@article{9972, abstract = {{The transportation of dry fine powders is an emerging technologic task, as in biotechnology, pharmaceu-tical and coatings industry the particle sizes of processed powders get smaller and smaller. Fine powdersare primarily defined by the fact that adhesive and cohesive forces outweigh the weight forces, leadingto mostly unwanted agglomeration (clumping) and adhesion to surfaces. Thereby it gets more difficult touse conventional conveyor systems (e.g. pneumatic or vibratory conveyors) for transport. A rather newmethod for transporting these fine powders is based on ultrasonic vibrations, which are used to reducefriction between powder and substrate. Within this contribution an experimental set-up consisting of apipe, a solenoid actuator for axial vibration and an annular piezoelectric actuator for the high frequencyradial vibration of the pipe is described. Since amplitudes of the radial pipe vibration should be as large aspossible to get high effects of friction reduction, the pipe is excited to vibrate in resonance. To determinethe optimum excitation frequency and actuator position the vibration modes and resonance frequenciesof the pipe are calculated and measured. Results are in good accordance.}}, author = {{Dunst, Paul and Hemsel, Tobias and Sextro, Walter}}, journal = {{elsevier}}, keywords = {{Powder transport Piezoelectrics Ultrasonics Pipe vibration Finite element simulation Fine powder}}, pages = {{733--736}}, title = {{{Analysis of pipe vibration in an ultrasonic powder transportationsystem}}}, volume = {{Sensors and Actuators A 263}}, year = {{2017}}, } @inproceedings{9955, abstract = {{Wire bonding has been an established packaging technology for decades. When introducing copper as wire material for high power applications, adaptations to the bonding process and to machines became necessary. Here, challenges occur due to the stiffer wire material and changing oxide layers on the contact partners. To achieve sufficient process stability, a clean bond area is required, which can only be achieved with high shear stresses in the contact partners surfaces. These necessitate high normal forces to plastically deform the wire and substrate. To achieve such high stresses in the contact area, the bonding tool needs to be able to transmit the needed tangential forces to the top side of the wire. The wire itself performs a shear movement and transmits the force into the contact area to clean the contaminant and oxide layers and to level the desired bond surfaces. The main function of the tool is to transmit these forces. If the bond tool can only transmit low forces in the direction of excitation, the parameter space for a stable bond process is severely restricted. Here, a modeling approach to estimate how well different tool shapes meet the demand of transmitting high tangential forces is presented. The model depends on wire deformation and thus on the ultrasonic softening effect.}}, author = {{Althoff, Simon and Meyer, Tobias and Unger, Andreas and Sextro, Walter and Eacock, Florian}}, booktitle = {{IEEE 66th Electronic Components and Technology Conference}}, keywords = {{finite element simulation, wire bonding, tool geometry}}, pages = {{2103--2110}}, title = {{{Shape-Dependent Transmittable Tangential Force of Wire Bond Tools}}}, doi = {{10.1109/ECTC.2016.234}}, year = {{2016}}, } @article{34442, abstract = {{Radial shaft seals are used in a variety of applications, where rotating shafts in steady housings have to be sealed. Typical examples are crankshafts, camshafts, differential gear or hydraulic pumps. In the operating state the elastomeric seal ring and the shaft are separated by a lubrication film of just a few micrometers. Due to shear strain and fluid friction the contact area is subject to a higher temperature than the rest of the seal ring. The stiffness of the elastomeric material is intensely influenced by this temperature and thus contact pressure, friction and wear also strongly depend on the contact temperature. In order to simulate the contact behavior of elastomer seal rings it is essential to use a comprehensive approach which takes into consideration the interaction of temperature, friction and wear. Based on this idea a macroscopic simulation model has been developed at the MEGT. It combines a finite element approach for the simulation of contact pressure at different wear states, a semi-analytical approach for the calculation of contact temperature and an empirical approach for the calculation of friction. In this paper the model setup is presented, as well as simulation and experimental results.}}, author = {{Frölich, D. and Magyar, Balázs and Sauer, B.}}, issn = {{0043-1648}}, journal = {{Wear}}, keywords = {{Radial shaft seal ring, Contact temperature, Wear, Friction torque, Finite element simulation}}, number = {{1}}, pages = {{71--80}}, title = {{{A comprehensive model of wear, friction and contact temperature in radial shaft seals}}}, doi = {{https://doi.org/10.1016/j.wear.2013.12.030}}, volume = {{311}}, year = {{2014}}, }