At Kewell Converters Ltd. we not only cut foam blocks into shapes, we also mould foam to create 3D end products. We work with our clients from development and prototyping through to production, whether for a single item or bulk production of thousands of units, combining our years of experience as engineers with the efficiency of automation.
We work from your design or can make CAD drawings to your specifications,
For moulding of rigid objects, polyurethane (PU) foam is the most often used and can be manufactured with different grades of density and properties, depending on the ratio of constituents but we specialise in closed cell PE foam mouldings like knee pads etc.
Open cell foams are used for flexible mouldings, such as seat padding, and again, it's possible to vary the density as required from 50 - 600kg per cubic metre.
We provide an excellent range of foam mouldings. Here we offer you the opportunity to understand exactly what they are and how they can be used. This will allow you to discover just how integral this technique is to everything you come across in your everyday life. Whether you’re sat in the car, in the office or watching the television, one way or another you come across something that is produced by the use of foam moulding.
What Are Foam Mouldings?
Structural foam mouldings are parts that have been made up using Structural Foam technology. The foam mould has its own structural core in which it is surrounded by extremely dense outer skin layers. These combine to give each of the parts excellent strength to weight ratio.
This style of foam process is produced using gas, typically nitrogen gas, mixing it with the likes of melted polymer before injected into a specific mould. This will usually be done using very low pressures. Instantly after the injection, the mixture will then expand to pack out the mould, creating a dense, rigid part of foam mouldings.
Yours And The World’s Uses Of Foam Mouldings
Reasons can differ in terms of your reasoning for using foam mouldings, for instance as you will come across products in your everyday life that have been produced and constructed with this technique. From items such as armrests, steering wheels, headrest, seats and gear sticks. This use can also be used in order to produce certain kinds of toys for children, even furniture components and decorative trims, such as skirting and chair rail mouldings. We’d be pretty lost without the use of foam mouldings, and the chances are you didn’t even know it was such a fundamental part of our everyday lives.
As there is such a heavy use in the world of mouldings, your use for them is endless. Commonly this tends to be used when people are executing an interior design, as the foam can perform various different uses; for example, producing window frames and door frames, as well as various kinds of skirting; not to mention using these as a way of decorations around your home.
The Production Process Of Injected Foam Mouldings
The production process of structural foam mouldings, otherwise known as the injection of moulded foam begins with the inclusion of melted plastic filling up the injection unit. Once this is done the substance is ready to be injected into the accumulator. When this has been done, there is a large ball positioned in the valve, therefore preventing any weeping into the accumulator. With the use of different heating elements, as well as thermocouples it enables you to maintain the correct melt temperature.
Following this, the melted plastic will then be transferred into the accumulator, into a designated area where it will stay. Once this substance of melted plastic is in position, it will be ready for the gas to be injected into the mix; at this stage both of the balls will prevent any escape at this moment in time.
Gas is then injected into the melted plastic, therefore increasing the pressure within the area. The top ball in the valve will prevent any feedback into the Injection unit. However, the front ball valve will prevent weeping through the nozzle until it is ready to do so.
The mixture of melted plastic will then be injected at speed into the mould tool that is used, to facilitate this; the inclusion of large gates and runners is needed. The front ball valve will now trigger allowing the injection of the melted plastic to go through. The top ball, however, will remain shut in order to prevent any flow back of the materials into the injection unit.
As the gas has a lower atmospheric pressure it will expand when, meeting the melted plastic, therefore allowing the substance to begin expanding to fill the tool. Once this has been completed the material will then be cooled, forming into a solid; following this the tool will open and eject the moulding.
Once the substance has been ejected, the outer surface skin and core is foamed, which is now thicker than normal, there are wall sections that then impart a rigidity part to the product. The final outcome will be your own foam mouldings of whichever shape you require.