# Smart Factory Web--A Blueprint Architecture for Open Marketplaces for Industrial Production
## 3 State of the Art
### Manufacturing as a Service (MaaS)  
MaaS platforms take a detailed product description as an input (often including CAD files to describe the product geometry) and determine how and by whom the product can be manufactured as a customized production service. Typical production processes are:  
* CNC machining;
* Three-dimensional printing;
* Urethane casting;
* Sheet metal fabrication; \begin{table}
\begin{tabular}{c c c} \hline \hline
**Number** & **Requirement** & **Priority** \\ \hline NFR01 & \begin{tabular}{c} **Interoperability** with other industrial marketplaces and \\ software systems (support for federations) \\ \end{tabular} & M \\ \hline NFR02 & **Applicability** to new industrial domains and sub-domains & O \\ \hline NFR03 & \begin{tabular}{c} **Openness** in the sense of supporting international and \\ national standards to avoid vendor lock-in and follow \\ future technological trends \\ \end{tabular} & M \\ \hline NFR04 & **Adaptability** to new business models & M \\ \hline NFR05 & **Scalability** of user, data and app management & M \\ \hline NFR06 & \begin{tabular}{c} **Security** to protect company data from unauthorized access \\ and assure its integrity \\ \end{tabular} & M \\ \hline NFR07 & \
\begin{tabular}{c} **Data Sovereignty** to maintain control over the complete \\ processing chain of data and also the independent decision \\ on who is permitted to have access to it \\ \end{tabular} & M \\ \hline NFR08 &
\begin{tabular}{c} **Extensibility** to support new types of production assets \\ (e.g., virtual assets such as production-related services) \\ \end{tabular} & O \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Non-functional requirements of the marketplace architecture (M = mandatory, O = optional). Injection molding. The other main aspect of the MaaS is the material type, which may also be hierarchically structured. Materials at the top level are metal, rigid plastics and elastomers. An essential part of the platform service is to check the manufacturability of the product with the proposed process and materials (e.g., are connecting elements too weak, or are holes in 3D objects too difficult to produce?). Platforms may offer to modify the design (Design for Manufacturing) and optimize the production process with regard to cost and quality. The platform service may also include the desired product finishing. Metal finishing in particular has many different options, e.g., relating to anodizing, plating, media blasting, powder coating and tumbling. The MaaS platform provides a quotation ('instant pricing') for the requested manufacturing capability. Examples of process-dependent properties of the factory capabilities are:  
* Min and max of the product sizes;
* Minimum hole size;
* Tolerances;
* Production time;
* Field of application (e.g., exclusion of fields where products must be certified). Several examples of MaaS platforms and their offered processes are given in Table 4 (in alphabetic order) with no claim to completeness, and just based upon publicly available information. A detailed comparison would require a survey, which is beyond the scope of this article. However, as a common denominator, all of these platforms address a limited range of manufacturing processes (mostly CNC machining) or focus on dedicated market segments or regions. None of these platforms, as of today, aim at leveraging a network of marketplaces or a production ecosystem and therefore do not support the non-functional requirements of interoperability, openness and data sovereign