SHINAS COLLEGE OF TECHNOLOGY

CHAPTER – 1

Introduction to Manufacturing Process

Manufacturing (Technologically)

Manufacturing is the application of physical and chemical processes to alter the geometry, properties and appearance of a given starting material to make parts or products and also the assembly of multiple parts to make final products.

The process to accomplish manufacturing involves a combination of machinery, tools, power and labor.

Manufacturing (Economically)

Manufacturing is the transformation of materials into items of greater value by means of processing operations or assembly operations.

Examples: When iron ore is converted into steel, value added. When sand is transformed into glass, value is added. When petroleum is refined into plastic, value is added.

Note: In this course we adopt the manufacturing technically.

Model of manufacturing

Material is fed into the process, energy is applied by the machinery and tooling to transform the materials and the completed work part exits the process with minimal scrap and waste.

Manufacturing Process

Manufacturing process is a designed procedure that results in physical or chemical changes to a starting material with the intention of increasing the value of that material.

Manufacturing process can be classified into two basic types:

i) Processing operationsii) Assembly operations

PROCESSING OPERATIONS:

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SHINAS COLLEGE OF TECHNOLOGY

Processing operation uses energy to alter a work part’s shape, physical properties or appearance to add value to material. The forms of energy include mechanical, thermal, electrical and chemical. The energy is applied in a controlled way by means of machinery and tooling. Human workers are sometimes needed to control the machines, manage the operations, and load and unload parts before and after each cycle of operation.

There are three categories of processing operations:

1) Shaping Operations2) Property – enhancing Operations3) Surface processing Operations

SHAPING OPERATIONS:

Most shaping process operations apply heat, mechanical force or a combination of these to effect a change in geometry of the work material. Based on the state of the starting material, it is classified into four categories:

1) Solidification process: Starting material is a heated liquid or semifluid that cools and solidifies to form the part geometry. Example:

2) Particulate process: The starting material is a powder, and the powders are formed and heated into the desired geometry.

Example:

3) Deformation process: The starting material is a ductile solid that is deformed by the application of forces to shape the part. Example:

The category includes forming process such as forging, rolling, extrusion and drawing, etc. and sheet metal working process such as deep drawing, bending, etc.

4) Material removal process: This process removes excess material from the starting workpiece so that the resulting shape is the desired geometry. These cutting operations are performed by cutting tools that are harder and stronger than the work metal. Example: Turning, Drilling, Milling, Broaching, Grinding

PROPERTY – ENHANCING PROCESSES

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The property-enhancing process is to improve mechanical or physical properties of the work material. These processes do not change the shape of the part. The most important property-enhancing process involves heat treatments, which include various annealing and strengthening processes for metals and glasses.

SURFACE PROCESSES

Surface processing operations include

1) Cleaning 2) Surface treatments 3) Coating

1) Cleaning Process: Cleaning includes both chemical and mechanical processes to remove dirt, oil and other contaminants from the surface.

2) Surface treatments: Mechanical working such as shot peening and sand blasting, and physical processes such as diffusion and ion implantation.

3) Coating: It is a thin film deposition processes apply a coating of material to the exterior surface of the work part. Common coating processes are electroplating, anodizing of aluminium, organic coating ( painting), etc.

ASSEMBLY OPERATIONS

In this two or more separate parts are joined to form a new entity. Components of the new entity are connected either permanently or semi permanently.

Permanent joint:

A joint provides rigid mechanical connection between components that cannot be easily disconnected. Permanent joining process includes welding, brazing, soldering and adhesive bonding. Other mechanical techniques for more permanent joints are rivets, press fitting and expansion fits.

Semi permanent joint:

Some mechanical assemblies are available to fasten two parts together in a joint that can be easily disassembled are called as semi permanent joint. Screws and bolts –nuts are important traditional methods in mechanical assembly methods in semi permanent joint.

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