This paper addresses Virtual Reality-assisted pre-testing of NC programs and describes the benefits of testing them with respect to processing on the NC control unit. Thereby collisions of machine axes can be recogniz...
详细信息
Surfaces in a wide range of engineering applications are subject to tribological loads. Many of these surfaces have a profound effect on the efficiency of manufacturing processes and products during service. This pape...
详细信息
ISBN:
(纸本)9780955308291
Surfaces in a wide range of engineering applications are subject to tribological loads. Many of these surfaces have a profound effect on the efficiency of manufacturing processes and products during service. This paper focuses on the effect of surface microstructure geometry on the friction coefficient between lubricated sliding partners. Initially, the Computational Fluid Dynamics (CFD) package COMSOL Multiphysics was used to determine the effect of geometry parameters of semi-spherical cavities on hydrodynamic pressure. The simulations showed that surface microstructures act as micro pressure chambers that would allow the sliding partners to reach hydrodynamic lubrication at lower operating speeds. Patterns of the microstructure that showed the highest pressure build-up in the simulations were then manufactured by Jet-ECM and tested in a tribometer. It was determined that patterned spherical segment cavities 10 μm deep and 500 μm wide yield a friction coefficient reduction of up to 35 %.
Tool making is a very time consuming and expensive operation because many iteration loops are used to manually adjust tool components during the try-out process. That means that trying out deep drawing tools is 30% of...
详细信息
This paper deals with the investigation of orthogonal turn-milling of aluminium matrix composites using CVD (chemical vapour deposition) diamond tipped end mills. The influence of eccentricity, tool position and milli...
详细信息
ISBN:
(纸本)9780955308291
This paper deals with the investigation of orthogonal turn-milling of aluminium matrix composites using CVD (chemical vapour deposition) diamond tipped end mills. The influence of eccentricity, tool position and milling strategy on the surface integrity is described. The results show that the lowest roughness values can be achieved by positioning the tool below the work piece axis, using an eccentricity e = 2.5 mm and choosing up milling.
In this paper the influence of different forming velocities (stamp velocities) on the micro impact extrusion is investigated. The research is done on precision micro cavities which were formed into aluminium sheet mat...
详细信息
ISBN:
(纸本)9780955308291
In this paper the influence of different forming velocities (stamp velocities) on the micro impact extrusion is investigated. The research is done on precision micro cavities which were formed into aluminium sheet material using micro impact extrusion. The dependency of the stamp velocity is characterized using geometric parameters, metallographic analysis, and surface roughness. It was found that the grade of influence of forming velocity on characteristic parameters of the formed micro geometry depends on the sheet material thickness. For low thickness no influence was found, but for large thickness the velocity influences the achieved forming result.
The basic principle of Electrochemical Machining is an anodic dissolution of metallic work pieces at their interface to a liquid ion conductor, called electrolyte, under the influence of electric charge transport. Ele...
详细信息
ISBN:
(纸本)9780955308291
The basic principle of Electrochemical Machining is an anodic dissolution of metallic work pieces at their interface to a liquid ion conductor, called electrolyte, under the influence of electric charge transport. Electrochemical Machining with closed electrolytic free jet (Jet-ECM) is a new procedure which applies high current densities with a high degree of local removal, high localization of erosion and high surface quality [1]. Starting from this point machining of rotating work pieces by help of Jet-ECM is investigated [2]. Therefore a Jet-EC Turning prototype system was developed at Chemnitz University of technology. In this study experimental investigations for a characterization of the influence of different process parameters on the Jet-EC turning result are presented.
During the past decade great success has been achieved in the development of duplex and multilayer multi-functional surface systems. Among these surface systems outstanding properties have nanoscale multilayer coating...
During the past decade great success has been achieved in the development of duplex and multilayer multi-functional surface systems. Among these surface systems outstanding properties have nanoscale multilayer coatings. Within the framework of the M3-2S project funded in the 7th European Framework Programme, several nanoscale multilayer coatings have been developed and investigated for experimental and industrial validation. This paper shows the performance of TiN and TiN/CrN nanoscale multilayer coatings on WC cutting inserts when machining GJL250 cast iron. The thin films have been deposited by cathodic arc evaporation in an industrial PVD system. The multilayer deposition characteristic and its properties are shown. The inserts have been investigated in systematic cutting experiments of cast iron bars on a turning machine specifically equipped for force measurements, accompanied by wear determination. Furthermore, equivalent experiments have been carried out on an industrial turning unit. Industrial validation criteria have been applied to assess the comparative performance of the coatings. The choice of the material and the machined parts is driven by an interest in automotive applications. The industrial tests show the need to further optimise the multi-scale modelling approach in order to reduce the lead time of the coating development as well as to improve simulation reliability.
Due to their high specific workloads and small spatial requirements, shape memory alloys(SMA) possess an outstanding potential to serve as miniaturized positioning devices in small machinesThey provide sensory and act...
详细信息
Due to their high specific workloads and small spatial requirements, shape memory alloys(SMA) possess an outstanding potential to serve as miniaturized positioning devices in small machinesThey provide sensory and actory capabilities, being self-sufficient and a structure inherent control loopBased on its unique properties we present examples of SMA-actuated applications and methods of modeling systems, in which the material is used to compensate thermal induced strain in machine tool relevant applications and show how the overall system design can be achieved.
暂无评论