Additive manufacturing: A threat to machining?

Don Smolenski | TLT Machinery April 2021

Complementing and competing with computer numerical control machining.

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Computer Numerical Control (CNC) machining is a common subtractive manufacturing technology. The process takes a block of material (blank), and, using a variety of rotating cutters, removes material to achieve the desired shape. CNC is popular for small to high volume production.

Additive manufacturing, on the other hand, is a process of building an object one layer at a time using CAD data. (The terms 3D printing and additive manufacturing are often used interchangeably, but additive manufacturing is broader, covering more commercial and industrial applications.) I’ll only discuss CNC and additive manufacturing in the context of manufacturing metal products, since machining these typically requires the use of some type of lubricant in the process.

Let’s compare and contrast the two technologies in general:



The benefits of additive manufacturing are reduced waste, higher production efficiency, greater design freedom and flexibility, low cost for small parts runs, ability to produce complex parts and lower operator training and involvement required. The benefits of CNC machining include low cost for high-volume parts, great repeatability, precision surface finish (particularly in relation to tight tolerances), good mechanical properties and ability to make parts of all sizes. So, to answer the initial question, additive manufacturing will compete with CNC machining in some applications, but they also are likely to complement each other, while providing a manufacturer with the greatest flexibility. For instance, if tight clearances are required in a very complex part, it could be additive manufactured slightly oversized, and then CNC machined.



FOR FURTHER READING 
1. Click here.
2. Click here, Ingo Uckelmann.
3. Click here.

Don Smolenski is president of his own consultancy, Strategic Management of Oil, LLC, in St. Clair Shores, Mich. You can reach him at donald.smolenski@gmail.com.