## 1 Introduction  
### Motivation  
Micro-assembly is used in different fields of activity like electronics packaging or the production of optical devices. The main task is to pick, place, and join small components on substrates under the condition of tolerances in the micrometer range. The primary application in the industry is the mounting of components on flat substrates, most often printed circuit boards (PCB). This can be done using fast and precise pick-and-place machines. The whole PCB manufacturing process is standardized with special guidelines as a part of the so-called design for manufacturability (DFM) [1, 2]. Due to this high standardization, new products can be developed and manufactured without the need for integral changes of machinery and overly frequent feedback loops. There are powerful software solutions that incorporate those DFM guidelines in PCB manufacturing [3]. They help engineers to design their products, so that they are automatically suited for the manufacturing systems used. However, this process comes with several limitations while designing a product. Most importantly, product engineers have to work with flat substrates, so components cannot be mounted on spatial substrates. Furthermore, those substrates may be flipped in the process, but not freely moved in space. Many micro-assembled products need to overcome those limitations to be produced, e.g., specialized sensors and actuators, optical assemblies, or parts with a high sensitivity to the installation space. If the quantity needed is small and if it is feasible regarding tolerances and handling, such products can be built manually. Another option is special-purpose machines, constructed and built just for a single product or product family. However, those machines are costly and only pay off if they are highly utilized and in use long enough. This can be a problem in several situations:  
* There is a gap in the upscaling process between the low volume manual and the high volume special-purpose production. Companies cannot commission foundries for such medium-sized volumes as would be possible with the highly standardized PCB process. Therefore, they are not able to realize efficiency benefits because of a better capacity utilization at foundries. * Many markets have become more volatile in the last few decades, and product lifecycles are getting shorter [4; 5]. This makes the forecast of a future production volume more difficult. Hence, investments in special-purpose machinery is getting riskier [6]. * Individualization is a growing trend for many products. Customers demand products explicitly tailored for their needs. While this is possible with manual manufacturing, it is not doable with special-purpose machines [7]. All these reasons lead to companies rejecting potential product ideas due to a missing feasible business model. Plant engineers try to improve the situation using reconfigurable manufacturing systems (RMS) that allow the manufactures to reuse large amounts of a machine system for different products [8; 9; 10]. RMS in the field of micro-assembly have a core machine that provides a power supply, a control system, and different slots to install processing modules. Often, those processing modules are separated into processing heads attached to an axis system and base plate systems attached to a base plate. Figure 1 exemplarily shows such a system. Figure 1: The Desktop D1 from the OurPlant platform of Häcker Automation GmbH (Schwarzhausen, Germany) is a medium-sized reconfigurable manufacturing system (RMS) for micro-assembly purposes. The rendering shows the axis system with the attached processing heads, as well as the base plate with different installed base plate systems. With RMS, it is possible to build up a manufacturing system by only adding some special-purpose modules to already existing standard modules in a core machine. This reduces the investment risk for the production of new products. Only the special-purpose modules may suffer from low utilization; the standard ones can be reused over multiple projects.