ICMCTF2004 Session E5/G4: Tribological Studies of Coatings for Green Manufacturing and Dry Machining

Wednesday, April 21, 2004 1:30 PM in Room Royal Palm 4-6

Wednesday Afternoon

Start	Invited?	Item
1:30 PM	Invited	E5/G4-1 Various Applications of DCL Including DLC-coated Rubber Components Takahiro Nakahigashi (Nippon ITF, Inc., Japan) DLC (Diamond Like Carbon) as a hard carbon film has such features as the lowest friction coefficient among various ceramics coating materials, high hardness, and less aggressiveness to other parties. Because of these features, its practical use for sliding is in progress. However, people now call other films DLC too even though they are different from those defined in ‘80s. Moreover, new manufacturing methods such as spatter method and arc method are now used in addition to the conventional ones like radio frequency (r.f.) plasma assisted chemical vapor deposition (PACVD) and ionized deposition. Another topic in these days is a flexible DLC film that uses rubber as radical material in stead of the formally used radical materials such as metal and ceramics. We thought that three issues have to be resolved. (1) Low heat resistance of the polymer materials such as rubber and resin. (2) Pollution of the polymer material surface by oil, fat, resin, and oxidation prevention agents, etc., and (3) Transformation of the polymer materials. To resolve these possible problems: (1) We have developed a processing method by using the Amplitude-Modulated RF Plasma Chemical Vapor Deposition method which enables coating at lower temperature (below 80°C) and does not allow the processing temperature to rise any higher. (2) To prevent the pollution, we decided to clean the polymer surface by plasma. (3) To prevent the transformation, the film should be flexible enough to absorb the polymer material transformation. We have modified the DLC film structure to permit expansion and contraction. This new DLC film is applied as a coating of ‘O’ ring for 35 mm zoom camera. This paper reports a technological trend of various applications of the recent DLC films and an example of sliding use of the ruber radical material.
2:10 PM		E5/G4-3 Semidry and Dry Drawing using Diamond-like Carbon (DLC) Coated Roller Die M. Jin, M. Hayashi, M. Murakawa (Nippon Institute of Technology, Japan) In the application of drawing in recent years, from the viewpoints of the reduction of environmental burden, improvement of hygiene of labor environment and reduction of production costs, the following actions are necessary; the reduction of the amount of drawing lubricant used, the replacement of currently used lubricants with environmentally friendly lubricants, and the reduction of costs for the washing of lubricant adhering to products and the disposal of used lubricant. In this research, we explored methods for the realization of semidry and dry drawing in order to resolve the above issues. As a result of the findings, we studied drawing using a DLC-coated roller die. We investigated the effect of diamond-like carbon (DLC) coating on the dies. In other words, the possibilities of the realization of semidry drawing with the use of a wash-free lubricant and of completely dry drawing were studied by coating the die with DLC in addition to the use of measures considered to be effective for realizing semidry and dry drawing. As a result of this study, it is concluded that the drawing method utilizing the DLC-coated roller die is effective in realizing semidry and dry drawing for aluminum materials.
2:30 PM		E5/G4-4 Tribological Properties and Dry Machining Characteristics of PVD Coated Cemented Carbide Inserts B.C. Schramm, H. Scheerer, H. Hoche, E. Broszeit, E. Abele, C. Berger (Darmstadt University of Technology, Germany) Tools for cutting operation are subject to very high abrasive, adhesive, and thermal loads. Process security and preparation quality as well as a sufficiently high tool life demand for the development of hard coatings with reduced seizure tendency, high hot hardness, and increased wear resistance especially under dry machining conditions. TiAlN coatings are the state of the art coatings for machining operations. Hard materials on chrome basis like CrN, CrAlN, CrON are preferably used for bending and stamping tools. Thus, these coatings could have a high potential in machining operations. The aim of using chromium-based coatings is to redirect the heat from work piece and tool into the chip, thus acting as a thermal barrier. Due to their high resistance for oxidation CrN and Cr_xAl_yN coatings were deposited on WC/Co inserts. In order to find improved coatings for dry machining operations both tibological and wear tests were performed. The characterization of the coatings include fundamental properties such as thickness, hardness, and critical load. With Glow Discharge Optical Emission Spectroscopy (GDOES) depth profile analyses were performed. In reciprocating sliding tests using an SRV III apparatus from Optimol friction and wear has been studied in a ball-on-disc arrangement. Topographical and micro topographical analyses were done in order to characterize the wear mechanisms. Turning operations were performed in model tests to characterize the dry machining characteristics. The wear properties of CrN and Cr_xAl_yN coatings were compared with industrially coated TiAlN cemented carbide inserts. REM analyses supplemented the picture of the wear mechanisms in dry machining with chromium-based tools.
