ProjectSOULAP

Laser welding of polymers is now establishing itself as a strategic joining technology for many industrial sectors. It eliminates the need for chemical adhesives while guaranteeing high precision, excellent sealing and economic competitiveness.

Beyond its technical performance, this process fits squarely within a sustainable manufacturing approach, thanks to reduced energy consumption and less use of auxiliary materials.

However, weld quality – particularly mechanical performance and sealing – remains highly dependent on the molecular structure of the polymers. Current models, which are essentially macroscopic, cannot accurately describe the physical phenomena occurring at the interfaces.

An in-depth understanding at the nanometre scale is therefore needed to take the optimisation and reliability of this technology to the next level.

This is the context of the SOULAP project, which aims to link molecular mechanisms with the industrial performance of welded joints.

1 year – from 1 January to 31 December 2026

The SOULAP project pursues one central objective: better understanding laser welding of polymers in order to control it better.

More specifically, it aims to:

• Decipher the physical phenomena at polymer interfaces, from the nanometre scale to the macroscopic scale
• Characterise welded joints in detail (micromechanical properties, interfacial structure, stability)
• Model the interdigitation mechanisms of polymer chains using molecular dynamics
• Identify the molecular parameters that determine joint quality
• Optimise laser process parameters (power, speed, thermal cycles) through a coupled experimental/simulation approach
• Strengthen the robustness, repeatability and performance of industrial processes
• Contribute to more sustainable production by reducing the energy and material footprint

• Understand the interdiffusion mechanisms of polymer chains at the interface
• Link the interface structure to the mechanical properties and sealing of the joint
• Control the influence of laser parameters on joint quality
• Predict and optimise weld quality according to materials and joint configurations

The SOULAP project aims to deliver tangible benefits for industry, from a technological, economic and environmental standpoint.

Improved joint performance
A better understanding of interfacial phenomena will make it possible to optimise the mechanical strength and sealing of welds.

Process control and reliability
Identifying the key parameters will strengthen the robustness and repeatability of laser welding processes in industrial environments.

Faster innovation
The simulation tools developed will pave the way for predictive approaches, reducing testing phases and accelerating new product development.

Contribution to sustainable industry
By limiting the use of adhesives and optimising energy consumption, the project fully supports a more responsible approach to manufacturing.

Strengthened technological skills
The project contributes to upskilling in cutting-edge technologies at the crossroads of materials, digital technology and advanced processes.