ICMCTF2006 Session G4/E5: Coatings for Cutting and Forming Tools, and Green Manufacturing Applications
Monday, May 1, 2006 1:30 PM in Sunrise
G4/E5-1 Properties and Cutting Performance of AlTiN, AlCrSiN, AlCrTiN and TiCrN Multi-Layer Coatings by Cathodic Arc Deposition
H.O. Gekonde, R. Aharonov (IonBond, LLC)
In an attempt to meet the growing challenge met in severe dry cutting of hardened materials, the effect of multi-layering films on properties and machining performance of AlTi(Si, Cr) coatings was investigated. The effect of process parameters on film properties and performance was also investigated and the ensuing properties were correlated with performance characteristics of the films. An analysis of the cutting process and performance of the tool-coating system is provided with emphasis on the interaction between the tool and the work-piece material to provide a sound basis for design of coatings for extremely severe cutting conditions. Microstructural analysis shows that phase transformation plays a role in chip formation and tool wear mechanisms. The role of phase transformation and other dynamic phenomena in cutting are discussed.
G4/E5-2 PVD Coated Tools and Native Ester - an Advanced System for Environmentally Friendly Machining
F. Klocke, K. Gerschwiler, D. Lung, R. Fritsch (WZL, RWTH Aachen, Germany)
Today's demands towards advanced cutting tools are driven by much more than further extended tool life. Environmental aspects play a rapid increasing role in industrial production. One outstanding example is dry cutting which gained enormous importance within the last years. However, not all machining processes can be performed under completely dry conditions respectively under use of minimal quantity lubrication MQL. Native ester lubricants, free of additives and biologically degradable, possess the potential to replace water based cutting fluids. But this can only be exploited if their lack of tribological performance is compensated by advanced tool surface properties, i. e. advanced hard coatings. For that reason, some of the fluid functions, especially wear protection, have to be transferred to the coatings with the aim to develop a new environmentally friendly cutting system. The paper presents results from turning, drilling and milling of stainless steel and of the nickel based alloy Inconel 718 with differently PVD coated carbide tools. Newly developed coating systems, like nanolayers and nanocomposites, mainly based on TiAlN or AlTiN, and crystalline gamma-Al@sub 2@O@sub 3@ have been investigated in such cutting tasks. The examined PVD coating systems are characterised by a low tendency towards adhesive work piece material transfer to the cutting tools and also by high wear resistance at elevated temperatures. The coatings were applied in combination with biodegradable lubricants which, to a large extent, are free of additives. The phenomena and the causes of tool wear have been studied and evaluated with regard to abrasion, adhesion and chipping.
G4/E5-3 Wear Development of Cemented Carbide Inserts Coated with Mono and Multi-Layer PVD Films, Considering their Strength Properties and the Cutting Loads
K.-D. Bouzakis, J. Anastopoulos, A. Asimakopoulos (Aristoteles University of Thessaloniki, Greece)
Through multi-layer PVD film structures, a cutting performance enhancement may be achieved. In the frame of the described investigations two different coatings, a monolayer TiAlN and a multi-layer TiN/TiAlN, with the same coating thickness, were examined concerning their mechanical properties and their wear behavior in milling and turning. The materials stress-strain laws of both examined films were extracted with the aid of nanoindentations and appropriate FEM supported results evaluation. Impact tests were conducted to determine film fatigue properties.@paragraph@ Wear investigations in milling and turning revealed different wear mechanisms in the two coating cases. By means of a FEM simulation of the cutting process the wear initiation and development in the investigated films with mono and multi-layer structures were clarified. Moreover the results demonstrated the superior performance of the multi-layer coating compared to the corresponding monolayer one. Although the fatigue strength of the investigated multi-layer film was comparable lower, the deceleration of the crack propagation induced mainly by the multi-layer structure, led to a cutting performance enhancement. A superior wear resistance of the multi-layer structure was also recorded after a coating annealing at 400@super o@C.
