Currently composites are being used to replace conventional metallic materials in a wide range of industries including aerospace, aircraft and defense which require structural materials with high strength-to-weight and stiffness-to-weight ratios. GFRP composites are used in fairings, passenger compartments, and storage room doors due to their high mechanical properties. Out of all the machining operations, most commonly used operation is drilling. But drilling of these composite materials, irrespective of the application area can be considered a critical operation, owing to their tendency to delaminate when subjected to mechanical stresses

1. INVESTIGATIONS & OPTIMIZATION OF CONTROL VARIABLES ON
VARIOUS DRILLING TECHNIQUES TO REDUCE THE DELAMINATION
OF GFRP COMPOSITES USING ANN AND GA INTEGRATED
APPROACH
.
Dr.M. Bala Theja,M.Tech,Ph.D
Associate Professor
Department of Mechanical Engineering

2. Overview of the Presentation
1.Abstract
2.Introduction
3.Literature Survey
4. References

3. Abstract
 Currently composites are being used to replace conventional
metallic materials in a wide range of industries including
aerospace, aircraft and defense which require structural
materials with high strength-to-weight and stiffness-to-
weight ratios.
 GFRP composites are used in fairings, passenger
compartments, and storage room doors due to their high
mechanical properties. Out of all the machining operations,
most commonly used operation is drilling.
 But drilling of these composite materials, irrespective of the
application area can be considered a critical operation, owing
to their tendency to delaminate when subjected to
mechanical stresses.

4. Abstract… (contd.)
 With regard to the quality of machined component, the
principal drawbacks are related to surface delamination,
fibre/resin pull-out and inadequate surface roughness of
the hole wall.
 Hence it is essential to understand the drilling behavior
by conducting a large number of drilling experiments
using various drilling techniques available.
 At the same time many industries are using advanced
drilling processes over conventional drilling techniques,
for Ex: Laser Beam Drilling, Friction Stir Drilling etc.

5. Abstract… (contd.)
 As the advanced drilling processes are complex in nature
involving large number of input process parameters to be
controlled, it is difficult to attain the best quality holes
unless the parameters are set at the optimal values.
 This is not possible using trail and error methods. Hence
there is a need to develop the methodology for finding the
optimal parameters.
 Hence it is essential to understand the drilling behaviour
by conducting a large number of drilling experiments using
various drilling techniques available. All the experiments
were conducted as per the DOE.

6. Abstract… (contd.)
Also it is very much essential to optimize the drilling
parameters such as feed rate and spindle speed in order
to automate the process.
 This Research mainly focusses on finding the effects of
individual process parameters on the delamination
mechanism when the composites are subjected to
mechanical stresses.
 In order to predict the optimal values of input process
parameters, there is need to develop the methodology
with which we can able to find the optimal parameters
at which the delamination is very low.

7. Abstract… (contd.)
This methodology mainly follows the following steps
1. Developing the design matrix as per the design of
experiments for conducting the experiments.
2. Prediction of Empirical models using the
experimental data.
3. Empirical modeling will be done using Artificial
Neural Networks.
4. ANOVA Analysis.
5. Formulation of optimization problem.
6. Solving the optimization problem using Genetic
Algorithm.
7. Validation of Results.
8. Automating the process.
9. Statement of Savings to the Industry.

8. Introduction
Composite materials offer the highest specific strengths and
moduli among engineering materials. For this reason, they
are in great demand in aerospace and aircraft application
where high strength and stiffness to weight ratios are
required. Recently, due to increased pressure to develop
lighter structures, to increase payloads and to improve fuel
economy, composites are being considered for a variety of
applications including automobile structures, commercial
aircraft and high speed machinery. The applications of
composites lie in various sectors as shown in table.

9. Applications of Composites
Areas Areas Components/product
Aerospace Brake disc, aircraft interiors, canopies, wing etc
Automobile Metal matrix composites for brake-drums, cylinder-blocks
Chemical
Industry
Storage tanks, scrubbers, ducting, piping, exhaust stacks, pumps,
columns, reactors, gratings and structural supports
Electrical In switchgear and laminates
Marine Trawlers, barges, naval vessels and other ship components
Building and
Construction
Doors and windows, paneling and other interiors
Consumer and
Sports goods
Trays, furnitures, accessories, tennis racquets, golf clubs,
archery equipment, hand gliders etc
Bio-Medical Artificial limbs for handicaps, dentistry

10.  Keeping in mind the life-cycle operating costs in all of the
applications, composite materials are found to be cost
effective in the long run.
 Out of various composite materials, Glass Fibre Reinforced
Plastic (GFRP) composites are becoming more important in
various fields of technology such as aerospace, naval and
automotive industries owing to their properties such as high
strength to weight ratio and a high specific stiffness, as well
as superior corrosion resistance, light weight construction,
low thermal conductivity, high fatigue strength, ability to
char and resistance to chemical and microbiological attacks.
 GFRP composites have the advantage of tailoring and
achieving the desired size and shape depending upon the
structural design requirement. Although we can tailor and
mould composite material to the required pattern, final finish
machining of these materials becomes mandatory in
situations where dimensional accuracy and surface quality
are key factors.

11.  Inspite of those efforts, it has resulted only in partial
success because the existing knowledge of metallic
materials cannot be directly applied to the composite
materials to understand the events that occur during
machining. While machining, the two phases, the fibre
and the matrix that are coexistence behave differently
than when they are separate.
 In addition to their properties being much different from
metal, different fibre orientations can pose further
problems. So, the various problems that occur in
composite materials have to be analyzed and efforts
need to be taken to overcome these problems.

