MAURBHANJ SCHOOL OF ENGINEERING

BARIPADA : 757107 , ODISHA

CHAPTER – 06

TOPIC- JIG AND FIXTURE

BRANCH- MECH.

SEMISTER- 3^rd

SUBJECT- PRODUCTION TECHNOLOGY

FACULTY- ER S BARIK

Estd:.1994

Jigs and fixtures

• Jigs & Fixtures are special purpose tools which are used to facilitate production in mass scale
• They eliminate the necessity of a special set up for each individual part
• Jigs & Fixtures provide a means for manufacturing interchangeable parts
• They establish a relation between tool and work with predetermined tolerance.
• Once a Jig or fixture is properly set-up any number of same parts may be readily produced without additional set-up.

Jig

• A device that holds the work and locates the path of the tool.

Fixture

• A device fixed to the worktable of a machine and locates the work in an exact

Uses of J & F in Manufacturing Industries

1. To reduce production cost
2. To increase production rate
3. To ensure high accuracy in part manufacture
4. To enable heavy and complicated complex shapedparts to be machined by being held rigidly to amachine
5. To provide interchangeability
6. Reduce quality control expenses
7. Less skilled labour & save labour costs.
8. Improve work safety

Why are they important in Production

• Locate parts for precision
• Repeating process on a series of parts
• Holding parts for machining, painting, assembly

Basic Elements

1. A sufficiently rigid body (plate, box or frame structure) into which workpiece is loaded.
2. Locating elements
3. Clamping elements
4. Tool guiding elements (for Jigs), Tool setting elements (for Fixtures)
5. Elements for positioning or fastening the jig orfixture on the machine on which it is used

Locating & Clamping

• The overall accuracy depends on consistent location
• Location refers to the establishment of relationship between the w/p and Jig or Fixture.
• Clamping is to hold the work in position inside the Jig/Fixture body so that there is no work movement during maching

Clamping devices

Clamping devices

Differences between jig and fixture

Clamping devices

• If the work piece can not be restrained by the locating devices or elements, it become necessary to clamp the work piece in jig or fixture body. The most common example of clamping devices is bench vice. The purpose of the clamping is to exert a pressure to press a work piece against the locating surfaces and hold it there in a position to the cutting forces. In bench vice the movable jaw of the vice exert force on the work piece, their by holding it in correct position of location in the fixed jaw of the vice.

Types Of Drilling Jigs

Drilling jigs may be classified as follows:

1.Template jig

2. plate type jig

3.Open type jig

4. Channel jig

5.Leaf Jig

6. Box type jig

Template Jig

• This is the simplest type of jig; It is simply a plate made to the shape and size of the work piece; with the require number of holes made it. It is placed on the work piece and the hole will be made by the drill; which will be guided through the holes in the template plate should be hardened to avoid its frequent replacement This type of jig is suitable if only a few part are to be made.

Plate Type Jig

• This is an improvement of the template type of jig. In place of simple holes, drill bushes are provided in the plate to guide the drill. The work piece can be clamped to the plate and holes can be drilled. The plate jig are employed to drill holes in large parts, maintaining accurate spacing with each other.

Open type jig

• In this jig the top of the jig is open; the work piece is placed on the top.

Channel jig

• The channel jig is a simple type of jig having channel like cross section. The component is fitted within the channel is located and clamped by locating the knob. The tool is guided through the drill bush.

Leaf Jig

• It is also a sort of open type jig, in which the top plate is arrange to swing about a fulcrum point, so that it is completely clears the jig for easy loading and unloading of the work piece. The drill bushes are fitted into the plates, which is also known as leaf, latch or lid.

Box Type Jig

• When the holes are to drill more than one plane of the work piece, the jig has to be provided with equalant number of bush plates. For positioning jig on the machine table feet have to be provided opposite each drilling bush plate. One side of the jig will be provided with a swinging leaf for loading and unloading the work piece, such a jig would take the form of a box. Such a jig should be as light as possible. Since it will have lifted again and again. Typical figure of box type jig is shown:

Thank you

Created by:Er KHAGESWAR PATRA