Papers by Author: Naohiro Nishikawa

Abstract: This study was examined about the relationship between the fillers added to the grain layer of a resinoid bond diamond wheel and mechanical properties, the grade, the grinding performance. In the abrasion test using a constant pressure grinding, it was shown clearly that the critical grain holding power changed by kinds of fillers. On the other hand, in the constant cut surface grinding, the grinding interval was evaluated based on the grinding force. And, it was confirmed that the grinding interval changed by kinds of filler. Also, it was found that the characteristics of truing and dressing changed by kinds of filler. In addition, Young's modulus and bending strength of the grain layer of a resinoid bond diamond wheel was measured by three point bending test and ultrasonic pulse method. In the results, it checked that the mechanical properties such as bending strength and Young's modulus of a grain layer changed by kinds of filler. And, the modulus of rupture was calculated from the Young's modulus and bending strength.The result of having compared the modulus of rupture with the critical grain holding power, it was found that the modulus of rupture and the critical grain holding power have good correlation. Namely, the critical grain holding power of a resinoid bond diamond wheel can be evaluated by the modulus of rupture. Furthermore, it was shown that the grinding performance may be able to be predicted by the modulus of rupture of a grain layer of a resinoid bond diamond wheel.

Abstract: Green manufacturing is important subject. In order to reduce waste disposal cost and environmental load, decreasing machining fluid that contains several chemicals such as oil, extreme pressure agent etc. is demanded. In this investigation, the electric rust preventive machining method system that uses only water as machining fluid have been developed. This paper mentioned about evaluation of recycled water quality. The refined water that is purified with developed water recycle system which is installed reverse osmosis membrane (RO) is too clean to evaluate by normal method till now. Using laser turbidity meter, precise water purification is evaluated precisely. Therefore, it is clarified that RO refined water turbidity (RO1=0.0006, RO2=0.0003) is very low compared with clean tap water (0.1207). So, water recycle system can remove contaminating fine particle from water. It is expected that scratch less ultra precision machining with water is enabled to conduct with high filtration ability.

Abstract: The machining (cutting, grinding etc.) is conducted in manufacturing. Machining fluid (cutting oil, grinding fluid) that consists of oil, surface active agent, and extreme pressure agent, anti rust agent etc. is used. It improves machining performance, but it needs waste fluid disposal that is incineration or coagulative precipitation and so on. It causes huge cost and environmental load. Furthermore, it is afraid of workers health hazard for several chemicals while machining. Therefore, the electric rust preventive machining method system (water machining) is proposed and developed. This method uses only harmless water (tap water etc.) as machining fluid. In this paper, improvement of electric rust preventive chip sedimentation system that is part of water recycle system which is used for machining water purification and re-use. On long time (3 days) preservation of iron chip in water, decreasing of rust and turbidity is examined. Improved electric rust preventive chip sedimentation system is equipped simple circulation filter unit newly and its effectiveness is clarified. When many quantity of iron powder (3kg) likened to actual sludge is sunken in sedimentation water tank, if electric rust prevention and simple circulation filter activated, turbidity and colour would be decreased greatly. Therefore, it is expected that purification load of next part of filters is decreased and life-time of filter and system will be prolonged.

Abstract: In production site, machining fluid (cutting oil, grinding fluid) is used. It contains several chemicals that are oil, surface active agent, and extreme pressure agent, anti rust agent and so on. Waste fluid disposal which is incineration etc. is necessary and arise huge cost and environmental load. In addition, workers health hazard is concerned for several chemicals while machining. In this investigation, new water machining method system (electric rust preventive machining method system) that uses only water as machining fluid for solving of conventional machining fluid problems is developed. In particularly, this paper mentions optimization of used machining water recycle on purification rate and refined water flow quantity in developed water recycle system. Therefore, high speed adjustment test liquid equipment is developed for stable experimental condition for evaluation. Test liquid turbidity is random for sludge particle and simple filter decreases this fluctuation. However, water recycle system is aimed for constant refined output despite fluctuation of input dirty water, and it is achieved. The optimized refined water flow quantity is 13.3 L/min at 1.0 MPa from viewpoint of purification on iron, turbidity, colour, conductivity and flow rate and purification load for reverse osmosis membrane.

Abstract: Roughness is important criterion of ground surface. When the surface roughness is demanded to be smooth, it is required to make the grinding conditions optimum. To optimize the grinding conditions, relationship between grinding conditions and ground surface roughness must be known. Therefore, it has been attempted to reveal the effect of grinding conditions on the roughness of ground surface over the years. From previous researches, it becomes possible to estimate the ground surface roughness with statistical grinding theory. However, there are some parameters, such as wheel depth of cut and distribution of abrasive grain, are not factored in the theory. In this paper, fundamental research on cross sectional profile is carried out to consider the relationship between the wheel depth of cut and ground surface roughness.

Abstract: Currently, the machining fluid includes several chemicals such as cutting oil and grinding oil is used for the machining. However, such the machining fluid that is caused enormous disposal cost and environmental load, should reduce using. Therefore, in this investigation, electric rust preventive machining method which uses only water for machining fluid is developed. Because using only water without extreme pressure agents, oil and so on, this method decreases disposal of waste machining fluid. In this paper, the system to remove impurities from a used machining fluid, and to reuse machining fluid is designed. To reproduce water efficiently, the order of arranging the filter is changed. In consequence, it has been efficient when the filtration filter is set up first, and the activated carbon filter is set up in the second. In addition, the reproduction of the water when the supply pressure is 0.75 MPa is verified by using this system. As a result, the water which passed a water recycle system, the impurities such as iron, conductivity, turbidity, colour decreased, and purification of the water is possible for this system. And, 5.2 L/min refined water recycle is achieved.

Abstract: Both form accuracy and smooth surface is required in precision grinding. And the form accuracy and surface roughness are improved year by year. However, the more the surface roughness becomes smoother, the more the grinding marks become remarkable. The grinding mark deteriorates the accuracy of optical parts. It is found that the vibration of grinding wheel is transcribed to the ground surface and forms the waviness named nano-topography. And the nano-topography causes grinding marks. In this study, relationship between the nano-topography on non-axisymmetric aspherical ground surface and grinding condition is analyzed theoretically to control the distribution of nano-topography. As a result, simulation method of nano-topography distribution is developed.

Abstract: A prototype three-dimensional tool oscillation system for finishing metal molds, which can oscillate a tool in a figure-8 motion, has been developed. When such a tool motion is used, the lapping direction alternatively changes and consequently a very smooth surface might be achieved in a relatively short time in the presence of a very fine abrasive compound. The developed tool oscillation system consists of three multilayer piezoelectric transducers. The orientation of the tool motion can be changed in three dimensional space. This paper describes the structure of the tool oscillation system, the driving method of the three piezoelectric transducers for oscillating a tool in a figure-8 motion and the measurement results for the tool motions.