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EN
These days, most machine tools are interlocked by an enclosure for safety control. At that time, internal heat generation in machine tools first causes thermal deformation of the machine structure, which reduces the machining accuracy of the workpiece. Furthermore, the internal heat generation heats the air inside the enclosure, causing a heat build-up phenomenon, and the trapped heat causes re-thermal deformation of the machine tool structure. As a result, machine tools with enclosures are subject to extremely complex thermal deformation. On the other hand, we would like to use FEM thermal simulation to study thermal deformation countermeasures for machine tools with enclosures at the design stage, but it is difficult to analyse the heat build-up phenomenon usingconventional FEM thermal simulation. In this research, the new FEM thermal simulation technology for the heat build-up phenomenon was developed and heat build-up phenomenon in a CNC lathe with enclosure was calculated using the proposed FEM simulation technology. As a result, it had been concluded that the proposed FEM simulation could calculate with high accuracy for the phenomenon of heat build-up in a CNC lathe with enclosure, and the proposed technology is very effective in the design.
EN
In wet cutting, lubricants are used to improve lubrication, forced cooling and chip evacuation. In particular, improving the lubrication between the tool and the chip results in a lower coefficient of friction, suppressing the tool temperature change and improving the cutting properties. For this reason, tools coated with DLC (Diamond Like Carbon) or diamond have been developed to further reduce the coefficient of friction. However, the tool life is still not sufficiently long. Therefore, in this study, a cutting fluid for polishing tools during cutting was developed and evaluated. First, using the author's previous research, the function, effect and influence of several cutting fluids on milling were identified. Secondly, a new criterion for determining tool life was defined and, based on this criterion, a cutting fluid was proposed to polish the tool during the cutting process. Next, the machining conditions under which the proposed cutting fluid would be effective were identified. Finally, the cutting properties of the proposed cutting fluid were evaluated. The results showed that (1) the cutting fluid was developed to polish the tool during the cutting process and the optimum machining conditions were clarified, (2) the proposed cutting fluid was very effective in increasing the tool life.
EN
In recent years, manufacturing must not only focus on high precision and productivity, but also on saving energy, resources and the environment. At the same time, there are increasing demands for high quality, high grade, wear resistance, heat-resisting property and high rigidity in machining workpieces. Therefore, for example, when creating NC programmes for machining difficult-to-machine materials such as titanium alloys and nickel alloys used in the aerospace industry, it has been very difficult to determine their optimum cutting conditions and create highly productive NC programmes due to lack of experience. Therefore, an AI optimizing technology of NC program using tool free-cutting temperatures for turning was developed and evaluated. The turning was used for this research and neural networks were used for AI optimizing. The algorithm for optimizing NC program using tool free-cutting temperature was firstly developed. Then the AI optimizing program for NC program was developed by C programming language. Previous NC program can rewrite for optimum condition by using the AI optimizing program. The proposed AI optimizing technology of NC program was evaluated by the several experiments. It is concluded from the results that; (1) The AI optimizing program for NC programmes using tool free-cutting temperatures in turning was developed, (2) The developed program was very useful for high productivity, long tool life and environmentally friendly.
EN
Mirror-polishing processes have recently been required to add high quality, high-precision precision and multi-functionality to industrial products. However, this requires skilled manual work, making it difficult to improve productivity. Automatic polishing of these products is also very difficult. Furthermore, mirror-polishing process of stainless steel, titanium and glass, which are often used in high-value-added medical products, is also difficult. Therefore, in this study, a technology for high-precision, automatic mirror polishing of three difficult-to-polish materials - stainless steel, titanium and glass - was developed and evaluated. First, the difficult-to-polish properties of different materials were considered, and then tools were developed to improve these properties and enable suitable mirror-polishing processes. Next, a polishing slurry was developed to improve the surface roughness (Rz = 0.1 μm or less). Finally, the optimum polishing conditions for the proposed mirror-polishing process were determined by design of experiment and then evaluated. It was concluded that; (1) In order to perform mirror-polishing processes of three types of workpieces, stainless steel (SUS304), titanium (pure titanium) and glass (quartz glass), new polishing tool and slurries corresponding to each material were developed and the optimum polishing processing conditions were clarified, (2) Using (1), mirror-polishing processes of each material with a surface roughness of Rz = 0.1 μm has been achieved.
EN
The Sustainable Development Goals (SDGs) were proposed to ensure the well-being of everyone on earth, a purpose to which all the fields, including manufacturing, must contribute. However, although industry is implementing this laudable concept in a piecemeal fashion, it is currently unlikely to achieve all 169 targets in the 17 Goals by the SDG deadline of 2030. Therefore, qualitative and quantitative achievement indicators and effective evaluation methods are needed to achieve the 17 goals of the SDGs when developing industrial products. Therefore, in this study, the manufacturing in response to the 17 goals and the 169 targets of the SDGs is considered, and the application of the pentagonal W-ECO model for manufacturing based on the SDGs was proposed. First, the current situation of manufacturing was considered from an environmental perspective, which is also important for the SGDs. Secondly, product’s lifespan which is deeply related to the environment, was discussed in terms of the correlation between time, technology and environment, and "Re" technology was proposed to extend product's lifespan and save resources. Then three cases of development for environmental conservation were introduced to understand the current situation, and it was confirmed that the new technologies in the three cases can contribute to the achievement of SDGs, however the degree of their contribution couldn't be evaluated quantitatively. Finally, the previous three cases using the proposed pentagonal W-ECO model quantitatively evaluated and confirmed that the results of the evaluation provide a quantitative indicator for achieving the SDGs. As a result, the effectiveness of the pentagonal W-ECO model for manufacturing based on SDGs is evaluated.