G4/E5-5 Effect of an Al@sub 2@O@sub 3@ Interlayer on Cutting Performance of Superhard (Ti,Si,Al)N Nanocomposite Films
C. Fernandes, S. Carvalho, L. Rebouta, F. Vaz, A.C. Monteiro (Universidade do Minho, Portugal); A. Cavaleiro (ICEMS - University of Coimbra, Portugal)
This paper reports the optimization of coating properties for the improvement the performance of tools in dry cutting applications. The performance and the wear mechanisms of tungsten carbide tools coated with (Ti,Si,Al)N have been investigated. A d. c. reactive magnetron sputtering technique was used to deposit the (Ti,Si,Al)N coatings. In order to analyze the microstructure and hardness RBS, XRD and nanoindentation experiments were performed on the coated tools. Before the cutting experiments, the XRD results revealed a structure indexed to fcc TiN. Tool life and tool failure modes were examined for various cutting conditions. The tools were thoroughly examined under SEM and EDX spectroscopy in previous studies, showing that after 15 min. at low cutting speed (100 m/min) the cutting edge of all coatings still remained in a good condition. However at a higher cutting speed (200 m/min) the commercial TiN coating, which was used as a reference, presented a longer tool life than the (Ti,Si,Al)N tool. The aim of this work is to improve the wear resistance of (Ti,Si,Al)N films by thermal annealing before the turning tests in order to relax internal stresses, and by deposit an amorphous Al@sub 2@O@sub 3@ interlayer before the (Ti,Si,Al)N coating.
G4/E5-6 Elevated Temperature Nano-Impact Testing of PVD Coatings
J.F. Smith, B.D. Beake (Micro Materials Ltd, United Kingdom); G.S. Fox-Rabinovich (McMaster University, Canada); J.L. Endrino (Balzers AG, Liechtenstein)
This paper introduces a novel nano-scale test technique - elevated temperature nano-impact testing - developed to mimic conditions in cutting tool operation. Its application to the study of the properties of hard PVD coatings designed for high speed and dry machining where high thermal gradients exist in the cutting zone is described. The correlations between elevated temperature nano-impact testing results on PVD coated carbide inserts and trials of tool performance under different interrupted cutting conditions are investigated.
G4/E5-7 Pulsed DC Magnetron Sputtered Tantalum Nitride Hard Coatings for Tribological Applications
A. Aryasomayajula (University of Arkansas); S. Aryasomayajula (Indian Insititute of Technology, India); D.G. Bhat (University of Arkansas)
Transition metal nitride coatings are being used in many applications due to their high hardness, mechanical strength, chemical inertness and high temperature stability. Tantalum nitride (TaN) thin films are very promising in tool coatings but these films are presently used in electronic industry and very little work has been carried with reference to the tribological coatings. In the present study, tantalum nitride thin films were coated at room temperature (300K) on various substrates, such as cemented carbide milling inserts, glass and silicon wafers, using reactive DC magnetron sputtering technique. The target was pure tantalum metal sheet. Tantalum was sputtered with pure argon gas in the presence of pure nitrogen gas. The ratio of argon to nitrogen was varied to study the properties of deposited TaN films. The surface of the substrates was treated with plasma for better adhesion of the coating. Optical emission spectroscopy (OES) was employed to analyze the sputtering plasma to understand the reaction kinetics of tantalum nitride formation. The mechanical properties, such as adhesion and hardness, were evaluated by scratch tester; the thickness was estimated by the ball and crater method. The phase composition and texture of the film were studied by X-Ray diffraction (XRD) technique. Results of the characterization of films on various substrates will be presented, and discussed in the context of machining application.
