I Have a PCS – How Can I Apply It? (Part 6)
What’s most important: The PCS must reliably and securely adhere to its substrate. It also goes without saying that the PCS must be smoothly integrated into the whole production process to ensure quick, neat and reliable application.
There are several ways to apply PCSs to components. The perfect method depends on parameters such as the required function, the component and the environmental conditions the component will be exposed to. This includes, for instance:
- material composition and component design,
- contact of the component – and thus the PCS – with media, liquids or chemicals,
- process and cost aspects relating to the component price,
- required housing adaptations,
- cycle time for the application process,
- initial investment for the application/affixing units.
I have compiled some information below about the most important application processes and their benefits and disadvantages:
Application of self-adhesive PCSs
The easiest and quickest solution is to use self-adhesive PCSs.
The self-adhesive PCSs are supplied on reels, thus enabling automated application and correspondingly short cycle times.
Automated application of self-adhesive PCSs
The range of application of self-adhesive Pressure Compensation Seals goes from -40°C up to +150°C.
Special versions such as PCS HighProtect combine the benefits of self-adhesive PCSs (easy and quick handling, almost no housing adaptations) with the protective properties of PCS caps which are clipped or screwed into the housing.
2. Ultrasonic welding
Application of ultrasonically weldable PCSs
Composition of ultrasonically weldable PCSs
You can affix Pressure Compensation Seals made of 100% PTFE membranes by ultrasonic or thermal contact welding.
For this, a sonotrode (a tool set into resonant vibration by inducing high-frequency mechanical (ultrasonic) oscillations) is positioned on membrane and component. The vibrations produce a welded joint that has excellent thermal and chemical resistance and complies with the IP 66 and 67 protection classes. Ultrasonically weldable PCSs can also be processed from the reel.
The technically feasible and reasonable sonotrode diameter is limited. Therefore, the minimum PCS size ranges between a membrane disc diameter of approximately 7-9 mm. Mini PCSs with a diameter of 3 mm are increasingly being used in sensor technology applications. They are only available in a self-adhesive version.
DAE im Ultraschallschweißprozess
(DAE mit Sonotrode)
- 3. Clipping / Screwing
When being clipped or screwed, the membrane is frequently integrated into a plastic housing referred to as a cap. It is either clipped onto the housing through a corresponding opening in the component or screwed on by means of a thread. From a mechanical point of view, this variant is a very robust solution, since the ventilation membrane is completely protected by the housing. Disadvantages include the frequently higher costs, the required housing adaptations (such as ensuring a certain wall thickness when planning and producing the housing) and the application process (the caps are supplied in bulk; automated application is difficult).
Schreiner ProTech does not offer clipping or screwing solutions. If you are interested in a similar product we can provide you with contact details of competent partners.
Alternatively to using caps, film-based, adhered or welded PCSs can be installed in a protected position inside the housing. In this case the PCS is positioned behind a thread, channel or the like. By this you can combine the benefits of easy application ‒ such as using a self-adhesive version ‒ with the advantages of robust, mechanical protection.
This was the sixth and second-to-last part of our blog series. If you have any questions or remarks, I´m looking forward to hearing from you via mail: firstname.lastname@example.org. The final part will be an interview that will be published in January.
This post is also available in: German