JAME-1-107

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Volume 1 Issue 1 1000107J Appl Mech Eng

ISSN: JAME, an open access journal

Open AccessResearch Article

Lokhande and Tembhurkar, J Appl Mech Eng 2012, 1:1

http://dx.doi.org/10.4172/jame.1000107Applied MechanicalEngineering

Keywords: CAFD; Drilling xture; Angular drilling; Drilling atspecic angle

Introduction

Fixtures accurately locate and secure a part during machining oper-ations such that the part can be manuactured to design specications.o reduce design costs associated with xturing, various Computer-aided xture design (CAFD) methods have been developed throughthe years to assist the xture designer.

A key concern to a manuacturing company is the ability to manu-acture high quality products in as short a time as possible. Quick re-lease o a product into the market place, ahead o any competitors, iscrucial to securing a higher percentage o the market place. Fixturesplay an important role within many manuacturing processes. Tey ac-curately locate and secure a workpiece during machining such that thepart can be manuactured to design specications. Tus xtures have adirect eect upon machining quality, productivity, and the cost o prod-ucts.

Currently a soware implementation o the CAFixD method is be-ing developed as a stand-alone system that communicates with otherCAD/CAM packages as and when it needs to pass or receive inorma-tion rom external sources. Te purpose o CAFixD is to process this

inormation, use it to generate a xture design, and then pass on thedetails o this xture design to a CAD package that will create the x-ture design drawings. System development is currently ocusing on twomain areas. Te rst is that the decomposition reconstitution approachresults in the dynamic creation o constraints during the adaptationstage and these constraint eects must be incorporated into the evalua-tion o design adaptability. A simple example o this constraint genera-tion is that checks must be perormed to ensure that individual unitsare compatible with each other and can be combined to orm a com-plete xture. A second issue is the learning mechanism. Tis is a keyarea o development. Due to the high levels o computation involvedin CAFixD, work is ongoing to develop strict criteria or managing thegrowth o the case base [1].

Literature Review

Existing fxture design or drilling

A drilling xture or drilling either cylindrical or at workpieces on

*Corresponding author: Nikhil G. Lokhande, Department of Mechanical

Engineering, G.H. Raisoni college of Engineering, Nagpur, India, Email:

[email protected]

Received April 05, 2012; Accepted April 28, 2012; Published April 30, 2012

Citation: Lokhande NG, Tembhurkar CK (2012) Design of Angular Drilling Fixture

and Analysis of Cutting Forces during Drilling on Cylindrical Surfaces. J Appl Mech

Eng 1:107. doi:10.4172/jame.1000107

Copyright: 2012 Lokhande NG, et al. This is an open-access article distributedunder the terms of the Creative Commons Attribution License, which permits

unrestricted use, distribution, and reproduction in any medium, provided the

original author and source are credited.

Design of Angular Drilling Fixture and Analysis of Cutting Forces during Drill-

ing on Cylindrical SurfacesNikhil G. Lokhande* and C.K. Tembhurkar

Department of Mechanical Engineering, G.H. Raisoni college of Engineering, Nagpur, India

Abstract

Applications such as in defense sector, manufacturing of grenade fuse required angular holes on fuse body,

producing holes in turbine blades for the aerospace industry, generating micro-holes in diesel fuel injection nozzles

etc requires angular drilling. Trepanning, gun drilling are the operations available for drilling at specic angle, but

they can be useful when drilling angle should be less than 10 degree. The job having a cylindrical shape and number

of holes are required on it at an angle is challenging task for design engineer and hence Computer Aided Fixture

Design (CAFD) is incorporated in manufacturing industry. It deals with the integration of CAD and CNC programming

in CAM systems using softwares for xture design. Except V block, no other option is available to hold cylindrical

object and hence special type of xture is designed for this case, which can be used for angular drilling. In this paper,

a literature survey of computer aided xture design and automation over the past decade is proposed. First, anintroduction is given on the xture applications in industry. Then, signicant works done in the CAFD eld, including

their approaches and customer requirements are discussed.

or o center is disclosed. Te xture includes a base having v- shaped

groove or receiving larger cylindrical workpieces, a pair o smaller v

shaped openings in the side walls o the base or receiving smaller cy-

lindrical workpieces, a cover attached to the base and a rotatable, index-

able drill bushing mounted to the cover.

