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International Journal of Mechanical Engineering and Technology (IJMET) Volume 8, Issue 11, November 2017, pp. 889–898, Article ID: IJMET_08_11_090

Available online at http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=11

ISSN Print: 0976-6340 and ISSN Online: 0976-6359

© IAEME Publication Scopus Indexed

DESIGN AND ANALYSIS OF INDEXING TYPE

DRILL JIG FOR A MISSSILE COMPONENT

S R V Narsaiah .S, L.Radhakrishna

Department of Mechanical Engineering, S R Engineering College, Warangal, India

Lakshmipathi Yerra

Department of Mechanical Engineering, MLR Institute of Technology, Hyderabad, India

Prasanna V

Department of Mechanical Engineering, Kakatiya Institute of Technology, Warangal, India

ABSTRACT

The main objective of this project is to design an “Indexing Type of Drill Jig for a

missile component” by understanding the design concept, modeling it and to perform

the analysis by which the design is validated. The component design was studied in

detail and then the drill jig was designed, and tested and was found to produce

components of acceptable quality. The design of each component of jig was carried

out and the designs of all components are included in this thesis.

The evaluation technique generally involves the implementation of CAD software

that helps for designing drafting, assembly and analysis which may be useful for

customized applications and manipulations.

Keywords: Aluminum alloy, Drill jig, indexing, Cylindrical Shells.

Cite this Article: S R V Narsaiah .S, Lakshmipathi Yerra, Prasanna V and

L.Radhakrishna, Design and Analysis of Indexing Type Drill Jig for a Misssile

Component, International Journal of Mechanical Engineering and Technology 8(11),

2017, pp. 889–898.

http://www.iaeme.com/IJMET/issues.asp?JType=IJMET&VType=8&IType=11

1. INTRODUCTION

Mass production aims at high productivity to reduce unit cost and Interchangeability to

facilitate easy assembly. This necessitates production devices to increase the rate of

manufacture and inspection device to speed-up inspection procedure.

Jigs are special purpose tools which are used to facilitate production like machining,

assembling and inspection operations. The mass production of work-piece is base on the

concept of interchangeability according to which every part produced within an established

tolerance. Jigs provide a means of manufacturing interchangeable parts since they establish a

relation with predetermined tolerances, between the work and the cutting tool. Once the jig is

Design and Analysis of Indexing Type Drill Jig for a Misssile Component


properly set up, any number of duplicate parts may be readily produced without additional set

up

To increase production in drilling and milling process for cylindrical part, it is a challenge

to hold with an angle. This chapter discussed about project background to design jigs for

holding cylindrical part and the important to use jig in production.

1.1 Problem Statement

Holding cylindrical parts to be drilled is one of major problems faced by the manufacturing

company, especially small medium company. Sometimes they need expensive equipment to

holds the parts to be drill. Today, customers request in industries is increasing. So, the

company must find new method to improve their productivity.

2. DESIGN OF DRILL JIG

2.1. Design Procedure Of Indexing Type Of Drill Jig:

In this design of indexing type of Drill Jig for a casted component can be explained in a

systematic procedure.

Initially the component was designed, modeled and edited to get the necessary details for

designer of the jig.

Secondly the individual parts such as Base plate, Locator, Clamping Devices, Bushes, Jig

plate and Indexing mechanism has been developed. All these parts have been Designed,

Modeled, Drafting has been done individually.

The whole Design procedure was completed with the help of CAD software(Pro-e) by

which the software helps for Designing, Drafting, Assembly, and Analysis done by ANSYS

software and manipulations.

2.2. Component Details

The component for which the Jig is designed is a casted component which is having angular

hole inclined at 25degrees equi-shaped.

The particulars of the component can be stated as follows

• Component: Casted component

• Material: Al Alloy (LM20)

• Operation performed:

1. Boring.

2. Facing.

3. Drilling.

APPLICATION: These types of components are used in missile applications where

propulsion of gases takes place and the gases are released through Four Holes.

The design done with the help of AUTO CAD where the component is studied, designed,

modeled and drafting is done.

S R V Narsaiah .S, Lakshmipathi Yerra, Prasanna V and L.Radhakrishna


Figure 1 Component Aluminium Casting Alloy (AL - Si12Cu)

2.3. Designing of Drill Jig Components

2.3.1. Design of base plate

The base plate designed here is also a casted component in which some cavities are provided

to reduce the material cost.

According to the dimensions of the component the base plate is designed and modeled and

it satisfies all the parameters to support the other parts.

Figure 2 Base Model Figure 3 Locator Model

2.3.2. Design of locator

A large portion of the tool designer`s time spent in the solution of locating and clamping

problems.

The type of locator used in this design is locator for circular surfaces in which the inner

diameter is taken as the locating surface of the component. The surface clamping and other

mechanisms are developed.

2.3.3. Design of clamping device

While performing a manufacturing operation it is necessary to provide some kind of

CLAMPING mechanism to hold the work piece in the desired position and to resist the

effects of gravity and operational forces.

