Additive vs Subtractive Manufacturing

Additive vs. Subtractive Manufacturing

Custom parts can be as simple as a battery mount to something as large as a parallel plate chassis. The key to designing successful functioning mechanisms is to balance custom and off the shelf parts.

Custom Parts can be made in many different ways. You should always design parts while keeping in mind how you will manufacture them. There are 2 different types of manufacturing techniques. Additive and Subtractive Manufacturing.

Additive Manufacturing

Additive Manufacturing involves adding successive layers of material to create an object.

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Additive Manufacturing works by either

• melting or fusing powders

• curing liquid polymer materials

• melting spools of composite materials

These methods are used to form final parts based off of technical sketches. Some services online even take CAD files and post process them in-house to manufacture your design.

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The surface finish is not as smooth as subtractive manufacturing, and the tolerances aren’t as precise. These processes are ideal for lighter parts, material efficiencies, rapid prototyping, and small to medium-batch manufacturing.

Complex geometries, including the printing of articulating joints with additive manufacturing, are available. The geometries are more complicated, and set-up is quick and easy, with no operator required during the printing process. The most common materials used in additive manufacturing are plastics and metals. The equipment cost is less than subtractive manufacturing, and various material colors are available for most 3D printing operations.

Subtractive Manufacturing

Subtractive manufacturing removes material to create an object.

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Subtractive manufacturing works by material removal by

• Milling

• Drilling

• Grinding

• Cutting

• Boring

The material is typically metals or plastics, and the end product has a smooth finish with tight dimensional tolerances. A wide variety of materials are available.

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Change-overs are longer, but automatic tool changers help reduce time-consuming delays. The processes can be fully automated, although an attendant may oversee two or more machines.

The equipment costs are higher and usually require additional jigs, fixtures, and tooling. It is best suited for large production with reasonably fast manufacturing time but lengthy changeovers. Material handling equipment helps both processes with material loading and removal. Geometries are not as complex as additive manufacturing processes.