Adding and subtracting: Turning Performance

The 3D printer was introduced in 1981 and ultimately gave rise to rapid prototyping. Advancements in this technology have resulted in a new form of manufacturing that we now call additive manufacturing. In one way, it has fulfilled the dreams of engineers as it gives us the ability to go directly from design in CAD to a finished part with no intermediate processing.

Additive manufacturing has evolved since the introduction of the 3D printer to become the latest manufacturing process to revolutionize engineering design and the production of prototype parts. A lot of people believe that additive processes are poised to replace many of the more familiar processes like casting, forging, machining and stamping.

Although developments are vigorous and focused on removing limitations, additive manufacturing has not become a mainstream manufacturing process, and we are still a long way from it replacing the more traditional processes.

Speed is a significant drawback to using additive processes. They build parts one layer at a time, usually only a few thousandths of an inch thick, and printing complex parts can take hours. Casting processes can fill a mold in just a few seconds and have the ability to produce multiple parts in a single operation. Stamping produces completed parts that are more accurate than most printed parts, with speeds that cannot be matched by any other process. Printing parts at rates comparable to stamping and casting would require an immense number of machines.

Entry costs for additive are very high compared with traditional machine tools. Additive processes that produce metal parts employ other advanced technologies, such as laser sintering, which bear high maintenance and operational costs. When the expense of the machines is considered, along with the slower production rates and reduced capacities, the cost of production parts is unacceptably high versus traditional processes.

3D printing is the fastest way to turn ideas into parts.

Materials are another limitation of additive manufacturing. Unlike other processes, parts produced by additive manufacturing usually need an additional processing like sintering to achieve the necessary mechanical properties, increasing complexity, lead times and the number of operations.

Finding acceptable alloys is a challenge as well. Castings, forgings and stampings are available in countless alloys, so finding a material with the desired mechanical properties is relatively straightforward. Additive manufacturing processes are
limited to a small number of alloys with limited mechanical properties, which limits their use in production parts. These materials also are produced in much smaller quantities, making them far more expensive than common products used in traditional manufacturing processes.