Challenges in the manufacturing of hairpin windings and application opportunities of infrared lasers for the contacting process

Challenges and Future opportunities of Hairpin Technologies

“…1a. This is the most common solution for an automated process and big scale production, but achieves very low fill factors, usually lower than 55% [21], [22]. A second winding mechanism consists in placing tidily the wires in layers, as seen in Fig.…”

“…4. Since they are characterised by a rectangular cross section, the electric fill factor can achieve values of 80-85% in machines where they are employed [21].…”

“…The shaping phase can be very complex if performed "manually", i.e. with no automation of the process [21], [36]. Therefore, in order to reduce the production times, an automatized mechanism is usually utilised.…”

“…Contacting between two terminals of different hairpins is considered a crucial point by electrical machines' manufacturers in defining the efficiency of the whole technology, as it involves the qualification of the contact resistance and the characteristics of the manufacturing process. The choice between welding or soldering techniques is influenced by both these aspects [21]. According to [22], the "resistance welding" pros are mainly related to the ease of mass production due to the process' low costs.…”

“…Additional benefits include the short cycle time and the possibility of automation. However, the high frequency vibrations are a potential source of damage of the material structure, so quality and reliability may be compromised [21].…”