Embed Size (px)
Citation preview
FEA
3.1 INT
milling
fluid ap
fluid ap
identifie
wear an
dry mil
3.2 DEV
SYS
photogr
electric
axis an
provisio
ASIBILIT
TRODUCTI
Based on th
of hardene
pplication pa
pplication p
ed that will
nd cutting fo
ling and con
VELOPME
STEM
A special fl
raph of the f
It consists
drive. The
d the degree
on is used to
TY STUDI
F
ION
he literature
d AISI 434
arameters th
parameters, a
bringforth
orce using T
nventional w
ENT OF MI
luid applicat
fluid applicat
Fig. 3.1 S
of a P-4 fu
fuel pump h
e of rotation
o control the
CHAIES ON H
FLUID AP
e survey it w
0 steel with
hat affects th
a set of lev
better cuttin
Taguchi tech
wet milling.
INIMAL PU
tion system w
tor is shown
Schematic view
uel pump (B
has a plunge
n of the plun
rate of cuttin
46
APTER 3HARD MIL
PPLICAT
was decided
h minimal fl
he cutting p
vels of fluid
ng performan
hnique and t
ULSED JET
was develop
n in Fig. 3.2.
w of fluid appl
Bosch make
er with helic
nger determi
ng fluid deli
LLING W
TION
d to conduc
luid applicat
performance
d application
nce in terms
the results a
T FLUID AP
ped for this p
lication system
) coupled to
al groove wh
ines the rate
ivered per st
WITH MIN
t a feasibili
tion and to
. After iden
n parameter
s of surface
are to be com
PPLICATIO
purpose (Fig
m
o an infinit
hich can rot
e of fluid de
troke accurat
NIMAL
ity study on
identify the
ntification of
rs are to be
finish, flank
mpared with
ON
g. 3.1). The
ely variable
tate about its
elivery. This
tely.
n
e
f
e
k
h
e
e
s
s
47
Fig. 3.2 Photograph of fluid applicator
1. Fluid tank 2. Delivery tube, 3. Variable speed controller 4. Fluid pump 5. Four outlets 6. DC Motor
An injector nozzle of single hole type with a specification DN0SD151 with a spray
angle of 0° was used as the fluid injector in this investigation. Fig. 3.3 presents the
photograph of the fluid injector.
Fig. 3.3 Photograph of fluid injector
1. Fluid inlet 2. Fluid delivery nozzle 3. Screw for adjusting fluid delivery pressure
reciproc
The del
fluid no
cutting
pressure
in Fig. 3
Fig. 3.4 sho
cates as the
livery pressu
ozzle pressu
fluid into th
e at the injec
1.
The fluid co
3.4, the velo
ows the line
DC motor r
ure at the fl
ure tester as
he nozzle. A
ctor.
Nozzle 2. P
oming out o
ocity of whic
Fig.3.4 Line sk
e sketch of
rotates and d
luid injector
shown in Fi
pressure ga
Fig 3.5 Pressure gauge
f the injecto
ch depends u
48
ketch of the flu
the fluid je
delivers cutt
can be set
ig 3.5. It ha
auge fixed at
Nozzle testere 3. Fluid tank
or consists o
upon the pre
uid jet
et. The plun
ting fluid thr
at any prede
as a hand op
t the top of t
k 4. Handle of
f myriads of
ssure set at t
nger of the
rough the flu
efined value
perated plun
the device w
f the plunger
f tiny drople
the fluid inje
fluid pump
uid injector.
e by using a
nger to force
will show the
ets as shown
ector nozzle.
p
.
a
e
e
n
.
49
Higher the pressure at the injector, higher will be the velocity of the individual particles.
The test rig facilitated independent variation of pressure at fluid injector (P), frequency of
pulsing (F) and the rate of fluid application (Q). The system can deliver cutting fluid
through four outlets simultaneously so that cutting fluid could be applied to more than one
location or more than one machine tool at the same time. The frequency of pulsing can be
varied infinitely through a DC variable speed motor with a control system designed for
this purpose.
The fluid applicator delivers cutting fluid at a rate of one pulse per revolution of
the DC motor. This facility enables application of very small quantity of cutting fluid per
pulse. If Q is the rate of fluid application in ml/min and F is the frequency of pulsing in
pulses/min, fluid applied per pulse is given by Q/F. For example if Q is 1 ml/min and F is
1000 pulses/min and the pressure at the fluid nozzle is set at 100 bar, then fluid delivered
per pulse is equal to 1/1000 = 0.001 ml while the velocity of the individual fluid particles
will be approximately equal to about 70 m/sec (Philip et al., 2000; Heywood, 1996). Thus
by varying the frequency of pulsing, the rate of fluid delivered per pulse can be controlled.
