic device drivers. It was suggested that the new polishing process adopting the diamond grinding wheel and polishing tool instead of multi stage lapping processes, which enables the mass production of the bearing by reduction of polishing time. Polishing mechanism was analysed and the results were applied to the design and manufacturing of the polishing system. Experiments for selection of optimal polishing conditions were carried out using the polishing system.
-
A Study is a experiment which is figure out to aptimum discharge cutting condition of the surfaceroughness, electric discharging speed and electro wear ratio with Ton Toff and V(voltage) as an input condition according to the current(Ip) in an electric spark machine ; 1)Electrode is utilized Cu(coper) and Graphite. 2)Work piece is used the material of carbon steel. The condition of experiment is; 1)Current is varied 0.7(A) to 50(A). 2)Pulse time(Ton) is varied 3(
$\mu$ s) to 240($\mu$ s) and also Toff is varied 7($\mu$ s) to 20($\mu$ s). 3)The time of electric discharging to work piece in each time is 30(min) to 60(min) 4)After the upper side of work piece was measured in radius (5${\mu}{\textrm}{m}$ ) of syulus analyzed the surface roughness to made the table and graph of Rmax by yielding data. 5)Electro wear ratio is; \circled1Coper was measured cx-machining and post machining but the electronic baiance. \circled2The ex-machining of graphite measured by it, the post-machining was found the data from volume specific gravity and analyzed to made its table and graph on ground the data 6)In order to keep the accuracy of voltage affected to the work piece was equipped with the A.V.R(Automatic Voltage Regulator). 7)The memory scope was sticked to the electric spark machine. 8)In order to preserve the precision of current, to get rid of the noise occured by internal resistance of electric spark machine and to force injecting for the discharge fluid, it made the fixed table for a work piece to minimize the work error by means of one's failure during the electric discharging According to above results, the surface roughness by the variation of electrodw and current was analyzed to compare KS(Korea Standards) It was decided the optimum condition of electric discharge cutting through analyzing the effect of electric discharge speed and electro wear ratio. -
Magnetic-electrolytic-abrasive polishing system(MEAPS) was developed for machining national standard electrode and its finishing characteristics was analyzed. The paper describes the operational principle of MEAP system by experimental results. The finishing characteristics and optimal finishing condition for national standard electrodes were experimented and analyzed. As a result, MEAPS can improve straightness as well as surface roughness.
-
In this paper, we have studied internal quality including chemical compositions, microscopic structure and nonmetalic inclusion of test materials. We have analyzed dynamic characteristics of cutting force of milling including tensile strength value hardness etcs. Test materials are used the tempered carbon steel and the non-tempered carbon steel. The obtained results are as follows: 1.In analyzing internal quality, the tempered carbon steel have typical martensite structure and the non-tempered carbon steel have ferrite+pearlite structure. 2.Yield strength, tensile strength and hardness value are in the non-tempered carbon steel but elongation is maximum value in the tempered carbon steel. 3.Cutting force is smaller non-tempered carbon steel than tempered carbon steel when feed speed and depth of cut is constant. 4.Cutting force is smaller to the tempered carbon steel and smaller non-tempered carbon steel than tempered carbon steel when cutting conditions
-
The applicability of a new method, termed the whirling motion concept, for the iprovement of the surface finish in milling three-dimensional sculptured surfaces has been investigated. A method for implementing this concept on conventional NC machines that utilize a suitably configured attachment has been proposed. The tool path equation for the ball-end milling process, based on the Surface-Shaping system, has been obtained. Both results of the computer simulation and the experiment verified the computer simulation and the experiment verified the proposed approach.
