At Robafoam, plasma treatment is an important part of our processing, although it’s not required for all parts. When a customer first approaches us with a prototype or part, one of their first questions is ‘will the foam stick to our part?’. The short answer is yes, but it may take some other processes before achieving a suitable adhesion.
Some substrates have a natural adhesion to our polyurethane foam and therefore don’t require additional interference. If there isn’t a natural adhesion then there’s usually something we can do to achieve it, which often is incorporating the use of plasma.
The adhesion of the Robafoam seals to a component’s surface is dependent on the surface energy of the material or the surface treatment in question, as well as any possible contamination of the surface. Different material surfaces exhibit a different level of natural adhesion depending on their surface energy. Surface energy is measured in Dyne/cm2 and the optimal value for adhesion with our foam products is 50 Dyne/cm2.
One way to change the surface energy, to ensure the adhesion of the foam, is through the application of ‘atmospheric plasma’. All our 6-axis robots are equipped with a plasma system to use with our Contract Gasketing customers. The application of plasma is part of the same process, carried out just before the foam bead is applied. Below is a table that shows how the use of plasma changes the adhesion to substrates that our foam doesn’t normally have a natural adhesion.
To find out more about plasma or to speak to someone about your sealing needs, get in touch today.