Pulsing jet aids in fluid minimization without compromising the velocity of individual
particles as the pressure at the fluid injector remains constant at the set value. It is reported
that the frictional forces between two sliding surfaces can be reduced by rapidly
fluctuating the width of the lubricant filled gap separating them (Uzi Landman, 1998).
When the pulsing jet is used, the width of the lubricant filled gap between the tool rake
face and the chip fluctuates with a frequency equal to the frequency of pulsing of the fluid
jet. Hence a pulsing jet of cutting fluid was used in this investigation to exploit the
expected reduction in the frictional forces between tool and chip.
Special fixtures (Fig. 3.6) were designed so that the injector nozzle could be
located in any desired position without interfering with the tool or work during metal
cutting operation.
50
Fig. 3.6 Fluid application at the backside of the chip 1. Fixture 2. Tool holder 3. Insert
3.3 SELECTION OF CUTTING FLUID
Since the quantity of cutting fluid delivered per pulse is extremely small, a
specially formulated cutting fluid was employed in this investigation. The base was a
commercially available mineral oil and the formulation contained other ingredients such as
friction modifiers, emulsifying agents, coupling agents and anti-corrosion agents
(Varadarajan et al., 2002b). It acted as an oil in water emulsion. Table 3.1 shows the
various constituents present in the cutting fluid formulated.
Table 3.1 Composition of the cutting fluid
S No. Name of the constituent Percentage
1 Petroleum Sulfonate (Molecular Weight=490 to 520) 15%
2 Ethylene Glycol 1% 3 Oleic Acid 3% 4 Triethaol Amine 3%
5 Alcohol Ethoxylate 2% - 6%
6 Mineral Oil (Paraffinic) the rest
Petroleum Sulphonate acts as a multifunctional additive. It can act as an
emulsifier, a rust inhibitor, a surfactant and as an EP agent. The polar nature of the
Sulphonate end of the molecule functions as a typical anionic surfactant. The tail of the
Sulphonate is made up of a hydrocarbon chain which has no charge. Sulphonates act on
the surface of oil droplets by binding at the tail. The head of the Sulphonate has a polar
51
charge, allowing the head to bond to water droplets. Thus, the Sulphonate can hold oil and
water apart so that they can co-exist and form an emulsion.
Ethylene glycol resists freezing due to its low freezing point and acts as a coupling
agent to increase the stability of the emulsion. The use of ethylene glycol not only
depresses the freezing point but also elevates the boiling point such that the operating
range for the heat transfer fluid is broadened on both ends of the temperature scale. The
increase in boiling temperature is due to pure ethylene glycol having a much higher
boiling point and lower vapor pressure than pure water.
Oleic acid is an unsaturated fatty acid which is used as an emulsifying or
solubilizing agent in aerosol products. Besides serving as an agent for improving the
lubricity of the cutting fluid (agent for lowering the friction coefficient – friction
modifier), this compound forms an effective agent for enhancing permeability.
In water soluble cutting fluids, Triethaol Amine is used to provide the alkalinity
needed to protect against rusting and it acts as an anti-oxidant. It also controls the
evaporation rate of water in cutting fluid.
Alcohol Ethoxylate is a nonionic surfactant created by adding ethylene oxide
groups to a long chain (high molecular weight) alcohol. Alcohol ethoxylates possess
greater resistance to water hardness than many other surfactants. It also acts as a secondary
emulsifier which enhances the emulsification capability of the sulfonate. It is formulated
from selected aliphatic hydrocarbons and alcohol ethoxylates known for its
biodegradability. It is approved as a product which is readily biodegradable falls into the
most biodegradable classification as defined by EPA.
Mineral oils are hydrocarbons obtained from the petrol refining of crude oil. Their
properties depend on the chain length, structure and refining level. This formulation was
developed and used successfully by varadarajan et al. (2002b) during their investigation on
turning of hardened AISI4340 steel. The same formulation is being tried in the present
investigation also.
