## 3 Case Studies and Results  
The adoption of the proposed approach allows the definition of 46 DFW rules, all in the class of fusion welding. The overall list of DFW rules is reported in Appendix A. The structure of the DFW rules list (Appendix A) is the same reported in Table 1, which presents the overall structure of the repository used for collecting and storing the rule-related information. In the first column of the repository are stored the rule number, which is a positive, progressive number. The central columns contain three clusters of information, namely, (i) manufacturing technology, divided into manufacturing technology class and manufacturing process type; (ii) material, composed by material class and material type; and (iii) CAD feature recognition, identifying geometric parameters and thresholdsassociated to a given rule. In addition to these sections, information about rule type is stored (i.e., info, warning, critical). The last two columns contain the guideline and the reference. The first represents the suggested guidelines displayed to the designer, while the reference is the rule's source (reference).  
It is worth noting that this rules list is only a preliminary study and more rules will be added in further development to consider industrial knowledge, which is a crucial and long-term activity in the definition of DFW rules. Considering the guideline sources can be noticed that the majority (33 of 46) came from handbooks and reports [3; 4; 5; 6; 7; 8; 9; 10; 11; 12; 13; 14; 15; 16; 17; 18; 19; 20; 21; 22; 23; 24; 25; 26; 27; 28; 29; 30; 31; 32; 33; 34; 35; 36; 37; 38; 39; 40; 41; 42; 43; 44; 45; 46], 10 rules came from company practices and only three rules came from other sources (i.e., DFMPro tool) [47]. In this preliminary version, the distribution of the DFW rules among different fusion welding technologies is the following: (i) overall, 29 have general validity for all welding technologies, (ii) eight refers to resistance welding, and (iii) nine refers to arc welding. Among the nine DFW rules referred to as the arc welding processes, six belong to the gas metal arc welding (GMAW) process. On the other hand, among the eight DFW rules referred to the resistance welding processes, all of them are specific for the spot-welding process. Concerning the rules distribution among different materials can be noticed that the majority of rules can be applied to all metal materials, while only three rules are focused on a specific welded material (W031, W032, and W033). These rules define the gas mixture for a particular welded material (aluminum alloys, carbon steel alloys, and stainless-steel alloys).  
The rules presented in Appendix A can be also classified in relation to the CAD features to recognize. Many of them use plate thickness (12 of 46) as the main feature to recognize and/or bead dimensions (7 of 46). Rules focused on bead dimensions' features could be also divided based on bead parameters. Most of them (five of seven) consider bead height or thickness, four are focused on bead width and two rules use bead length as the parameter. It is worth noting that each rule could be considered more than one CAD feature or one parameter at the same time. Following the collection of these DFW rules through the knowledge-based approach previously described, the overall approach has been applied to a couple of real case studies.