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EN
Titanium alloy and nickel alloy are mainly used for several aeronautical parts due to their high strength and durability at high temperature. However, thermal conductivity of these materials are very low and most of the heat generated during cutting are concentrately conducted into the cutting tool. Therefore, the tool become extremely high temperature resulting shorter tool life. In this paper, a method for calculating the optimum cutting condition for cutting low thermal conductivity materials such as titanium alloy and nickel alloy is developed and evaluated. The temperatures on the cutting tool tip for various combination of tools and work piece materials were calculated by dynamic FEM simulation and the estimation tool for optimum cutting condition is created based on these results. The amount of heat flow and the temperature on the cutting tool were calculated based on cutting theory. Then, optimum cutting conditions for those materials were estimated by newly developed program. The method was finally evaluated by several experiments. It is concluded from the results that (1) The developed program is applicable for estimation of optimum cutting conditions regarding titanium alloy and nickel alloy. (2) Titanium alloy (Ti6Al4V) can be machined with longer tool life using estimated optimum cutting condition.
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Recently, high efficient solar power generation is required because eco-awareness is increasing. High efficient generation becomes possible by focusing sunlight on electric generating element, i.e. CPV (Concentrator photovoltaic). Although the concentrator is used for focusing sunlight, it demands large spherical surface with high solar reflectance, fine accuracy and lightweight. Aluminum is considered as suitable material for concentrator. However, mirror-like processing on large spherical surface is very difficult. Therefore, new polishing technology for aluminum was developed and evaluated in this paper.Main objective is to obtain high solar reflectance by improving surface roughness. As a trial study, workpiece was not large spherical but small and flat. Firstly, the polishing tool which attached polishing cloth was developed.Optimum polishing cloth for tool was investigated by trial and error approach. When workpiece was heated before starting polishing, a number of oxides were adhered to polishing cloth and surface roughness was improved efficiently.Then optimum polishing condition was decided by using design of experiments method. Finally, solar reflectance on polished surface was measured and evaluated. It is concluded from these results that (1) the developed polishing technology was effective for processing the mirror-like surface on the surface of aluminum, (2) 82% solar reflectance was obtained with developed polishing technology by improving surface roughness of workpiece.
EN
Recently, cemented carbide dies are used for many industrial products, due to their high stiffness and long life. Electric discharge machining is conventionally used and then, hand lapping is finally undergoes for mirror-like finishing of these products. In privious research, a simple lapping system for only plane surfaces of cemented carbide die was developed. In this study, several lapping tools for lapping of side, edge and corner were developed and evaluated by experiments. The system consists of a lapping tool, lapping vessel and conventional NC milling machine. The lapping vessel is placed on the table of the NC machine and the lapping tool is fitted with the spindle of the NC machine. Cemented carbide work piece is sunk and fitted in the lapping slurry and lapping processing is taken using the developed tools. Each lapping tool consists of a coil spring for supplying lapping pressure and the NC program was made possible to move the lapping head to contact and leave the work surface regularly for catching new grains and dressing. These lapping tools were finally evaluated by experiments. It is concluded from the results that the developed lapping tools were capable of lapping side, edge and corner of the cemented carbide work pieces for mirror-like surface finishing.
EN
Establishment and selection of proper cutting condition can improve tool life and final cutting result. Cutting speed, feed speed, depth of cut and selection of tools are conditions of cutting that determined the cutting accuracy. However, when the optimum cutting condition with selected cutting speed coincides with machine resonance frequency, large vibration will occur. Consequently, even small periodic of driving forces can produce large amplitude vibrations. The simple technique to lower resonant frequency of machine tool was developed in previous research by using mixture of water and polymer with 6wt% concentration. As it was difficult to obtain damping ratio when the concentration is larger than 6wt%, therefore, the aim of this paper is to change machine resonant frequency for optimizing cutting condition by improving mixture concentration of water and polymer. It is concluded from the results that (1) By controlling machine tool resonance frequency enable cutting speed to be used for processing at its optimum cutting condition (2) New damping value of polymer mixed with water was presented, (3) Machine vibration reduced as resonance of machine was successfully avoided and surface roughness was also improved.