3.4 SELECTION OF WORK MATERIAL
AISI4340 steel was selected as a work material which is widely used in die
making, automobile and allied industries. Its applications include structural use such as
aircraft
connect
as rotor
strength
conside
the Tab
were us
this inv
3.5 SEL
TT8020
engine m
ting rods, ge
r shafts, disc
It is a throu
h and fatigue
This grade
ering its wide
ble 3.2.
Plates of 12
sed for this i
vestigation.
LECTION O
Coated carb
0 of TaeguT
mounts, gene
ear shafts, cr
s and welde
ugh hardenab
e strength. It
of steel is c
e range of ap
Table 3.
25mm length
nvestigation
F
OF CUTTIN
bide cutting
Tec which h
eral enginee
rank shafts,
d tubing app
ble low allo
t is less costl
considered a
pplication in
2 Chemical c
Element
C
Cr
Mn
Mo
Ni
P
Si
S
Fe
h, 75mm bre
n. Fig. 3.7 pr
ig. 3.7 Photogr
NG TOOL
g tools wit
has helical h
52
ering applic
landing gea
plications (V
oy steel and
ly compared
as the work m
n the industry
composition of
0.38
0.7
0.6
0.2
1.6
0.0
0.1
0.0
Ba
eadth and 20
resents the p
raph of the wor
th the spec
higher positiv
cations suc
ar componen
Varadarajan e
is known fo
d to high allo
material in t
y. It has a c
f work material
%
8 – 0.43
7 – 0.9
6 – 0.8
2 – 0.3
65 – 2.0
35 max
15 – 0.3
04 max
alance
mm thickne
photograph o
rkpiece
ification AX
ve cutting e
h as prope
nts, heavy fo
et al., 2002a)
for its toughn
oy steels.
the present i
composition
l
ess hardened
of the workp
XMT 0903
edges as in F
eller shafts,
orgings such
).
ness, tensile
nvestigation
as shown in
d to 45 HRC
piece used in
PER-EML
Fig. 3.8 and
,
h
e
n
n
C
n
L
d
Fig. 3.9
of the in
AXM
investig
respecti
the rec
technica
9 was used in
nsert.
Designation
T 0903 PER-E
A tool holde
gation. The
ively (Fig. 3
commendatio
al/material s
n the investi
F
T
D
EML 9.4
er with the s
length and
3.11). The c
ons of M/s
support for th
igation. Tab
Fig. 3.8 Photo
Fig. 3.9 Differe
Table. 3.3 Dim
D d₁
499 6.19
specification
d diameter o
cutting tool
TaeguTec
his research
53
ble 3.3 gives
ograph of the i
ent views of the
mensions of the
Dim
a
97 1.245
n TE90AX 22
of the tool
inserts and t
India (P) L
work.
the dimensi
nsert
e insert
e insert
mension (m)
t
3.607
20-09-L (Fig
holder are
the tool hold
Limited who
ions of vario
R
0.508
g. 3.10) was
170 mm a
der were sel
o were exte
ous elements
ap
8.890
s used in this
and 20 mm
lected as per
ending their
s
s
m
r
r
of type
the pho
Experiment
FN1U. The
tograph of th
1. Milling m5. Tool force
Fig
Fig.
s were carri
e clamping a
he experime
machine 2. Mie dynamometer
g. 3.10 Photog
3.11 Schemati
ed out in a c
area of the m
ental setup.
Fig 3.12 Exinimal fluid apr (Kistler type)
54
graph of the too
ic view of the t
column and
machine is 90
xperimental setpplicator, 3. Flu 6. Dynamom
ol holder
tool holder
knee type v
00 mm × 23
tup uid supply lineeter display 7
vertical milli
0 mm. Fig.
e 4. Fluid injec7. Charge ampl
ing machine
3.12 shows
ctor lifier
e
s
55
3.6 MEASUREMENT OF PROCESS PARAMETERS
Cutting force was measured using a Kistler dynamometer of type 9257B
(Fig. 3.13). It consists of a piezoelectric dynamometer (Fig 3.14) and a multichannel
charge amplifier (Type: 5070A) as well as a data acquisition and analysis
system (DynoWare). This multicomponent dynamometer facilitates dynamic and
quasi-static measurement of the three orthogonal components of cutting force.
Fig.3.13 Kistler - data analysis and display system
Fig.3.14 Kistler dynamometer (type 9257B)
(Fig. 3.
count o
Surface fini
15).
Flank wear
f 0.005 mm.
ish was me
Fig.3
was measu
.
