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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Journal of the Korean Society for Precision Engineering
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Journal DOI :
Korean Society of Precision Engineering
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Volume & Issues
Volume 14, Issue 12 - Dec 1997
Volume 14, Issue 11 - Nov 1997
Volume 14, Issue 10 - Oct 1997
Volume 14, Issue 9 - Sep 1997
Volume 14, Issue 8 - Aug 1997
Volume 14, Issue 7 - Jul 1997
Volume 14, Issue 6 - Jun 1997
Volume 14, Issue 5 - May 1997
Volume 14, Issue 4 - Apr 1997
Volume 14, Issue 3 - Mar 1997
Volume 14, Issue 2 - Feb 1997
Volume 14, Issue 1 - Jan 1997
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Indirect Cutting Force Measurement and Cutting Force Regulation Using Spindle Motor Current
Kim, G.D. ; Kwon, W.T. ; C.N. Chu ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 15~27
Quasti-static cutting force variations in milling process are measured indirectly using spindle motor current. Quasi-static sensitivity of the spindle motor current is higher than that of the feed motor current. Magnitude of the spindle motor current is independent of cutting direction. The linear relationship between the cutting force and the spimdle motor RMS current at various spindle rotational speed is obtained. Frequency/ Voltage(F/V) converter voltage is measured to identify the spindle speed and to determine the cutting force at various spindle speeds. Overload on the tool during milling process can be detected using the proposed indirect cutting force measurement. Based on these measurements, cutting force is regulated at a constant level by feedrate control.
Automatic Inspection of Assembly Tolerances of Cathod Ray Electron Guns by Vision Probe
Park, H.G. ; Park, M.C. ; Kim, S.W. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 28~34
This paper describes an automatic measurement method for the in-line inspection of assembly tolerances of cathod ray electron guns. The method uses an optical microscope with a CCD camera as a probe. An automatic gap recognition algorthm with digital image processing and a new software autofocus algorithm based on using an optimal edge detector have been developed to improve the measuring accuracy. An inspection system has been proposed and practically implemented for in-line inspection to a real factory automation line. The inspection system consists of a gap inspection part and an eyelet. Total time consumed for inspecting all measuring items is about 10 seconds and the repeatability is below .+-. 5 .mu. m
Mechanism Analysis and Optimum Design of Feeddog Transfer Mechanism and Needle Stitching Mechanism of an Industrial Needle Driven Sewing Machine
Lee, J.Y. ; K.J. Chun ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 35~43
In this paper, we perform a mechanism analysis and optimal design of the feeding system in a industrial sewing machine. Sewing machines are classified by the transfer mechanism as (1) transferred by feeddog only (2) transferred by feeddog and needle (3) transferred by feeddog, needle and pressure bar. The sewing machine classified as (2) is studied which is more efficient in transferring fabrics than the machine classified as (1). In analyzing the mechanism, we divide the feeding mechanism as feeddog mechanism and needle bar mechanism. The two mechanisms are conneted with each other kinematically because fabrics are transferred by two needles and a feeddog simultaneously and stitched by two needles which pass through the feeddog in every stitch cycle. We define good stitch as coincidence of stitch between the forward and reverse motion of feeding. We optimize the feeding mechanism for that purpose. It is illustrated that stitching performance of the optimized mechanism is compared to original feeding mechanism.
An Investigation into the Effect of Each Parameter on the Damping Forces Using Dynamic Behaviour Analysis P/G of S/A
Park, J.W. ; Shin, S.Y. ; Lee, S.B. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 44~49
The damping force is determined by four valves and the components which consist of the shock absorber for vehicle. In this study it is investigated the individual effects of four valves and these components on damping forces using dynamic behaviour analysis program of the shock absorber. In addition, opening of main valves are researched during compression and tension cycle due to up- down reciprocation movement of piston. We are to strictly control the properties and tolerance of componenets having important effects on the damping force. Thus we are intended to produce shock absorber of better quality.
Precision Position Control of a Fast Tool Servo Using Piezoelectric Actuators
Song, J.W. ; Kim, S.H. ; Kim, H.S. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 50~57
A fast tool servo (FTS) for diamond turning improves machining accuracy by quickly compensating relative position errors between the cutter and the workpiece. Therefore, the FTS needs to have large band-width with good tracking performance. Serious hysteresis nonlinearity of PZT actuators used in the FTS, however, deteriorates fast tracking performance. Several types of feedforward hysteresis compensators and feedback controllers are tested to improve tracking performance. Through simulations and experiments, control structure which yields the smallest tracking error is selected. The maximum peak to peak error in tracking a sinusoidal waveform is reduced by one fifth compared to that of a regular PID controller.