12. Literature Survey
 Mathew et al. developed predictive models based on some
important process parameters to determine the optimal
process parameter ranges for pulsed Nd:YAG laser
machining operation on carbon fibre reinforced plastic
composites. Using response surface methodology (RSM).
 Kuar et al. performed parametric analysis to determine
the optimal setting of process parameters, like pulse
frequency, pulse width, lamp current, and assist air
pressure, for achieving minimum HAZ thickness and taper
of microholes machined on zirconium oxide (ZrO2) by
pulsed Nd:YAG laser.
 Kuar et al.studied the effects of several laser machining
parameters on HAZ thickness and taper of the micro
drilled holes on alumina-aluminium composites using
RSM technique.

13.  K Palanikumar et al. conducted experiments on GFRP
composites using Brad & Spur drill and optimized drilling
parameters by using two input variables with four levels
and concluded that low feed rate and high spindle speeds
were beneficial to reduce delamination. Previous
researchers carried out the experiments with three or four
levels for optimization of input parameters. In the present
study the experiments are carried out using Twist drill
(HSS), end mill (Carbide)and Kevlar drill( Carbide) to find
the optimum drilling parameters using 5- level Taguchi’s
L25 orthogonal array and also to analyse the effect of drill
bit material and geometry on delamination.
 Mohan et al. have performed and analyzed delamination in
drilling process of GFRP composite material, in order to
understand the effects of process parameters on the
delamination.

14.  Rao et al. presented a comprehensive study of
delamination in use of various drill types, three different
feed rate and spindle speeds. The influence of drilling
parameters on the extension of delamination was
examined by conducting the number of experiments as
per the design of experiments and analysis of variance
techniques of Taguchi. For minimizing drilling damage,
low feed rates were preferred in drilling of composite
laminates. In order to understand the effects of
machining parameters in the various machining, a lot of
researcher used Taguchi techniques.
 Mohan et al. carried out delamination analysis in drilling
of GFRP composites. In their investigation, they have
asserted that the feed rate, cutting speed, and material
thickness are the parameters which influence the
delamination in drilling of GFRP composites.

15.  N. S.Mohan et al. carried out delamination analysis of
GFRP composite materials. The main objective of this
study is to determine factors and combination of factors
that influence the delamination using Taguchi and
response surface methodology and to achieve the
optimization machining conditions that would result in
minimum delamination.
 Balamugundan et al. used desirability function analysis
to optimize surface roughness and delamination during
milling of GFRP/Epoxy composites. It has been found that
the desirability is one of the important optimization
techniques and can be successfully applied for machining
process such as drilling.

16. Vinod Kumar Vankanti et al. proposed process
parameter optimization in drilling of GFRP Composite
using Taguchi method. In this work, experiments were
carried out as per the Taguchi experimental design and an
L9 orthogonal array was used to study the influence of
various combinations of process parameters on hole
quality. Analysis of variance (ANOVA) test was conducted
to determine the significance of each process parameter
on drilling. The results indicate that feed rate is the most
significant factor influencing the thrust force followed by
speed, chisel edge width and point angle; cutting speed is
the most significant factor affecting the torque, speed and
the circularity of the hole followed by feed, chisel edge
width and point angle.

17. References
[1] Tom sunny, J.Babu, Jose Philip, “Experimental Studies on Effect of
Process Parameters on Delamination in Drilling GFRP Composites
using Taguchi Method” Proceedings of 3rd International Conference
on Materials Processing andCharacterisation, March 2014, GRIET-
Hyderabad.
[2] M.A.J.Bosco, K.Palanikumar, B.Durga Prasad, A. Velayudham,
“Influence of machining parameters on delamination in drilling of
GFRP-armour steel sandwich composites” 3rdNirma University
International Conference-2012, Ahmedabad.
[3] E. Kilickap “Optimization of cutting parameters on delamination
based on Taguchi method during drilling of GFRP composite” Expert
Systems with Applications-2010.
[4] Vikas Sharma “An Experimental Study on Drilling of GFRP Composites”
Thapar University, Patiala.

18. [5] Vinod Kumar Vankanti, VenkateswarluGanta “Optimization of process
parameters in drilling of GFRP composite using Taguchi method”
Journal of Materials Research and Technology, 2014.
[6] M. Lakshmi Chaitanya, A. Gopala Krishna “Multi-objective
Optimization of Laser BeamCutting Process” IJRMET Vol. 3, Issue 2,
May - Oct 2013.
[7] N.S. Mohan, S.M. Kulkarni , A. Ramachandra “Delamination analysis
in drilling process of glass fiber reinforced plastic (GFRP) composite
materials” Journal of Materials Processing Technology 186 (2007).
[8] T.V. Rajamurugan, K. Shanmugam, K. Palanikumar “Analysis of
delamination in drilling glass fiber reinforced polyester composites”
Materials and Design 45 (2013).
[9] K. Palanikumar “Experimental investigation and optimisation in drilling of
GFRP composites” Measurement 44 (2011).

19. [10] P.J. Pawar and G.B. Rayate “Multi-objective Optimization of Laser
BeamMachining Process Parameters” International Journal of
Advanced Mechanical Engineering. Volume 4, Number 3 (2014).
[11] ErolKilickap“ Determination of optimum parameters on delamination in
drilling of GFRP Composites by Taguchi method” Indian Journal of
Engineering & Material Sciences, Vol 17, August 2010.

20. THANK YOU