Papers

ICMCTF2008 Session G6-1: Surface Pre-Treatment, Coating Post-Treatment and Treatment Process Integration

Monday, April 28, 2008 10:00 AM in Room Sunset

Monday Morning

Start	Invited?	Item
10:00 AM		G6-1-1 Approaches to High Performance Coating Solutions by Means of Hybrid PVD and Duplex Process Technologies G. Erkens, J. Vetter, J. Mueller (Sulzer Metaplas GmbH, Germany) In the field of high precision tools and components end users demand more and more unique and customized solutions for their current challenges. For innovative tools and components increased load carrying capacities (mechanical loads, thermal loads, etc.), longer life time, higher performance and thus higher productivity, reduction of weight and friction and the improvement of corrosion resistance are demanded. To meet functional and decorative requirements in particular, surface treatments and related coating technologies are selected to be used in the day-to-day mass production of precision components and to provide application specific cutting tool solutions. The ever increasing demands on high performance tools and components are directly connected to higher requests on the hard coatings for wear and oxidation protection. Advanced coating systems offer multiple solutions to meet these demands. Application tailored hybrid and duplex technologies provide the chance to synthesize the next generation of high performance PVD coatings. With the hybrid (AIP plus MSIP) technology conductive and non-conductive materials can be combined nearly without limits. Running all sources and the bias in dc mode, pulsed mode or a combination of these options could approach to a wide range of nanostructured and unique micro alloyed coatings for various applications. The duplex in-line process combines plasma nitriding and PVD the way that the substrate subsurface area can be affected positively to support the consecutively deposited PVD coating much better. The interface area can be designed and adjusted best to the requests of the PVD film. By this different steel grades including HSS, cold and hot working steels and stainless steels can be treated. The potentials of the hybrid PVD technology using advanced evaporator sources and the duplex treatment will be illustrated. First coating solutions from latest approaches to hybrid processes that combine sputtering and arc technology as well as from duplex processing with a combination of nitriding and PVD will underline the leading edge technology presented.
10:40 AM		G6-1-3 Performance of Arc Coated Carbide Drills in Dependence of Post-Treatment-Techniques S. Sattel, E. Stumpp, S. Fritz, I. Garrn (Guehring oHG, Germany) The use of arc PVD coatings on cutting tools for improved function is well established since the last two decades. Now, the usage of pre- and post-treatment of coated tools expands more and more to a key knowledge of optimizing the performance of coated tools. Post-treatment is mostly important for the smoothness of the flute, the decreasing of friction and the reduction of residual stress in the coating. Different mechanical post treatment techniques such as automatized dry- and wet-blasting, brushing and granulate grinding have been used on similar pre-treated and coated carbide drills in order to examine the influence of the post-treatment on the tool performance. All carbide drills have been coated with a standard TiAlN based film using an arc-PVD-technique for deposition. Depending on the different post-treatment techniques the carbide drills have been examined concerning to their surface roughness, possible changes of the cutting edge and finally to their durability.
11:00 AM		G6-1-4 Improvements in High Performance Cutting Due to Cutting Edge Design D. Biermann, I. Terwey (Technische Universität Dortmund, Germany) High Performance Cutting is characterized by high material removal rate, heavy cutting parameters and hence, high resultant forces. Thus there are significant demands on the cutting material and the coating like high stability and wear resistance. Cutting edge design also gains in importance beside the tool strength. By dint of cutting edge preparation, the capability of cutting tools can be increased due to higher cutting edge stability. Cutting edge preparation properties are to reduce the cutting edge chipping and to create a defined rounding of the cutting edge. Furthermore, the hardness and the oxidation resistance of the coating and the adhesion of carbide and coating are accountable for the process reliability which can be enhanced by the cutting edge design. Among brushing and slip grinding, the abrasive water jet blasting is also an industrial method for cutting edge treatment and allows forming varied cutting edge portions with different radii. In this research, the abrasive water jet blasting process was used to prepare different cutting edge designs of carbide twist drills having the same point shape previously. After the precoating cutting edge preparation, the twist drills were coated with the wear resisting PVD-TiN coating. The cutting edge design proves to be an important aspect for the adhesion of the coating to the substrate in context of the conditions of the high performance cutting process. Based on the results of drilling tests, it was determined that there is an effective potential to optimize the high performance process by selective variation of the microscopic cutting edge form.
11:20 AM		G6-1-5 Mechanical Post-Treatment of CVD Coated Cemented Cutting Tools for Increased Toughness and Failure Resistance H. Holzschuh (Walter AG, Germany); M. Klaus, Ch. Genzel (Hahn-Meitner-Institut Berlin, Germany) Post-treatment of cemented carbide cutting tools can influence the residual stress status and increase toughness and failure resistance in interrupted cutting by far. To know about the use of the appropriate blasting media, blasting parameters and coating properties (composition, microstructure, morphology, texture and adhesion) is essential to influence residual stresses to meet one’s expectations. In this presentation wet and dry blasting processes are compared in order to improve residual stresses in CVD coated cutting tools. Of utmost importance to influence the residual stress are hardness and ductility of the blasting media compared to the coating material. But phase composition, microstructure, texture, adhesion and coating thickness limited the stress input and level. Interrupted cutting tests verified the influence of residual stresses on toughness and failure resistance.