The benefits of ultrasonic welding for membranes used in filtration and venting

Whether in the automotive or medical industry, ultrasonic welding has established itself as a proven process for integrating membranes into applications with pressure equalization or filtration functions. Shorter process times and clean, reproducible results make this joining technology particularly attractive for automated production systems where the focus is on increasing output and efficiency.

How ultrasonic embedding of membranes works

When embedding membranes in a pre-syringe filter, for example, high-frequency mechanical vibration energy is introduced into the joining zone via a welding tool known as a sonotrode.

The resulting melt penetrates into the superficial pores of the membrane and forms a micromechanical anchoring there. This creates a tight, firm bond without additional additives such as adhesives.

Tip: You can find out which plastics are best suited to the ultrasonic welding process here:

Discover suitable plastics for ultrasonic welding

Highlight: Punching and welding in one step

To shorten process times and further increase efficiency, our innovative ultrasonic joining process makes it possible to combine several work steps in a single automated process. The membrane is punched directly from a tape material and precisely embedded in the plastic component in a second step. This significantly reduces both material consumption and cycle times.

The process is carried out in four coordinated steps:

1. Punching: The membrane is punched out of the tape material in the desired diameter.
2. Positioning: The membrane is sucked onto the sonotrode using a vacuum and then transported precisely to the intended welding position.
3. Embedding: The membrane is anchored in the plastic component by means of strategic ultrasonic application and a defined force.
4. Tape advancement: The tape material is automatically advanced to start the next cycle.

Benefits for users:

• Short cycle times
• No pre-punching necessary
• Weld seam can be loaded directly
• Ideal for round membranes 

Case study: Application in the automotive industry

KACO was looking for a precise and fast joining process for embedding a membrane in an emergency degassing system.

The challenge: Despite its low weight and slight curvature, the membrane had to be positioned exactly in the centre of the housing. Inaccurate positioning could have impaired the functionality of the overall system.

Alternative joining methods, such as adhesive bonding, could not fulfil these criteria. In addition, the chemicals contained in the adhesive would have restricted the breathing activities of the fine membrane. The process cycles would also have been longer due to the drying time of the adhesive.

The solution: ultrasonic welding - precise and gentle on the material. Ultrasonic welding enables a permanent connection without the use of adhesives or other joining agents. This fully preserves the sensitive material properties of the membrane. Thanks to a customised tool solution and expert, application-specific process advice, the membrane can be positioned precisely in the component - reproducibly, reliably and with process safety.

Customer benefits: 

• safe, reproducible results
• fast cycle rates in an automated process
• gentle process for sensitive membranes
• firm connections between membrane and housing

Find out more about the customer benefits for KACO

Ultrasonic welding of membranes in medical applications

In medical engineering, there is a growing demand for reliable joining processes with high automation potential. Ultrasonic welding of membranes offers decisive advantages over adhesive bonding or thermal sealing:

Advantages of the ultrasonic welding process for manufacturers of medical devices:

• No pick-and-place handling necessary: Punching & embedding in one step
• Documentation: Seamless measuring and documentation of the process data for each individual weld

• Gentle energy input: Even more sensitive filter media are joined reliably and without damage

   

Typical applications:

• Pre-filled syringe filter / Pre-fill syringe filter
• Needle stroke membranes
• Inline filters for infusion systems
• Sterile aeration of IV solutions (PTFE venting membranes)
• Aeration and venting solutions for ostomy bags
• IV filters
• Infusion filters
• Needle-free inline filter
• Aeration and venting caps for cell culture bottles
• Pressure balancing elements (DAE)

Find out more about the benefits of ultrasonic welding in the medical industry here:

Ultrasonic welding for medical devices

Conclusion: Process-safe embedding of membranes with ultrasonic — ideal for large series

Ultrasonic welding is an optimal solution for the reliable, clean and economical joining of membranes in plastic components. The process fulfils the highest requirements for tightness, process safety and reproducibility for membranes from leading suppliers such as Gore, Porex, Berghof and Schreiner.

Thanks to the gentle working method and precise controller of the welding parameters, even more sensitive membrane materials can be reliably and permanently connected. Easy integration into automated production lines and the possibility of seamless process monitoring make ultrasonic the preferred joining process for large-scale applications.

Sound consulting by ultrasonic experts is crucial here. They provide support with component design, process development and the integration of ultrasonic systems into existing or new production systems — enabling a smooth and fast start-up.