Jigs and fixtures are devices used to accurately locate and secure workpieces during machining operations. They help produce identical duplicate parts by guiding tools in the same way for each part. Jigs are typically used for drilling and boring, while fixtures are used on milling machines and sometimes other machines like lathes. The key components of jigs and fixtures include clamps, chucks, vices, and bushings to hold the workpiece firmly in place. They provide benefits like reduced costs, increased production rates and part interchangeability. Careful design following principles such as fool-proof locating points and quick-acting clamps is important for effective jigs and fixtures.

1. Jig and Fixture

2.  Jigs and fixtures are used to locate and hold the work
that is to be machined.
 These devices are provided with attachments for
guiding, setting, and supporting the tools in such a
manner that all the work pieces produced in a given jig
or fixture will be exactly alike in every way.
 Jigs and fixtures may be defined as devices used in the
manufacture of duplicate parts on machines.
Introduction

3.  A device that holds the work and locates the path of
the tool.
Or
 A jig is a special tool, which, while it holds the work, or
is held onto the work, also contains guides for the
respective tools to be used.
Jig

4.  A device fixed to the worktable of a machine and
locates the work in an exact position relative to the
cutting tool.
or
 A fixture is only holding the work while the cutting
tools are performing the operation on the piece,
without containing any special arrangements for guiding
these tools.
Fixture

5.  Jigs as special tools used particularly in drilling and
boring operations.
 fixtures as special tools used on milling machines, and,
in some cases, on planers, shapers, and slotting
machines.
 Special tools used on the lathe may be either of the
nature of jigs or fixtures, and sometimes the special
tool is actually a combination of both, in which case the
term drilling fixture, boring fixture, etc., is suitable.
Difference b/w Jigs & Fixtures

6. 1. For machining purposes
Locates the component, holds it firmly in place, and
guides the cutting tool.
2. For assembly purposes
Locates separate component parts and holds them
rigidly in their correct positions while they are being
connected.
Types of Jigs

7. Clamping jigs or Open Jigs:
 It is adapted for use
on work pieces on
which the axes of all the
holes that are to be
drilled are parallel.
 These jigs are being
placed on the work,
rather than the work
being placed in the jig.

8. Box jigs or Closed Jigs:
 Many machine parts
must be drilled on
different sides and
frequently castings or
forgings are very
irregular in shape, or
where holes are to be
drilled in the work at
various angles.

9. Basic Components of Jig
 Clamps
 Chucks
 Vices
 Bushings
 Modular Fixtures

10. Conventional Fixtures
 Bulky
 Complex
 Multilateral
 Dedicated, Expensive
 Long Lead time,
 Designed by human
intuition
Types of Fixture
Ideal Fixtures
 Compact
 Simplified
 Unilateral
 Modular, Amortizable
 Rapid Setup,
 Designed by CAD/CAM
software

11.  Fixture base
 Clamps
 Set Blocks
Fixture Components

12.  Reduce cost of production.
 Increase the production.
 To assure high accuracy of parts
 Provide for interchangeability
 Enable heavy and complex parts to machine
 Reduced quality control expenses.
 Increased versatility of machine tool.
 Less skilled labour.
 Saving labour.
 Partially automates the machine tools
 Use improve the safety, accidents low
Uses of Jig & Fixture

13. 1. Before planning the design of a tool, compare the cost
of production of the work with present tools with the
expected cost of production, using the tool to be
made, and see that the cost of building is not in excess
of expected gain.
2. Before laying out the jig or fixture, decide upon the
locating points and outline a clamping arrangement.
3. Make all clamping and binding devices as quick-acting
as possible.
4. In selecting locating points, see that two component
parts of a machine can be located from corresponding
points and surfaces.
Principles of Jig & Fixture Design

14. 5. Make the jig "fool-proof "; that is, arrange it so that
the work cannot be inserted except in the correct way.
6. For rough castings, make some of the locating points
adjustable.
7. Place all clamps as nearly as possible opposite some
bearing point of the work, to avoid springing.
8. Core out all unnecessary metal, making the tools as light
as possible, consistent with rigidity and stiffness.
9. Round all corners.
10. Provide handles wherever these will make the handling
of the jig more convenient.
Principles of Jig & Fixture Design

15. The End