2:50 PM		E5/G4-5 Improvement of Cutting Performance for TiN Coated Carbide Tools Via Chlorine Ion Implantation A. Mitsuo, S. Uchida (Tokyo Metropolitan Industrial Technology Research Institute, Japan); S. Yamamoto, T. Aizawa (University of Tokyo, Japan) Recent demand for reduction of environmental burdens requires minimum use of lubricant oils even in machining the automotive parts. In order to put this dry machining into practice, the tribological properties of cutting tools must be significantly improved. Authors have proposed the self-lubrication of TiN coating films on high speed tool steel via the chlorine ion implantation. Since the implanted chlorine works as a catalysis for surface reaction from TiN to TiOx (1 < x < 2) in the wear track, the wear volume as well as the friction coefficient are significantly reduced by successive formation of lubricious oxides, TiOx. In the present paper, the turning test was employed to investigate the effect of this chlorine implantation on the cutting performance of TiN coated carbide tools. The cutting performance was compared among three specimens: carbide tool without coating, TiN-coated carbide tool and Cl-implanted, TiN coated carbide tool. Direct measurement of cutting forces reveals that the threading cutting force should be significant reduced when using the Cl-implanted tool. In addition, the adhesive wear is suppressed by using this Cl-implanted cutting tool, so that high speed machining could be conducted up to the velocity of 1000 m/min.
3:10 PM	Invited	E5/G4-6 Synthesis and Characterization of Three Dimensional Hybrid Structures in Amorphous Carbon Thin Films E.I. Iwamura (Japan Science and Technology Agency and The University of Tokyo, Japan) A new form of carbon incorporating different carbon configurations has recently attracted extensive interests in order to accomplish high performance by combining diverse physical properties which arise from the carbon configurations. Amorphous carbon with fullerene inclusions which shows outstanding mechanical properties of high hardness and elastic recovery is one of the typical examples. This presentation focuses on order/disorder nano-composite structures formed in amorphous carbon thin films. While nanocomposite concepts embodied by multilayered and functionally graded structures have been successfully developed and used in various applications, the architectures explored in this study are the dispersed graphitic clusters in amorphous carbon matrices and the anisotropic quasi-periodic arrays consisting of ordered/disordered carbon arranged normal to the film plane. A new technique using low-energy electron beam radiation system in which preformed amorphous carbon thin films were exposed to an electron shower was introduced to modify the amorphous carbon structures. Metal clusters and column/inter-column network structures were utilized as a template for encouraging structural ordering in the amorphous carbon films. Features of the electron beam irradiation process operated at relatively low temperature and characteristics of the hybridized amorphous carbon thin films will be presented.
3:50 PM		E5/G4-9 Aluminum Nitride Coating of Aluminum Alloys via Plasma Nitriding T. Aizawa, P.V. Visuttipitukul (University of Tokyo, Japan); H. Kuwahara (Research Institute for Advanced Sciences, Japan) Aluminum nitride coating is preferable to improvement of wear resistance for aluminum alloy parts. Formation of AlN layer is often prohibited by pre-existing oxide films, αAl₂O₃. This oxide layer is so stable and hard that long pre-sputtering is needed to eliminate its coverage. In addition, the formation rate of AlN layer is usually very slow due to low diffusion coefficient of nitrogen in the aluminum or in th formed AlN layer. Furthermore, the deposition rate of AlN is too slow to fabricate thick AlN layer. In order to fabricate thin and thick AlN protective layers on the aluminum alloy parts, new method is necessary to make fast-rate formation of AlN layer. In the present paper, the plasma nitriding method is proposed as the first step to search for fast-rate AlN-layer formation processing. Al-6Cu alloy was employed as a typical high-strength aluminum alloy part material. Pre-sputtering with N₂⁺ species at 723 K for 1.8 ks is enough to equip the nucleation sites in this system. In case of the plasma nitriding at 723 K under N₂⁺H₂ mixture gas flow, the formation rate of AlN layer is improved by two orders or more than the conventional nitriding. This fast-rate formation of AlN is sustained by inner nitriding reaction with the precipitate of Al₂Cu. The precipitate-accommodated inner nitriding mechanism is also discussed.
