Open Jigs

Introduction jigs and fixtures are production work

holding devices used to manufacturing sector.

a jig or fixture is designed and built to hold, support, and locate every part.

A)Jig

B)Fixture

Jigs and Fixtures

Jigs

Special device that holds, supports, or is placed on a part to be machined.

it not only locates and holds the work piece but also guides the cutting tool as the operation is

performed.

Fixtures

Production tool that locates, holds, and supports the work

securely so the required machining operations can

be performed.

Fixtures vary in design from complicated

devices. Fixtures also help to simplify

metalworking operations performed on special

equipment.

Objectives Analyze part data to determine suitable

jig types to perform specified tasks

Specify locating, supporting and clamping methods and details to suit sample parts

Design two plate type jigs to suit specified sample parts and construct the required tool drawings

3K’s

Know

Classify jigs and fixtures

Usage in industrial

Don’t Know

Function of jigs and fixtures

Characteristics of each jigs

Need to Know

Function of open jigs

Types of open jigs

Overview of Open Drill Jigs The work piece is placed on top and

widely exposed Easily to be used. Cheap in cost.

Various Types of JigsTable

Plate

Sandwich

Angle (Modified and Normal)

Template

Table Jigs Table jig is plain plate jig with legs. Main purpose is holding irregular or non-

symmetrical work pieces that cannot be held in other plate jig forms.

The part is referenced by the surface being machined rather than the opposite side.

Table jigs can accommodate almost any shape work piece.

Limitations are the size of the part and availability of clamping surfaces.

Sample of a Table Jig

The part is clamped between jig plate and the clamping device

Angle Jigs Angle plate jigs are used to hold parts

that are machined at right angles to their mounting locators.

A variation is the modified angle plate jig, which is used for machining angles other than 90 degrees.

Allow the drill to complete the hole . avoid drilling the relieved portion of the

locator.

Sample of Angle Jigs

Additional clearance here would allow the drill to complete the hole and avoid drilling the relieved portion of the locator.

Plate Jigs plate jigs are basically modified or improve

template jigs. while performing the same locating function

as template, they also incorporate a mean of securing the part.

this added feature, clamping, is what allow plate jigs to locate part with a high degree of accuracy and repeatability.

plate jigs are actually a family of jigs rather than a single type of tool.

Sample of Plate Jigs

It is moveable on big plate type objects as a guide.

Sandwich jigs

the sandwich jig is almost identical to a plain plate jigs.

the only difference is the backup plate found on the sandwich jigs.

this back up plate allows the jigs to hold very thin part that could bend or distort under tool pressure.

another use of a sandwich jig is as a combination jig

Sample of Sandwich Jig

The work piece is placed in between.

Template Jigs Template jigs are the simplest and most basic jig type used in production Guide for locating holes and contours or as a jig for low speed production

of accurate workpieces Generally made without clamps and depend on pins nests or part shapes

to refrence them to the part.

Variation of template jigs To accommodate the many types of parts. Made to suit each part

Layout template -used as a rapid refrence tool for laying out several identical parts Used as for locating holes contours and external part details Material used for templates is normally determined by the projected tool

life. Made from plastic or soft aluminium sheet.

Sample Of Template Jig

Thickness of material should be sufficient to maintain the proper relationship between template elements

Conclusion Open Jigs are convenient and simple. Cheap to produce which is good for

economical reasons. Suitable for home and industrial