Additive manufacturing has a distinct materials advantage when it comes to producing a component or part from either a polymer or metal printer versus traditional subtractive manufacturing techniques. In a traditional subtractive manufacturing process, a piece of bar stock can be reduced up to 95% through milling work. This process takes several hours, is limited to one component per piece of material, and may require several machines running at the same time.
Additive manufacturing changes this process significantly. Instead of starting with a base piece of stock, additive manufacturing starts with metal power. This powder is then placed into a machine and is rendered into molten metal and drip fed to assemble parts layer by layer through a process called Directed Energy Deposition (DED). There is also a Binder Jetting process, which involves spraying powder with a glue which is then placed into a sintering oven to become a part.
The advantages here are threefold:
- Material expenditure is reduced in the example part. Instead of transporting a piece of bar stock and then milling 90-95% of the base material out, additive manufacturing only processes the amount of base metal needed to complete the end product.
- Additive manufacturing also enables increased production volume. A five or six axis CNC machine is limited to a part at a time. Depending on the build chamber size of an additive machine, multiple parts can be printed, layer by layer, at the same time.
- Finally, the design of the part can be adapted for printing in ways that traditional subtractive processes cannot accomplish. For example, using Design for Additive Manufacturing (DfAM) and generative design, a part or a series of parts can be created for incorporation into one part, which may have internal structures that would be impossible to create through traditional subtractive processes.
Materials recycling
Another area where additive manufacturing has a sustainable advantage is in the powder or filament used. Though 3D printing allows for a minimum expenditure in material, there may be some powder or filament that goes unused in the process. For example, for Laser Powder Bed Fusion printers, part of the process usually involves decaking the part from powder, some of which may not be reusable given its proximity to the finished part. Rates of recyclability are based on printer and material, and any attached recycling system sold alongside the printer. Metals can be recycled like other subtractive processes, but powder printing is unique in that it is not necessarily a one-time use product. Powder could be re-used several times, mixing in fresh powder to renew the rest of the powder. This decreases time needed before recycling the product, as well as minimizing the amount of product that is unused or unusable requiring recycling.
Recommendations
Additive manufacturing has several benefits over traditional manufacturing processes that make it a more sustainable manufacturing process. Through its manufacturing process, materials advantage, and its ability to cut down emissions across all scopes make it a much more sustainable process com-pared to traditional processes.
Based on ARC research and analysis, we recommend the following actions for owner-operators and other technology users:
- Assess additive manufacturing and if it can fit into your business operations, weighing out cost and benefits.
- Make an action plan to convert industry to additive manufacturing if the cost benefit ratio allows your business to better meet sustainability goals.
- Assess further expanding business operations to a more sustainable alternative.
