We will continue this week to look in a bit more detail at CeraCon’s Design Guide brochure. It was created for designers and R&D experts to give an overview of CeraCon’s CeraPUR® foam, its properties and how it can be adapted for their companies’ sealing needs. The brochure contains a range of information on how we are able to adapt the foam as well as the impact that can have on the seal of the parts it is being applied to. This week we will focus on joint design, adhesion and the curing process of our foam.
When looking to include a seal within a joint on a part, the joint design can be an important factor to consider to give the best possible seal. CeraPUR can be used in a range of joint types, working with various levels of compression to provide different sealing abilities. The higher the compression of the foam within the joint, the better the sealing capabilities are. However some joint designs limit the capability for said compression. The design of the joint can also impact how wide/narrow the foam bead will be which also impacts the seal performance. One way of overcoming difficulties with joint design and compression is by using a tongue and groove joint. Many of customers choose this design as there less surface area needed to provide a higher seal performance.
The adhesion of CeraPUR to a component’s surface is dependent on the surface energy of the material or the surface treatment in question. Different material surfaces exhibit different level of natural adhesion, as well as potential contamination having an impact.
One way to change the surface energy in order to ensure the adhesion of CeraPUR is through the application of ‘atmospheric plasma’. All of CeraCon UK’s 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.
Another way of increasing adhesion is through the use of liquid surface primers. By increasing the ‘wetting’ of the foam to the surface part, adhesion can be improved, however this may compromise the height of the bead.
When good surface adhesion already occurs, CeraPUR is also able to be used an adhesive/bonding agent, both in its liquid foam or unfoamed state. Many customers require us to apply CeraPUR in order to secure parts together, alongside providing a high performance seal. This quality means that it can be used in multiple ways, all in the same process, meaning it saves time, space and investment for our customers.
Whether requiring CeraPUR for bonding or foam sealing, the material cures rapidly at temperature on or above 80ᵒC. On its own subjected to these temperatures it will cure in a matter of seconds. The part itself and its heat sink properties determines the length of time it needs to cure. In most cases this is 2 to 7 minutes. During the initial enquiry and sample phase of working with a customer, the requirements of the part curing can be adjusted in order to find the appropriate curing time needed for each part.
Generally conventional oven systems are used to cure CeraPUR, however the raw foam will also cure in microwave ovens. The temperature of the part at the time of application can also have an impact on the cure time of the foam. For example, CeraPUR® applied to a plastic part which had been taken directly from an injection mould machine (which could be around 60ᵒC), will require significantly less time in the oven compared to a part being processed at an ambient temperature of 20ᵒC.
The flexibility of CeraCon’s oven systems (CeraTHERM®) mean that they can be customised to work for any requirement or production environment. Ambient to 220ᵒC, our industrial ovens and thermal systems are suitable for material curing, drying, tempering, pre heating and cooling. Our vertical industrial ovens can help you save space, whilst our wide but flat industrial ovens can fit your current parts exactly.
For any further information about CeraPUR® and its properties, feel free to download the full Design Guide from the website. If you have any further questions on how we may be able to help with your company’s sealing need, please don’t hesitate to get in touch.