Influences on the Automated Assembly of Hybrid Microsystems with High Accuracy

Nowadays, an ongoing trend of miniaturization of products and components can be observed in nearly all application areas in the world. As for microsystems, a distinction is drawn between monolithic and hybrid microsystems. The latter group requires some kind of assembly process. For the assembly of hybrid microsystems, a high assembly accuracy in the range of a few micrometers is required. In order to reach this accuracy, an assembly system for sensor guided microassembly has been developed at the Collaborative Research Centre 516 “Design and manufacturing of active micro systems”. This paper describes the design of a system for automated assembly of hybrid microsystems. The influences on the accuracy will be analyzed on the basis of an example for an automated assembly process

Heat Management Concepts for a Precision Assembly of Mirco Components Using Hot Melt Joining

Nowadays, the production of 3D MEMS and MOEMS is carried out by using hybrid integration of single components, for which batch production is normally preferred. In this field, adhesive technology is one of the major joining techniques. At the Collaboration Research Center 516, a batch process based on a joining technique which uses hot melt adhesives was developed. This technique allows the coating of micro components with hot melt in a batch. The coating process is followed by the joining process. Due to this, the time between coating and joining can be designed variably. Because of the short set times of hot melt adhesives, short joining times are possible. For this assembly process adapted heat management is necessary. This paper presents adapted heating management concepts and gripping systems which allow a fast and accurate assembly of hybrid micro systems with hot melt coated components. Therefore, the chosen gripping system depends on the process and heat management concept as well as the thermal properties of the components. Furthermore, the simulative and experimental results of the heat management concepts will be discussed

Pseudo-elastic Flexure-Hinges in Robots for Micro Assembly

The increasing tendency of products towards miniaturization makes the substitution of conventional hinges to flexure hinges necessary, since they can be manufactured almost arbitrarily small. On account of their multiple advantages like no backlash, no slip-stick-effects and no friction, their application is especially reasonable in high-precision robots for micro assembly. Particular pseudo-elastic shape memory alloys offer themselves as material for flexure hinges. Since flexible joints gain their mobility exclusively via the elastic deformation of matter, the attainable angle of rotation is strongly limited when using conventional metallic materials with approximately 0.4% maximal elastic strain. Using pseudo-elastic materials, with up to 15% elastic strain, this serious disadvantage of flexure hinges can be avoided. A further problem of flexible joints is their kinematic behavior since they do not behave exactly like conventional rotational joints. In order to examine the kinematics of the hinges an experimental set-up was developed whereby good compliance with theoretical computed values could be achieved. A three (+1) degree of freedom parallel robot with integrated flexure hinges is investigated showing its kinematic deviations to its rigid body model. The data of the kinematic model of the flexible joint can then be implemented into the control of this compliant mechanism in order to gain not only a higher repeatability but also a good absolute accuracy over the entire working space

Assembly of Micro Systems with the High Precision Robot Parvus

In recent years, the development of micro systems has been widely discussed in research articles concerning a decrease in size, an increase of complexity and the variety of materials used. In contrast, manufacturing and especially assembly processes of millimetre-sized products with high complexity did not play a significant role. Conventional precision robots that provide adequate accuracies for micro assembly are relatively large and expensive. These machines have to be operated in clean rooms, which results in high costs of maintenance. These days, the assembly technology of electronic production and conventional assembly robots is often no longer suitable for the assembly of hybrid micro systems. The increasing gap between millimetre-sized products and the production machines has lead to a high proportion of manual assembly in the manufacturing process of microproducts. Assembly costs that sometimes account for up to 80 % of the costs of micro systems retard the commercialisation and bulk production of these products. [1] Especially for small and medium-sized businesses, new concepts for flexible and lower-cost micro assembly have to be found

In-Process Laser Scanning Technology for Micro Assembly

To recognize edges of components in an assembly process, in particular of microelectronic or micro system components, nowadays vision systems are preferred. These systems are working fast but the results strongly depend on ambient conditions. In most sensor guided assembly systems laser displacement sensors are implemented additionally to vision systems. These sensors are used for detection of the components height. In this paper a scanning method is presented that detects edges by using a laser displacement sensor. These data can be used by robot assembly system for a sensor guided assembly process. Further by this technique is extended in order to gain 3D-infonnation of micro components and a proposal of the field of application is outlined

Compliant parallel robot with 6 DOF

In this paper a patented parallel structure1 will be presented in which conventional bearings are replaced by flexure hinges made of pseudo-elastic shape memory alloy. The robot has six degrees of freedom and was developed for micro assembly tasks. Laboratory tests made with the robot using conventional bearings have shown that the repeatability was only a couple of 1/100 mm instead of the theoretical resolution of the platform of < 1 pm. Especially the slip-stick effects of the bearings decreased the positional accuracy. Because flexure hinges gam their mobility only by a deformation of matter, no backlash, friction and slip-stick-effects exist in flexure hinges. For this reason the repeatability of robots can be increased by using flexure hinges. Joints with different degrees of freedom had to be replaced in the structure. This has been done by a combination of flexure hinges with one rotational degree of freedom. FEM simulations for different designs of the hinges have been made to calculate the possible maximal angular deflections. The assumed maximal deflection of 20° of the hinges restricts the workspace of the robot to 28x28 mm with no additional rotation of the working platform. The deviations between the kinematic behavior of the compliant parallel mechanism and its rigid body model can be simulated with the FEM

Automated Assembly of Hybrid Microsystems

The paper describes the design of a system for the automated assembly of hybrid microsystems and the accuracies of the components. The influences on the accuracy will be analyzed on the basis of an example for an automated assembly process. While the object sizes reach centimeter range, they have to be assembled with an assembly accuracy of only a few micrometers. A relative positioning accuracy of 0.8 pm is reached in this process

Survey of the Current Activities in the Field of Modeling the Space Debris Environment at TU Braunschweig

The Institute of Space Systems at Technische Universität Braunschweig has long-term experience in the field of space debris modeling. This article reviews the current state of ongoing research in this area. Extensive activities are currently underway to update the European space debris model MASTER. In addition to updating the historical population, the future evolution of the space debris environment is also being investigated. The competencies developed within these activities are used to address current problems with regard to the possibility of an increasing number of catastrophic collisions. Related research areas include, for example, research in the field of orbit determination and the simulation of sensor systems for the acquisition and cataloging of orbital objects. In particular, the ability to provide simulated measurement data for object populations in almost all size ranges is an important prerequisite for these investigations. Some selected results on the distribution of space debris on Earth orbit are presented in terms of spatial density. Furthermore, specific fragmentation events will be discussed