It is very important to test circular motion accuracy of NC machine tools as it affects all other machines machined by them in industries. In this paper, it has become possible to detect errors of linear displacement of radial directions for circle tar motion accuracy test using newly assembled magnetic type of linear scale so called Magnescale ball-bar system. It has also organized computer program systems using tick pulses come out from computer for getting error motion data at colt start time interval in circular motion test on NC lathe. Error data gotten from test is expressed to plots and analysed to numerics by various statistical treatments.

We develop a method to analyze dynamic behavior off multi-stage gear train system. The example system consists of three shafts supported by ball bearings at the ends of them and two pairs of spur gear set. For exact analysis, the meshing tooth pair of gear set is modeled as spring and damper having time-dependent meshing stiffness and damping. The bearing is modeled as spring. The result of this analysis is compared to that of other model having mean mesh stiffness. The effect of the excitation force by the unbalance off rotor off motor is also analyzed. Finally, the change ova natural frequency of the whole system due to the change of an angle between three shafts is compared in each case, and from this analysis, the avoiding angle for design is advised.

This paper presents the experimental study of the static stiffness for the BT shank(7/24 long taper) and the HSK tool shank(1/10 short taper) in the main spindle taper of machine tool. The static stif71ess test was performed under different experimental conditions. It is turned out that the effective axial drawing force is larger than 6kN in the 7/24 test tool shank and BkN in the 1/10 test tool shank. As a test result, considering that the actual drawing force of the machining center is about 1300k2f and axal drawing force 12kN is equivalent amount as a 1220kgf, it is turned out that 1/10 test tool shank superior to 7/24 test tool shank in the static stiffness.

Analysis of squeal noise generated during brake operation is an important task for the improvement of brake noise prob-lem. By the use of measuring instrument and techniques, test and evaluation process are to be developed systematically in quantitative analysis. The cost far test and evaluation 7an be reduced, and the technical power can be raised by the devel- oped system.

The cutting characteristics of Ti-6Al-4V alloy and total wear when machining Ti-6Al-4V alloy was studied to understand the machining characteristics. This material is one of the strong candidate materials present and future aerospace or met ical applications. Nowadays their usage has already been broaden to commercial applications such as golf club head, finger rings and many decorative items. Anticipating the general use of this material and development of the titanium alloy in domestic facilities, the review and the study of the machining parameters far those alloys are deemed necessary. This study is concentrated to the machining parameters of the Ti-6Al-4V alloy due to their dominant position in the production of tita mum alloys.

This article presents a new acceleration/deceleration method for real-time control of autonomous mobile robots. In this method, a function which produces the table of acceleration/deceleration in real-time is proposed. This function, while sat- isfying the basic concept of mechanics, can choose both various ranges of velocity and distance ranges for the selected velocities. Moreover it can control motors in real time. This function is convenient to be realized by programming. In addi- tion, it is faster than other functions because it can be written by assembly language.

In this study, fatigue limit of ductile cast iron is evaluated based on phenomena of the microscopic observation, such as matrix structure, spheroidal ratio, size of graphite and distribution. Three different ferrite-pearlite matrix structure, GCD 45-), GCD 50, GCD 60 series, all of which contain more than 70% spheroidal ratio of graphite, were used to obtain the correlation between maximum size of graphite and fatigue strength. It was concluded as fellows. (1) In Ductile cast iron of ferrite-pearlite matrix, the fatigue limit of GCD 60 series with 73% pearlite structure was the highest. (2) From observation of the starting point of crack of all specimens, it is noted that the crack initiates, in graphite, goes through ferrite and propagates into pearlite. (3) A good quality of Ductile cast iron used in this experiment can be checked from uniformly distributed graphite. The negligible interaction effect between graphites was verified by microscopic observation and fracture mechanics investigation in surface and interior of the specimen.

In this paper, this study aims at the evaluation on the characteristics of CFRP laminate plates using a falling weight impact tester. The experiment was conducted on several laminates of different orientation. A system was built far measur- ing the impact strength of CFRP laminates in consideration of stress wave propagation theory using a falling weight impact tester. Delamination areas of impacted specimens for the different ply orientation were measured with ultrasonic C- scanner to find correlation between impact energy and delamination area. Absorbed energy of quasi-isotropic specimen having flour interfaces was higher than that of orthotropic laminates with two interfaces. The more interfaces, the greater the energy absorbed. The absorbed energy oft hybrid specimen containing a GFRP layer was higher than that of normal specimens.

Recently, it has increased that the importance of gas pressure weldment of steel bars in large construction bars. But there has hardly been any studies about it. Therefore we need more research. SD40 steel bar (32mm in diameter) which has been practically used at construction sites are tested about tension, bonding, fatigue, a macro structure and micro structure at foil gitudinal section and hardness to fed out the mechanical property and best welding ranges in some cases of mechanical cut and gas cut before gas pressure welded. It is that a gas-pressure welded zone of steel bar where was cleaned of impurities in way of two-upsetted method is more excellent bending and tension property than the regulation of KD D 0244. Also gas cut bars gained hardness from the heat affected zone so. In conclusion, to improve the weldability of steel bars, it is considered best to clean mechanically cut sutra- faces and then weld them by a method of 2 step upset way.

