The research of energy storage systems in the DC link of a machine tool is focused on the choice of the appropriate type of the energy storage system (passive or active) and its control strategy considering better ene...
详细信息
ISBN:
(纸本)9781612841670
The research of energy storage systems in the DC link of a machine tool is focused on the choice of the appropriate type of the energy storage system (passive or active) and its control strategy considering better energy efficiency. For the control strategy of the DC/DC converter two ways were taken into account: the proportional-integral and predictive control strategies. The energy consumption model of the drive group was developed in Matlab/SimPowerSystems for quantitative comparisons of the proposed energy storage systems. The model was validated by measurements of energy consumption in the drive unit of a machining centre.
The fabrication of high aspect ratio microstructures is very challenging, especially when the work piece material is hard to machine. Electro Discharge Machining (EDM) offers a contact- and nearly force free way of mi...
详细信息
ISBN:
(纸本)9780955308291
The fabrication of high aspect ratio microstructures is very challenging, especially when the work piece material is hard to machine. Electro Discharge Machining (EDM) offers a contact- and nearly force free way of micromachining and is therefore an appropriate means to producing microstructures. One key obstacle for a precise machining by micro-EDM is the tool wear. When ED-machining microstructures process speed, stability and thus tool wear are related to the aspect ratio of the structures. In this study, tool wear ratio within different stages of the EDM process is analysed when machining high aspect ratio micro bores in steel. Experiments with bores of different depths show the correlation between the stage of the process and the flushing conditions on the one hand and the tool wear ratio on the other hand. Thus, it is possible to find and apply optimized parameters for the different process stages. A better understanding of the tool wear will help to minimize it, reducing the cost of the tools and enhancing the precision of the process. This also shall allow an enhancement of the process speed because the need for flushing material out of the bore is reduced by the amount of tool material that can be saved.
This paper deals with the combination of micro milling and laser micro structuring for processing hot embossing dies for microfluidic applications. This strategy permits the advantages of each process technology to be...
详细信息
This paper deals with the combination of micro milling and laser micro structuring for processing hot embossing dies for microfluidic applications. This strategy permits the advantages of each process technology to be exploited in order to achieve a cost and time efficient process and also to process forms and structures which cannot be manufactured with the single processes micro milling and laser micro structuring. Basic requirements are a high-precision positioning of the single process areas and also a good machining of the parts and structures with the manufacturing processes micro milling and laser micro structuring. The intersections between the different processing areas present a challenge for this process technology.
Simulation, design optimization and controller design of modern machinetools heavily rely on adequat numerical models. In order to achieve results in shorter computation times, reduced order models (ROMs) are applied...
Current research activities in the field of manufacturing technology design increasingly focus on integrated approaches for process performance enhancements. As in many process development activities, systematic desig...
详细信息
Problems in using shape memory alloys (SMA) in industrial applications are often caused by the fragmentary knowledge of the complex activation behavior. To solve this problem, fraunhofer IWU developed a Matlab(R)-base...
详细信息
ISBN:
(纸本)9780819480606
Problems in using shape memory alloys (SMA) in industrial applications are often caused by the fragmentary knowledge of the complex activation behavior. To solve this problem, fraunhofer IWU developed a Matlab(R)-based simulation tool to emulate the properties of a SMA wire based on the energy balance. The contained terms result of the characteristic material behavior combined with thermal, electrical, and mechanical conditions. Model validation is performed by laboratory tests. It is shown that there is almost no difference between the measured and the simulated actuator movement. Due to the good quality of the model it is possible to use it in a control loop. Knowing current and voltage enables the computation of the electrical resistance of the actuator and can therefore be used for feedback control. Implementation of the results into industrial applications is exemplified by integration of an actuator in a flap as used in air condition systems of cars. Furthermore, the SMA-based drive will be compared to an electromechanical drive.
Surface structuring of workpieces has a significant influence on the tribological properties of contact partners and can therefore lead to a significant increase of the life time of components [1] . To identify an app...
详细信息
Surface structuring of workpieces has a significant influence on the tribological properties of contact partners and can therefore lead to a significant increase of the life time of components [1] . To identify an appropriate surface structure, analytical and experimental investigations were done at the institute for machinetools and Factory Management (IWF) in order to improve the tribological properties in the contact area appreciably. To validate the theoretical analyses, technological investigations were carried out. 3D-surface structures were created on workpiece surfaces by varying process variables for a high speed 5-axes machine system to generate knowledge for developing defined surface structures by using kinematically modified grinding processes. Initial results show a positive influence of defined surface structures on the performance of contact partners.
With the newly developed technology and hot embossing system presented, the manufacturing of double-sided precision optical lens arrays is possible (fig. 1 and fig. 2). The new process offers interesting options to op...
详细信息
暂无评论