The function of any clamping devices is that of applying and maintaining sufficient

counteracting and holding forces to a work piece to withstand all tooling forces.



Proper clamp design based up on simplicity utility. This affects the total tool cost and

product cost and permits optimum production, surface finish, and tool life. Clamp selection is

based up on the analysis of the work piece. Clamp design considerations should include its

location.

Figure 4 Strap Clamp Arrangement

2.3.4. Design of bushes

Bushings are used to guide drills, reamers, and other cutting tools into proper position on the

work piece.

These are made of tool steel and are hardened to RC60 to 64 to provide a wear resisting

surface.

The length of bushing is quite important and it is approximately equal to twice the

diameter of the bushing Hole.

2.5. Indexing Type Drill Jig Assembly

From this assembly clearly observed that the drill axis consider with the hole axis hence the

design is satisfied for hole positioning in which the hole are inclined at 25degrees with base.

In the design of drill jig the most vital part is locator pin, because it is very much

important that how the relationship is maintained hence for this a locator pin is used.

Hence the concept of fool proof design is also satisfied, it means that any unskilled

operator can easily operate the jig since the component is arrested in the desired position and

there is no other chance for any positional errors.

Figure 5 Drill Jig Assembly isometric View Figure 6 Assembly of Drill Jig Top View



3. CLAMPING FORCE

3.1. Calculation of Drilling Forces

One of the primary objectives for the design of Indexing type of drill Jig is the calculation for

the drilling forces.

The various calculation involved in the design process are explained in the following

While drilling the drill is subjected to the action of the cutting forces, which can be

continently resolved in to three components a tangential component Fz, a radial component

Fy and an axial component Fx, which is commonly referred to as thrust force in drilling. The

extrusion torque at the chisel edge is negligible and the torque acting in the drill is mainly

constituted by the Tangential force Fz. The radial component Fy on both lips usually cancel

out and are taken care of by the rigidity of the work piece and the drill.

Various empirical formulae exist for the calculation of the axial force F, and the torque.

But because of the uncertain conditions of the chisel edge and other more suitable factors,

there is considerable variation in the computed values. The following equation by Shaw and

Oxford can be used for the computation of the Torque and Thrust.

Drilling Thrust

The axial thrust F (N) can be estimated with the following formula:

F �kxk�xfxd

2

kc: specific cutting force (N mm−2

), which depends primarily on the material being

machined.

f: feed per rotation (mm)

d: tool diameter (mm) and

k: The coefficient depends on the geometry of the tip of the tool we can consider an

average value of 0.5.

From The Standard Tables,

kc = 1050N/mm2

f = 0.4mm

d = 24mm

k = 0.5

F �0.5x1050x0.4x24

2

Thrust Force =2520N

Drilling Torque

Example: drilling with a monobloc carbide spiral drill

Drilling torque is expressed as:

M� �k�xfxd

�

8000



Mc : drilling torque in m N

kc : specific cutting force in N mm−2

f: feed per rotation in mm

d: tool diameter in mm

M� ��. 4x24�

2

Torque=30.24N-mm

Cutting Parameters

The cutting parameters, and therefore the operating parameters of a drill for drilling

operations are:

d:tool and hole diameter (mm)

vc: cutting speed (m min−1

) which gives the rotational speed of the tool (rev min−1

)

N �1000xv�

∏xd

f: feed per rotation in mm rev−1

N=Spindle Speed in RPM

1400 �1000v�

π. d

vc=105.5 rev min−1

The resulting performance parameter is:

*vf: feed rate in mm min−1

vf = f × N

=0.4x1440

vf =576 mm min−1

The feed rate is one of the main factors of productivity, as it conditions chip-to-chip

Time t = p / vf.

p: hole depth

Time=20/576

=0.03472min.

t =2.08sec.

Power of Cut

Drilling with a Monobloc carbide spiral drill

Cutting power is expressed as:



P� �k�xfxv�

8000

Pc: cutting power in kW

kc: specific cutting force (N mm−2

)

f: feed per rotation (mm)

d: tool diameter (mm)

vc: cutting speed (m min−1

)

P� �1050x0.4x24x576

240000

Cutting Power=4.431KW

3.2. Strap Clamp Design

For our case we are selecting a bolt of M8 size

Width of clamp W=2.3 x d+1.5748

Where‘d’ is the diameter of the bolt selectors

W=2.3 x (8) +1.5748=19.17

W=20 mm

Thicknesses of clamp for bolt dia. ‘d’ is given as

T=√ [0.85dA (1-(A/B))]

Where‘d’ is the diameter of the bolt

‘A’ is the distance between pivot & bolt=40

‘B’ is the span, pivot to work piece =60

‘W’ is the width clamp

‘T’ is the thickness of clamp

T=0.85x8x40x (1-(40/60))

