Hard and Hybrid Coatings for Cutting and Forming Tools, and Surface Engineered Components
Thursday, May 3, 2001 1:30 PM in Room Town & Country
G4-2-1 New Wear Resistant Dry Lubricant Coatings for Forming and Cutting Operations
M. Lahres (DaimlerChrysler Company; Germany); K. Bewilogua (Fraunhofer Gesellschaft)
Today, cooling lubricants will be applied in many cutting and forming operations. The production and the disposal of these lubricants cause high costs. Furthermore, their use is accompanied by dangerous for the environmental and humans health. The goal of our project was to develop wear resistant self - lubricant coatings for different cutting and forming operations under dry conditions and for different workpiece materials. A first estimation of the potential of these new coatings was derived from standard adhesion, friction and wear tests. Following to that pre-selection, the coated tools were tested in a next step at different Institutes under laboratory conditions. The successful coatings finally were implemented in field tests under production conditions at the different plants of the partners. The new developped lubricant coatings were deposited by different CVD and PVD techniques. The coatings in this project had been devided into four material groups designated as - metal sulfides and selenides - oxides - carbon based materials - borides and silicides. Results for the different lubricant coatings with regard to the operations thread forming, drilling, milling, forming and punching will be presented. Summarizing it can be stated that for each operation and for each work piece material an independent optimization of the coating is necessary. The presented project is sponsored by the German Government Ministry "BMBF". .
G4-2-2 Innovative Mono and Multilayer Hard and Autolubricant PVD Coatings for Nearly-Dry and Dry Broaching and Other Complex Shape Difficult Machining Operations
F. Rabezzana (Metec Technologie, Italy); D. Franchi (Ferioli & Gianotti, Italy); S. Durante (Centro Richerche Fiat, Italy)
The aim of the paper is to present data related to the characterization and the use of innovative mono and multilayer PVD coatings for difficult cutting tool applications, in particular broaching and other machining operations performed with complex shaped cutting tools; and to present the results of high performance and dry or nearly-dry machining tests performed with different complex shaped tools coated with innovative hard and autolubricant PVD layers in comparison with standard HSS and WC uncoated and coated tools.
G4-2-3 Tribological Properties of MoS@sub 2@/Titanium Composite Coatings Deposited Onto Soft and Hard Substrates and Tested in Various Conditions
J. Renevier (Teer Coatings Ltd, United Kingdom); D.G. Teer (Teer Coatings Ltd., United Kingdom)
As previously reported the properties of MoS@sub 2@ coatings can be improved by the co-deposition of a small amount of titanium. These MoS@sub 2@ /Ti coatings known as MoST@sup TM@, are harder, much more wear resistant and also less sensitive to atmospheric water vapour than pure MoS@sub 2@. These coatings have given excellent industrial results for a wide range of cutting and forming applications. @paragraph@ Plastic, glass and metallic (stainless steel, high speed steel…) substrates have been coated and rubbed against various counterparts (Al, bronze, stainless steel, Chrome steel, WC…balls) in pin on disc and reciprocating wear tests at several loads (from 5N to 100N) and under several conditions (humidity, oil, water…) and their friction and hardness have been reported. Different counterparts as well as the coated samples have been studied and the wear has been measured on both ball and coating. A comparison with traditional hard coatings such as TiN, TiCN, TiAlN, CrN, MoN, ZrN and CrC/C has shown that MoS@sub 2@/titanium composite coatings not only have lower friction, but also allow a protection of the counterpart. @paragraph@ This paper will an extension of the results presented at ICMCTF 2000- San Diego (USA), 10-14 April 2000.
G4-2-4 Development of Oxide PVD-Sputter-Coatings for Dry Machining Operations
M. Schulze (Euromat GmbH, Hückelhoven, Germany); I.J. Rass (Euromat GmbH, Germany); T. Leyendecker, G. Erkens (CemeCon GmbH, Germany)
Thin film oxide coatings are of more and more interest in the last years` thin film developments. Due to high binding energies oxide materials are highly resistant against adhesive wear. Furthermore, with increasing temperature the sliding coefficient decreases and the hardness reduction is slowly. This leads to high abrasion resistance and a high potential for dry machining applications. @paragraph@This paper describes the development of deposited Al@sub 2@O@sub 3@, ZrO@sub 2@, CrO and TiZrO multilayer coatings using a combined DC/RF Sputter Ion Plating process. All coatings were applied under production conditions at moderate temperatures below 400@super o@C in order to coat HSS as well as cemented carbide tools. Different layer arrangements and main metallographic data are presented. Furthermore,results of tribological tests and first performance tests in dry machining operations are shown.
