Takekazu Sawa

Development of Electric Rust Preventive Machining Method - Correspond to Difference of Water in World: Use of Deionized Refined Water

Grinding fluid & cutting oil are contained various chemicals. Waste fluid treatment causes huge disposal cost and heavy environmental load. This investigation proposes the electric rust preventive machining method system that water is used as machining fluid. However, there are various problems for this practical use. In this paper, using and re-using of machining water are considered. Water quality is different in various foreign regions for containing impurity ingredient varying with each area. Correspond to water difference, water purification and deionization is examined in developed machining water refine recycle system experimentally. Synthesized water that is likened to hard water is composed from refined water (pure water which is made by water recycle system). And, it is confirmed that synthesized water is refined to deionize by water recycle system. Moreover, 12.25L/min refined water is achieved. In addition, it is indicated that electric rust prevention is possible by refined water at least 1hour. However, high voltage and device twist is necessary.

Development of Electric Rust Preventive Machining Method - Correspond to Difference of Water in World: Use of Adjusted Synthesized Water

For low environmental load and decreasing waste fluid disposal cost, the electric rust preventive machining method that uses only water as machining fluid has been developed. However, there are several problems for this practical use. In this investigation, for using this method in various regions of the world, reset and synthesis of water quality that is different in regions for containing impurity ingredient and water hardness is examined. At first, water is deionized and purified with water refine recycle system. Afterward, synthesized water is reproduced. Hardness and conductivity is adjusted in water by addition of very small amount of natural hardness ingredient CaSO4. Consequently, even if water is different, constant quality of the water can be always secured anywhere in world. Furthermore, electric rust prevention is achieved 3hours with adjusted 100S/cm synthesized water. However, adhesion derived from anode is appeared in workpiece 2hours. It is possible that the electric rust preventive machining can be carried out stability anywhere in world.

Study on High-Speed Milling of Steam Turbine Blade Materials - Differences in Cutting Characteristics of an Unforged Ingot and a Forged Part of Stainless Steel

Stainless steel is an excellent material that has properties such as heat and corrosion resistance. Thus, stainless steel is used as a material in steam turbine blades. Steam turbine blades are mainly manufactured using two methods. One is the cutting of unforged metal ingots. Another is the cutting of forged parts. Small blades are made by cutting metal ingots. Large blades are made by cutting forged parts. The mechanical characteristics of a metal ingot and a forged part, such as hardness and toughness, are almost the same. There were not researches related to a relationship between “an unforged ingot and a forged part of stainless steel” and “the differences of the tool wear and the finished surface by high-speed milling”.In this study, the high-speed milling of stainless steel was attempted for high-efficiency cutting of a steam turbine blade. The differences of the tool wear and the finished surface in the cuttings of an unforged ingot and a forged part were investigated. In the experiment, the cutting tool was a TiAlN coating radius solid end mill made of cemented carbide. The diameter of the end mill was 5 mm, and the corner radius was 0.2 mm. The cutting speed were 100 m/min-600 m/min. The workpieces used were a metal ingot and a forged part of stainless steel. In the results, it was found that the differences of the tool wear and the finished surface in the cuttings of an unforged ingot and a forged part. In the case of the unforged ingot, the flank wear became large with increasing cutting speed. On the other hand, in the case of forged part, the flank wear rapidly increased at a cutting speed of 100 m/min. In addition, the flank wear became smaller than the cutting speed 100 m/min at the cutting speed 200 m/min. Further, the flank wear became large with increasing cutting speed at cutting speeds higher than 200 m/min. That is, the flank wear was at a minimum at a cutting speed of 200 m/min. Although it could not be confirmed the characteristic of high speed milling at an unforged ingot, it has been identified at a forged part.

Study on high speed milling of steam turbine blade materials - Differences in cutting characteristics of titanium alloy and stainless steel

Titanium alloy and stainless steel are used as steam turbine blade materials. However, their machining efficiency is low because they are difficult-to-cut materials. In particular, the high cutting point temperature and short tool life are major problems. Highspeed milling can reduce the cutting point temperature and tool wear. In this study, highspeed milling of a titanium alloy and stainless steel was investigated for the high-efficiency cutting of a steam turbine blade. In the experiment, workpieces were made of titanium alloy Ti-6Al-4V and stainless steel 13Cr. The experiment was conducted at cutting speeds from 100 m/min to 600 m/min. The flank wear increased rapidly with increase in the cutting speed. The loss of the coating on the flank of the end mill was confirmed via energy-dispersive Xray spectroscopy analysis. It was demonstrated that the cutting point temperature was higher than the heat resistance temperature of the coating. The cutting point temperature was analyzed using AdvantEdge FEM. It was found that the cutting point temperature at a cutting speed of 350 m/min or more was higher than the heat resistance temperature of the coating. On the other hand, in the case of the stainless steel 13Cr, the flank wear increased in proportion to the cutting speed, and the loss of the coating on the flank of the end mill was also confirmed. However, the loss of the coating was less than that in the case of the titanium alloy. It was found that the high-speed milling of the stainless steel did not reach the heat resistance temperature of the coating. The cutting characteristics of the high-speed milling of the titanium alloy and stainless steel differed, which was mainly attributed to the difference in the thermal conductivity. In the high-speed milling of the titanium alloy Ti-6Al-4V and stainless steel 13Cr, it was not possible to determine the factors that result in a low cutting point temperature. If the cutting point temperature is lower than the heat resistance temperature of the coating, high-speed milling may be possible. Therefore, the ways in which the cutting point temperature can be lowered will be examined in the future.

