Compression molding is a forming/fabricating process used to form thermoplastics and rubbers into different shapes. Compression molding of foam is a go-to for manufacturers looking to create to make regular and contoured 3D parts and products that may or may not feature intricacies.
Manufacturers like compression mold foam because doing so creates products that are, depending on their foam composition, some variety of durable, strong sterile, versatile, flame retardant and/or generally resistant to impact, vibration, chemicals (such as solvents and acids) and bacteria. Manufacturers use both open celled and closed cell foams. Examples include: ethyl vinyl acetate (EVA) foams, polyvinyl chloride (PVC) foams, open cell urethane foams and cross-linked polyethylene foams. They can also use composite foams, which feature other materials, such as: polyolefin films, woven fabrics, medical grade coatings and pressure-sensitive adhesives. For speciality applications, manufacturers can also compression mold foam parts that meet Mil-Spec or FDA standards, among others.
Manufacturers make these parts first by taking the foam, pre-heating in an oven until it is pliable, and then placing it in an open mold. Once the part is in the mold, they close a hydraulic press over it. The press puts pressure on the foam, causing it to make contact with the entire mold surface, taking on its shape. Once it has assumed the shape of the mold, manufacturers allow the foam to cool and harden. After this, they open the mold up again and remove the new parts. Very rarely does it require secondary tooling after this, because the process does not create waste like runnings or sprues.
Customers in a wide range of industries rely on compression molding foam. Such industries include: aerospace, automotive, consumer, defense and military, electronics, healthcare and physical rehabilitation, industrial manufacturing, packaging and shipping, sports and recreation and transportation. Examples of the many, many products from which the compression molding of foam may be made include: 3D gaskets and seals, military and sport helmet padding, orthotics, wrist supports, backpack elements, case inserts, insulation, paneling and general padding.
We highly recommend compression molding foam for a variety of reasons, among them the facts that: the design options are versatile, the process is low cost and the process does not produce waste. If you have questions, we urge you to reach out to an experienced manufacturer, such as those listed on this page. All of those with whom we partner are proven, high quality and reliable.