Laser Plastic Welding: Important Development in Italy

Product Stories20 Apr 2020

Laser plastic welding is undergoing an important development phase. Leister, the Swiss multinational company that has been a reference in the field of plastic welding technologies for over 70 years, has successfully developed solutions for the automotive, electronics and micro-technology, medical and textile sectors.

Author: Alberto Pecchio, Marketing Specialist, Leister Italy

The principle of Laser Plastic Welding

Developed in university laboratories in the early 1990s, laser welding technology for thermoplastic materials began to be used for industrial applications in the second half of the 1990s and is now fully mature. Also referred to as «laser radiation welding», it allows the joining of two plastic parts, one absorbent and one transparent. The laser beam passes through the transparent joining part and transmits energy to the absorbent part, which, as it heats up, transmits heat by conduction to the transparent part until it too melts. For this purpose a physical contact on the junction plane is required, which is achieved by mechanical clamping. Thanks to local heating and expansion, an additional internal joint pressure is also created. The two pressures, external and internal, ensure robust welding of both parts.

  1. transparent joint part
  2. absorbent joint part
  3. laser emission
  4. melting area
  5. welding seam

Benefits of Laser Technology

There are numerous benefits that this welding method guarantees:

  • flexible and non-contact welding process
  • minimum thermal stress on the parts to be welded
  • minimum mechanical stress
  • simple weld seam profile
  • no particle release
  • vibration-free working
  • aesthetically flawless weld seam
  • high accuracy
  • suitable for sealing welds
  • no tool wear

Laser emission welding also makes it possible to process virtually any type of thermoplastic material and thermoplastic elastomers including ABS, PA, PC, PP, PMMA, PS, PBT as well as fibre-reinforced polymers. The weld seam strength corresponds approximately to the strength of the base material.

Main areas of application

Automotive: the range of applications ranges from sensors for the control of the most varied components, to the realization of fluid tanks up to the welding of optical groups (lights).

Medical technology: there are products on the market equipped with laser welded components. Microfluidics or analysis chips are a clear example.

Electronics: In many areas of modern life, electronic components are used, usually assemblies that are isolated from the environment by their housing. Laser technology is perfect for making watertight enclosures.

Textiles: Laser welding is used to make filters or to weld membranes on plastic frames.

Why Leister

Few companies in the world are able to offer their customers the ability to develop solutions for laser welding of plastic materials.


Leister is the company that can offer the greatest number of alternative techniques for directing the laser beam and thus carrying out the welding process. These include the patented GLOBO-welding which allows welding of plastic parts in 3 dimensions in one process. Leister also provides its customers with decades of application experience and a laboratory at the parent company in Switzerland to carry out feasibility tests, develop new applications or optimise the production cycle. The Italian subsidiary can count on competent technicians able to support customers in the various stages of the process.


NOVOLAS is the name of Leister's main line of laser welding machines. The machines of the NOVOLAS WS-AT series are modular and universal turnkey laser systems. They can be equipped with various laser modules and processing heads to increase productivity and thus economy.


For a further increase in productivity, NOVOLAS WS-AT can be completed with the integration of a rotary table. NOVOLAS welding machines can be used as manual workstations or integrated into automated production lines. Thanks to the experience and know-how of the Leister developers, these systems can be manufactured according to the individual technical and application specifications of the customers.