Manufacturing Processes

There are six main categories of manufacturing processes: forming, casting, molding, joining, machining, and additive manufacturing. Each category encompasses various techniques with distinct characteristics, advantages, and disadvantages related to material compatibility, production volume, part geometry, cost, automation levels, and achievable tolerances. Understanding these differences is crucial for selecting the most appropriate manufacturing process for a given application.

The six main manufacturing categories are fundamental classifications, each addressing different approaches to creating and assembling products.

Categorization of Manufacturing Processes

Forming:

Involves applying forces or pressure and plastically deforming the material to produce the desired shape. Forming can produce parts with high strength, durability, production rates and can work with a wide range of materials including metals, polymers and composites. Primarily used for metals, with processes often performed above (hot working) or below (cold working) the recrystallization temperature, affecting material properties. Shaping material through plastic deformation by applying force or pressure, primarily used for metals.

Casting:

A primary shaping process involving pouring molten metal into a mold. Often requires secondary machining for desired surface finish. Involves pouring molten material into a mold to solidify into the desired shape, mainly used for metals and considered a "primary shaping process."

Molding:

Like casting but primarily used for shaping plastics. It is a process for producing parts by injecting molten material into a mold. Molding can be performed with a host of materials including metals (metal injection molding).

Joining:

Combining multiple separate components into a larger assembly, considered a secondary process. Note: The process of putting parts together to form the product, is called assembly. An assemblage of parts may require some parts to be joined together using various joining processes. But assembly should not be confused with the joining process.

Machining:

A material removal process used to shape an object by removing material with a tool. Often a secondary shaping process. Applicable to a wide range of materials, including metals, plastics, and wood.

Additive Manufacturing:

Also referred to as 3D printing enables the creation of three-dimensional objects through successive layering of material. It significantly reduces waste and allows for intricate designs that traditional manufacturing processes cannot achieve. Because of its long cycle times and limited material choices, it is typically used for prototypes and low quantity production runs.

Process Selection Factors

When selecting a manufacturing process, engineers must consider several factors:

• Material Compatibility - Certain processes work better with specific materials


• Production Volume - Some processes have high tooling costs but low per-unit costs, making them economical only at higher volumes


• Part Complexity - Complex geometries may require specific manufacturing approaches


• Tolerances - Required precision influences process selection


• Surface Finish - Different processes yield varying surface qualities


• Cost Constraints - Including tooling, material, labor, and processing time