SDC is Developing Joining Technology for Thermoplastic Missile Components in a Phase I SBIR
San Diego, CA, March 6, 2012 - San Diego Composites, Inc. (SDC) has designed a fusion bonding machine for thermoplastic cylinders for its Army Phase I SBIR program: Fusion Bonding of Thermoplastic Missile Structures. The Army has a specific interest in thermoplastics for missile components as this class of resin lends itself to automated composites processing. This strategic win for SDC allows our company to build capability in joining technology that complements our historical knowledge of thermoplastics in general.
Back in the 1980's, the Air Force Materials Laboratory invested tens of millions of dollars in thermoplastics development, driven mainly for its potential for lower cost fabrication, and also for its toughness and low moisture absorption characteristics. During that period, Gary Wonacott, SDC's CEO, led a program to develop and demonstrate low cost thermoplastics for missile defense applications. Much of the work focused on two thermoplastic materials: polyphenylene sulfide (PPS) and polyetheretherketone (PEEK).
Unfortunately, when the funding for advanced materials and structures declined in the nineties, so did the interest in thermoplastics, as most of the work since then has focused on the most mature thermoset fibers and resins. However, the interest in thermoplastics is growing again as data from Europe shows that thermoplastics can be both cost effective as well as effective at resisting foreign object damage (FOD).
In this program, SDC has intensely examined all of the issues that can affect the joining process, including polymer degradation, intimate contact, and autohesion. As a result, SDC has been able to model the joining process, establish processing trends, and design a machine for the joining process. SDC's machine, shown below, can accommodate a range of cylinder sizes, and through a combination of selective heating and mechanical force, will be able to achieve the critical values required to fusion weld the two cylinders together. While the near term goal for the project is to join cylinders, the technology being developed by SDC may be applied to a variety of thermoplastic materials and structures. SDC believes that this program can be a stepping stone to larger production opportunities for missile, aircraft, and helicopter thermoplastic structures.
SDC's Fusion Bonding Machine for Thermoplastic Cylinders