G4-2-5 Performance of Oxide PVD-Coatings in Dry Cutting Operations
H. Schulz, J. Dörr (Darmstadt University of Technology, Germany); I.J. Rass, M. Schulze (EUROMAT GmbH, Germany); T. Leyendecker, G. Erkens (CemeCon GmbH, Germany)
Dry cutting processes effect increased economic efficiency and fulfill at the same time ecological requirements. However elimination of coolants involves absence of their positive influences on the metal cutting process such as lubrication, heat dissipation and chip evacuation. This leads to high adhesive, abrasive and tribo-chemical tool wear. Innovative oxide coatings meet the sophisticated demands of dry cutting applications as high wear resistance and the reduction of friction which minimizes the thermal load. The oxide materials provide a high resistance against adhesive wear due to the high binding energy. Furthermore the friction coefficient is decreasing with increasing temperature and a high hardness even at elevated temperatures is provided. This paper shows the performance of the deposited Al@sub 2@O@sub 3@, ZrO@sub 2@, CrO and TiZrO coatings in dry drilling of high strength spheroidal graphite cast iron (SGI). Influences of the coating composition on the tool wear behavior, the cutting forces and the chip flow are highlighted. Additionally the coatings are evaluated by determinating the absolute temperature on the cutting edge of the drilling tool. Therefore a suitable measuring technique was developed.
G4-2-6 Dry Machining of Aluminum - A Challenge Tackled by New Hard Coatings
T. Schuelke (Fraunhofer USA - Center for Surface and Laser Processing); H. Wirtz (Fraunhofer USA - Center for Manufacturing Innovation); J. Trump (Johnson Carbide Products, Inc.); H.-J. Scheibe, S. Grosser (Fraunhofer Institute for Material and Beam Technology, Germany)
Dry and high-speed machining of non-ferrous lightweight materials is becoming increasingly important, e.g. for a new generation of vehicles, due to environmental considerations etc.@paragraph@ The present paper summarizes the results of dry drilling experiments, which have been executed to evaluate the performance of a new super-hard coating (Diamor) in comparison to a commercially available TiAlN coating and uncoated hard-metal tools. The machined material was aluminum 6061, a standard off-the-shelf material used in numerous applications in the aerospace and automotive industries. The machine tool used was a three axis Chiron FZ 28 L. A full-factorial two-level statistical experimental design, including a center point for the two factors cutting speed (140 ..180m/min) and feed rate (0.3 ...0.5 mm) has been applied. All of the experiments have been repeated once for statistical purposes. The drill diameter, as well as the depth of the drilled holes, was 10 mm. The total cutting length based on breaking of the tools has been evaluated. The Diamor coated tools performed more than 100% better compared to TiAlN for almost all of the tested parameter combinations.
G4-2-7 On the Acoustic Emission And Motor Current Associated With Drill Wear Under Dry Cutting
J.R.T. Branco (Fundação Centro Tecnológico De Minas Gerais- Cetec, Brazil); I.F. Silva (Rede Temática Em Engenharia de Materiais - REDEMAT, Brazil)
The need for sustainable development has increased the attention on dry cutting. Therefore, the present study was carried out to investigate the effect of MoS@sub2@ and hard carbon as solid lubricant coatings on the wear and performance of high speed twist drills, coated with TiCN and TiN. Coating characteristics were determined by ball cratering and scracth testing. The working material was AISI D3. During drilling acoustic emission - AE and motor current - MC were monitored. The drilling MC and AE in the range of 10 kHz to 1000 kHz frequency were analyzed as a function of drilling depth for holes along each drill life test. Drill wear was analyzed by light and scanning electron microscopy, combined with 3D profilometry. The effect of coatings on AE parameters were analyzed at different cutting stages, as distinguished by AE.