The EMPF is currently executing a Defense Acquisition Challenge Program (DACP) whose goal is to provide improvements to electronic hardware that is currently being acquired by the Department of Defense for the continuing Land Warrior program (Figure 1-1).

The Land Warrior System is a computer, navigation, and communication system worn by the combat soldier. It requires a system of interconnection cables and electrical connectors to interconnect the various line replaceable units (LRUs), such as the computer, batteries, weapon, local area network radio, GPS, weapons sights, and others (Figure 1-2). The system has been deployed in Iraq and is now deployed in Afghanistan with selected Stryker brigade combat teams. The Land Warrior Ensemble (the hardware and interconnections) enables the soldier to communicate, locate, and designate as friend or foe, various entities on the battlefield, thus preventing fratricide while increasing combat effectiveness.

The EMPF role has been to conduct research into the potential for cost and weight reduction to the system by improving the electrical connectors and cable/connector assemblies in the Land Warrior ensemble. This is being accomplished with the process shown in Figure 1-3. Some of these improvements could potentially be applied to the automated combat soldier called Future Force Warrior (FFW) and Ground Soldier System (GSS).

The first of several improvements being considered is metal injection molding (MIM) for the connector shells. These are the parts of the connector that house the connector pins or receptacles and are fabricated with rugged alignment keys and keyways. The EMPF partners in the DACP include Glenair (the connector fabricator for the existing connectors), General Dynamics (the prime contractor for Land Warrior), DuPont Titanium Products (a titanium products fabricator), and Smith Metal Products (a MIM fabricator).

Metal injection molding is a process that is used for large volume, small, precision consumer items. Just as for injection molded plastics fabrication, the MIM process for metals excels at low cost, high volume manufacturing. Figure 1-3 shows a schematic diagram of the MIM process.

In this process, the metal powder mixture is heated and injected into a mold, where it cools and solidifies into the shape of the desired part. Many MIM parts do not require any draft (unlike plastic injection molding) since the binder used releases more easily from the mold. Also, the metal powder in the part cools more slowly allowing the MIM part to continue to shrink after being ejected from the mold. The mold cavities are designed approximately 20% larger to account for part shrinkage. Metals commonly used for MIM parts include steel, cobalt, copper, nickel, tungsten, and titanium alloys.

The final step is to remove the unwanted binder and produce a high-density metal part. This sintering removes the empty space within the part and causes shrinkage of 75-85% of the original mold. Since the shrinkage occurs uniformly, the resulting part retains the high tolerance of the molded dimensions with a much higher density.

When compared to other fabrication methods (Table 1-1), MIM can produce geometrically complex parts with fine details and thin walls while conserving materials and time. A wide variety of materials can be easily shaped with the corrosion resistance, strength, hardness, and wear resistance of the pure metal.

The MIM process for electrical connector components represents a potential method for reducing the cost of the Land Warrior connectors if injection molded parts can be proven as rugged, both electrically and mechanically, as the machined parts in use currently.
For details on the optimal use of the MIM technology for any small detailed metal components, contact the EMPF at www.empf.org.