EN
In the 21st century, as it is important to produce the products with high accuracy, high quality and eco-friendly, the most of manufacturers need several daring plans, unique ideas and new technologies. For example, in machine tool technology, restraint of vibration on the machine tool was required for high accuracy and quality, and several countermeasures using costly equipment and large quantity of electrical energy were used for the restraint, however those countermeasures are not enough. Therefore a countermeasure of vibration for machine tool using alkaline water with polymer was developed and evaluated. Polyethylene oxide was used for the polymer because of the low cost and the safety for health. Relationship between the mixed polymer in the alkaline water and the damping ratio were firstly investigated. And the optimum percentage of the polymer was decided for restraint of vibration on a machine tool. Then the damper structures using alkaline water with polymer were development, and the three dampers were set for restraint of vibration in the small machine tool; those are the support units, the vise and the head stock. Each damper was evaluated regarding noise and vibration on the machine tool and surface roughness on a work piece in the experiment. It is concluded from the results that; (1) the optimum percentage of the polymer for the damper was 6 wt%, (2) the damper structures using alkaline water with polymer were very effective for restraint of both noise and vibration on the machine tool and smoothly surface on the work piece.
EN
The geometrical accuracy of the products are essential for high quality and interchangeability. Lapping processing is mostly using for final improvement of geometrical accuracy. Geometrical accuracy includes cylindricity, circularity and straightness. In this paper, lapping processing using a normal lathe was investigated for improvement of geometrical accuracy. Firstly, normal turning process is taken and then, the lapping process is performed using the same lathe. The lapping tool consists of a lapping head made of polypropylene (PP), a coil spring for supplying lapping pressure and holder for fitting on tool post. Lapping slurry is composed by mixing water, PEO (Polyethylene Oxide) and diamond grain. This lapping slurry is supplied between the work piece and the lapping head during lapping processing. The lapping head is made to contact and leave from work piece in regular intervals for catching new grains and removing chips. The optimum lapping condition was investigated for high productivity and high accuracy by experiments. It is concluded from the results that; (1) The geometrical accuracy were improved by using developed lapping system with ordinary lathe machine. (2) The optimum lapping condition was revealed experimentally. (3) The surface roughness and dimensional accuracy are also improved using this developed lapping system.
EN
An eco-friendly manufacturing approach is important for the environment. Enhancing machining performances is not only required to improve product’s quality, time saving, and reduces costs; it is also contributed to the environmental protection efforts. Cooling is important aspect for obtaining this purpose. Therefore the benefits of Strong Alkaline Water (SAW) cooling method was assessed and compared with conventional wet cutting method. An experiment was performed at Nagaoka University of Technology machining centre. Three machine tools including a milling machine, a drilling machine and a turning machine were used. The study shows that using SAW for cooling is far more efficient than conventional cooling method. It reduces annual global warming potential by 72.95%, acidification potential 98.18%, ozone depletion potential 99.6%, smog formation potential 85.71% and human toxicity potential 42.86% compare with conventional method. The study concludes that besides inhibiting corrosion, prolonging tool life, improving surface roughness of final cutting and reducing energy usage, strong alkaline water cooling is an environmentally friendly approach and has positive impact on human health.
EN
Recently, the use of hard materials has increased for product quality and safety reasons. Consequently, the cutting conditions for these materials become severe resulting in shorter tool life due to higher cutting temperature. In this paper, tool technology to reduce heat generation and its influences during cutting is investigated and evaluated experimentally. The approach for reducing cutting heat generation is considered by changing the tool geometry and reducing the frictiona coefficient between tool and chip. The approach for reducing influence of the generated heat is application of a therma insulator (coating) on the tool material having high thermal conductivity and heat-resistance. The turning process is used in the experiments. The thermal influences are made clear by each experimental parameter and then, the optimum tool parameters were considered from experimental results. It is concluded that; (1) When rake angle was 15 degree, temperature rise on the tool was smallest. (2) Temperature rise on the tools coated with TiAlN or DLC (Diamond Like Carbon) were reduced from 20 % to 30 %. (3) Several tool materials were quantitatively evaluated by consideration of the thermal conductivity, as well as thermal dependency of their hardness.
