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

Tuesday, April 29, 2003 8:30 AM in Room Royal Palm 1-3

Tuesday Morning

Start	Invited?	Item
8:30 AM		G4/E5-1 The Use of Soft / Lubricating Coatings when Dry Drilling BS L168 Aluminium Alloy H.L. Coldwell, R.C. Dewes, D.K. Aspinwall (University of Birmingham, United Kingdom) The paper briefly reviews the development / implementation of soft / lubricating coatings and details published machinability data for dry / near dry machining applications. Following on from this, statistically designed experimental work is presented relating to the performance of PVD coated cutting tools (Uncoated, Graphit-iC, Dymon-iC and MoST, with and without a hard coating underlayer) when dry drilling BS L168 aluminium alloy. Suitable coatings / coating combinations were determined using a uni-directional single pass wear-testing procedure which previously has been successfully used to determine coatings suitable for forming applications. The results from the new testing procedure were correlated with the machinability data obtained from the experimental work and the validity of using such a procedure for identifying coatings for machining applications is discussed. Machinability was assessed in terms of tool life / wear, cutting force, chip morphology, hole diameter, cylindricity and out of roundness. Despite the use of soft / lubricating coatings, there was a strong tendency for the aluminium to adhere to the drill which contributed to low tool life. Chip packing in the drill flutes was a highly significant feature and largely governed cessation of tests. Tool life was lower when cutting dry as opposed to wet. When compared with uncoated drills, the combination of a hard underlayer and soft / lubricating top coat (MoST), improved hole quality with lower dispersion of values recorded for hole diameter, roundness and cylindricity.
8:50 AM		G4/E5-2 A Systematic Study on the Effect of MoST^TM Coatings on Drilling Performances N. Rafieian, J. Wallbank, S. Barnes (University of Warwick, United Kingdom) It is known from previous studies [1,2] that MoST^TM coatings can improve the performance and life of cutting tools. This paper presents the results of a systematic study of the performance of HSS drills coated with hard nitride coating and drills with a top coating of MoST^TM. The lifetime of drills operating under accelerated conditions with flood coolant was measured and the drill wear, feed force and torque were recorded throughout the tests. It was found that MoST^TM coatings reduced the drill wear, the feed force and the torque significantly as well a extending the drill life. Some preliminary dry drilling experiments are also included. The mechanism of the improvements given by MoST^TM are discussed. [1] N.M. Renevier, H. Oosterling, U. Koenig, H. Dautzenberg, B.J. Kim, L. Geppert, F. G.M. Koopmans, J. Leopold, presented at ICMCTF 2002, San Diego, Ca, USA, 22-26/04, in print in Surface and Coatings. Technology. [2] N.M. Renevier, N. Lobiondo, V.C. Fox, D.G. Teer and J. Hampshire, Surface and Coatings. Technology, Volume 123 (2000) 84-91.
9:10 AM		G4/E5-3 Influencing Variables on High Performance AlTiN Arc Coatings M. Arndt (Metaplas Ionon, Germany) The AlTiN-Saturn coating, deposited by cathodic arc evaporation, has proven its outstanding properties in many high demanding cutting processes. Due to the excellent adhesion, high hardness, extremely smooth surface, and finecrystalline morphology combined with a superior oxidation resistance AlTiN-Saturn is best suited for sophisticated applications. One example is the avoidance of coolants in high performance machining processes, which means an important contribution to environment protection. This paper deals with the influence of different pretreatments like microblasting or stripping processes on the properties of AlTiN-Saturn. Furthermore, the possible dependency of coating behaviour on different doping elements is investigated.