-
For the purpose of establishing laser welding condition(laser power, welding speed and beam focus) and of evaluating tailor welded blank for three kinds of thin steel sheets of SPCC, SK5M and SUS304 using in the thin plate structure such as automobile, train and so on. Their
$CO_2$ laser weldability were primarily tested under various welding condition. SPCC and SUS304 thin sheets showed good weldability under some welding condition. But, high carbon steel sheet SK5M needs heat treatment after welding to obtain higher tensile strength and ductility of the welded joint. And next, laser welding condition. Butt-welded specimens were not nearly broken at weld bead. However, base material were ruptured in the direction of circumference. The forming depths by tailor weld bead. However, base material were ruptured in the direction of circumference. The forming depths by tailor welded blank were SPCC+SPCC=22~25mm, SUS304+SUS304=25~43mm and SK5M+SK5M=13~17mm. -
In this study residual stress in weldment was considered about the effect on the fatigue propagation and about the effect of redistribution of residual stress. Then, fatigue tests were conducted by the center notched specimens machined with welded plate. The residual stress and its redistribution after the crack growth were measured by the magnetizing stress indicator and hole-drilling method. Fatigue crack propagation was estimated by the specimens having residual stress redistributed after the cracks growth and having the effects of crack closure. Crack growth rates were predicted and compared with experimental results. It had been found that the predicted crack propagation rates have a good agreement with experimental results when the redistribution of residual stress was considerd.
-
A Sintered carbide roller mold for reflectors which is used for cover of automobile lamp and beacon plate of highway has been developed. The geometry of sintered carbide roller mold has been determined from the analysis of reflector geometry. An acute angle diamond wheel and dressing system also has been designed and developed to manufacture the sintered carbide roller mold.
-
The objective of this thesis is to investigate the influence of welding residual stresses on the fatigue growth behavior of welding residual stresses on the fatigue growth behavior of cracks located transverse to the weld bead. For this purpose, G.T.A. (Gas Tungsten Arc) welding was performed on the Al. Alloy 1100-0 plate and the same initial crack is made on HAZ(Heat Affected Zone), weld metal and base metal respectively. C.T.(Compact Tension) specimens were used as experimental material. Initial welding residual stresses were measured by using strain gage sectioning method. All specimens were tested under constant amplitude load with stress ratio R=0.1
-
On the machine measuring system composed of touch trigger probes, a DNC module, a CMM module, an analysis module and a man-machine interface unit was developed. Measuring accuracy is affected by working accuracy of the on the machine measuring system. The working accuracy of the system is due to geometric errors of th machine tool, servo errors of feed drives and positioning errors of probes. In order to compensate for the measuring errors due to the working accuracy, a calibration module was developed. The measuring automation system was realized with the on the machine measuring system and an IBM-PC on the machine center through a RS-232C. It turns the machining machine (CMM). The system is used for dimensional checking of machined components. initial job setup, part identification, identification of machining errors due to deflection and wear of tools. cutter run out, and calibration of machine tools. A horizontal machining center equipped with FANUC OMC wre used for verification of the system. The validity and reliability of the system. The validity and reliability of the system were confirmed through a series of experiments with gage blocks, ring gages, comparison measurement with a commercial CMM, and so on.
-
This study was performed the blankholding force and vee-ring effects on Blanking characteristics, such as maximum blanking force, burnish, dish-shape, hardness. etc, in fine-blanking die by the experimental method. Two types of aluminum (Al. 1050-0, Al 5052-H) Such as annealed and unannealed materials were used for the experiment. In order to get a hydrostatic pressure effect, the clearance was set to 0.5% of the thickness of strip, and the counter punch and stripper plate with Vee-ring was set-up. While this experiment was carrying out, the average blanking Velocity was constant (37.5mm/sec) As a result of this study, we got a good surface roughness and a glassy shear plane(burnish) of the sheet over 90% thickness, and such as the excellent accuracy of dimensions, the good squareness and the reduction of dish-shape could be obtained, and also the additional results obtained were such that the hardness of shear plane was increased and the maximum blanking force was reduced in the condition of Vee-ring height of 1.0~1.5mm, and blankholding force of 1200kg.
-
It is a great number of problem for the man to perform maintenance and repairing work owing to radioactive effusion for a nuclear fuel and the pollution of an related equipment in nuclear power plants. Therefore, the vision processing system presented in this research requires to maintain the good performance under the radioactive circumstances and to safety the real time processing system presented in this research requires to maintain the good performance under the radioactive circumstances and to safety the real time processing. The proposed vision scheme adapts the gradient and Laplacian operator to perform the high speed processing in an edge detection and the centroid formula at each direction to obtain the center position of a holes using DSPs