Liquid foam sealing and formed in place foam gaskets have been used for decades across a range of industries. There are a few different methods of generating these seals, CeraCon specialise in a single component foam system which we will focus on as the example.
The standard definition of a foam formed in place gasket or seal is that the seal material being applied is a liquid; this way it can flow in to the groove or intimately mate with the surface it has been applied to. Because of this, formed in place gaskets can be applied to a wide range of surface finishes, part geometries and can vary in size and shape as it’s applied depending on flow rate and dispensing rate of the material.
Once on the surface, the liquid then has to undergo some form of curing; this can be heat cure, two component chemical reaction or air cured.
Most of the foam materials being applied (and non-foamed materials) are either thixotropic or have high viscosities which stops them losing their shape when sat on the surface.
The aim of using a formed in place seal is to create a truly bespoke seal that is applied direct to the part. This means the seal is bonded onto the part either onto a flat surface or more often, into a groove which ensures that the most intimate seal can be formed and any surface imperfections such as sink within a moulded part or surface scratches on a metal part do not affect the seal performance as the seal will fill the gaps and not just sit on the surface.
Depending on the level of accuracy and the performance requirements of the seal, you can apply these seals in two main ways:
Direct from a cartridge, manually applied
- Just like at home when applying silicone to your bathroom suite, applying a sealant to a part is possible but it will not give you the best repeatability and you are dependent on the operator doing a good job.
- Often useful for small projects or where the seal will be highly compressed to take out the variation, it is a cheap and easy way to start.
- Usually good enough for low to mid IP ratings, good for NVH reduction, bonding, potting and cushioning.
Using CeraFlow foam generation and dispensing equipment, applied robotically
- For the best repeatability and accuracy, applying a seal by robot ensures the seal is the same every time. Using this method, you can control the seal very accurately, this can allow for tolerances to 1/10th mm which can be important for technical applications.
- Perfect for large projects where tooling can be manufactured, leading to high throughput of parts with low numbers of rejects and low downtime.
- With the higher degree of accuracy, this is the best way to get top IP ratings and highest performance for NVH reduction, bonding, potting and cushioning.
This style of applying seals and gaskets is a great alternative to tape seals, moulded seals, cord seals and o-rings where they are either expensive or labour intensive to apply properly.