The two processes defined.

Subtractive manufacturing is the process of beginning with more material than is needed and selectively removing what is not required until the final shape emerges. This process is easily explained by using the marble sculptures of the famous artist Michelangelo as an example. When asked by the Pope how he made his statue of David so beautifully lifelike, he replied “I simply remove everything that doesn’t look like David”. This is the basic principal of subtractive manufacturing; start with too much and then remove what you don’t need.

Additive manufacturing, on the other hand, is the process of producing objects by adding only what is needed, along with any support material required. The most common way to do this is by placing very thin layers of material on top of one another to stack up and form the final object, like layers of a cake. This process dramatically reduces the time, cost and waste produced from its subtractive competitor, and allows a much more efficient production process.

Their common applications.

Subtractive manufacturing has been the way that almost everything was made, going all the way back to man’s earliest tools having been shaped from sticks and stones. From the simple to the inconceivably complex, subtractive manufacturing has been the worldwide standard for bespoke and mass-produced products and tools alike.

Additive manufacturing processes have in the past been too expensive for mass-produced products, but have still found their way into the production process. They have been commonly used for some time now to prototype and test new product designs. For companies like Nike, the production of ‘one of a kind’ test products is a highly cost-effective use of additive manufacturing.