Fig.3.16 Too
easured usin
3.15 Surface r
red using to
ol makers micr
56
ng TR100 P
roughness teste
ool makers m
roscope (Metze
Portable Sur
er (TR100)
microscope
er- megastar 80
rface Rough
(Fig. 3.16)
031)
hness Tester
with a least
r
t
57
Surface morphology of the worn tool was carried out using Scanning Electron
Microscope of type JSM-6390 (Fig 3.17) with a magnification range of 5X to 300,000X.
The closer view of the worn tool on the display of Scanning Electron Microscope is shown
in Fig. 3.18.
Fig.3.17 Scanning electron microscope (JSM-6390)
Fig.3.18 A closer view of surface morphology of worn tool as the display
All measurements were repeated two times, and the average of these two
measurements was taken as the final value of tool wear, surface roughness, and cutting
force.
58
3.7 PRELIMINARY CUTTING EXPERIMENTS
Preliminary experiments were conducted using a single jet configuration
(Fig. 3.19) to find out the viability of fluid minimization scheme for hard milling and to
arrive at a set of fluid application parameters that can bring forth minimum surface
roughness, minimal flank wear and minimum cutting force. The experimental conditions
at which the preliminary cutting experiments were conducted are shown in table 3.4.
Fig. 3.19 Directions of cutting fluid application using single jet configuration
Table 3.4 Experimental conditions
Machine tool Vertical milling machine (FN1U)
Work material AISI4340 steel
Cutting insert AXMT 0903 PER-EML
Tool holder TE90AX 220-09-L
Tool Geometry Length – 9.499 mm, width – 6.197 mm, thickness - 3.607 mm, nose radius – 0.508 mm
Cutting speed 45 m/min
Feed 0.25 mm/tooth
Depth of cut 0.4 mm
Type of cutting fluid Specially formulated mineral oil based cutting fluid.
Environment Cutting fluid application through minimal fluid application
An eight run experiment was designed based on Taguchi technique (Lochner and
Matar, 1990) and the design matrix is shown in Table. 3.5.
4
injector
fluid ap
cutting
Fig. 3.
Table 3
R
The experim
r (P), freque
pplication (D
fluid was ke
Table 3.6
Inpu
Pressure at f
Frequency of
Rate of fluid Direction o
.20 presents
Fig.
3.5 Design mat
Run No.
1 2 3 4 5 6 7 8
ments were c
ency of puls
D) were varie
ept at 10% o
Input paramet
ut parameter
fluid injector P
f pulsing (Pulse
application (mof fluid applica
a block diag
. 3.20 Block di
trix for eight-ruF
1 1 1 1 1 2 2 2 2
carried out w
sing (F), rat
ed at two lev
oil and the re
ters and their l
P(Bar)
es/min)
ml/min) ation Back
gram of the i
iagram represen
59
un, two-level eFACTOR COLU
2 1 1 2 2 1 1 2 2
with two rep
e of fluid ap
vels as show
st water.
evels during pr
Level 1
50 (P1)
500 (F1)
5 (Q1) k side of chip (
input and ou
ntation of inpu
experiment withUMNS
3 1 2 1 2 1 2 1 2
plications. T
pplication (Q
wn in Table 3
reliminary cutt
(D1) Tool-w
utput parame
ut and output pa
h four factors
7 1 2 2 1 2 1 1 2
The pressure
Q) and the
3.6. The com
ting experimen
Level 2
100(P2)
750 (F2)
15 (Q2) work interface (
eters.
arameters
e at the fluid
direction of
mposition of
nts
(D2)
d
f
f
in Table
single j
Fig
Fig. 3.1
tool-wo
directio
respecti
The respons
e 3.7
Table 3
Fig. 3.21 sh
et configura
g. 3.21 Schem
The two dir
19 namely fl
ork interface
on of fluid a
ively.
se table for
3.7 Response ta
hows the sche
ation.
atic view of di
rections of fl
luid applicat
e. Fig. 3.2
application a
eight-run, tw
able for eight-r
ematic view
rections of cut
luid applicat
tion at the ba
22(a) and Fi
at the back
60
wo-level exp
run, two-level e
w of direction
tting fluid appl
tion employe
ack side of t
ig. 3.22(b)
side of the
periment wit
experiment wit
ns of cutting
ication using s
ed in this inv
the chip and
shows the
chip and at
th four facto
th four factors
fluid applic
ingle jet config
vestigation a
d fluid applic
schematic v
the tool-wo
ors is shown
ation during
guration.
are shown in
cation at the
view of the
ork interface
n
g
n
e
e
e
(Thepso
depth o
compos
2002b).
