An MH-53E hauls an M777 ashore in Australia from USS Essex, 2009. Navy photo.
We’ve been evangelical about additive manufacturing around here, and we’re far from the only ones. An article in the current (6/2) issue of Additive Manufacturing magazine tells the story of how a Columbia, NJ company, Imperial Machine & Tool, proposed using additive manufacturing — specifically, Selective Laser Melting — to halve the weight of some large nuts that are critical components of the air-transportable M777 howitzer. Imperial, in the hands of 3rd- and 4th-generation family owners, sees the defense and aerospace markets as places the skill they’re gaining with this new technology can complement their traditional subtractive CNC processes. From an online version of the article:
A recent example involved a well-known piece of military artillery, the M777 howitzer. Military engineers regularly seek to make improvements to the design of this gun that increase its weight. However, the weight of this gun is constrained—it has to be light enough to be underslung and carried by aircraft. Therefore, before any hoped-for improvement can be made, weight savings have to be found elsewhere on the gun. Through additive manufacturing, Imperial was able to deliver a new option for weight savings. On its SLM machine, the company grew large fastening nuts for the gun’s assembly that were not solid like the existing nuts, but instead had a honeycomb structure inside. The new nuts were just as strong as the old ones, but half the weight. The combined weight savings from all of the M777 nuts produced this way gave the military engineers freedom to add new components.
That military connection is another advantage relevant to additive manufacturing, says [CEO Christian] Joest. Granted, it is not a sweeping advantage, because the military makes manufacturing changes slowly. However, he says spare parts for military hardware represent an area in which additive manufacturing could deliver considerable value. The ability to “print” these spare parts as needed, instead of requiring depots to store either shelves full of finished parts or shelves full of bar and billet stock for machining them, promises dramatic savings. The chance to also redesign some of these parts for improved performance, as in the case of the howitzer nuts, makes the case even more compelling.
One other attribute of the company that favors additive manufacturing is this: Imperial’s machining area is already committed to lights-out production. The shop is staffed only by day, routinely leaving CNC machine tools to continue running through the night. For example, a common practice in this shop is to fixture a vertical machining center for the daytime project only on the right side of the machine’s table, because fixturing is kept in place on the left side of the table that will allow the machine to run a batch of production parts through the night. This culture of running unattended makes additive manufacturing a natural fit, because with cycles times of 20 hours or more for even a moderate-size part, additive manufacturing is inherently a lights-out process.
via Learning Curve : Additive Manufacturing.
As the title of the article suggests, the learning curve of the SLM machine was steep, and “3D printing” is a misnomer, given the many failed prints necessary to get the hang of setting the machine’s all-important parameters for each material.
But Joest was willing to lose money on the machine until it could be mastered, and now the company’s capability has the potential to benefit the Armed Forces — as well, of course, as the owners and employees of Imperial Machine.
This is what we’re seeing everywhere in the defense and aerospace industry: today’s bleeding-edge technology is going to be, soon enough, just one of the machines. And it’s going to benefit consumers and end users as much as it will benefit designers and manufacturers.