우리나라 전산업의 R & b 투자율을 보면 표5에서와 같이 1.01%로서 일본의 2.03% 미국의 2.88%에 비해 크게 부족한 실정이다. 또한 기계공업에서는 2.25%로서 상당히 높은 비율로 나타나고 있으나 역시 일본 및 미국에 비해 뒤떨어지고 있음을 볼 수 있는데 그러나 타업종과 달리 기계공업중 전기. 전자와 정밀기기업종이 중심이 되어 기업의 기술 개발투자를 선도하고 있으나 기술집약도가 높은 이 부문에서 선진국과 큰 격차를 나타내고 있음을 알 수 있다. 이와같이 우리나라 기계공업체도 최근에는 많은 기술개발투자를 하고 있으나 이에 비해 개발실적은 우리기술이 크게 낙후된 실정이어서 아직도 선진공업국수준 이하의 기계를 개발중에 있는 것으로 평가되고 있는데 즉, 선진국에서는 이미 5-10 년전에 개발 공급한 제품들을 개발하고 있어 한마디로 복사단계의 기술개발이라고 하겠다. 그리고 국내 베어링회사인 K사의 R & b 투자실적 및 계획을 '85 년도에 1.4%로 저조하였으나 '88 년에는 2.9%로 계획하고 있어 R & b 투자에 많은 관심을 가지고 있음을 알 수 있으나 다른 투자를 할 수 없는 실정인 것으로 나타나고 있어 베어링산업의 또하나의 문제로 지적하지 않을 수 없다.

Turning property of metal is affected by the cutting condition, tool geome- try and cutting material. But the turning property of welded material is not welknown. Welded structures usually contain nonhomogeneity, defects and resi- dual stresses due to differential contraction between welded metal and base metal. In this paper, authors conducted the experimental test on the turning property, by changing turning condition and welding electrodes of the welded specimens. The results obtained in these experimental tests are as follows; (1) Within the limit of this experimental test, the cutting force of the weld zone is bigger than that of base metal, and this phenomena is caused by the different mechanical property of the weld zone. The range of the variation of cutting force in the weld zone is caused by the nonhomogeneity of the weld zone, respectively. (2) The surface roughness follows the general characteristic of the effect of cutting condition on the surface roughness and the surface roughness of the weld zone shows coarse surface comparing with that of the base metal. (3) The specimen welded by the electrode E4301, shows worse cutting property than that of E4361 and E4313.

In Korea, all the photoelastic materials are imported from foreign countries. The cost of these materials are expensive and problems in importing have been restrained research and development in this field. To reduce these problems, the domestic EPOXY RESIN which is made of bisphenol type epoxy resin have been investigated in this study to find to find a photoelastic characterics by tensile test and to measure photoelastic sensitivity coefficient and transition temperature and the optimum using condition was also investigated.

The burr worsens the accuracy of a workpiece and decreases a lot of pro- ductivity because it takes so much time and efforts to remove it. In this paper, the height, thickness and size of a drilling burr were derived from the drilling variables of drill diameter, chisel edge angle, web rate =($\Frac{2{\times}\;web\;thickness}{drill\;dia}$) and yielding stress of the workpiece as wel as feed, point angle and helix angle. The theoretical and experimental values of drilling thrust, torque and burr size of the testpiece were analyzed with the method of numerical analysis in a standard drilling condition. The order of choosing the drilling variables for the purpose of controlling the burr size was dealt in this paper with burr forming ratio. The results are as follows: (1) The drill diameter forms 42 percents feed 25 percents point angle 23 percents and web rate, chisel edge angle and gelix angle 5 percents of the partial differential slope of drilling thrust within the usual available ranges of drilling variables. (2) The drill diameter forms 55 percents feed 26 percents web rate 9 percents and chisel edge angle, point angle and helix angle 10 percents of the par- tial differential slope of drilling torque in the usual available ranges of drilling variables. (3) About 70 percents of the burr size can be controlled by feed, 29 percents by web rate in the case of a fixed diameter. It is recommended drilling10 variables to be chosen in the order of feed, web rate, drill diameter, point angle, chisel edge angle and helix angle so as to control the burr size effectively.

By developing a computer program for the systematic design of worm gears, the design formulae and tables of AGMA, JGMA, BS and DIN are analized and compared. The computer program can be used on micro-computers. According to the input data of the reduction ratio, the center distance. the driving torque and the material as design parameters, the program calculate the most efficient worm gear dimension. The variation of the design parameters and other empirical coefficients in case of resulting an inadequate design gear dimension can be easily modified throuth the way of interactive method between the user and the monitoring system of computer. A proposal of the standardization of worm gears was made in which a standard module according to the DIN 323 standard series number was applied. For the more exact and effective calculation of the stress concentration and the deformation of gear teeth, a computer program using the boundary element method is also developed. Even the strength of the special gear shape such as Niemann's "Cavex" gear can be calculated in a short CPU-time. The most effort of this study has been layed on the developing a computer program for the correction of a tooth profile and face width which is most important design factor for an exact and wide teeth contacts under loads, especially by great and wide gears. For this purpose were investigated the tooth stiffness, the mesh interferences and the kinematics and the dynamics of gear mesh. The deflection and the deformation of the gear shaft due to the loads acting on gear and shaft were aslo considered. Some examples have shown the sufficient good status of teeth contact in which the correction of the tooth profile and face width were accomplished due to the calculated results.d results.