Fig. 3.2
Fig. 3
Cutting par
onthi et al., 2
of cut were m
sition of cut
. .
22(a). Schema
.22(b). Schema(tool rotates
rameters we
2009; Rahm
maintained a
tting fluid w
atic view of flui(tool occupie
atic view of flus through 180˚
ere selected
man et al., 2
at 45 m/min,
was maintai
61
id application aes the location a
uid applicationand occupies t
based on e
002). Acco
, 0.25 mm/to
ined at 10%
at the back sidat B)
n at the tool-wothe location at
earlier resea
ordingly the
ooth and 0.4
% oil in wa
e of the chip
ork interface
A)
arch work i
cutting spee
4 mm respec
ater (Varadar
in this field
ed, feed and
ctively. The
rajan et al.,
d
d
e
,
3.7.1 R
attainab
flank w
parame
individu
analysis
ANOVA
cutting
at the fl
followe
applicat
Results of th
Fig. 3.23(a)
ble surface f
wear is availa
ters on the
ual fluid ap
s of variance
A summary
force. From
luid injector
ed by direc
tion.
Fig. 3.23(a)(P – Pressu
Fig. 3.23(P – Pressu
he prelimin
) presents th
finish. The r
able in Fig. 3
cutting forc
pplication p
e (ANOVA)
for the diffe
m the ANOV
forms the m
ction of flu
Relative signiure at fluid injec
3(b) Relative sure at fluid injec
nary exper
he relative s
relative sign
3.23(b) and
ce is presen
parameters o
) using Qual
erent input p
VA results (T
most significa
uid applicati
ificance of fluidctor, F – Frequ D – Direction
ignificance of ctor, F – Frequ D – Direction
62
riments
significance
nificance of
the relative
nted in Fig.
on cutting
litek-4 softw
parameters on
Table 3.8(a)
ant paramete
ion, frequen
d application puency of pulsinn of fluid applic
fluid applicatiouency of pulsinn of fluid applic
of fluid app
the fluid ap
significance
3.23(c). Th
performance
ware. Table 3
n surface rou
) – 3.8(c)), it
er influencin
ncy of puls
parameters on sng, Q – Rate ofcation)
on parameters ng, Q – Rate ofcation)
plication pa
pplication pa
e of the fluid
he relative i
e was estim
3.8(a) – 3.8(
ughness, flan
t is evident t
ng the output
sing and ra
surface roughnf fluid applicati
on flank wear f fluid applicati
arameters on
arameters on
d application
influence of
mated using
(c) show the
nk wear and
that pressure
t parameters
ate of fluid
ness ion
ion
n
n
n
f
g
e
d
e
s
d
63
x
Fig. 3.23(c) Relative significance of fluid application parameters on cutting force (P – Pressure at fluid injector, F – Frequency of pulsing, Q – Rate of fluid application
D – Direction of fluid application)
Table. 3.8(a) ANOVA summary for influence of fluid application parameters on surface roughness
Col#/ Factor
DOF (f)
Sum of sqrs (Ss)
Variance (V)
F – Ratio (F)
Pure sum (S′)
Percent P (%)
Pressure (bar) 1 0.601 0.601 40.929 0.587 59.141 Frequency (pulses/min)
1 0.056 0.056 3.862 0.042 4.24
Rate of fluid (ml/min)
1 0.007 0.007 .489 0 0
Direction 1 0.282 0.282 19.233 0.268 27.006 Other/Error 3 0.043 0.014 9.613
Total 7 0.992 100.00%
Table. 3.8(b) ANOVA summary for influence of fluid application parameters on flank wear Col#/ Factor
DOF (f)
Sum of sqrs (Ss)
Variance (V)
F – Ratio (F)
Pure sum (S′)
Percent P (%)
Pressure (bar) 1 0.003 0.003 104.583 0.003 58.338 Frequency (pulses/min)
1 0 0 10.533 0 5.369
Rate of fluid (ml/min)
1 0 0 0.843 0 0
Direction 1 0.001 0.001 58.593 0.001 32.437 Other/Error 3 -0.001 -0.001 3.853
Total 7 0.005 100.00%
Table. 3.8(c) ANOVA summary for influence of fluid application parameters on cutting force Col#/ Factor
DOF (f)
Sum of sqrs (Ss)
Variance (V)
F – Ratio (F)
Pure sum (S′)
Percent P (%)
Pressure (bar) 1 43725.331 43725.331 80.7 43183.505 64.026 Frequency (pulses/min)
1 2265.834 2265.834 4.181 1724.009 2.556
Rate of fluid (ml/min)
1 443.89 443.89 0.819 0 0
Direction 1 19385.597 19385.597 35.778 18843.771 27.938
Other/Error 3 1625.476 541.825 5.48
Total 7 67446.13 100.00%
64
The results of the analysis which led to a set of levels of fluid application
parameters to minimize surface roughness, flank wear and cutting force are summarized in
Table. 3.9.
