Metal Manufacturing Processes

Casting Processes

Metal casting processes involve pouring molten metal into a mold cavity where, once solid, the metal take on the shape of the cavity. They can be divided into two categories based on the type of mold:

  • Expendable Mold Casting: where the mold must be destroyed in order to remove the part
  • Permanent Mold Casting: for which the mold is fabricated out of a ductile material and can be used repeatedly.
  • Powder Metallurgy: In powder metallurgy a metal powder is compacted into the desired shape and heated to cause the particles to bond into a rigid mass.

Deformation Processes

Deformation processes include metal forming and sheet metalworking processes. These processes use plastic deformation resulting from the use of a tool that applies stresses to the piece which exceed the yield stress of the metal. There are two types of deformation processes:

  • Bulk Processes: Bulk deformation processes are characterized by large deformations and shape changes and by the fact that the surface area to volume ratio is relatively small. Bulk processes include rolling, forging, extrusion and wire and bar drawing.
  • Sheet Metalworking: Sheet metalworking processes are performed on metal sheets, strips and coils having a high surface area to volume ratio. These operations use a punch and die to form the workpiece. Bending, drawing and shearing are types of sheet metalworking processes.

Material Removal Processes

These processes remove extra material from the workpiece in order to achieve the desired shape and include:

  • Machining Operations: These are cutting operations using cutting tools that are harder than the metal of the product. They include turning, drilling, milling, shaping, planing, broaching and sawing.
  • Abrasive Machining: In these methods material is removed by abrasive particles that normally form a bonded wheel. Grinding, honing and lapping are included in this category.
  • Nontraditional Processes: These methods use lasers, electron beams, chemical erosion, electric discharge and electrochemical energy instead of traditional cutting and grinding tools.

Joining and Assembly Processes

In Joining and Assembly Processes, multiple parts are connected either permanently or semipermanently to form a new entity.

This material is based upon work supported by the National Science Foundation under Grant No. 0633602. Any opinions, findings and conclusions or recomendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation (NSF).

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Pennsylvania State University
Department of Engineering Science and Mechanics
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