9:30 AM		G4/E5-4 Properties and Performance of High Aluminum Containing (Ti,Al)N Based Supernitride Coatings in Innovative Cutting Applications G. Erkens, R. Cremer, T. Hamoudi, R. Wenke (CemeCon AG, Germany); K.-D. Bouzakis (Aristoteles University of Thessaloniki, Greece) The development of new workpiece materials processed so rapidly that it is partly not known, how these materials can be economally processed with respect to measures of reducing costs. In order to meet the different requirements a range of developments have been brought forward in the area of coating technology. One of the most promising state of the art coatings is the metastable solid solution phase (Ti,Al)N in cubic B1 structure. These coatings offer a superior oxidation resistance and hardness as compared to conventional TiN or TiCN. The oxidation resistance of these coatings increases with increasing Al content of the solution phase. Based on a unique pulsed DC magnetron sputtering process, the High Ionization Pulsing process (H.I.P.), electrically insulating (Ti,Al)N coatings with Al/Ti ratios up to 5 have been developed, in which the high hardness of the well known, commercially available coatings with Al/Ti ratios of about 1 are preserved. These variants of the novel Supernitrides, a new class of coating system, combine the outstanding mechanical properties of typical group IVA nitrides with the superior chemical inertness of alumina. The properties of these coatings make them a number one choice in High Performance Cutting (HPC) applications with high mechanical and thermal load like dry hard milling and hard turning. The deposited films were evaluated by metallographical examinations (microhardness, film thickness, adhesion, structure (SEM, X-ray defraction) etc.). The results from cutting tests will show the high potential of coatings with Al/Ti ratios up to 5 as variants of the novel Supernitrides.
9:50 AM		G4/E5-5 Performance of Filtered Arc Coated Rotary Tools in Dry Cutting E. Bergmann (Geneva School of Engineering, Switzerland); B. Heckerman, V. Gorokhovsky (Arcomac Surface Engineering, LLC.) Large Area Filtered Arc Deposition (LAFAD) technology is a tool to deposit atomically smooth coating at high depositing rate over extended coating areas¹. While inheriting all the advantages of conventional filtered arc technology (superhardness, improved adhesion, low density of pin-holes) the LAFAD technology allow the formation of functionally graded, multilayer and super-lattice architectures of multi-elemental composite coatings by electro-magnetic mixing of two plasma flows consisting of two different metal vapor plasma compositions. Nano-indentation was used to evaluate the mechanical properties of the coatings. The outstanding sharpness of the cutting edges of filtered arc coatings compared to coatings deposited by conventional technology is shown by SEM observations. For this study carbide drills and carbide end mills coated with Ti_xAl_1-xN coatings deposited by dual arc large area filtered arc plasma source (LAFAS) were tested in dry cutting of pre-hardened D2 steel. For the chosen cutting parameters uncoated tools failed by high temperature oxidation. A comparison with tools coated by unfiltered arc deposition is presented. ¹Vladimir I. Gorokhovsky , Rabi Bhattacharya and Deepak G. Bhat, Surface and Coating Technology, 140 (2) 2001, pp. 82-92.
10:10 AM		G4/E5-6 Smart Coatings: Wear Resistant Layer Systems with Integrated Thin Film Sensors H. Luethje, R. Bandorf, S. Biehl (Fraunhofer IST Germany) This contribution deals with novel smart coatings for tool application. Based on the combination of advanced coating techniques with an efficient sensor- and MEMS technology smart coatings have been realized, which enable on-line control of the cutting conditions measured directly at the cutting edges. For achieving this, special thin film sensors for measurement of wear have been integrated into the hard coating system of cutting inserts. The whole layer system consist of an interface, a hard isolating layers of Al₂O₃ and a nano-sensor film of TiN sputtered in one run on the surface of standard inserts. Whereas interface and sensor layer are in the order of 100 -500 nm, the Al₂O₃ layer was between 2 -5 µm, depending on the roughness and shape of the insert. After micro structuring of the sensor film, a second insulating layer of Al₂O₃ or AlN was applied followed optional by a typical wear protection of TiAlN or TiN. The thickness of these layers were in the range of 2 -5 µm. The hardness of Al₂O₃ and AlN measured by nano-indentation was 25 GPa and 18 GPa respectively. Scratch measurements showed good adhesion Since the sensors are arranged at the vertical flank of inserts, the electrical wiring must run over the edges to a shadowed flank area, where electrical contacts are placed. The sensors are being connected by theses contacts to an electronic module, which contained signal conditioning and telemetric transfer of the data to the control station of the lathe. We will report on the whole fabrication technique incl. a novel micro structuring technique based on photolithography and reactive ion etching. Moreover, first results on application tests by cutting steel will be shown.