DDM gains momentum in the defence industry

The trainers and training aids may be either original products or replicas of existing ones, depending on the training need. Some devices are not required to be working units, so it usually isn't cost-efficient to purchase the actual item. For most training applications, it is more economical to train students on replicas. The TDF uses direct digital manufacturing to fabricate a wide range of its training products. To do so, it employs four FDM additive fabrication machines in a centralised location with AFSO 21 (Lean) processes incorporated into the overall process. Before adding direct digital manufacturing to its processes, the TDF used conventional manufacturing methods to make its products. Conventional manufacturing typically requires longer lead times because there are often multiple steps, such as machining, lathe work, welding, sheet metal bending and cutting. A similar difficulty occurs when producing tooling to mould a part. "Because most of our projects are either one-of-a-kind or very low volume, conventional methods become very expensive," says Mitchell Weatherly, chief of the TDF. "Only about 10% of our work is for prototyping, and 90% is production." Before settling on FDM, the TDF considered 'a multitude' of other additive processes, says Weatherly. "With FDM, the investment is up front, not ongoing," he says. "The parts are durable, and they have the high level of detail we require. In addition, the process is environmentally safe and 100% green, with zero waste." The TDF is responsible for designing and manufacturing an exact replica of unmanned aerial vehicles (UAVs) or 'drones' for training repair technicians. It has built a variety of internal and external components using its FDM machines. The components include most of the body components as well as several cowlings, propellers, and antennae. Producing the UAV's large antenna using the FDM machines took about a tenth of the time it would normally, and it delivered an ROI of over $12,000. The savings go beyond time, though. For the antenna, it would have taken an outsourced machine shop up to 20 days to produce the part, where it took only two days using FDM — but only 15 to 20 minutes of labour. For the entire UAV project there was a total time saved of more than three years in some areas. This project, along with other trainer savings has been very impressive, with an $800,000 cost avoidance over the last four years. "Major advantages to the FDM system include its speed over other processes or alternative build methods, the versatility of FDM versus injection moulding, and the ability to run multiple parts simultaneously through the system," says Weatherly. Additional capabilities include the ability to design based on functional needs instead of manufacturing constraints, and the ability to implement design changes immediately and at minimal costs. "The versatility to manufacture any item coupled with zero hazardous waste is one of the greatest advantages to the Air Force," says Weatherly. "The FDM-based machines have been used for a number of trainer projects with tight budgets.