Evaluation of Grinding Performance by Mechanical Properties of Super Abrasive Wheel - Evaluation of Grade by Grinding Force

There is the grade as one of the selection criteria of a grinding wheel like WA whetstone or GC whetstone. The grade of grinding wheel is defined as an index which shows the strength of connection of a grain and a grain, and is usually estimated by bending strength. There are many papers about the relationship between the grade of a grinding wheel and the grinding performance. And, the relationship between the grade of a grinding wheel and the grinding performance is almost clear. Also, the relationship between mechanical properties of a grinding wheel and the grade is also clear. On the other hand, since the grain layer of a super abrasive grinding wheel is thin, it is difficult to apply the conventional evaluation test of the grade. And, the evaluation method of the grade which can be adapted the super abrasive grinding wheel is not established. In addition, since the grade of a super abrasive grinding wheel is a manufacture manufacturers original standard, there is a minute difference by manufacturer. The super abrasive grinding wheel as well as the grinding wheel is conjectured that the grade influences the grinding performance. Namely, it is important to relate the grade and the mechanical properties of a grain layer. However, researches which relate the grade, the grinding performance and the mechanical properties of a super abrasive grinding wheel are not done so far. Therefore, this study examined the relationship between the mechanical properties of a grain layer of a super abrasive grinding wheel and the grade, the grinding performance. The final objective of this study is to evaluate the grinding performance from mechanical properties of a grain layer of a super abrasive grinding wheel. The purpose of this report is to clarify relationship between the grade and the grinding force in a resinoid bond diamond wheel. The specific experiment procedure is as follows. When carrying out surface grinding of the diamond sticks using a grinding wheel, the relationship of the grade and the grinding force was clarified. And based on the knowledge acquired in this experiment, relationship between the grade of a super abrasive grinding wheel and the grinding force was considered. As the results, it confirmed that the grade of a resinoid bond diamond wheel could be evaluated by the grinding force.

Development of electric rust preventive machining method system – safe water using for machining fluid: complete removal of bacteria (Legionella pneumophila) and assay

In manufacturing, machining fluid as cutting oil or grinding fluid is used for machining. This fluid contains several chemicals such as oil, surface active agent, extreme pressure agent (chlorine, phosphorus, sulphur, etc.), rust preventive agent, antiseptic agent, germicide and so on for improvement machining performance. However, it is not good for human body and environment. It is afraid that workers health hazard is occurred by fluid mist absorption in breath and splash contacting. In addition, waste fluid needs disposal treatment (incineration or coagulative precipitation and landfill, etc.) that is high cost and heavy environmental load. Therefore, environmental friendly and harmless machining is proposed for nanomanufacturing and green manufacturing. The electric rust preventive machining method system is developed in this investigation. This method system use only water (tap water, under ground water, industrial water) as machining fluid. Water only machining lead to greatly decreasing of waste fluid treatment and petroleum oil resources saving. In addition, complete removal of bacteria (Legionella pneumophila) for safe machining water by improvement water recycle system installed reverse osmosis membrane and ultraviolet radiation unit with non-using chemicals is evaluated by biological cultivation assay. And artificially contaminated tank water bacteria amount tendency is estimated.

Development of an Innovative Water Machining System Employing the Electric Rust Preventive Method - Precise Evaluation of Purity of the Refined Water with a Laser Turbidity Meter

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.

Development of Electric Rust Preventive Machining Method - Improvement of Electric Rust Preventive Chip Sedimentation System

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.

Development of Electric Rust Preventive Machining Method – Optimization of Water Recycle System

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.

Basic Study on the Development of the General Purpose Vertical Milling Machine for Educational Skill Training

In this study, covering for the skill training centers in Japan, we performed surveillance study about the functions required for the general purpose milling machines for educational skill training. As a result, it was found that the function of recognizing machining state is desired for milling machines besides higher stiffness, higher accuracy, and the ease of chip treatment. Based on this fact, the general purpose vertical milling machine was developed for educational skill training. First, a beginners work analysis was conducted and the functions which control the mishandling were developed. The operation mistake has decreased by this function. In addition, the cutting power inspection system was built by using high sensitive micro-wattmeter. And, the possibility of judgment of tool wear was found by inspecting the change of the wave profile in the wattmeter.