Tis invention relates to a drilling xture or accurate positioning o

drill bits and control o the direction during cylindrical shaped suraces

either on or o center. Te drilling xture locates the drill bits precisely

with the spot to be drilled, maintains the drill in that location without

wondering during the drilling operation weather drilling the curved orat suraces and maintains the alignment o drill throughout the drill-

ing operation [2].

A tool is used or guiding and ensuring the correct position or

cross drilling in a rod. Further tool will unction as various types o

work holders or tool holders. Te tool is a cube with chamered corners

that orm eighteen sided symmetrical polygon. Each side has bored

holes therein arranged in an appropriate size and location to permit the

tool to be used or its many unctions.

Tis device consist o a one piece, uniormly square metal cube hav-

ing all corners chamered at a 45 degree angle to provide each corner

with at surace to yield an 18 sided symmetrical polygon. Seventeen

o the side provided with bored holes o dierent sizes with each hole

concentric and parallel to the center line o two opposite and parallel

surace o the cube [3].

U.S. pat. No. 4,955,766 discloses the combination o drill bit with

the stop collar and a xture used or making pocket holes at an angle to
http://dx.doi.org/10.4172/jame.1000107http://dx.doi.org/10.4172/jame.1000107

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Citation: Lokhande NG, Tembhurkar CK (2012) Design of Angular Drilling Fixture and Analysis of Cutting Forces during Drilling on Cylindrical

Surfaces. J Appl Mech Eng 1:107. doi:10.4172/jame.1000107

Page 2 of 4



the surace o the workpiece. Te xture has L-shaped base with one legserving as a guide portion or job and other portion holding a clamp-ing device. An angled channel having a stop ange at its upper end is

provided on guide portion leg. Te drill bit inserted into channel anddrills the hole at an angle upto the point where the stop collar engagesthe ange[4].

Computer aided fxture design (CAFD)

Intelligent techniques or CAFD: ypically, xture design in-volves the identication o clamps, locators, and support points, andthe selection o the corresponding xture elements or their respectiveunctions. Tere are our main stages within a xture design process-setup planning (D1), xture planning (D2), xture unit design (D3)and verication (D4).Setup planning determines the number o setupsrequired to perorm all the manuacturing processes, the task or eachsetup, e.g., the ongoing manuacturing process and workpiece, orienta-tion and position o the workpiece in each setup. A setup represents the

combination o processes that can be perormed on the workpiece by asingle machine tool without having to change the position and orienta-tion o the workpiece manually.

Fixture design still continues to be a major bottleneck in the pro-

motion o current manuacturing. Tis work currently, is implemented

by a typical designer-centered pattern, that is, all xture design related

work is heavily dependent on the experience and knowledge o xture

designer. Tis situation hampers the improvement o productivity, re-

quires a long time to cultivate an experienced xture designer and make

the xture design job weak with a major bottleneck. Tus, new intel-

ligent or automatic technologies on synthesizing traditional geometric

design tools, design knowledge, and past design cases have attracted

much interest in both academic institutions and industries. Te eorts

over past decades in this eld have resulted in numerous ComputerAided Fixture Design (CAFD) applications using various intelligent

methods, such as expert system, case based reasoning, and Genetic

Algorithm (GA), etc.