EN
Thermally induced errors have been approached in multiple ways due to the influence these have over the positional accuracy of a machine tool. Here, approaches regarding environmental thermal fluctuations surrounding a machine tool remain to be explored in detail. These fluctuations have been explored in terms of the heat transfer coefficient and thermal radiation of the machine shop walls, as well as in terms of seasonality and varying thermal gradients. This paper presents additional considerations regarding environmental temperature perturbations, as heat transfer coefficient fluctuations in the machine shop were thought to play a significant role in machine tool thermal deformation a broader term for these phenomena, environmental thermal fluctuations, was defined and evaluated. Specifically, an environmental thermal data survey of a machine shop was explored. This data was then applied to a NC milling machine and a CNC jig borer FEM analyses and compared to experimental data. FEM simulations were then used to demonstrate that convection regimes and heat transfer coefficient values at a machine shop have a significant influence over machining precision. Here, under maximum and minimum heat transfer coefficient values, the NC milling machine and CNC jig borer simulations results showed an error of cut difference up to 36.5 μm and 18.17 μm, respectively. In addition, as the importance of the heat transfer coefficient was highlighted, considerations regarding machine tool surface color were deemed relevant and were described.
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Characteristic that is hard to obtain in the calculation in product development. The sensory characteristic is often had such as sound quality, visual sensation and tactile sensation. The evaluation method for visualizing the determination of the customer is being established by applying Taguchi-methods and so on. The fact is still got many corresponds with the method of Try & Error as numbers of cases are small in order to optimize the properties. Therefore, the study was conducted of the method for optimization of sound quality by using the innovative tool using Taguchi-methods that newly developed. The research results are summarized as follows. (1) Sensory characteristic tuning method by using Taguchi-methods was calculated the values to be optimized in a few studies, and the result was equal to or greater than the result of specialists is carried out. (2) Commonly, the sensory characteristic of optimization is conducted with the method of Try & Error; moreover, it could be confirmed that leading to improvement of productivity by using this method even though it takes time to perform so as to optimize under changing in physical condition and environment.
EN
This paper presents a study on optimization of single side U-shaped yokes. Single side U-shaped yokes are usually used in the measurement of a magnetic properties of magnetic materials such as in a single sheet tester. It is difficult to measure the magnetic properties accurately, because of the large eddy currents. The influence of the angle between the poles and sample sheet and the thickness of the insulator has been investigated by using the finite element method and considering the lamination of yoke materials. We applied a special element concerning the insulator to the yoke parts so that we can save the memory and time.
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As swift development with low cost was required for the manufacturing in industry, CAE simulation was used to predict the result of the design process, and Taguchi methods was used to decide optimum conditions for minimizing the dispersion.In this study, the perfectly design system without trial production using CAE and Taguchi methods was developed and evaluated. Software for original Taguchi methods and software for productivity management were firstly created, these softwares were combined with established CAE, and software package was developed for estimating the optimum combination of design parameters. Then the quality and the functionality were advanced to gain the optimum condition for the maximum profit considering the function of the grading of products, the delinquent charge and the loss function in the quality engineering based on the developed software. The research results are summarized as follows. (1) Perfectly design system without trial production using Taguchi methods was developed for calculations of the grading products, adding the delinquent charge and the loss function. (2) The evaluation with Kami-copter contributes to the profit evaluation of the grading; the delinquent charge and the loss function with high dimensional accuracy and is evaluated effective on industry.
