Selection of Manufacturing Process (Process Mapping)

This section discusses the importance of proper selection of manufacturing processes and how the selection process is related to the characteristics of materials, the dimensional tolerances and surface finish, and manufacturing cost. The most manufacturing processes have been automated and are increasingly computer controlled, in order to optimize all aspects of operations. Computerization is also effectively increasing the product reliability and product quality and reducing labour costs.

The choice of a manufacturing process is dictated by the following considerations:

• Characteristics and properties of the workpiece material;
• Shape, size, and thickness of the part;
• Dimensional-tolerance and surface-finish requirements;
• Functional requirements of the part;
• Production volume (quantity);
• Level of automation required to meet production volume and production rate; and
• Costs involved in individual and combined aspects of the manufacturing operation.

Some materials might be processed at room temperature, while others require elevated temperatures and therefore need furnaces and suitable tooling. Some materials are easy to work, because they are ductile and soft; others, being brittle, hard and abrasive, require special processing techniques and tool and dies.

Different materials have different manufacturing characteristics; such like castability, forgeability, machinability, workability and weldability, and few materials have favourable characteristics in all of the relevant categories. For instance, a material that is castable or forgeable might later present difficulties in grinding, machining or finishing that might be required to generate a product with acceptable surface finish, dimensional accuracy, and quality.