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Brecher C.,Laboratory for Machine Tools and Production Engineering | Gerlach G.,Laboratory for Machine Tools and Production Engineering
Tribology Transactions | Year: 2012

Spindle ball bearings as a central component are decisive to the reliability and performance of the entire machine tool. Insufficient lubrication of the bearings represents the principal cause of spindle failures. To increase the reliability and reduce friction, heat input and wear coatings are a possible option.In this article, the testing of spindle bearings coated with an amorphous hydrogenous carbon with metal doping, referred to as a-C:H:W, is presented. The running behavior under different operating conditions and wear of components will be analyzed. The tests were carried out on two test benches and were subdivided into seven different test conditions according to the rotational speed profile and load application of machine tools. Two synthetic esters were employed as a lubricant, one of which not only contains an additive but is also contaminated with abrasive particles for analysis of the influence of the contaminant.The analyses show that during operation at standard, medium, and higher loads up to a material fatigue limit of p&inf>H&/inf> = 2,500 MPa, the running behavior of the coated bearings when lubricated with a particle-free lubricant was better than or equal to that of the reference. No wear could be determined on the bearing rings up to 5.5 × 10 9 rolling events. During operation with a particle-contaminated lubricant under high load, the considerable number of rolling events led to wear on the inner rings only. The wear on the coating may be classified as mild polishing wear of the layer and can lead to entire delamination. © 2012 Copyright Taylor and Francis Group, LLC. Source

Brecher C.,Laboratory for Machine Tools and Production Engineering | Manoharan D.,Laboratory for Machine Tools and Production Engineering | Ladra U.,Siemens AG | Kopken H.-G.,Siemens AG
Production Engineering | Year: 2010

The productivity of machine tools is often limited due to chatter vibrations caused by relative displacements between the tool and the workpiece. The following article presents the systematic approach of the integration of an active workpiece holder with two high dynamic axes controlled by piezoelectric actuators onto a milling machine. With these additional highly dynamic axes near the tool center point, the active workpiece holder offers possibilities to prevent chatter vibrations. © 2010 German Academic Society for Production Engineering (WGP). Source

News Article
Site: http://www.materialstoday.com/news/

The Fraunhofer Institutes for Production Technology IPT and Laser Technology ILT, and RWTH Aachen University’s Laboratory for Machine Tools and Production Engineering (WZL) have launched the International Center for Turbomachinery Manufacturing (ICTM) in Aachen together with 19 renowned industrial partners. The center will focus on research relating to the repair and manufacturing of turbomachines, and, according to one partner, will be used in part to research 3D printing for turbine manufacture. The industrial partners in the new network include turbine manufacturers as well as corporations and medium-sized companies. Another company is interested in improving the surface quality of aerospace components made of titanium. This story is reprinted from material from Fraunhofer Institute, with editorial changes made by Materials Today. The views expressed in this article do not necessarily represent those of Elsevier.

Klocke F.,Laboratory for Machine Tools and Production Engineering | Zeis M.,Laboratory for Machine Tools and Production Engineering | Harst S.,Laboratory for Machine Tools and Production Engineering | Klink A.,Laboratory for Machine Tools and Production Engineering | And 2 more authors.
Procedia CIRP | Year: 2013

In order to increase the efficiency of jet engines hard to machine nickel-based and titanium-based alloys are in common use for aero engine components such as blades and blisks (blade integrated disks). Here Electrochemical Machining (ECM) is a promising alternative to milling operations. Due to lack of appropriate process modeling capabilities beforehand still knowledge based and a cost intensive cathode design process is passed through. Therefore this paper presents a multi-physical approach for modeling the ECM material removal process by coupling all relevant conservation equations. The resulting simulation model is validated by the example of a compressor blade. Finally a new approach for an inverted cathode design process is introduced and discussed. Copyright © 2013 Elsevier B.V. Source

Schuh G.,Laboratory for Machine Tools and Production Engineering | Arnoscht J.,Laboratory for Machine Tools and Production Engineering | Volker M.,Laboratory for Machine Tools and Production Engineering
Procedia CIRP | Year: 2012

The current situation of the manufacturing industry is characterized by permanent development in economics, politics and society. In order to react to those, companies have to be able to adapt the organization to these changes. Therefore a certain degree of changeability is inevitable. Today companies are seeking for the optimal degree of changeability. To determine it and to reduce the necessary changeability, its drivers have to be identified. The main internal factor are the products. Depending on future customer needs and requirements, different products and product designs force companies to change their production systems. Therefore instruments are required which enable companies to reduce the necessary changeability already in the creation process. © 2012 The Authors. Source

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