Injected molded foams are not new, matter or fact they have been utilized in the footwear industry for many years. What is new is PopFoam commitment to be the leader in injection molded foam technology and the expansion of these extraordinary compounds into markets not foreseen. With this we offer services from product development to complete retail ready products to assure our customers ultimate success.
Interesting? Let us explain the process; Pop Foam is a pellet compound of the base material with the addition of microcellular cross linking agents and compounds to achieve the desired characteristics and physical properties. The compound is then processed using precision injection equipment expressly designed for the purpose of processing the five basic polymers, being EVA (Ethyl Vinyl Acetate), TPO’s (Polyolefin), TPR’s (Thermoplastic Rubber), TPU’s (Thermoplastic Polyurethane), and PVC (Polyvinyl Chloride). This process can be reviewed into four basic categories: a) Injection Phase b) Material Heating Phase c) Mold Opening Phase and d) Post Injection Phase.
The Injection Phase begins after the tooling is under clamping tonnage and can be controlled at any given segment by temperature, volume, velocity, pressure and time, all of which is monitored precisely. The compound is injected into the tooling under these controlled conditions at about 100 degrees Celsius (material dependent) and once the cavity of the tooling is filled the material flow is shut off by means of a shut off nozzle built into the tooling.
We than proceed into the Material Heating Phase of which the tooling temperature is controlled to 180 degrees Celsius (again material dependent). During this phase the compound is heated in the tooling to excel the cross linking of the compound. This phase will continue until the controlled temperature has been fully absorbed through the compound contained in the tooling cavity.
The Opening Phase is when the mold half’s separate at a rapid speed and allows the compound to expand to the parts final geometry. This rapid opening is accomplished by means of an accumulator on the equipments clamping system. Please review the photo at the right, the foam component next to the tooling shows a typical expansion rate, nearly double the size of the tooling cavity. (I project you designers are already thinking)…
The Post Injection Phase is when the product is removed from the tooling. Due to the elevated procession temperatures the product leaves the tooling extremely soft and presents an over expanded ratio. Within this phase the product will conform closely to the products final geometry. Keep in mind these compounds represent excellent insulating properties; therefore we must progressively cool the product in precisely controlled cooling stations to maintain significant differences between the products internal and externally temperatures. This Post Injection Phase assures the products proper size and dimensional stability. Many foam injection molders skip this key step.
All of the above categories are critical to control the products expansion ratio, density, elongation, size, dimensional stability, shrinkage and cosmetic Appearances. The task of assuring and maintaining these processes equates to the quality of your products, at PopFoam our team effort and the implementation of inspection procedures throughout each and every step of our processes is what we do.
Beginning with your first contact with PopFoam’s philosophy of delivering quality products creates the foundation for a lasting business relationships, today and in to the future.