Development of Expert System for Optimal Condition of Automatic Die Polishing
Lee, D.C. ; Jeong, H.D. ; T. Miyoshi ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 58~67
Generally, die polishing process occupies about 30 .approx. 50% of the whole die manufacturing time. However, die polshing has not been automated yet, since it needs a great deal of experience and skill. This study aims at development of an expert system for die polishing which gives such optimal parameters as tool and polishing conditions. Through experiments, polishing characteristics such as surface roughness, stock removal and scratch were analyzed quantitatively for each polishing tool, and a knowledge base for the expert system was established. Evaluation tests show that the developed system works well to suggest the optimal polishing conditions and it is very promising.
A Study on the Mirror Surface Finishing System Using Micro Abrasive Film
Kim, H.B. ; Kim, K.S. ; S. Namgung ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 68~74
The surface finishing system using the micro abrasive film was designed and manufactured to make the mirror surface of the cylindrical workpices. An experimental study of srface finishing was carried out to investigate the performance of mirror surface finishing system. The surface roughness value of stainless steel was about 0.2 .approx. 0.25 .mu. m Rmax, 0.02 .approx. 0.04 .mu. m Ra, using abrasive grain size of 12, 9 .mu. m. The surface roughness value of chrome coated workpiece was about 0.07 .approx. 0.11 .mu. m Ra using abrasive grain size 3 .mu. m. In the same condition, the chrome coated workpiece has obtained better surface roughness charateristics than the one of stainless steel.
Integrated Process Planning and Scheduling for Machining Operation in Shipbuilding
K.K. Cho ; J.S. Oh ; Kim, Y.G. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 75~84
This paper describes the development of an integrating method for process planning and scheduling activities for block assembly in shipbuilding. A block is composed of several steel plates and steel sections with the predetermined shapes according to the ship design. The parts which constitute the block are manufac- tured by cutting and/or bending operations, which are termed as machining operation in this paper. The machining operation is the first process for block assembly which influences the remaining block assembly processes. Thus process planning and scheduling for machining operation to manufacture parts for block are very important to meet the assembly schedule in the shipyard. An integrating method for process plan- ning and scheduling is developed by introducing the concept of distributed process planning and scheduling composed of initial planning, alternative planning and final planning stages. In initial planning stage, nesting parts information and machining emthods are generated for each steel plate. In alternative plan- ning stage, machine groups are selected and workcenter dispatching information is generated. In final planning stage, cutting sequences are determined. The integrated system is tested by case study. The result shows that the integrated system is more efficient than existing manual planning system.
Finite Element Analysis for Forming Processes of
-Type Bellows Tubes
Lee, J.H. ; Kim, N.S. ; B.H. Jeon ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 85~90
The study presents a computer-aided analysis and its design for the forming process of .OMEGA. -type bellows tubes. Finite element analysis was carried out to perform the process simulation. Bsed on the analytic results of various conditions, the forming conditions used for angled U-type bellows tubes were determined. The 3-D modeling was constructed by I-DEAS and the process simulation was constructed by PAM- STAMP. It is concluded that the difference of height between die and bellows during the forming process causes a non-uniform shape of the bellows and also influences .OMEGA. -shape. These results can be utilized for the process design.
Evaluation of the Complexity of the Product According to Access and Handling
H.S. Mok ; H.C. Shin ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 91~101
In this paper, the complexity of the product is evaluated quantitatively regarding to access of assembly tools and handling of part. To evaluate the complexity of the product, we grasped factors that could influence on the complexity of the product with access and handling, and then we determined the criteria of comparison for each complexity factor. The criteria compare the complexities of product alternatives on each access and handling.
Finite Element Analysis of Compression Holding step Considering Solidification for Semi-Solid Forging
Park, J.C. ; Park, H.J. ; Cho, H.Y. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 102~108
The technology of Semi-Solid Forging (SSF) has been actively developed to fabricate near-net- shape products using light and hardly formable materials. Generally, the SSF process is composed of slug heating, forming, compression holding and ejecting step. After forming step in SSF, the slug is compressed during a certain holding time in order to be completely filled in the die cavity and be accelerated in solidification rate. This paper presents the analysis of temperature, solid fraction and shrinkage at compression holding step for a cylindrical slug, then predicts the solidification time to obtain the final shaped part. Enthalpy-based finite element analysis is performed to solve the heat transfer problem considering phase change in solidification.
