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1
Content available Surface treatment for improvement of coefficient of friction on sliding surfaces
Tanabe I., Soe Y. H., Iyama T.
Journal of Machine Engineering
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2012
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Vol. 12, No. 1
7--17
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.
2
Content available Lapping system for improvement of geometrical accuracy using lathe machine
Soe Y. H., Tanabe I., Iyama T., Da Cruz J. R.
Journal of Machine Engineering
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2012
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Vol. 12, No. 1
28--40
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.
3
Content available Estimation tool for optimum cutting condition of difficult to cut materials
Soe Y. H., Tanabe I., Iyama T., Da Cruz J. R.
Journal of Machine Engineering
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2012
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Vol. 12, No. 1
76--88
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.
4
Content available Development of lapping tools for mirror-like surface processing of cemented carbide die
Soe Y. H., Tanabe I., Iyama T., Nishiyama S.
Journal of Machine Engineering
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2012
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Vol. 12, No. 1
66--75
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.
5
Content available Tool technology to reduce cutting heat generation and its influences
Soe Y. H., Tanabe I., Iyama T., Hoang T. B.
Journal of Machine Engineering
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2010
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Vol. 10, No. 3
5--16
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.
6
Content available Lapping for mirror-like finish on cylindrical inner and end surfaces using the lathe with linear motor
Moe A. L., Tanabe I., Iyama T., Nasu F.
Journal of Machine Engineering
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2010
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Vol. 10, No. 1
13--25
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.
7
Content available High speed lapping for mirror-like finish using the lathe with linear motor
Moe A. L., Tanabe I., Iyama T., Nasu F.
Journal of Machine Engineering
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2010
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Vol. 10, No. 1
26--38
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.
8
Content available Development of intelligent lapping system estimation of finished surface roughness and its improvement speed
Iyama T., Tanabe I., Moe A. L., Yoshi K., Nasu F.
Journal of Machine Engineering
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2010
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Vol. 10, No. 1
5--12
EN
The lapping process is one of the traditional finishing processes and generally it is conducted as manual process by skilled worker. The productivity of these manual processes is lower and difficult to control. Hence, we developed an automatic lapping system for moulds and dies. The lapping system consists of simple lapping tools and conventional milling machine. Several materials were machined as mirror like surface using the system. The lapping conditions are usually decided by skilled worker's experience or knowhow. Therefore, in this study, an intelligent lapping system with the optimum conditions calculated by the lapping model was developed. Specifically, the relationship between the finished quality (surface roughness Rz and improvement rate of Rz) and each parameter of the system, Vickers hardness of work piece and lapping head, lapping pressure, grain size, is investigated. Then, an intelligent lapping system is developed. Finally, the HPM31 are machined as confirmatory experiment by developed system with calculated lapping conditions. It is concluded from the result that: (1) The relationship between the surface roughness and lapping parameter was cleared. (2) The intelligent lapping system using the lapping model was developed. (3) The estimated limit surface roughness and improvement rate by calculated condition satisfactorily agreed with the experimental results.
9
Content available Control of tool temperature using neural network for machining materials with low thermal conductivity
Soe Y. H., Tanabe I., Iyama T., Abe Y.
Journal of Machine Engineering
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2010
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Vol. 10, No. 3
78--89
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.
10
Content available Development on diamond tool with forced cooling system for high speed cutting of aeronautic and astronautic parts
Tanabe I., Hoang T. B., Iyama T.
Journal of Machine Engineering
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2009
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Vol. 9, No. 1
58--65
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.
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