Jigs and Fixtures: Their Purpose

Jigs and fixtures are essential work-holding and tool holding devices in industries. These devices facilitate clamping of workpiece on the machine tool in correct relationship with the cutting tool.

Jigs and fixtures are often used in interchangeably and sometimes in pairs, but there is a difference between two terms jigs and fixtures.

Jig:

Jig(tool) is defined as a device which holds and positions the work, locates or guides the cutting tool relative to the workpiece and usually is not fixed to the machine table.

Jigs are used in performing the operations of drilling, reaming, tapping and counter boring.

Fixture:

Fixture(tool) is a work holding device which only holds and positions the work but does it in itself guide locate or position the cutting tool. The setting of the tool is done by machine is done by machine adjustment and a setting block or by using slip gages. A fixture is bolted or clamped to the machine table and is usually heavy in construction.

Fixtures are generally designed for specific purposes of machining operations, such as turning, milling, grinding, shaping, planning and boring operations.

Purpose of using jigs and fixtures:

• To reduce the cost of production, By using them, they eliminate the laying out of work and setting up of the tools.
• To increase the production rate.
• To ensure high accuracy of parts produced without any manufacturing defects.
• To provide for interchangeability.
• To ensure heavy and complex shaped parts are to be machined easily.
• Reduce quality control expenses.
• Increased versatility of the machine tool
• Their use partially automate the machine tool.
• To provide safety at the work point.