WELCOME

DESIGN AND FABRICATION OF ANGULAR POST JIG

TEAM MEMBERS

T.ARUNGIRI(21809114006)B.ASWINKUMAR(21809114007)MOHAMMED RAUB(21809114028)

ABSTRACT

Based on the need for work holding devices Our project will enable operations like drilling, reaming

and tapping easier even if the job profile is angular Design and fabrication of angular post jig cover the

absolute design to the specified dimensions of the work piece .

Jig permits drilling holes in one side of the work piece with a single location and clamping operation

OBJECTIVES OF OUR PROJECT

Jig is a source which holds the job and also guides the tool

It eliminates the need for marking on the job

Even an unskilled technician can use them

Jigs are light weight ,they can be used either by fastening it with the

table or holding it in hands

INTRODUCTION GENERAL

Drilling jigs are used

To machine holes in mechanical products

To obtain positional accuracy

To locate and guide the drill, reamers etc., in relation to the work piece

Jigs prove to be economical and technically desirable

Drilling jigs makes feasible the drilling of holes at higher speeds

With greater accuracy and with less skilled labours, holes are laid out and drilled by

hands

Jigs produce interchangeable parts

DEFINITION

JIGS

Device which holds and positions the work, locate and

guides the cutting tool relative to the work piece

Not fixed to the machine table

Lighter in construction

FIXTURES

Work holding device, which holds and positions the work but

does not guide itself, locate or positioning the cutting tool.

It is usually heavy in construction.

ESSENTIAL FEATURES OF JIGS

Reduction of idle time Cleanliness Replaceable parts Hardened surface Economic soundness Easy manipulation Position of clamps Clearance Rigidity and stability Safety

GENERAL RULES FOR DESIGNING JIGS

Cost of production

Locating point and clamping arrangement

Fool-proof

Avoid complicated clamping

Provide holes

Provide clamping lugs

FACTORS TO BE CONSIDERED

Component

Capacity of the machine

Production requirement

Location

Loading and unloading arrangements

Clamping arrangements

Clearance between the jigs and components

Base frame and welded construction procedure

Tool guider and cutter setting

Rigidity and vibration

Cost

TOLERANCE AND ERROR ANALYSIS

• Limits and fits

Classification of fits

Running fit

Push fit

Press fit

Force fit

ELEMENTS OF JIGS

Jig body

Jig feet

Jig bushing

Jig plate or bush plate

Locaters

Clamps

Fool proof element

TYPES OF JIGS Template jig Plate jig Channel jig Leaf jig Pot jig Turnover or table jig Box jig or tumble jig Trunnion jig Indexing jig Post jig Sandwich jig Nut cracker jig Pump or universal jig Latch jig

DESIGN CALCULATIONS

DESIGN CALCULATION Dimension of the jig components:

1. Base plate of the jig =175 x 140 mm

2. Thickness of the base plate =10mm

3 Vertical jig plate length &Breadth, Width = 165x100x12mm

4. Top jig plate length & breadth, width =100 x100 x12

6. Angular post plate =175x100x12mm

7 .Locater outer diameter =Ø 40x20 height

8. Locater inner diameter = Ø27.5mm

DIMENSION OF THE JOB

Outer Diameter of the job =35mm

Height of the job =47mm

Inner diameter of the locator =27mm

Required diameter of the drill =8mm(No1)

DESIGN PROCEDURE OF THE ANGULAR POST JIG

SELECTION OF JIG

An Angular post jig is to be selected for making an

angular hole on Cylindrical surface required diameter=8mm

SELECTION OF BUSH

Press fit is preferred, therefore select fixed bush

with hole range diameter 8 mm.

SELECTION OF BUSH

Select bush of fixed type DDB; 5.100

The diameter to be drill the work piece is=8mm

As per design norms bush sizes (long) are

L1=20mm

L2= 16mm

D3=20mm

In our project bush dimensions are

L1=30mm

L2= 19mm

D3=26mm

SELECTION OF LOCATERS :

For side location, locater is to be

fabricated to the work piece. Locater

inner diameter is 27.5 mm that is

equal to outer diameter work piece.

Thickness of frame (t) = 10mm

Base length = 3 x length of work Piece

= 3 x 47 = 141mm

Working height (h2) = 2 x outer dia. of work piece

= 2 x 47 = 94mm

Total height of jig(ht) = 2t + h2 + bush head

= 20 + 94 + 10 = 124mm

SELECTION OF JIG BODY

DESIGN OF SCREW

Size of the screw (bolt) = M10

Pitch = 1.5mm (P.S.G. pg: 5.42)

For coarse thread dc = 8.4 mm

Stress area = 58 mm2

Initial tension in bolt P1 = 2860d = 28600N

But this, P1 =∏/4 * dc2 * ft

Tensile stress, ft = P1 / ∏/4 * dc2 = 516.05 N/ mm2

As the pin is double shear, P1 =2* ∏/4 * dc2 * ft

ft =28600*4 / 2 * ∏ *8.42 = 258.04 N/ mm2

Shear stress (fs):

As the pin is double shear

P = 2* ∏/4 * d2 * fs

Shear stress = load / area = 182.07 N/ mm2

Therefore, the design is safe.