Industrial use of micro components is determined by the availability of efficient manufacturing techniques. While micro injection moulding of plastic is common practice, metal and ceramic powder injection moulding (PIM) still is under development. High-pressure and low-pressure injection moulding methods complement each other ideally, covering the entire spectrum from prototype to large-scale production. With high-pressure PIM, micro gear wheels with diameters \300 lm can be fabricated using LIGA mould inserts. Densities between 97 and 99% of the theoretical values are achieved. Apart from oxide ceramics, metal materials like copper or powder metallurgical steels like 17-4PH or 316L are often applied. Multi-component injection moulding requires less mounting steps and, hence, offers decisive advantages for effective production of interesting material combinations like electrically conductive/insulating or hard/ductile. Studies relating to the fabrication of immobile as well as mobile shaft-wheel components were performed. Other activities focussed on in-mould labelling with foils containing ultrafine particles to improve surface quality and detail accuracy. Low-pressure injection moulding allows for the manufacture of small series within 1-4 weeks at low cost. However, the process has features which are not compatible with high-pressure PIM. Although use of a low-viscous feedstock is associated with various benefits, low-pressure injection moulding has not met with acceptance in micro moulding.

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Based on the results of this study, bioimpedance measurement seems to be a promising option for intra operative ad hoc information about the bone layer currently penetrated and could contribute to patient safety during neurosurgery.

In this paper, two methods for bridging line of sight interruptions occurring during the use of the synergistically operated semiautomatic trepanation system (STS) are presented. In the STS, position information is acquired using an optical tracking system with the disadvantage of possible line-of-sight interruptions. Their compensation is crucial, as a real-time control system automatically adjusts the cutting depth of the instrument on the basis of position information and a-priori data. The surgeon is only responsible for guiding the instrument along the resection line. Hence, availability of position information is crucial for depth control, set point generation, and thus for patient safety. In favour of enhancing reliability of position and orientation acquisition, two approaches were developed which are intended to estimate the position during line of sight interruptions on the basis of a-priori system information and process parameters. To assure patient's safety during this procedure, several parameters of the system (e.g. cutting radius, skull gradient) are used in order to estimate the possible cutting error while the redundant system is activated. These two algorithms and the online risk assessment were implemented, and afterwards evaluated. The evaluation was performed using a skull phantom, and yielded promising results.