by Joe Bauer
| February 9, 2015
Use of additive manufacturing (AM) has increased dramatically in the last 10 years, particularly in the automotive, healthcare and aerospace and defense industries. AM differs from traditional manufacturing processes in that raw materials are slowly added together by a chemical or heat process to form the finished component. In traditional manufacturing, material is typically removed from a larger piece of raw material until the finished component remains. With the increased use of AM comes an increase in capability, quality, and capacity. We will examine how additive manufacturing could change the way we estimate compared to traditional manufacturing processes.
A key benefit of AM is that complex components can be manufactured together as one part. Assemblies with complex internal structures, connections, or integrated tubing can now be created as a single item. Reduction in the number of parts has the obvious, immediate benefit of reducing the effort required to assemble an item. It also reduces the logistical burden on a program. For each part eliminated from the supply chain, support costs decrease. Reducing part count can also improve reliability and maintainability, thereby reducing support costs further. The picture below (left) shows an example how a hand tool that normally requires some assembly of moving parts can be printed as one component, retaining the wrench adjustment capability. The picture below (right) shows how additively manufactured components with very complex internal structures can be manufactured as one component, another example of eliminating assembly and integration effort. Pictures courtesy of www.3ders.org (left) and www.growit3d.com (right).
Tooling and test costs during development and production may be greatly reduced or possibly eliminated. AM does not require expensive tooling usually seen in a forging, casting, or machining process. In fact, some tools for the traditional manufacturing processes can be made through AM. To be clear, capital investment for an AM machine can be high. However, organizations should consider how these investment dollars can be amortized across a number of programs instead of attributing the cost to a single program.
Rapid prototyping through AM can eliminate or drastically reduce the need for engineering change orders (ECOs), as well as reducing overall development time. Form, fit and function can be quickly and inexpensively validated during development. The cost impact would be seen by a comparable reduction in Production Engineering effort.
Reduction in weight is often another goal for transitioning from traditional manufacturing to additive manufacturing. Internal voids and supports are easier to create with AM, resulting in less overall weight while maintaining the same structural integrity. Typical manufacturing processes do not readily allow intricate designs. We often find some of the product design is not for the intended end use, but a limitation of a forging or casting process.
Lastly, AM processes in general may have a lower overall manufacturing complexity than traditional processes. Less material is removed, fewer parts are involved, and fewer steps need to be completed during the manufacturing process. All of these point towards a simpler or less complex process.
While we have focused on those attributes of AM which may lower cost, it is important to acknowledge a few attributes that may increase cost. Even though we may use much less raw material in AM, the raw material cost per pound can be ten times as expensive. Powders used in AM machines are often proprietary blends made by the machine manufacturers and designed for use in a specific model. Raw material prices are falling, however, as third party vendors enter the market.
Additive manufacturing is not a “silver bullet.” One should not expect a fully functional end product to come out of a machine. Particularly with titanium powders and other metals, some post-processing is required to render the component usable. This post-processing could be further machining, surface finishing, polishing, or some other step.
Finally, one big unknown for AM components is the cost of certification by aviation administrations across the world. Some administrations have been slow to adopt a set of standards before certifying some parts, materials, or manufacturing processes. Standardization of certification procedures will likely cause the most uncertainty in AM use in the aerospace and defense industry.
Stay tuned for future blogs and articles on additive manufacturing, to include a demonstration of AM modeling in a TruePlanning® project file. If you are interested in cost modeling an additive manufacturing process, please feel free to email me at email@example.com or call 937-258-7187.