Ikuo Tanabe

High Speed and Fine Polishing Using Linear Motor

Recently, several machines with linear motor were developed for high productivity. Feed behaviour of these machines is required high speed, high acceleration and stable behaviour for feed. Other hand, mirror surface was required for adding high quality on the most products. We thought that this linear motor drive suit well for manufacturing on the mirror surface. Therefore, In this paper, high speed and fine polishing using linear motor was investigated for mirror surface. Polishing device was firstly developed for the experiment. The device consists of the NC milling machine, the linear motor driver and the polishing head. The linear motor driver with the polishing head was setted in the spindle of the NC milling machine. A shaver (=shaving device) was substituted for linear motor drive. Epoxy resin was used for the polishing head. Process for making the head, property of polishing and the optimum polishing condition are investigated in several experiments. This system was evaluated for high speed polishing on the flat surface and fine polishing using a minute part. It is concluded from the results that (1) Mirror surface was machined by this polishing system, (2) The polishing time using this polishing system is one tenth of that of the conventional polishing, (3) Minute part which size is about a few mm was machined for mirror surface by this polishing system.

Development of a Precision Assembly System Using Selective Assembly and Micro Machining

In this paper we propose a new combinatorial optimization method for parts matching in a precision assembly system. This method combines selective assembly with micro machining so as to produce high precision assembled units. From the simulation results, it is presented that the system is effective in a small lot production, where higher assembly rates can not be attained with conventional methods, in such that a higher rate is obtained if micro machining is used alongside.

Development of Manufacture Support System Using Taguchi Methods

A Manufacture Support System using Taguchi Methods was developed and evaluated. This system consists of a Taguchi methods part, a CAE simulation part and a management part of productivity. The Taguchi methods part was firstly used for calculating the average and the standard deviation regarding all combinations using all parameters. The CAE part was then used for shortening the total time of evaluation. The management part of productivity was finally used to select the optimum combination of all parameters for success percentage, accuracy, manufacturing time and total cost. The spring back of warm press forming on magnesium alloy plate was investigated for evaluating this system. It is concluded from the result that (1) This method effectively predicted optimum process conditions in each priority and (2) The predicted results conformed to the results of the spring back test.

MACHINE TOOL DISTORTION ESTIMATION DUE TO ENVIRONMENTAL THERMAL FLUCTUATIONS ― A FOCUS ON HEAT TRANSFER COEFFICIENT

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.

Environmental-Friendliness in the Manufacturing Field

In the 21st century, as the importance to manufacture products with environmental-consciousness has been highlighted, manufacturers face a constant challenge to conserve energy, resources and reduce polluting waste. Moreover, in the case of the manufacturing field, large quantities of machine tool lubricating oil, cutting oil, coolant and electricity are used to achieve a smooth drive, precision machining and forced cooling. This represents a significant environmental issue as environmentally-friendly decisions in the technology design, development and production stages are rarely taken. The current research attempted to contribute to the alleviation of the environmental impact of manufacturing. Here, calculation models for a simple environmental impact check and the “Double-ECO model” for technology development were proposed. The proposed methods were then applied and evaluated in a machine tool case that used strong alkaline water mist for forced cooling during machining. It was concluded that; (1) Strong alkaline water mist forced cooling method had a significant cooling performance over the machining-generated heat. (2) the mist was eco-friendly, (3) the calculation models and the Double-ECO model technology can contribute to improve environmental-friendliness.

Development of a Tool for the Easy Determination of Control Factor Interaction in the Design of Experiments and the Taguchi Methods

In recent years, the Design of Experiments (hereafter, DOE) and the Taguchi Methods have been used to decide optimum processing conditions with narrow dispersion and achieve robust designs. However, when large interactions between several control factors are present, since they behave as confounding variables, the estimation accuracy is significantly reduced and making practical use of the DOE and Taguchi Methods can be extremely difficult in some cases. As a common countermeasure, calculation accuracy is confirmed by comparing, through the S/N ratio and sensitivity results, the best and worst gain results. This can be of great harm in terms of time and labor and, if the difference between the best and worst gain results is large, could result in the Taguchi Methods estimations being ignored. In this study, a tool for the easy determination of control factor interactions in the DOE and the Taguchi Methods was developed and evaluated. Then a software of the tool was a developed and evaluated under several mathematical models. It was concluded that: (1) a usable tool for the easy determination of control factor interactions in the DOE and the Taguchi Methods was developed; (2) The tool was able to determine control factor interactions in DOE or the Taguchi Methods.