G4/E5-8 Tribological Properties of Cr@sub 2@N Ceramic Films with Tungsten Paper
C.-W. Chu (I-Shou University, Taiwan)
In PCB drill at high rpm (20krpm) due to its excellent oxidation and adhesive resistance .Cr@sub 2@NW is prominent material for protective coatings. The experiment(drill sample:UC 0.25*4.0 000D2) result are showed as follow:Cr@sub 2@NW: The hardness increase with increase W content . When w%=3.07% the hardness (HV=1790 increase to HV=2197), Thus IN Cr@sub 2@N when w%=8% then harness value will stable. the hardness range (Hf:2500-Hf:3000), use micro drill In pcb 30000 hole (w%=3.07%)wear contact angle better than others, it will have the minimum flank wear and more 5 times tool life than uncoating when the tunghen content 13.72 at% we get the best wear resistance it will have the minimum flank wear and more 4 times tool life than uncoating.
G4/E5-9 Superhard Amorphous (ta-C) Carbon Films for Machining and Forming Tools
B. Schultrich, V. Weihnacht (Fraunhofer Institute for Materials and Beam Technology, Germany); H.-J. Scheibe (Fraunhofer USA Inc.); T. Stucky (Fraunhofer Institute for Materials and Beam Technology, Germany)
Tetrahedral amorphous carbon (ta-C) films are the hardest in the family of DLC films and possess a sp@super 3@ contents of up to 80%. Using the industrial Laser-Arc-Module (LAM) equipment with the Laser-Arco technology (high-current pulse-arc techniques), ta-C films with thicknesses between 1 and 5 µm and an average hardness above 40 GPa have been deposited onto different tools for machining and forming applications. These films are characterized with respect to their density, elastic modulus, adhesion, surface roughness, friction coefficient and wear resistance. Due to their unique tribological properties and low sticking tendency to metals such films are applied for wear protection with a low coefficient of friction on tools for dry machining, cutting and forming, especially for AlMg-alloys. Results of field testing of tools will be presented, which demonstrated the improvements of such ta-C coatings in comparison to conventional DLC coatings. Further examples of applications for cutting and forming of different materials and their test results will be discussed.
G4/E5-11 Wear Studies and Dry Cutting Tests on Hardened Steel and Graphite with PVD-Nanocomposite Coatings of the Material System Ti-Al-N-C
M.A. Stueber, U. Albers, S. Ulrich (Forschungszentrum Karlsruhe, Germany); C. Sanz, E. Fuentes (Fundacion Tekniker, Spain); M. Solay, A. García (Universidad Autonoma de Madrid, Spain); P.Eh. Hovsepian, I.A. Gee (Sheffield Hallam University, United Kingdom)
The potential of new carbon-based PVD-nanocomposite coatings of the material system Ti-Al-N-C for dry machining of hardened steels (hardness up to 58 HRC) and graphite was evaluated. Various wear studies with instrumented cutting machines and cutting field tests were performed under dry conditions both in profile milling and ramp copy milling of Orvar (1.2344), Rigor (AISI A@sub 2@) and graphite (POCO EDM-200). Commercially available cemented carbide milling tools (8mm in diameter, both spherical and cylindrical, both 15° and 30° helix angle) were used for the magnetron sputter deposition with both single and multilayer nanocomposite coatings in a Hauzer HTC 625 machine. Benchmarking of the performance of the new coatings was done by comparing them with industrial state-of-the-art coatings recommended for the applications intended. The paper presents the concepts for the design of new nanocomposite coatings for tool applications. It reports on wear studies and cutting tests carried out with these coatings and discusses the possible future commercialisation of the coatings based on the most promising results achieved in the cutting tests.
G4/E5-12 Dry Turning of Austenitic Stainless Steel; Comparison of the Performance of CVD, Cathodic arc Ion Plated and Large Area Filtered Arc Deposited Coatings
W. Zhang, E. Bergmann (Geneva School of Engineering, Switzerland); T.I. Selinder (Sandvik Tooling, Sweden); J. Anklam (Eifeler Werkzeuge GmbH, Germany); V.I. Gorokhovsky (Arcomac Surface Engineering, LLC)
Dry and marginally lubricated turning tests of 316L was carried out with inserts coated with different coating technologies. CVD coated inserts were used as benchmark in a finishing operation. The results were then compared with ternary multilayer and single layer cathodic arc ion plated coatings from 2 technologies and coatings from the plasma of a Large Area Filtered Arc Source.