Recent achievements on some new knowledge related techniques,

such as knowledge modeling, data mining, machine learning, and so

on, indicate a more promising and ruitul uture or the development

o advanced computer aided xture design. In many manuacturing

companies, the technical knowledge o experienced xture designers,

a huge amount o technical les and many good design cases are a very

valuable resource or xture design. Using new technologies in the

knowledge engineering eld to rene model and utilize xture design

domain knowledge as an inormation base or intelligent and automatic

systems can assist a xture designer not only by simpliying the designprocess, but also by generating design ideas. For example, some inter-

esting progress on using XML technology as a xture knowledge rep-

resentation tool to support case-based reasoning in the xture design

process is attractive, despite the reality that it need more eort on the

systemization o intelligent techniques in xture design.

Integrated Fixture Design System or Manuacturing : In essence,xture design only is a partial process in manuacturing, and it shouldobey to the total objective o workpiece manuacturing requirementswhich oen are related with production resources, equipment, cost andmachining processes, etc. Tereore, it is necessary to put the xturedesign task into an overall manuacturing process to obtain best xturedesign solution.

CAFD systems with other manuacturing related technologies,even though many early researches are very limited in obtaining themanuacturing requirements rom and send the result o xture design

to other systems, e.g. PDM or PLM systems. Future research shouldemphasize the importance o more efcient integration o xture sys-tems with other manuacturing systems. Particularly, view the xture

design as one node in a whole chain o manuacturing process. So wehave to consider the impact o xture design result on the cutting cen-ter and machining toolpath, and meanwhile, we also may nd a neces-sary redesign o the xture solution due to various conditions o cuttingtools, production amount and cost, etc [5].

Challenges on angular drilling on cylindrical objects: With theadvent o CNC machining technology and the capability o multi-axismachines to perorm several operations and reduce the number o set-ups, the xture design task has been somewhat simplied in terms othe number o xtures which would need to be designed. However,there is a need to address the aster response and shorter lead-time re-quired in designing and constructing new xtures.

Problems occurring in todays scenario or drilling on cylindrical

objects are:

Drilling in various angles on curved body

Unavailability o xture or drill ing at specic angles

Poor repeatability and accuracy

Tere are not many xtures available or drilling on cylindrical ob-jects in todays scenario.

As application or drill xture diers rom industry to industry be-cause dimensions required by industries dier rom each other. Mainrequirement o customer is holes produced on use body should havehigh degree o accuracy and it is used or mass production. Also it canwithstand stresses acting on it during operation and can run or longlie. It is oen a problem to the small workshop to machine suraceswhich have to be turned, bored or aced at any angle other than a rightangle to a primary base or reerence surace. You may have to make ormanage special xtures to hold the work. A great deal depends on thesize o the work and the stiness o the mounting required to resist themachining load.

In some applications such as in deense sector manuacturing ogrenade use required angular holes on use body, producing holes inturbine blades or the aerospace industry, generating micro-holes indiesel uel injection nozzles etc requires angular drilling. In some ap-plications i the hole to be drill is greater than 10 degree then it is verydifcult to make hole in such object.

For mass production o above applications there is need to developa drilling xture which can make accurate holes at an angle with excel-lent repeatability and accuracy. Angular drilling on cylindrical suracesis task which required skills, and i it will be perormed without usingComputer Numerical controlled machines, and it will be tedious pro-cess which takes lot o time.

Development o fxture assembly or drilling at specifc angle

For making a xture or angular drilling steps involved are:

Analytical design or xture

3 - D Modeling in PRO ENGINEER Wildre 5.0

Assembly

Analysis by using ANSYS

Program generation by PRO ENGINEER Wildre 5

Import a program to CNC Machine

For this project, it is very necessary to study every aspect o existing

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design o drilling xture so that changes required can be easily dene.Comparison o existing design with the proposed enables us to ndcorrect way o design (Figure 1).

Approach to xture design:

Analysis o the work piece drawing

Identication o candidate elements (machined suraces or lo-cating, possible clamps positions, important regions o work-piece, tool path, possible tool intererence points, etc.)

Support, location, clamping, base, guiding, asteners taken inconsideration

Methodology (modular, vice, v-block, point surace, angularstructure, multiworkpiece clamping, 3-2-1 principle etc.)