EN
Several machines with linear motor have been developed for high productivity. The characteristics of these machines are high speed, high acceleration and deceleration with stable behaviors of feed. Moreover, mirror-like surface is required to add high quality on the most products. In this study high speed lapping by using the lathe with linear motor was investigated for mirror-like surface. Lapping was performed after turning with the same lathe Lapping tool consists of a lapping head, a spring and holder on the tool post to assemble the linear motor lathe. The spring is used to supply lapping pressure. Lapping slurry consists of water, PEO ( Polyethylene Oxide) and diamond grain. This slurry was supplied between a work piece and lapping head. Then, high speed lapping was performed. During the process, the lapping head temporarily left from work surface in order to catch some new grains and removed some chips. The optimum combination of both the spindle speed and the feed speed was investigated for high quality and productivity experimentally. Surface roughness and form accuracy were measured. It was concluded from the results that (1) Mirror-like surface was obtained by the high speed lapping, and (2) Optimun conditions for efficient high speed lapping was revealed experimentally.
EN
Recently, many micro structure products are used for compact, high precision and others functions in the field of measuring instruments, medical instruments, information processing devices and so on. However, in the small sliding parts of these products, the surface contact pressure becomes lowered and then, higher adhesive force occurs, resulting larger coefficient of friction. On the other hand, in the field of machine tools, lubrication free sliding parts are also demanded for eco-friendly. In this study, the surface treatment for improvement of coefficient of friction for both light load and heavy load applications are investigated. When laser ray is applied on stainless steel surface, CrO2 layer with small concaves like dimple is generated. This CrO2 layer is used in light load applications. Next, TiAlN and DLC coating are being used on cutting tools for reducing coefficient of friction and cutting heat. Therefore, these coating materials are used for heavy load and oil free applications. The improvement of coefficient of friction and life of coating are investigated by experiments. It was concluded from the results that; (1) Coefficient of friction for light load application can be reduced by coating CrO2 layer. (2) Coefficients of friction for heavy load application were reduced by coating TiAlN and DLC layer. (3) Life of both CrO2 and DLC layers are sufficiently long for practical applications at light load and heavy load respectively.
EN
Nowadays, eco-friendly manufacture has become common request in the manufacturing and production. The excessive electric power associated with the usage of large amount of oil for cooling and lubrication during machining can increase the CO2 emission which is considered as large problem for environment. On the other hand, the presence of the unwanted vibration during machine can affect the quality of production. The influence of immersed machine tool in strong alkaline water has been investigated in previous work for normal machine operation when no vibration occurred. In present research, the influence of immersed condition to the vibration of the bench lathe machine was investigated. Thermal deformations of the spindle when operating bench lathe coincide with machine resonances were also measured for evaluation of accuracy. The calculation of CO2 emission using immersed bench lathe machine was done by comparing with the conventional machining. It is concluded from the results that; (1) Excellent cooling efficiency can be achieved by using strong alkaline water added with microbubble, (2) Vibration of machine tool was reduced during immersed condition, (3) Thermal deformation of the bench lathe was very small despite no-forced cooling was used, (4) The large number of CO2 that released annually can be reduced by immersed of machine tool.
EN
In recent years, the urgency to create environmentally-friendly technologies has dramatically increased. However, these technologies are usually not adopted due to their large cost and low profit. Previously the “Double-ECO model” has been proposed as a methodology that reconciles both “Economy” and “Ecology”, which relies on the exploration of technology alternatives that offer an improved mechanical performance. Here, as mechanical performance, cost and environmental impact were meant to be approached under the same degree of priority, this model was thought to offer the basis for a broader technology development framework. The current research initiates said framework by proposing an evaluation platform, which through a transition from a focus on environmental-friendliness towards an improved eco-efficiency definition lays groundwork for an automated evaluation. This was done by defining a dimensionless evaluation parameter based on existing methodologies and referred as the “DE Index”. This paper applied the proposed evaluation method into a machine tool lubrication technology example. It was concluded that, (1) the platform was able to effectively compare technologies under the proposed eco-efficiency parameter, (2) the developed technology possessed improvements in the environmental pollution output, mechanical performance and cost when compared to conventional technologies.