This study is concerned with Finite Element Analysis on welded part of control link fur automobile. For analysis, control link was modeled into two parts, ring and rod. Heating condition, temperature distributions and fatigue fracture strength were analyzed using "HEAT III" and "NDURE" module of NISA II. Metal flow in the process of welding was simulat- ed by $DEFORM^{TM}2D$.The analyzed results were compared with experimental inspection. Quality of welded part was able to be improved by controlling metal flow in the process of welding by increase the friction constant of ring part. Heat transfer analysis and flow simulations were in good agreement wish welding experiments.

We have developed the exclusive CAD/CAM system for the machining of impeller blades. This study is about the mod-eling method for the effective machining of impeller blades farmed by ruled surface. As the impeller is consisted of boss part and blade part, the boss is modeled by rotational surface of hub curve on z-axis and the blade is described by ruled- surfaces between hub curve and shroud curve. This modeling process can be carried out on the software developed in this study. And, the developed software can describe the impeller as a solid model through interface with Solid-Works soul- ware. The developed software containing the interface method proposed in this study was very effective fur impeller modeling.

In the present study, SiCSi-$Si_3 N_4$-SiC ceramic composites that contained up to 30 wt% of dispersed SiC particles were fabricat-ed cia hot-pressing with an oxynitride glass. The microstructure, the mechanical properties and the cutting performance of resulting ceramic composites were investigated. By fixing the composition as $Si_3 N_4$-20wf%SiC, the effect of sintering time on the microstructure, the mechanical properties and the cutting performance were also investigated. The longer sir-tering time is, the bigger the grain size of SiC is. The fracture toughness(-$K_k$) of the $Si_3 N_4$-SiC ceramic composites increased with the increase of gain size, while the flexural strengthh($\sigma$) decreased. For machining SCM440, the insert with 20wt%r SiC sintered for 8 hours showed the longest tool life while the insert with 20wt% SiC sintered for 12 hours showed the longest tool life for machining gray cast iron.

Hydraulic systems of rope brake for elevators are modelled to evaluate design parameters such as cylinder pressure, pis-ton displacement, accumulator capacity, and so on. To assure the results, experiments were performed. The analysis results agree well with the experimental results. The scheme in this study is expected to be utilized in the design of rope brake system for elevators to get design parameters and to improve the safety.

This work is concerned with construction of the intelligence stress predictor far compression strength evaluation using neural network-ultrasonic waves. The contact pressure in jointed plates was measured by using ultrasonic technique. Neural network is used to evaluate and predict contact pressure from the results of the calibration curves. The organized neural system was leaned with the accuracy of 99%, as a result of learning the ultrasonic echo ratio to the contact pressure measurement between SM45C and STS410 materials. And it could be evaluated and predicted with the accuracy of 90% in the evaluation of ultrasonic echo ratio difference in the same surface roughness and contact pressure, and 85% in the prediction of virtual ultrasonic echo ratio. Thus the proposed stress predictor is very useful for the evaluation and prediction of the contact pressure between SM45C and STS410 materials.

To prevent green house effect and destruction of an ozone layer, an ozone destruction potential(OBP) must be zero and a refrigerant for low global warming potential(GWP) is needed. HFC-l34a, in which hydrogen is mixed instead of chlorine is a refrigerant used for automobile conditioners and its destruction potential is ecologically zero. However, it is not consid- ered as a perfect substitutive refrigerant as its GWP is high. It is studied refrigerant mixtures in which HFC-l52a and $CF_3 I$ in HFC-l52a with low GWP and zero ODP are mixed by experimentally and concluded as follows: 1) With the variation of speed of compressor outside temperature and flow rate, 7he heat of evaporator and compressor and coefficient of perfor- mance was varied, and influenced the air conditioner. 2) The pressure of evaporator was decreased with increasing the speed of compressor and the pressure of evaporator with the refrigerant HFC-l52a was higher 24% than that of azotrope refrigerant mixed with $CF_3 I$

This paper investigates the mechanical characteristics of angle-ply laminates with non-woven carbon tissue. The lami- nates were made by inserting non-woven carbon tissue at the interface. Specimens were rounded near the tabs by grinding and polishing to reduce the stress concentration. Cyclic loads were applied to the specimens and the stress and fatigue life curves were obtained. The matrix crack density was also evaluated to check the effects of non-woven carbon tissue on the fracture resistance of composite laminates. C-Sean technique was used to evaluate the delamination, and SEM was used to understand the fracture mechanisms of the laminates. Experimental results show that the fatigue strength and life of composite laminates were increased by inserting non- woven carbon tissues. The results also show that the matrix crack density and delamination area were reduced by inserting non-woven carbon tissues.

The comprehensive system analysis for contour milling operation has performed in this study, which combined the each element with proper connectivity into closed loop system, and determined the system response by numerical simulation technique. The obtained simulated results were then compared with the experimental results from the practical points of view, and so forth, the governing equations were formulated into the estimation model, which predicted the total contour machining error within 25% accuracy. Through the procedural evaluation, it could ascertain the characteristics of generation mechan- ifs in circular contour machining error, and the weight of each factor.

Recently, high productivity and cost reduction becomes the most important target of industries due to the worldwide economic competition. One of these efforts is High Speed Machining(HSM), which reduces machining time with the increase of machining speed such as cutting speed and feedrate. It is very important, especially in case that the portion of machining time in production cost is high. This research suggests optimum cutting conditions to reduce cutting time with minimizing term error. For this study, a comprehensive model representing the texture of machining surface is developed, including rubbing phenomenon on the tip of ball end mill and expanded fibbing zone trajectory caused by tool deflection. Experiments show that the suggested set of feed and pick feed is optimum for maintaining the surface roughness identified by rubbing and low cutting speed in minimum.