Month: September 2022

How we achieve it and the benefits

Robafoam’s foam seals have a predominantly closed cell structure. This means that they aren’t reliant on surface skin integrity for it to work and they perform well with watertight Ingress Protection (IP) rated seal requirements. In this blog post we will look at how an IP rating is achieved and the different components which can adapt it to the customer’s requirements.

Our foam characteristics

The 1K foam we create is a unique single part, low temperature heat curing foam and so isn’t reliant on any additional chemicals to be added to apply or cure it. The process takes the raw material from a drum, mechanically mixes it with an adjustable amount of air and then robotically applies to the part. The amount of air used in this process impacts the foam hardness, the more air added the harder the foam will be. Generally, the harder the foam the higher the sealing performance.

The part itself also plays a role in its sealing performance. Its flexibility, span, wall thickness and the size of the fixing points all have an impact on the seal. Although most problems can be overcome by adapting the compression, foam hardness or bead size, it is still crucial for designers to be taking the sealing of a part into consideration early in the designing process.

Achieving an IP rating – The relationship between bead size, hardness and compression

There are three main components to consider when looking to achieve an IP rating:

That being said, all elements can be adapted to fit with different requirements or differences in the part. As each individual part has certain seal requirements, the three factors much be varied to work with that part. For example, a part that has a butt joint may need to have the foam bead size increased to achieve a better IP rating, something that is not possible if using a tongue and groove joint. In this case, the bead may need to made higher or harder to improve the IP rating. Below are some more details on how we adapt these three key elements.

Change in bead size

By adjusting the flow rate, we can increase or decrease the volume of foam being applied. We are also able to produce different foam bead thickness within the same application by programming the robot to change speeds. This means that parts can have varied seal thicknesses without the need to stop and start the process.

Foam hardness:

By changing the frequency of the pulse valve, in relation to the movement of the piston pump movement (constant flow rate) it is possible to increase or reduce the levels of entrained air. Therefore, change the final hardness of the foamed material applied to the part. So, from the one base material a wide range of hardness’s can be created. We refer to this as a change in Foam Ratio. This foam ratio is the change in weight of a known volume of material. For example ratio 3.0 is 1/3 the weight of the unfoamed raw material.

Compression

As shown in the diagram below, the same bead size can be compressed within a range of different joint types to different percentages, in order to create different IP ratings. By looking at each individual part and its joint design, we can offer advice and recommendations for the best bead size, and joint design adjustments, to work with the compression that is needed. The compression is calculated dimensionally by the change in height. If the part uses a tongue and groove joint design, this is measured from the end of the tongue and therefore is generally the most reliable way of creating a higher IP rating.

Following on from our recent visit to the Emergency Services Show at the NEC in Birmingham, we thought we would look in more detail at automotive lighting and the sealing requirements they have.

Despite the extensive design process of creating a car, there can still be problems encountered once the car has gone to full production and is being sold on the market. One of these problems is water ingress into the lighting enclosures, resulting in water pooling in the light and eventually a reduction of the effectiveness of the lamp. Sorting this can be costly, which is why effective sealing which is incorporated into the design at an early stage is so important.

Most commonly, automotive companies were using manually fitted cord seals to prevent water ingress. Although generally effective, these are time consuming to apply and are also subject to human error. Therefore, the conversion to Formed in Place Gaskets, improves productivity and reduced the quality issues regularly seen with manually fitted seals. It also increases IP rating performance, improving service requirements due to the adhesion of foam to the part surface.

Robafoam has been working within the automotive industry since it was established in the UK in 2013 and today around a third of our customers are part of the automotive industry. We have a wealth of experience in applying seals to a wide range of parts, for both interior and exterior components, including lighting.

Robafoam’s foam has been subjected to vigorous testing during its development and continues to be tested to ensure its compliance with a variety of standards. One of these is the ASTM D1003 standard test method for haze and clarity which means that it can be used effectively within the lighting sector of the automotive industry.

We understand that no two application designs are the same. We use our expertise in working with the automotive industry to support designers, adapt designs as necessary and seal accordingly, all to achieve the standards required for the specific application. Each part can have the seal customised in size, hardness and design to ensure that specifications from the customer are met.