ICMCTF2003 Session E5/G4-2: Smart Coatings for Green Manufacturing Tools and Surface Engineered Components

Monday, April 28, 2003 1:30 PM in Room California

Monday Afternoon

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1:30 PM E5/G4-2-1 Tribology of Dry Deep Drawing of Various Metal Sheets with use of Ceramics Tools
S. Kataoka (Tokyo Metropolitan Industrial Technology Research Institute, Japan); M. Murakawa (Nippon Institute of Technology, Japan); T. Aizawa (University of Tokyo, Japan); H. Ike (RIKEN, Japan)
Dry deep drawing is attractive from an ecological point of view but suffers from difficulty to be applied to metal sheet forming. On the other hand, ceramics dies sometimes have superior tribo-properties and have been investigated widely for general purposes in tribology. In the present paper, the possibility of dry deep drawing is studied using ceramics dies. Selecting the suitable ceramic die to each group of metallic sheets, deep drawing can be performed even without use of any lubricants at all. Alloyed tool steel, alumina, zirconia, silicon carbide and silicon nitride, were used as a die material for deep-drawing tests. Sheet materials are chosen from commercially available pure metal sheets, i.e., titanium , soft aluminium , cold rolled mild steel and tough-pitch copper. Furthermore alloy metal sheet (stainless steel) and zinc-coated sheet were examined. The results were evaluated by Limiting Draw Ratio (LDR) in comparison with tool steel. LDR reflects friction between tool and blank. Friction between tool and blank was also evaluated by drawing load in a consecutive cupping test of 100 blanks without cleaning of tools. Ceramic tools have intrinsic compatibility to each selected group of pure metal sheets. Drawability is enhanced remarkably for mild steel and pure copper, whereas no improvement was experienced for titanium sheet, and only small improvement was observed for aluminum sheet. Silicon nitride and silicon carbide have higher drawability to mils steel and pure copper sheets than alumina and zirconia. Difference in chemical bonding reflects on this difference. Silicon carbide has the highest drawability to the zinc-coated sheet material. Alumina has higher drawability to metallic alloy sheets like stainless steel of type AISI304. Dry deep drawing using ceramics tools is quite promising when the adequate die material is selected to each metallic sheet. These findings will be important to create the environmentally friendly technology of metal forming.
2:10 PM E5/G4-2-3 Cutting Performance of DLC Coated Tools in Dry Machining Aluminum Alloys
H. Fukui, J. Okida, A. Ikegaya, H. Moriguchi, K. Tsuda (Sumitomo Electric Industries, Ltd., Japan)
In spite of having many beneficial properties, diamond-like carbon (DLC) coatings have not been widely applied for cutting tools compared to commercial titanium-based hard coatings like TiN, TiCN and TiAlN. In this work, cutting performance and tribological behaviors of DLC coated tools were investigated. The DLC prepared on cemented carbide substrate by physical vapor deposition. Pin-on-disk experiments were conducted on DLC coated cemented carbide disks, using an aluminum alloy ball as a pin material. DLC coatings had a low friction coefficient (0.1) against the aluminum alloys. The DLC coated tools were evaluated for aluminum alloys machining. The results show that DLC coated tools can be used to reduce adhesion between a tool and a workpiece. The reduction of adhesion occurred because of the low friction coefficient. Therefore, smooth surface of the workpiece was obtained. In order to analyze the cutting process, Finite Elements Method (FEM) simulation was used. The FEM simulation of a contact between the tool and the workpiece enabled to explain a phenomenon of the cutting process. In the case of dry machining of the aluminum alloys, DLC coated tools have excellent potential compared to non coated tools.
2:30 PM E5/G4-2-4 Study on Dry Cutting Using Heat Absorption Tool
M. Jin, M. Murakawa (Nippon Institute of Technology, Japan)
Currently, in the field of industrial cutting process, considering the viewpoints of decreasing the load on the environment, improvement of labor sanitation and cost reduction, the reduction or elimination of the use of lubricant in the cutting process is strongly demanded. Therefore, the semidry and dry cutting processes have been introduced. In this study, as a perfect dry cutting method, which is different from conventional semidry cutting processes, such as the MQL cutting process and the cooled air cutting process, we proposed a dry cutting technique using a heat absorption tool in which the tool life can be improved by interior cooling to reduce the cutting temperature. In the experiment, we fabricated a throw-away single point cutting tool and a throw-away drill, and cutting experiments were performed to investigate the above-mentioned benefits. As a result of the experiments, for the case of the proposed dry cutting system, the tool life is improved to more than twice that obtained with the conventional dry cutting system, and is found to have the same level as the case of the conventional semidry cutting system mentioned above.
2:50 PM E5/G4-2-5 Synthesis and Characterization of Nanolayered TiO2/a-Al2O3 Coatings for High-Temperature Machining and Other Tribological Applications
Y.-W. Chung, K.W. Lee, L. Keer, K.. Ehmann (Northwestern University)
It was demonstrated from previous studies that nanolayered coatings with the correct choice of components and layer thicknesses have enhanced hardness, due to interfaces providing barriers against dislocation motion and multiplication. We expect superlattice coatings made of two immiscible components to be stable against interdiffusion. Therefore, the layer structure and reasonable hardness for such nanolayered coatings should be preserved at high temperatures. These thermally stable coatings are desirable for protection of cutting tools in dry machining applications, which may operate at temperatures in the 800-1000°C regime or higher. More importantly, if a coating has low adhesion to aluminum, then aluminum machining can be improved by reducing the material transferring to the tool surface resulting in tool life reduction and unacceptable surface finish. For this reason, TiO2 and a-Al2O3 were chosen for this investigation. Nanolayered coatings made of these two immiscible components were synthesized by dc dual-cathode reactive magnetron sputtering. Substrate rotation was used to enhance uniformity of the coating. Substrates included silicon, M2 steel and WC cutting inserts. These coatings were exposed to an oxygen-containing environment at 1000°C. Coatings deposited on silicon were characterized before and after the heat treatment in terms of surface roughness, residual stress, and nanoindentation hardness. High-resolution transmission electron microscopy and scanning electron microscopy were used to study the oxidative resistance of these coatings. Actual dry machining will be performed using aluminum and steel alloys to evaluate the performance of these coatings. These results will be presented and discussed in terms of the coating potential in dry machining and high-temperature tribological applications.
3:30 PM E5/G4-2-7 Plasma Diagnostics as a Tool for the Modeling and Simulation of Sputter Processes
N. Papenfuß-Janzen, E. Lugscheider (Aachen University, Germany)
Modeling and simulation is an increasing research field within the last decades. This is related to the immense progress in computer power, recently. It is now possible to perform detailled simulations of processes with a great complexity like the MSIP process. Process simulation has two outstanding features. On the one hand it enables to calculate not measurable values. On the other hand many expensive experiments can be omitted. This leads to a cost reduction and - while working with toxic materials - less danger. Commonly, MSIP simulations are difficult to verify and there are only a few applications of plasma diagnostics in modeling and simulation, yet. But it is neccessary to have detailed knowledge of plasma properties to get realistic results from the simulations. In this article we give a short introduction into the modeling and simulation of the MSIP process, first. Then we present the energy resolved mass spectroscopy as a tool for the generation of boundary conditions. This diagnostic method enables to measure the composition, the energy distribution, and the degree of ionization. Therefore, we take the cathode power, and the coating pressure as basic variables. The cathode power represents one main factor influencing the degree of ionization, the pressure is connected with the mean free path and the collision of the particles. Those measurement were performed for nitride hard coatings. Finally, we give a perspective for the use of further plasma diagnostics in the MSIP simulation.
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