Fluoropolymers / Alfa Chemistry

Welding & Sealing


Welding and sealing customized services

  • The heat sealing process melts the resin tube and seals the tube end. We can manufacture round, angled or flat sealed plastic tube ends according to your requirements.
  • Smoothness, clarity and thickness are critical to equipment performance. We can provide very personalized customized tip profiles for equipment with these high-performance requirements.
  • We can provide customized service for all kinds of fluoropolymer tubes we stock, and we can customize the size according to the order. Alfa Chemistry Fluoropolymers has years of experience in welding fluoropolymers and the most commonly sealed materials are PTFE, FEP and PFA.


  • FEP and PFA tubes can be reformed into a solid or hemispherical tip, where the wall thickness remains the same size throughout the tip area. These can be push-in tubes or heat shrink tubes.
  • FEP and PFA tubes can also be tapered to reduce the tip diameter before sealing.
  • PTFE tubing can use custom technology to weld the plug into the tubing to ensure a leak-proof seal.

Welding and sealing technology

  • Ultrasonic welding
  • Ultrasonic welding uses mechanical high-frequency vibration to form joints. The parts to be assembled are clamped between the oscillating welding head and the fixed welding head under pressure, and then at right angles to the contact surface, receiving ultrasonic vibration with a frequency of 20-40KHz. The alternating high-frequency stress generates heat at the joint interface to form a high-quality weld. The tools used in this process are inexpensive, so they are suitable for use when the production volume is large. This welding method is only suitable for small parts whose welding length does not exceed a few centimeters.

  • Friction welding
  • Thermoplastic friction welding (also called "spin welding") has the same principle as metal welding. In this welding process, one substrate is fixed and the other substrate is rotated at a controlled angular velocity. When the parts are pressed together, frictional heat causes the polymer to melt, and after cooling, a weld is formed. Friction welding can produce excellent welding quality, the welding process is complicated, and the relative error is strong. However, due to the complexity of the process, it is only suitable for applications where at least one part is circular and does not require angular alignment.

  • Hot plate welding
  • For plastic joining, hot plate welding is the simplest mass production technique. The high-temperature hot plate is sandwiched between the surfaces to be seamed until softened. At this time, the hot plate is drawn out, the two surfaces are attached under a controlled pressure, and they are held together for a certain period of time. Then, the molten surface is allowed to cool to form a weld.

  • Polymer laser welding
  • Polymer laser welding is an emerging technology. For applications that require manufacturing flexibility and precision non-contact processes without arc burns, this technology can compete with ultrasonic welding; in these cases, this technology can provide reliable and cost-effective bonding Various solutions for thermally weldable polymer materials.

Get in touch with us

If you have any services of interest, you are welcome to contact us to discuss the solutions that best suit your requirements.

※ Please kindly note that our services are for research use only.