MicroFactory

Production in a controlled environment is becoming an increasingly important issue in various branches of industry. In the food, pharmaceutical, optical and semiconductor industries, today’s mass production would not be possible without so-called “cleanrooms” controlling the amount of pollutants such as dust, airborne microbes, aerosol particles and chemical vapors. At the same time, it guarantees a common requirement of all production systems, notably a steady production environment in terms of temperature and humidity (prevention of internal stresses, thermal expansion of the structure, unwanted chemical reactions or unpredictable surface forces). Moreover, the high installation costs are one of the main drawbacks for automated production or for controlled environments. To make a return on investment, large quantities must be produced. Due to a lack of modularity, manual assembly is often the only possibility for products with many variants or with small to medium batch sizes. A steady production with a repeatable quality is difficult to obtain in this case. This thesis thus introduces the concept of a circular assembly line, which aims to provide a modular production platform for microcomponents. Firstly, the system is miniaturized in order to match the size of the product it produces. This greatly reduces the acquisition, maintenance and reconfiguration costs, as well as installation and down time. Secondly, an integrated mini-environment similar to common cleanrooms ensures a steady working condition with a controlled level of airborne particles. This approach reduces the cleanroom to the absolute minimum, is faster to configure (high air renewal guarantees decontamination delays of less than a few minutes) and it can work stand-alone in a non-controlled environment. The proposed framework is demonstrated by a true-to-scale prototype with two production cells. Furthermore, this thesis provides an appropriate spatial allocation of the numerous production elements within this microfactory concept and the GyRob4 robot has been developed as a case study for a suitable design. The first evaluation of the robot performance is very satisfying and confirms a good compromise between size, modularity and cleanliness requirements. Auxiliary devices such as an automated tool-holder and an air conditioning unit have been developed in the frame of this work. With regard to the manipulation of standardized production trays, referencing systems as well as docking stations and the opening mechanism for hermetic containers have been achieved. The key aspect of this thesis is the circular microfactory layout, which is based on the combination of a rotary conveyor and a radial clean air inlet. This simple and reliable configuration provides a high modularity comparable to the other miniaturized concepts. However, its advantage lies, in particular, in achieving a laminar air flow without discontinuities, which is a fundamental requirement to attain the highest cleanroom standards. Therefore, this thesis covers the issue of developing a radial air inlet (also referred to as a homogenizer) and the constraints on the production cells to maintain a laminar air flow, which are particularly challenging due to the increasing cross-section in a circular arrangement. The second part of this work details the mechanical design of a large work space robot called GyRob4 with four degrees of freedom. Strategies to reduce the impact on the miniaturized cleanroom have played a major role in the selection of the robot kinematics. Besides the cleanroom-suitable design, Gyrob4 highlights numerous interesting technical aspects such as the high working range to footprint ratio, the automated tool-holder and the cable routing through the double-arm structure and through the joint of the main rotation axis. Thanks to the miniaturized design, GyRob4 is able to outperform many other serial robots with a similar working volume. The thesis addresses the industrial requirement for production tools that support the ongoing miniaturization trend. Therefore, the proposed circular assembly line, the manipulator and auxiliary features respond to this need and aim towards a multi-purpose platform providing a rapid implementation of different production tasks and push miniaturization towards the technological limits.