EN
The Mahalanobis-Taguchi System (MTS) is, today, widely used to define the optimal conditions for the design stage of product development especially, in the field of Artificial Intelligence (AI) considering the non-linear properties and non-digital data. In this paper, an approach to identify the several interactions in a MTS is proposed. The MTS contains four methods; Mahalanobis-Taguchi (MT) method, Mahalanobis Taguchi Adjoint (MTA) method, Recognition Taguchi (RT) method and Taguchi (T) method. The method to use for the analysis is selected based on the system’s properties. For the case of study used in this research, the unit space is created through the RT method and used to calculate the Mahalanobis-Taguchi distances (MTD). For the method proposed in this paper, the relationships between control factors and MTDs were firstly clarified by MTS (RT), then the same relationships were clarified using a modified design of experiments method, and the several interactions between control factors in MTS (RT) were finally identified by comparing the two relationships. Then effectiveness of the proposed method was evaluated by using a mathematical model.
EN
In recent decades, the technological devices have become a big burden for the environment. In fact, the production processes are depleting the natural resources and the end-of-life processes are emitting big amounts of heavy pollutants and toxic gases. Today, there is an agreement among researchers that the environmental issues must be considered from a life cycle perspective. In order to reduce the negative impacts of technologies on the environment, the best scenario would be to extend their lifespan. However, an old device, is usually linked to low performances, low profit for the manufacturer, additional reparation costs, high risks, etc. In this paper, the Double-Eco (DE) model, an evaluation platform of the compromise between the performances, cost, ecology, safety and lifespan is developed. Also, the environmental impacts of the lifespan are highlighted through the example of personal computers (PCs) and the DE model is applied to three types of grease lubrication as case of study. The results show that (1) evaluating a technology with all its aspects is efficient when deciding whether to extend its lifespan (2) based on the DE model, the lubrication with the longest lifespan has a better evaluation than the two other studied cases.
EN
Over the last few decades, titanium alloys have become an important ingredient in many industrial sectors. In fact, titanium with additional characteristics, such as: high strength, heat resistance, low thermal conductivity, light weight and biocompatibility are being more and more used. However, the machining of titanium products tends to result in a thermal oxidation process and the development of a coloured layer. Therefore, a research regarding the thermal oxidation phenomena and its prevention was conducted. In this regard, cutting and grinding processes were experimentally investigated. Subsequently, L-ascorbic acid, a substance used against food oxidation, was used as an agent against oxidation during grinding. The main conclusions of the current study are the following: (1) Causes leading to the thermal oxidation during cutting and grinding were defined, (2) Prevention against oxidation was established by using L-ascorbic acid and strong alkaline water solution, (3) Optimum density of the solution with L-ascorbic acid and strong alkaline water was only 7.5 wt. % for grinding.
EN
In recent years, titanium alloys and nickel alloys have become eminent for making aeronautic and astronautic parts. Since both nickel and titanium alloys have a very small thermal conductivity, the being used tool will suffer from huge damage by heat generated during the grinding process. Therefore, there is a requirement for a durable tool with excellent cooling capacity. In this research, the technology regarding the new forced cooling using with high-pressure coolant for machining difficult-to-machine material was developed and evaluated. A through-hole in the near the tip on the rake face of the turning tool is firstly machined by electrical discharge machining. High-pressure coolant was then supplied to the turning tool from the hole on the bottom of the tool. Several values of pressure were tried in many experiments. It is concluded from the results that; (1) a new forced cooling method in the form of drilling a hole at the tip of the tool from which supply high-pressure coolant, a tool temperature decrease and a tool-life prolongation could be achieved, (2) the technology could effectively cool near the tip of turning tool, (3) the chip was effectively broken by the high pressure, (4) It was confirmed that the tool cutting edge condition was stabilized, the surface roughness of the machined workpieces was improved, the tool hardness was maintained and the tool-life was prolonged due to the cooling effect of the devised tool.
EN
As high speed, high acceleration and stable drive on machine tools is constantly growing in demand, the use of linear motors in machine tools has increased. On the other hand, in order to achieve a high degree of quality, the need for mirror-like finish surfaces on industrial products has also considerably increased. This research explores the use of linear motors to develop a high-speed fine polishing process that achieves a mirror-like finish surface on small parts. The first stage of this process consisted in developing a polishing device, which was composed of a NC milling machine, a linear motor drive and a polishing head. Specifically, a polishing head attached to a linear motor drive was coupled with the spindle of a NC milling machine. A substitute for a small linear motor drive was obtained from a commercially available shaver, while the polishing head was made of propylene. The polishing head elaboration process, linear motor drive properties, lapping agent and the optimum polishing conditions were investigated in several experiments. The evaluation consisted in the high-speed polishing of minute areas on flat surfaces using the selected optimum conditions. It is concluded that, (1) the proposed system was able to achieve a mirror-like finish surface, (2) when compared to polishing with an ultrasonic motor, the machining time of the proposed system was reduced by half, (3) the proposed system was able to achieve a mirror-like finish on a 3 mm square sided area.
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