Case Study: RPK Group & Leartiker, joint innovation in advanced Bus Bars for E-Mobility

As part of the HAZITEK R&D support program, RPK Group and Leartiker have jointly developed an ambitious industrial research project focused on electric mobility. This collaboration has significantly enhanced the technical capabilities of both organizations in polymer overmolding and ultrasonic welding, with a particular focus on high-value bus bars for electric vehicles. The technical knowledge, simulation and validation capacity, and component results position RPK Group as a key partner for complex solutions that combine precision metal technologies with lightweight, reliable polymer structures.

Project context and objectives

Under the name COMBINE, the project aimed to design and manufacture functional components for vehicle electrification. By combining high-value metal inserts, produced through stamping and bending technologies, with advanced polymer materials, the project explored new technical solutions utilizing overmolding and ultrasonic welding.

Key project goals:

• Acquire technical expertise in polymers for electric mobility
• Develop advanced bus bars through polymer overmolding onto metal parts
• Validate the feasibility of the ultrasonic welding assembly
• Use advanced simulation tools (Moldex3D) to optimize design and process
• Ensure product reliability under demanding conditions (tensile and aging tests)

Technical collaboration with Leartiker

Leartiker, a technology center specialized in polymers, played a strategic technical partner role by providing:

• Expertise in polymer material selection and characterization
• Advanced rheological simulation to define optimal process parameters
• Support for mold, tooling, and ultrasonic welding design
• Experimental validation according to automotive sector standards (e.g., PV1200)

Thanks to this collaboration, two functional demonstrators were redesigned, including complex components divided into several parts that were later assembled using ultrasonic welding.

Materials and methodology

To meet the mechanical, thermal, and electrical requirements of electric vehicles, two key materials were selected:

• PPA (Polyphthalamide) reinforced with 30% glass fiber: rigidity and dimensional stability
• Specialized polyurethane for mobility applications: flexibility and insulation

Integration with the metal inserts—manufactured by RPK using high-precision stamping and bending technologies—was critical to ensure a strong and durable bond.

Validation and results

The prototypes were assembled using ultrasonic welding and passed demanding validation procedures:

• Tensile tests: Strengths of up to 20 kgf were achieved with no failures in the weld lines
• Thermal shock tests (PV1200): No cracks or deformations were observed after test cycles, demonstrating excellent assembly quality

These results confirm the industrial feasibility of the solution and reinforce RPK Group’s technological positioning in a highly competitive environment.

Consolidated know-how and future vision

The COMBINE project has marked a qualitative leap in RPK Group’s technical capabilities, strengthening its leadership in overmolded metal components and advanced polymer welding assemblies.

Thanks to the knowledge generated in collaboration with Leartiker, RPK Group is now better equipped to meet challenges in designing high-value bus bars, positioning itself as a strategic partner for OEMs and Tier 1s seeking lightweight, robust, and reliable solutions for their electric mobility platforms.