## 1 Introduction  
Current global policies in place plan to decrease greenhouse gas emissions, creating a path for the world to become climate neutral by 2050 [1, 2]. The European Union clearly sets a common goal for every enterprise, where ecology and digital transformation come together towards an enhanced portfolio of leading European sustainability companies [3]. Joining dissimilar materials can be highly demanding [4], but has the potential to increase a product's functionality and manufacturing efficiency, which is in alignment with the EU's sustainability objectives. Joining dissimilar materials spans multiple approaches and materials, which can increase its complexity in relation to other manufacturing techniques [5]. Examples of these applications can be found in the automotive [6, 7], aeronautics [8, 9, 10], textile [11], and tooling sectors [12], among many others [13]. The ever-increasing demand for sustainable and complex components opens a window of opportunity for additive manufacturing (AM) techniques that, after decades of improvement, began to fabricate end-use products rather than simple parts and prototypes [14]. Because AM is a tool-less technology it has flexibility to generate complex parts without increasing costs, and is an interesting option for many companies worldwide to adopt and fabricate products with it [15, 16]. One possible application is to use AM to fabricate parts and specimens with dissimilar materials due to the potential to create optimal, lightweight, and high-performance components [5]. Regardless of the interest in dissimilar materials using AM techniques, adopting the combining of aluminium and polymers using AM is far from widespread. There are several challenges to overcome, but the potential for the automotive, power production, aerospace, medical, and many other sectors exists [5]. Challenges arise with materials of different chemical, mechanical, thermal, or electrical properties, or when those produced by different processes are to be joined together, namely regarding the structural integrity of the joints [9]. Comparing with others' materials, polymer/metal components are the best in terms of ease of manufacture and increased weight-to-strength ratio [17]. The ability to fabricate such parts, added to industry's significant demand for them, provides a strong advantage to some AM techniques [18; 19]. Among the available AM techniques [20], fused filament fabrication (FFF) is now perceived as one major AM technology platform to produce polymer/metal multi-material components [21; 22; 23]. The FFF is an AM technique that starts with filament material being guided to the extruder, where torque and a pinch system is used to feed and retract precise amounts of it. A heater block then heats the filament to a controllable temperature that is well above the glass transition temperature of amorphous polymers or the melting point of semi-crystalline ones [24; 25], and is forced out of the heated nozzle. The extruded material is laid down on the model through the correct positioning of the print head and/or the build plate, placing the material where it is needed [26; 27]. The value of FFF techniques for rapid prototyping or end-user products is undeniable [28]. However, the process is highly dependent on the optimization of numerous parameters to achieve parts with a high-quality surface finish [29; 30; 31; 32], dimensional accuracy [33; 32], and mechanical performance [34; 32; 35; 36; 37]. Adhesive joining is the most appropriate technique for bonding metallic and non-metallic structures where the strength-to-weight ratio must be maximized [38]. This technique utilizes polymeric substrates to join a large variety of material combinations. The adhesive joining between polymer-based materials and metals often involves the application of heat and pressure [39; 40].