Development of Cutting Technology in Strong Alkaline Water

Recently titanium and nickel alloys have become eminent for making aeronautic and astronautic parts. Since both titanium and nickel alloys have very low thermal conductivity, the tool will be suffered from a huge damage by the generated heat during machining process. It is required for a durable tool with excellent cooling capacity. Therefore, in this research, cutting technology in strong alkaline water for machining of titanium and nickel alloys was developed and evaluated. Before cutting experiment, the corrosion resistance for titanium alloy and other materials were investigated. Then this cutting process was performed for evaluation in the vessel with strong alkaline water. The assayed materials were mainly Ti6Al4V. The cutting conditions were investigated in experiments. It is concluded from the results that; (1) The cooling capacity using strong alkaline water is very effective to maintain the cutting potential of tool, (2) The new tool is effective for high speed cutting of titanium alloys and nickel (3) The new tool and compulsory cooling system are economical and eco-friendly.

Development of cost-effective and eco-friendly permanent grease lubrication for the machine tool slildes

In this paper, permanent lubrication using grease with polymer for the sliders in the machine tool was developed and evaluated. Firstly, the grease with a polymer was developed for high cohesion property. The grease with a polymer has non-Newton property which can be followed with moving substances. Next, the W-rollers were developed for collecting and distributing of the grease around the slider in the machine tool permanently for the whole machine life. This device consists of the outside roller for collecting, holding and distribution of the grease and the inside roller for adjustment of thickness of the grease layer. Four W-rollers were fitted on the slider in the machine tool. Finally, the level of the “Eco-friendly” regarding the proposed method was evaluated by Life Cycle Assessment. It is concluded from the results that the permanent lubrication using grease with polymer and W-rollers for the slide in the machine tool was highly effective for both industrial and environment. This method is extremely useful for supporting both “Ecology” and “Economy” simultaneously.

Warm Press Forming of Magnesium Alloy with Assist of Direct Cooling and Induction Heating

Warm press forming is very effective to improve draw ability of magnesium alloy. Generally, increasing the temperature of metal makes it soften. In warm press forming, heating the blank on the die decrease its deforming resistance. On the other hand, cooling the blank on the punch increases its tensile strength of sidewall of the product. Draw ability is increased by these methods. But there is a forming limit in this process. Because, excessive high heating of the die increase the temperature of the sidewall, then its strength is decrease. Similarly, high punch speed increase the temperature of the sidewall, then draw ability is decrease. In this study, warm press forming of magnesium with assist of direct cooling and induction heating is investigated. Sidewall of the product is directly cooled by water. Temperature of the blank on the die is increased very quickly and locally without increasing the temperature of the side wall by induction heating. The optimum condition and its performance of this forming system are fisrt investigated by FEM simulation. And real press test is performed for confirmation. It is concluded from the results that (1) Warm press forming with assist of direct cooling and induction heating can increase draw ability from D. R. 3.0 to 4.0 and D. R. 2.4 to 3.2 each punch speed 2.5 and 10 mm/s respectively, (2) Scheduled induction heating power that decided using FEM simulation improves the thickness distribution of sidewall of drawing cup.

Surface Treatment Regarding Coloring of Titanium Using Laser and Its Photocatalytic Effects

Recently, titanium is mainly used as a structure material with many functions. And surface treatments regarding coloring for this metal, are used for high quality products. In previous study, we proposed that the coloring of titanium using an YVO4 laser was possible. In this paper, several properties regarding coloring of titanium were investigated. Relationship between the interference color of titanium and the thickness of oxide film was researched at first. The oxide film of titanium has not got photocatalytic effects, because its crystal texture was amorphous. Therefore, the heat treatment after the laser machining was performed in order to change crystal structure from amorphous to anatase structure. Optimum condition of the heat treatment was also investigated in several experiments. In addition, water repellent and corrosion resistance was also investigated. It is concluded from the results that (1) The oxide film after heat treatment became anatase structure and had photocatalytic effects, (2) Optimum conditions of the heat treatment for changing to anatase structure emerged, (3) The oxide film after treatment had hydrophilic nature and wear resistance.