## 1 Introduction
### Related Work  
Finding improvements for the conceptual design phase in manufacturing and especially assembly is an active research field. A broad range of different techniques and methods exist to handle this phase in product development. Originally, the conceptual design phase stemmed from the SAPB and was based on a functional description of the new product on a system level. This is followed by a functional decomposition, in which the defined functions are broken down into smaller subsystems and ultimately building blocks. If suitable building blocks are not available, possible solutions have to be found. Subsequently, those building blocks are reintegrated into a complete product, whereby intense verification and validation ensure a satisfying achievement of the original objectives formulated in the functional description [12]. This can be seen as a top-down design (TDD) method. The main disadvantage of the conceptual design phase method of the SAPB is its pure focus on the product itself. Neither production processes, nor their resources are considered.  
Figure 2: The four phases of the systematic approach of Pahl and Beitz (SAPB).  
Other authors tried to improve the TDD by combining or refining it with other techniques. [PERSON] and [PERSON] presented a framework that included a consistency management of design information across different engineering disciplines to foster concurrent engineering [15]. [PERSON] et al. used a multi-skeleton modeling approach to link a TDD with a modular product design (MPD) [16]. In this approach, different parts in the development of a product are partitioned into so-called skeletons. Those skeletons are connected by an overlying product description. The actual development can then be done by a TDD approach in each skeleton separately.  
A similar method is model based system engineering (MBSE). It is based on connecting product developers of different domains by creating linked structures between models. [PERSON] et al. showed how this method can be used to combine an assembly sequence with a simulation model [17]. Furthermore, they looked at a non-PCB, micro-assembled product as a use case, but did not work with an RMS. For modeling, the Automation Modeling Language (AutomationML) was used.  
[PERSON] introduced the Object-Process Methodology (OPM) [18]. In OPM, a product concept can be modeled by objects and processes. Processes can alter the objects. This method is not singular product-centric, but instead implements elements of processing. OPM uses the Systems Modeling Language (SysML) to model and visualize a product. While this is a working approach for designing products, it is not easy to analyze those models automatically. [PERSON] proposed a model-to-model (MtM) technique to improve this situation [19].  
[PERSON] presented a method to model RMS and their reconfiguration with colored Petri nets (CPN) [20], but neither considered a connection to conceptual product development nor applied the method to micro-assembly. [PERSON] and [PERSON] combined CPN with the OPM technique to create a holistic model. With this model, they were able to achieve a multi-objective optimization of an RMS configuration using a conceptual model as a base [21].  
The U.S. National Institute of Standards and Technologies (NIST) defines an open assembly model (OAM) as an extension of their core product model. It incorporates assembly as a concept, as well as a data structure and can be implemented in various applications [22]. Another possibility in assembly modeling and analyzing is a datum flow chain. [PERSON] and [PERSON] proposed a method where an assembly was described by a liaison diagram and flow chains and analyzed by using a state transition model [23]. With this method, designers should be able to get feedback regarding their assembly quality in terms of tolerances when editing the assembly sequence.