Foam and its encapsulation are major technologies of any running shoe company. New Balance running shoes come with three main types of foam: Fresh Foam, Vazee, and N2. In terms of encapsulation, it is Fresh Foam that offers tantalizing views of a major technological breakthrough in running shoe foam technology.
Specifically, closer examination of the foam of Fresh Foam running shoes from New Balance reveals its hexagonal honeycomb structure closely packed into an undulating foam layer that balances the impact forces on the forefoot and heel. Manufacturing this foam layer requires at least two injection molding technologies, which is the critical asset and trade secret of any running shoe company. In short, the strength of the injection molding technology in delivering running shoe suited to the size and shape of feet defines the continued success of a company.
In thinking about how the foam of Fresh Foam running shoe is manufactured, it occurred to me that it required first the compression of Fresh Foam into a shape opted by the foam, shoe and outsole design teams of the project. Doing so may appear to be easy; however, foam injection molding is a difficult and delicate task vulnerable to mis-fittings that results in significant costs to the company. Performed with dedicated equipment unique to the requirements of the company in terms of shoe size, design and comfort of the shoe wearer, injection molding technology is a closely guarded technology asset of a running shoe company.
The second molding technology requisite for manufacturing Fresh Foam lies in a compression technology capable of “stamping” hexagonal close pack patterns on the foam layer, that while allowing the foam to retain the pattern, does not result in degradation of the foam during manufacturing. More importantly, close examination of the foam layer in Fresh Foam running shoes reveals that the hexagonal close packs are aligned to the curvature of the foam layer, that allows the feet to sit comfortably in the shoe and on the foam. Such design requires a high level of sophistication in the molding technology that could deliver compressed patterns of defined patterns and depth with respect to requirements.
Collectively, injection molding technology is a key technology enabler in many areas of manufacturing such as foam technology. In delivering shape and customized design to materials, injection molding’s role is primarily in enabling functional comfort to the end user of the material (e.g., running shoe) or functionality to the object such as a plastic cup. Hence, technological sophistication of injection molding defines the type and degree of complexity of objects manufactured, which, to a certain extent, also determines the price of the object. As a key technology enabling manufacturing, advances in molding technology such as three dimensional printing are typically patented at the Patent and Trademarks Office rather than reported in the scientific and research literature. Useful for a wide range of applications and manufacturing tasks ranging from small tools to finished products, injection molding technology will continue to be a key area where companies plow in cash in search for answers to technological problems hampering efficiency and possibility in manufacturing.
Category: materials, mechanical engineering, materials engineering,
Tags: foam layer, injection molding, patent, innovation, hexagonal comb, close packed,
Acknowledgement: Ng Wenfa thank Seah Kwi Shan for co-authoring this blog post.