Subtractive Manufacturing 101

CNC Machine

A decades-old technique, subtractive manufacturing (computer numerical control, or CNC machining) is a tried-and-true manufacturing method used to produce a huge range of products for a wide variety of industries. The term “subtractive” is apt, as the machining process involves subtracting materials in order to produce an end product. A number of new industrial manufacturing processes have become popular over the last several years, but subtractive manufacturing still remains the most common method.

Subtractive manufacturing hit the world’s stage in the 1940s, and is primarily used for machining projects that require high complexity, reliable repetition, and optimal precision. It was initially known as numerical control machining. John T. Parsons, a self-taught engineer, developed the first numerical control machine, figuring out how to calculate airfoil coordinates on an IBM 602A multiplier and inputting the information into a Swiss jig borer. In doing so, Parsons discovered a more efficient way of manufacturing prototypes, and therefore accelerated the evolution of industrial manufacturing technology.

Today’s CNC machines comprise machine tools such as lathes, mills, routers, and grinders that are controlled through the use of numerical control technology — which is comprised of specialized G-code and CAD/CAM computer programs that instruct machine tools how to manufacture specific products. Specialized programming allows some CNC machines to operate autonomously while others operate manually, requiring the oversight of an operator.

Conventional and Unconventional Machining

There are two main categories of CNC machines: conventional machining technologies and unconventional machining technologies. Conventional machining processes utilize wedge-shaped cutting tools to remove material in order to create different geometric designs via machine tools such as lathes, milling machines, and drill presses. This method is ideal for producing large products with average surface quality. Conventional machining is also well suited for handling less complex geometric configurations.

Unconventional machining, meanwhile, refers to manufacturing processes that get rid of extraneous material through a variety of different methods involving mechanical, thermal, electrical, and chemical energy, or combinations of these types of energy. Unconventional machining works best with extremely tough or brittle materials, and is ideal for handling highly complex geometric configurations.

Subtractive manufacturing methods consist of processes such as milling, turning, laser cutting, wire EDM, and carving, which generally produce highly refined products that can withstand long-term and high-stress usage. Subtractive manufacturing is best suited for creating products made from various metals, woods, ceramics, and foams. It also grants research and development (R&D) teams more leeway when dealing with product engineering, prototyping, and testing, due to its ability to process multiple materials at once. Subtractive manufacturing methods are also ideal for long-run production machining that must be completed with quick turnarounds.

Industrial manufacturing technology is undergoing radical changes, evolving and shifting with the times. Major advancements in the areas of automation and robotics, the development of new materials, and a number of other exciting advancements will continue to change how things are done in the industrial sphere. But subtractive manufacturing, offering great reliability and versatility, will continue to be a mainstay within the manufacturing industry.




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