The Design of Cutter profiles for Manufacturing Rotors of Screw Compressor
Park, S.H. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 109~118
The purpose of this paper is to design cutter profiles for manufacturing rotors of screw compressor, which are based on universal milling machine. The surface profile of screw rotor which is helicoidal is derived as brief equation through the coordinates transformation of the section perpendicular to rotor axis. And the equations of contact lines between a cutter and the surface profile of screw rotor are derived. The computer program which can analyze the equation of contact lines numerically and design the cutter profiles of screw rotor is made, and verified through measuring screw rotors which are menufactured as the designed cutter by the computer program.
Stress Evaluation by the Measurement of Acoustoelastic Effect Using a Line-Foucus Acoustic Microscope
Kim, J.O. ; Lee, Y.C. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 119~126
The relationship between the applied stresses and the change of elastic wave velocity has been established based on the acoustoelasticity theory. The non-uniform stress field in a loaded specimen has been evaluated from the surface acoustic wave velocity measured by the line-focus acoustic microscopy with the acoustoelastic constants obtained form a calibration test. The evaluated stresses are in good agreement with the results calculated by finite element method.
An Investigation of the Formability of Thermoplastic Composite in Biaxial Stretch Forming
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 127~134
A Study on the Diagnosis of Cutting Tool States Using Cutting Conditions and Cutting Force Parameters(l) - Signal Processing and Feature Extraction -
Cheong, C.Y. ; Yu, K.H. ; Suh, N.S. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 135~140
The detection of cutting tool states in machining is important for the automation. The information of cutting tool states in metal cutting process is uncertain. Hence a industry needs the system which can detect the cutting tool states in real time and control the feed motion. Cutting signal features must be sifted before the classification. In this paper the Fisher's linear discriminant function was applied to the pattern recognition of the cutting tool states successfully. Cutting conditions and cutting force para- meters have shown to be sensitive to tool states, so these cutting conditions and cutting force paramenters can be used as features for tool state detection.
Theoretical Analysis on the Variance Learning Algorithm
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 141~150
Design and Analysis of Displacement/Length Measuring System Using Laser Interferometry
Kim, J.S. ; Kim, S.C. ; S.C. Chung ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 151~156
A laser measurement system, a modified Michelson interferometer, which can accurately measure high speed length and displacement of servomechanisms by detecting a phase shift in the measurement beam using an optical interference was developed. A frequency stabilized laser source and a 20 fold frequency interpolation and digitizing circuit were applied to the system. The refra- ctive index of the ambient air was calibrated through the Edlens formula. The system achieved a resolution of /40, 16nm, a maximum allow-able measurement speed of 600nm/sec, and a length measure- ment range of 1500 mm. Performance of the system was evaluated on the machining center in short and long length measurements.
A Study on the Optimum Cutting Conditions of CBN Ball Endmill
S.W. Choe ; Lee, K.W. ; Lee, J.C. ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 157~163
The needs to machine hardened steels with high productivity and good sufrace integrity have been increased in the dies & molds industry. This paper presents some experimental results on the CBN ball endmilling for hardened tool steel. This investigation concerns on the effects of cutting fluids, cutting speed, and feed on the cutting performance such as cutting forces, tool wear, and surface finish. The wear of CBN ball endmill for each cutting conditions were also examined through the microscopic observation. It has been found that the higher cutting speeds with cutting fluids result in better cutting performance.
Analysis of Response of Lumped Mass System Using Sensitivity Method in Frequency Domain
M.Y. Baek ; C.D. Kee ;
Journal of the Korean Society for Precision Engineering, volume 14, issue 10, 1997, Pages 164~169
The aim of this paper is to present some results of sensitivity analysis in frequency domain. The sensitivity fonctions in frequency domain is not depend on the external excitation but depend on the frequency of the system's resonance. The sensitivity functions are determined as function of partial derivatives of system transfer functions taken with respect to system design parameters. The logarithmic sensitivity function is the dimensionless sensitivity funciton available, making it useful to compare the influence of various parameters on system variables. Two degree of fredom system is used to illustrate the procedure for sensitivity analysis proposed in this paper.