For several years, the EMPF has been building its expertise in the field of power electronics. In 1999 and 2000 ACI, through the EMPF, developed a Power Electronics Training Facility (PETF) and curriculum to further educate industry members on improvements to power packaging. A significant influence to this effort was the Power Electronic Building Blocks (PEBB), a means to meet the affordable power generation for Naval applications.

As part of its commitment to be a rapid response technical resource to the Navy, ACI is currently contracted on a program called REPTILE (Regional Electric Power Technology Insertion and Leveraging Enterprise).

One key element of this project is the evaluation of Integrated Power System (IPS) prototype power conversion modules (PCM). The goal is to improve the manufacturability and thus the affordability of PCMs being developed for advanced surface combatant platforms which employ a zonal Integrated Fight Through Power concept.

The IPS concept consists of three basic PCMs:

• A3 megawatt (MW) 3-phase, 4160 VAC to 1000 VDC rectifier/filter
• A1000 to 800 V DC/DC Converter module configurable to deliver 500 kW to 3 MW
• An 800 VDC to 3-phase, 450 VAC inverter module configurable to deliver 500 kW to 3 MW

ACI is working with two independent teams working with the competing equipment manufacturers. The teams are each tasked with an in-depth review of the prototype design to conduct:

• Technology assessment
• Design for manufacturability assessment
• Manufacturing process evaluation

Following this, the teams are to deliver a comprehensive list of their findings. Ultimately, the ACI teams may be working with their respective manufacturers, and the Navy, to implement the findings and improve the manufacturability and affordability of the equipment.

Technology Assessment
The technology assessment is an objective review to determine if the design philosophy is consistent with cost minimization. A simple example would be that of over-design; a larger than necessary filter inductor may provide superior filtering, but it makes the end item larger and more expensive than required.

ACI feels that identifying issues such as this, is a valuable service to both the Navy and the supplier. Providing equipment exactly to specification should naturally be the supplier's goal and the end-user's expectation. Supplying equipment that exceeds specification may provide superior performance, but places the supplier in a non-competitive position. The role of ACI is to highlight areas where the proposed design performance exceeds specification, and allows the end-user to decide whether to change the requirements. This is a win-win condition. The end-user can elect to adopt a change and the manufacturers maintain competition.

DFM Assessment
The potential suppliers have a proven history of delivering equipment of the highest grade to the Department of Defense on previous contracts. However, in recent years, a combination of changes in government acquisition policy, massive cost saving initiatives, and substantial realignment in the supply chain (where many traditional American suppliers have abandoned on-shore production or been absorbed into global entities) has made procurement an arena of constant change.

One element in this environment is the transition to commercial-off-the-shelf (COTS) procurement. Additional factors include:

• Supply line reliability: Are the selected parts available from two or more sources?
• Parts selection: Are MIL-grade parts used where industrial grade/ COTS parts will perform satisfactorily? (Particularly in areas where redundancy and spares availability.)
• Design: Are mechanical designs based on standard stock material with a minimum number of unique mechanical drawings? This an area where some additional non-recurring engineering costs can be more than recovered through reduced production material acquisition costs, smaller inventories and increased savings through a broader supplier base.

Manufacturing Processes
This is the assessment of the actual assembly process in an effort to drive down the project manufacturing cost. One significant area, which ACI is pursuing, is in parts commonality throughout the design that leads to inventory reductions. This impacts not only the material side, but also the accompanying labor costs of procuring, stocking, and kitting.

Mechanical assembly hardware or, more specifically, the sheer number of different fasteners is one area worth investigation. On the surface, it may not appear to be an area of substantive savings, but reducing the variety of fasteners used for assembly of complex equipment has ripple effects that are often ignored. Typically, 40 to 70 per cent of the line items on an assembly's bill of materials are fasteners. This hardware has to be kept organized.

Since it needs to be conveniently available to many assemblers on a production line, the fasteners take up room at many different workstations. Each bolt or screw generally has an accompanying set of locks and/or flat washers and nuts, and its own torque requirements. When a wide variety of fasteners is used, each operator needs to have a larger tool set and maybe larger tool boxes; the potential for assembly error increases; and on and on.

Substantial gains have been made in industry through outsourcing the production of particular subassemblies to a combination of specialty suppliers with specific areas of expertise, such as harnesses or mechanical subassemblies. Manufacturing process assessments should include the inputs of the assemblers themselves. It is they, through the experience of assembling the prototype assemblies, who have valuable insight into areas where substantial savings in assembly time may be made, sometimes through simple design changes not obvious to the designer early in the program.

Conclusion
ACI believes that through the design and manufacturing assesment of PCMs for Naval IPS, manufacturability and affordability will improve through implementation. A valuable service to both the Navy and suppliers will be realized as the issues are presented, and rectified through technological upgrades and/or manufacturing improvements.