Plastics Joining

With vast materials expertise, broad fusion and non-fusion joining capabilities, and years of shop-floor application experience, EWI’s plastics joining group offers manufacturers a variety of resources to help enhance flexibility and durability while reducing weight and improving efficiency.

Laser Plastic Welding

EWI has a history of innovation in plastics joining, including development of the through-transmission infrared welding process. We work with all plastics joining processes, including ultrasonic welding, laser welding, adhesive joining, and spin welding. Joining of plastic parts requires consideration of a wide range of factors including material selection, joint design, environmental conditions, and cycle time. Our experts are intimately familiar with the advantages, disadvantages, and critical requirements of each unique process variation and can provide objective recommendations on process and equipment selection. Our customers benefit from this expertise as they tackle challenges related to product design, prototyping, production launch, and failure analysis.

EWI has expertise in virtually all plastics joining technologies; however, our core strengths lie in ultrasonic welding, laser welding, spin welding, and adhesive bonding.

Technical Expertise

  • Adhesives
  • Ultrasonic welding / inserting / staking / swaging / cutting / sewing
  • Laser welding (through-transmission and keyhole)
  • Laser surface treatment
  • Infrared welding (through -transmission and standard)
  • Spin welding
  • Vibration welding
  • Hot plate welding
  • Thermal staking
  • Thermal sealing of films
  • Extrusion welding
  • Hot gas welding
  • Implant induction welding
  • Resistive implant welding
  • Radio frequency welding
  • Material weldability and selection
  • Joint design / design for assembly
  • Tooling design
  • Process optimization and parameter development
  • Troubleshooting
  • Cross-section / microtome analysis
  • CT scanning
  • Pull / peel / push / leak testing
  • Dynamic mechanical analysis
  • Fourier transform infrared spectroscopy
  • Differential scanning calorimetry
  • Microscopic analysis

Equipment and Lab Resources

  • Ultrasonic plastic welding equipment
    • 20 kHz servo press
    • 20 kHz pneumatic press
    • 20 kHz dual pneumatic press
    • 40 kHz pneumatic press
    • 15 kHz pneumatic press
    • 30 kHz servo press
    • 50 kHz probe & generator
  • Dual servo 4000 rpm spin welder
  • 940 μm laser diode with XY table
  • Microtome
  • Polarized light microscope
  • Plastic weld testing and evaluation equipment
    • 250 lb capacity peel tester
    • Dynamic machine analysis (DMA)
    • Fourier transform infrared (FTIR)
    • Differential scanning calorimetry (DSC)
    • Computed tomography (CT) Scanner


  • Developed ultrasonic technology to enable high speed package sealing. This solution can be easily integrated into most standard thermal sealing bag makers. Large scale demonstrations of high speed ultrasonic packaging equipment has achieved significant reduction in package material and associated cost and improved seals that provide enhanced shelf life. In addition, manufacturing data has documented improved quality that translates to reduced package and product waste. EWI has also recently completed a study on determining the correct ultrasonic tooling design for various films and can apply this method to any film being considered for ultrasonic joining, including bio-degradable and -compostable films.
  • Conducted an in-depth laser welding evaluation for American Axle & Manufacturing, Inc. (AAM) to determine the processing window for joining 15% glass-filled nylon components, identifying settings for multiple key process variables, verifying that joint strength and leak rates were within allowable ranges, and positioning AAM to implement laser welding in future applications.
  • Completed an in-depth comparison of various joint designs for ultrasonic welding of polybutylene terephthalate (PBT). This work involved modeling the heat generation rate in the polymer to predict the melting rate and optimizing weld parameters for a shear, 90-degree, 60-degree, and a new round energy director joint design. This work demonstrated that a longer lasting and less expensive to manufacture round energy director can be used effectively with servo motion control during ultrasonic welding.
  • Developed a method to bond a polymer film to a thin metal sheet without the use of adhesives. This method resulted in bond strength such that, when the polymer was peeled from the metal, the polymer film broke outside the weld and left material adhered to the metal.
  • Evaluated a welded plastic assembly via CT scanning to help troubleshoot a joining issue.