Identication o solutions (successul sequence o local solutionsand creation o a consistent solution, selection o a pattern or

modular xtures (positioning o 2 or more workpieces) Fixture design

Building o assembly

Functions o parts:-

Square block: It is used to hold cylindrical objects and can rotateat particular angle with supporting plates. It acts as locator or workpieces.

Le hand and Right hand circular plate: It is used or locating andsupporting a square block.

Te main purpose o providing these plates is to adjust square blockat any angle, and drilling can be done accurately.

Analysis o cutting orces in drillingDrill is subjected to action o cutting orce, which can be conve-

niently resolved into three components (Figure 2):

angential (Pz)

Axial (Px)

Radial (Py)

Data:

Drill rpm = 1200

Diameter o drill = 5 mm

Feed = 0.1 mm/ rev.

ype o drill = wist drill

Power (KW) = 1.25d2 K1 n (0.056+1.5s)

105

Where,

K1= Material actor or brass (1.5)

d= Dia o drill

s = Feed mm/rev

n=RPM o drill [6]

Trust (kg) = 1.16 K1* d * (100s) 0.85

Ks = Pz/ A

Where,

Ks = cutting orce = (1.5*0.1)

Pz = orce acting on each lip in kg

A= Ds/4

orque (M) = Pz * d / 20Result

Power = 0.1158 kw

Trust = 61.59 kg

P (z) = 0.0187 kg

orque = 4.67 e 10-3 kg.mm

Analyzing the drill or 0.183 N by using Ansys Workbench 12(Fig-

ures 3,4)

Steps o Analysis:

Import model in IGES ormat in Ansys workbench 12

Divide the model in elements by meshing

Apply the orce

Solve or stress calculation

SCALE 0.800

Figure 1: Drilling Fixture Assembly.

PY

PY

PZ

PZ

PX

PX

Figure 2: Twist drill showing cutting forces.

Figure 3: Shear Stress Analysis of Drill by ANSYS.

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Conclusion

Tere are not many xtures available or angular drilling in to-days scenario. As application or xture design diers rom industryto industry because dimensions required by industries dier rom eachother. Tis simple design o drill ing xture assembly enables to perorm

such operation with accuracy and repeatability by attaching U- CAM4th axis attachment on Vertical Machining Center (VMC).

Aer analyzing the drill by Finite element method by consider-ing axis symmetric loading, the results obtained are validating withAnsys results. Problems involving three dimensional axis symmetricsolids subjected to axis symmetric loading reduce to two dimensionalproblems. Because o total symmetry about z axis all deormations andstresses are independent o rotational angle. Tus, the problem needs tobe looked at as two-dimensional problem (able 1).

Te cutting orces and torque are much lower when drilling onbrass. Tereore negligible amount o stress and deormation takesplace while operation.

References

1. Boyle IM, Rong K, Brown DC (2006) CAFixD: A Case-Based Reasoning

Fixture design method. Framework and Indexing Mechanisms. J Comput Inf

Sci Eng 6: 40.

2. klee G, De Noma GR, Collier SL, Newman RJ (1984) Drilling xture.

3. Robert L. Reynolds (1987) Drilling xture and work holder. United states patent

4. Burton Weinstein, Richard H. Deaton (2001) Fixture for drilling pocket holes.

United States patent.

5. Hui Wang, Yiming (Kevin) Ronga, Hua Li, Price Shaun (2010) Computer aided

xture design: Recent research and trends. Computer-Aided Design 42: 1085

1094.

6. (1980) Handbook on Production technology. HMT Banglore published ,Tata

McGraw hill.

Figure 4: Static structural Deformation.

Parameters Analytical ANSYS

Deection in mm 0.052 0.00401

Von mises stress in MPa 110.23 132.06

Maximum shear stress inMPa

69.26 75.551

Table 1: Comparison between analytical calculation of cutting forces and ANSYS.

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