## 1 Introduction
Other works have focused on manufacturing the following: an ontology-based product design framework for manufacturability verification and knowledge reuse to support the sharing and reuse of design and manufacturing knowledge [23], a failure-assessment based design revision of manufacturing equipment based on the lessons learned from forensic metallurgical analysis [24], and an approach to capturing systematic knowledge for manufacturing process innovation [25]. These multiple approaches achieve the KBE application with very specific tools. However, the complex products we are dealing with would require an effective integration. In particular, they require an integrated approach to retrieve and reuse existing CAD models and technical documentation. Furthermore, many mechanical products have been developed with the systematic design approach [6]. Therefore, it is very effective to adopt the same approach for their knowledge management. In many companies, designers frequently face projects with the same design phases for products with similar structure but just small variants for specific requirements. Therefore, designers could benefit from the support of a knowledge tool that aids the execution of design tasks. A possible solution could be the application of archetypes of systems, defined as solutions for facilitating sharing knowledge and system interoperability [26]. Therefore, we introduce the design archetype (DA), a design tool that stores the knowledge on a subsystem design in its algorithms and supports the designer in selecting and dimensioning the most suitable working principles to address the project requirements [4; 27; 28; 29; 29]. Following the systematic approach, a specific contribution is the organization of the tool on the following two levels: the first is the layout and the second consists of the linked parametric models. With the aim of discussing the method for the DA implementation, we report its application in two case studies, selected since they are complex assemblies requiring an integrated approach to retrieve and reuse existing CAD models and technical product documentation. In particular, we focus on mechanical transmissions, which are widespread systems in industry, from vehicles to renewable energy, and from machine tools to automation and robotics [30; 31; 32; 33]. Many studies focus on transmission machines from multiple perspectives, such as manufacturing and finishing [34; 35; 36; 37; 38], or metrology and tolerances [30; 39; 40; 41], but only a few of them deal with their design knowledge management. The studied subsystems for mechanical transmissions are both designed and manufactured by a leader multinational corporation and are definitely defined mature products with stable technologies. As mature technical products, they are particularly suitable to be addressed by a DA application because of the following:  
* The designer quite often faces design problems that have been previously solved by someone else for different requirements;
* The company had and has a complete view over their whole lifecycle;
* The applications of the method use the PTC Creo(r) package integrated with MathWorks Matlab(r) environment. This paper is organized as follows: First, the two-level systematic method used for the development of machine DAs is introduced in Section 2; Section 3 reports the two case studies for the definition of a DA for mechanical transmissions; in Section 4, the results of the DA implementation are discussed; and the conclusions are summarized in Section 5.