T= 9.60≈10mm

Width of the slot C = d+1.5748

C = 8+1.5748=9.57

C = 10mm

3.3. Clamping Forces

CLAMPING FORCE OF STANDARD CLAMP STRAPS

Stud size Recommended torque

N-M

Clamping force

KN

Tensile force in stud

KN

M6 5.42 2.24 4.44

M8 12.20 4.0 8.00

M10 27.11 6.67 13.34

M12 47.45 9.78 19.57

M16 113.88 17.79 35.58

M20 223.71 28.02 56.04

M24 383.69 40.03 80.06



Figure 7 Clamping Arrangement

The clamping force generated can be calculated from the following equation:

P �B

AxF

Where,

P = output force (clamping force acting on the part)

F = input force (applied force or effort)

B = input distance (from fulcrum to input force application location

A = output distance (from fulcrum to output force application location

1. For maximum use of leverage, the support or fulcrum should be placed as close as

possible to the work piece.

F � 4003.40 127

76.2

F = 6672.33N

2. The required torque to produce the needed input force is

T=0.2 x 24 x 6672.33

Torque=10.620 NM

This is in fact equal to T = k x d x F, where k is torque coefficient.

k is written in terms of coefficient of friction as k = 1.33μ, but sometimes it is considered

as:

k = 0.2 for unlubricated case

k = 0.15 for lubricated case (greased)

4. RESULTS AND DISCUSSION

• The Thrust force is 2520N

• The clamping force is 6672.33N

• The analysis i.e. Maximum equivalent stress obtained is 24.058 Mpa,

• Maximum deflection obtained is 0.048409 mm,



4.1. Drill Jig Fixed Support and structural force Representation

4.2. Total Deformation Representation & Equivalent Stress Representation

5. CONCLUSIONS

• The design of Indexing type of drill jig for BDL involved about 308x312mm

dimensions.

• The clamping force is more than the drilling force (calculated)

• The analysis i.e. Maximum equivalent stress obtained is 24.058 Mpa, maximum

permissible limit is 450 Mpa, and the values are within the elastic limit, hence the

design is safe.

• Maximum deflection obtained is 0.048409 mm, so, it is within the elastic limit hence

it can be concluded that the structure designed is safe and it can withstand the

maximum Cutting forces developed during machining.

• The assembly of the Indexing type of Drill Jig is found satisfactory.

• The results obtained after drilling like bore, surface finish. etc. are found to be within

the limit as specified by the customer.

• The design of the Indexing type of Drill Jig was verified and approved by BDL

Hyderabad.

REFERENCES

[1] M. Donoldson.C and Others, Tool Design, Tata McGraw Hill, 1978

[2] Kempster, Introduction to Tool Design and Jigs and Fixtures, ELBS

[3] ASTME, Hand book of Fixture design



[4] Korsakov, Fundamental of Fixture Design, MIR Publication, Moscow

[5] Goroshkin.A.K., Jigs and Fixtures Handbook, MIR Publication

[6] Colvin, F. H.; Haas, L. L. Jigs and Fixtures: A Reference Book. New York and London:

McGraw-Hill Book Company.

[7] NBV Lakshmi Kumari, G.Prsasnna Kumar, Design and Analysis of Indexing Type of

Drill Jig, IOSR Journal of Mechanical and Civil Engineering (IOSRJMCE) e-ISSN: 2278-

1684,p-ISSN: 2320-334X, Volume 12, Issue 2 Ver. I (Mar - Apr. 2015)

[8] P H Joshi, Jigs and fixtures Tata McGraw-Hill Education, 2010

[9] P. Stephen Antony Predeep , S. Sivason raja, C.Rammurugan, R.Senthil Kumar,

Optimizing the Method of Work Holding Device- Drill Jig with Adjustable Drill Bush,

IJIRSET, and ISSN (Online): 2319 – 8753, ISSN (Print): 2347 – 6710,Vol. 4, Special

Issue 6, and May 2015.

[10] Bralla, J. G, Design for manufacturability handbook. New York: McGraw-Hill, pg.4‐56.

ISBN 978-0-07-007139-1.

[11] Akash Thammannagowda, Venkatesh H and Santhosh Kumar T C, Design and

Fabrication of Drill JIG for the Component "Aileron Lever Frame 6 Upper" for "Hawk

Mk-132" An Advanced Jet Trainer. International Journal of Mechanical Engineering and

Technology, 8(4), 2017, pp. 372–379.

[12] Ragip Hadri and Ali Muriqi, Aluminum Alloys and Behavior under Cyclic Loading in

Joints of Truss Structures, International Journal of Civil Engineering and Technology,

8(11), 2017, pp. 746–752

[13] Ranjith. R, Giridharan. P. K and Senthil Kumar. B, Predicting The Tensile Strength of

Friction Stir Welded Dissimilar Aluminum Alloy Using Ann, International Journal of

Civil Engineering and Technology, 8(9), 2017, pp. 345–353.

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