What is JIGS & FIXTURES and LOCATION OF WORK PIECE

What is DESIGN OF JIGS FIXTURES

The work piece is held in a jig or a fixture during the machining operation; a jig incorporates means of locating and clamping the workpiece and also means of guiding the cutting tool during the actual cutting; a fixture incorporates means of locating andc Clamping the workpiece but does not incorporate means of guiding the tool, but may incorporate tool-setting arrangements. The derivation of the terms jig and fixture is described, but jigs are usually used for drilling and associated operations, whilst fixtures are used for other machining operations; the term jig is often used in assembly work, to describe the equipment used to hold parts that are to be joined by welding or fastening devices.

THE PRINCIPLES OF JIG AND FIXTURE DESIGN

 Location

a) Ensure that the workpiece is given the desired constraint.

b) Position the locators so that swarf will not cause mal-alignment.

c) Make the location points adjustable if a rough casting or forging is being

machined.

d) Introduce foolproofing devices, such as fouling pins and projections, to

prevent incorrect positioning of the workpiece.

e) Make all location points visible to the operator from his working position.

f) Make the location progressive (i.e. locate on one locator and then on to the

other).

g) Ensure that redundant location is not present (i.e. two location points to control one constraint).