EN
Recently titanium and nickel alloys have become pre-eminent for aeronautic and astronautic parts. Since these cutting and becomes severely demaged. It is important to control cutting tool temperature. In this paper,the control system of tool tip temperature using inverse analysis of neural network for machining these materials was developed and evaluated. The neural network between cutting conditions and tool temperature was firstly created by a set of teaching data. Then, a mathematical model using algebra was developed. Cutting speed was selected as parameter to be controlled in reducing tool temperature. The relationship between the optimum cutting speed and cutting time was calculated with the inverse analysis of neural network by pre-reading of NC program before cutting. The tool temperature can be maintained at the desired value. The developed system is evaluated by the expaeriments using the turning process and workpiece of Ti6Al4V. From the results, it is concluded that; (1) Tool tip temperature can be controlled by using the proposed inverse analysis of the neural network, (2) CThe cutting tool life can be maintained by this method, for cutting materials with low thermal conductivity.
EN
Recently titanium alloys and nickel alloys have become eminent for making aeronautic and astronautic parts. Since both nickel alloys and titanium alloys have a very small thermal conductivity, the being used tool will suffer from a huge damage by heat generated during cutting process. Therefore, there is a requirement for a durable tool with excellent cooling capacity. In this research, a new electro-deposited diamond tool for high speed cutting of nickel alloys and titanium alloys was developed and evaluated. The new tool is a cup shaped end mill, its body is made from copper (due to its superior heat conduction characteristics) and the platting layer for bonding the diamond grains #120 is nickel. The cooling system is an advancement of the former used heat pipe. Water is supplied from outside through a thin tube, that is integrated in the tool body. Thereby the effect of water evaporation, featuring a very large cooling capacity, could be applied. The assayed materials were Ti6Al4V and Inconel 718. The cutting conditions were investigated by some pre-experiments. It is concluded from the results that; (1) The cooling capacity of the new tool using water evaporation is very effective to maintain the grinding potential of electro-deposited diamond tools, (2) The new tool is effective for high speed grinding of nickel alloys and titanium alloys (3) The new tool and compulsory cooling system are economical and eco-friendly.
EN
Recently Taguchi methods are used to decide optimum processing conditions with narrow dispersion for robust design. On the other hand, innovative development with short-term, low cost, labor and energy saving is also required in the world. In this study, the software for development of a product with optimum condition using Taguchi methods is developed and evaluated. There are two trials in the software using Taguchi methods. First trial investigates rough functions regarding all levers of all control factors, then important control factors and meaningless control factors were sorted with the several comments for the second trial. At that time, maximum, intermediate and minimum values for each lever of each of the control factors should be used for pursuit of all possibilities. In the first trial, the relationship between each level value of each of the control factor and the desired property is also decided by the function, then the optimum combination using each level of each of the control factors were calculated for the second trial by using the function. The second trial is confirmed for the best combination using the estimated optimum level values. For example of an application, the optimum design for the paper craft “airplane” was investigated for evaluating this software in the experiment. It is concluded from the result that: (1) The proposed software was useful for developing with short-term and lower cost, (2) This tool could quickly and exactly decide the optimum design condition and (3) The paper craft “airplane“ with most long flying length is manufactured by using the developed software.
EN
Lapping is an old traditional machining process that has been useful all along in the human history. Uniform surface finishing by manual hand lapping on cylindrical inner and end surfaces are very difficult. Additionally, the geometrical form accuracy and productivity are lower. In a previous study, the new lapping method for outer cylindrical surface using the lathe with linear motor has been reported. However, this method could not be applied directly for the cylindrical inner and end surfaces. Therefore, lapping for mirror-like finish on cylindrical inner and end surfaces using the lathe with linear motor is investigated. In this study, lapping tool was modified from previous study to be suited for the cylindrical inner and end surfaces. Then, lapping methods for inner and end surfaces were developed for uniform mirror-like finish. Surface roughness and geometrical form accuracy improvement were measured for both surfaces. The optimum conditions for high productivity and high quality mirror-like surfaces were investigated. It was concluded from the results that, the developed lapping system was able to process mirror-like surface on cylindrical inner and end surfaces. Moreover, the optimum conditions for the mirror-like surfaces were revealed experimentally.
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