4:10 PM		E5/G4-10 Dry Machining: Nanostructured Coatings for Automotive, Aerospace and Dies Industries M. Rostagno (Centro Ricerche, Italy); S. Veprek (Technische Universität Munchen, Germany); S. Durante, M. Comoglio (Centro Ricerche Fiat, Italy); D. Franchi (Ferioli & Gianotti div. Genta-Platit, Italy); F. Rabezzana (Metec Technologies, Italy) In the last decades, research for materials innovation in manufacturing fields pushed towards the development of machining technologies able to sustain continuous challenges. Nanotechnologies will have a key-role in the machining of difficult to cut materials, especially as ultra hard coatings due to their high hardness, toughness and oxidation resistance. This paper gives an overview about applications of anti-wear nanostructured coatings in industrial cutting test. These last ones were carried out in automotive, aerospace and dies machining shops and were focused on three classes of difficult to cut materials: - steels and cast iron (hardened steels, high speed steels, innovative cast iron) - light alloys (aluminum alloys, titanium alloys) - high temperature resistant super-alloys (Inconel 718, Renè 80, In 100) Different coatings chemical compositions, coating thickness, cutting parameters and lubrication conditions were tested in order to build a know how of metals machineability with the innovative nanostructured coatings. Cutting tools wear analysis together with coatings characterization provided with data useful to improve further performance in tool life and reliability. The main target has been to extend the dry machining as far as possible. Replacement of coolant with dry machining will bring an improvement of the ecological impact with strong benefits on process efficiency and cost reduction.
4:30 PM		E5/G4-11 The Effect of the Coating Thickness Distribution on the Tool Rake and Flank on the Cutting Performance in Milling K.-D. Bouzakis, S. Hadjiyiannis, G. Skordaris, I. Mirisidis, K. Efstathiou (Aristoteles University of Thessaloniki, Greece); G. Erkens, I. Witrh (CemeCon AG, Germany) During the Physical Vapour Deposition (PVD) the orientation of cemented carbides insert surfaces to the plasma flux direction affects the film growth, which in turn might influence the wear propagation in cutting processes. In the present paper the wear behaviour of PVD coated cemented carbides inserts with various coating thickness on the tool rake and flank in the cutting wedge region, will be introduced. The various coating thickness distributions were achieved through the inserts cutting edge positioning against the plasma flux direction during the PVD procedure, by means of appropriate fixtures. The coating material properties and especially their stress-strain laws were determined by means of nanoindentations in combination with a Finite Elements Method (FEM) based evaluation procedure of the related results. The initiation and progress of the coating and tool wear in milling were investigated using scanning electron microscopy and energy dispersive X-ray spectroscopy. Furthermore the experimental results in milling were explained with the aid of a FEM simulation of the cutting process, which takes into account the geometry of the cutting wedge and the coating thickness distribution around it, as well as the actual coating strength properties on the tool flank and rake. The investigations revealed that an increased film thickness on the tool rake in comparison to the flank enhances the cutting performance in milling.
4:50 PM		E5/G4-11 Future Directions in Green Manufacturing and Dry Machining T. Ovaert (University of Notre Dame - A Novel 1 hour session dedicataed to exploring future directions in green manufacturing and dry machining) This wrap-up session is co-sponsored by the Tribology Division of the American Society of Mechanical Engineers (ASME ). The purpose of the session is to foster a discussion by researchers in this important field, focused on the major issues (challenges) and opportiunities (future research needs) that are currently limiting widespread growth potential in green manufacturing and dry machining. These issues and opportunities may be of a technical or non-technical nature. This is an opportunity for researchers and authors to provide their frank opinions and predictions in a non-peer reviewed setting.