Classification of Manufacturing Processes

  • Develop understanding of basis manufacturing processes and capabilities of each.

  • Able to select manufacturing processes appropriate for particular applications.

  • An understanding of the importance of economic and environmental factors when considering a manufacturing process.

  • Develop an understanding of Concurrent Engineering and the importance to manufacturing industries.

Manufacturing processes can be broadly classified in four major groups as follows:

  1. Shaping or forming: Manufacturing a solid product of definite size and shape from a given material taken in three possible states:

    • in solid state e.g., forging rolling, extrusion, drawing etc.

    • in liquid or semi-liquid state e.g., casting, injection moulding etc.

    • in powder form e.g., powder metallurgical process.

  2. Joining process: Welding, brazing, soldering etc.

  3. Removal process: Machining (Traditional or Non-traditional), Grinding etc.

  4. Regenerative manufacturing: Production of solid products in layer by layer from raw materials in different form:

    • liquid e.g., stereo lithography

    • powder e.g., selective sintering

    • sheet e.g., LOM (laminated object manufacturing)

    • wire e.g., FDM (Fused Deposition Modelling)

Solved Examples

Solved Example:


Which of the following is NOT a metal joining process?


Lapping is a machining process in which two surfaces are rubbed together with an abrasive between them, by hand movement or by way of a machine.

Soldering is a process in which two or more items (usually metal) are joined together by melting and putting a filler metal (solder) into the joint, the filler metal having a lower melting point than the adjoining metal.

Brazing is a metal-joining process in which two or more metal items are joined together by melting and flowing a filler metal into the joint, the filler metal having a lower melting point than the adjoining metal.

Riveting is a process where a metal pin for passing through holes in two or more plates or pieces to hold them together, usually made with a head at one end, the other end being hammered into a head after insertion.

Correct Answer: A

Solved Example:


What is a method of forming polymer sheets or films into three-dimensional shapes in which the sheet is clamped on the edge, heated until it softens and sags, drawn in contact with the mold by vacuum, and cooled while still in contact with the mold?

Correct Answer: C

Solved Example:


The function of cutting oil when threading a pipe is to:

Correct Answer: D

Solved Example:


Aircraft body is usually fabricated by:

Correct Answer: C

Solved Example:


What is a process of forming continuous shapes by forcing a molten polymer through a metal die?

Extrusion is a process used to create objects of a fixed cross-sectional profile. A material is pushed through a die of the desired cross-section.

Correct Answer: D