Table 3.9 Summary of fluid application parameters for optimum performance during preliminary experiments
Sl. No.
Output parameters Objective
Pressure at the fluid injector
(bar)
Frequency of pulsing
(pulses/min)
Rate of cutting fluid
(ml/min)
Direction of fluid
application
Projected values
1. Surface roughness (µm)
To minimize surface roughness 100(P2) 500(F1) 5(Q1) Tool-work
interface(D1) 0.623
2. Tool wear (mm)
To minimize tool wear 100(P2) 500(F1) 5(Q1) Tool-work
interface(D1) 0.025
3. Cutting force (N)
To minimize cutting force 100(P2) 500(F1) 5(Q1) Tool-work
interface(D1) 148.161
From the summary of results it was clear that fluid application parameters namely
pressure at fluid injector, frequency of pulsing and rate of fluid application have their own
influence on cutting performance. The set up for conventional wet milling is shown in
Fig. 3.24.
Fig. 3.24 Conventional wet milling setup
65
Confirmatory experiments were conducted to check the validity of the projected
values of surface roughness (Ra), Flank wear (Vb) and cutting force (F). During the
confirmatory experiments the cutting parameters such as cutting speed, feed and depth of
cut were maintained at 45 m/min, 0.25 mm/tooth and 0.4 mm respectively. The
composition of cutting fluid was maintained at 10% oil in water and the fluid application
parameters were maintained constant as in Table 3.9. The results of the confirmatory
experiments are shown in Table. 3.10. The experimental results matched well with the
projections.
Table 3.10 Results of the confirmatory experiments
Sl. No.
Output parameters Projected values Experimental
values
Percentage error (%)
1. Surface roughness (µm) 0.623 0.644 3.26
2. Tool wear (mm) 0.025 0.028 10.71
3. Cutting force (N) 148.161 168.56 12.10
Cutting experiments were conducted to compare the performance during dry
milling, conventional wet milling and milling with minimal fluid application with cutting
speed, feed and depth of cut maintained at 45 m/min, 0.25 mm/tooth and 0.4 mm
respectively. The fluid application parameters were maintained constant as in Table 3.9.
The results are presented in Table 3.11 and shown graphically through Fig. 3.25(a),
Fig.3.25(b) and Fig.3.25(c).
Table 3.11 Comparison of performance during dry, wet and milling with minimal fluid application
Sl. No. Cutting condition
Surface roughness (μm)
Flank wear (mm)
Cutting force (N)
1. Dry milling 1.671 0.131 483.61
2. Wet milling 1.193 0.059 239.56
3.
Milling with minimal fluid application (Optimized) 0.644 0.028 168.56
66
Fig. 3.25(a) Comparison of surface roughness during dry milling, wet milling and milling with minimal fluid application using single jet in optimized condition
Fig. 3.25(b) Comparison of flank wear during dry milling, wet milling and milling with minimal fluid application using single jet in optimized condition
Fig. 3.25(c) Comparison of cutting force during dry milling, wet milling and milling with minimal
fluid application using single jet in optimized condition
The results show a definite advantage for milling with high velocity pulsed jet fluid
application when compared to conventional wet milling and dry milling.
67
3.8 Summary
The preliminary experiments clearly indicated that the fluid application parameters
such as pressure at the fluid injector, frequency of pulsing, rate of fluid application
and direction of fluid application do influence the cutting performance.
Comparison of surface roughness, flank wear and cutting force revealed that better
cutting performance can be achieved by hard milling with minimal cutting fluid
application.
During the preliminary experiments cutting parameters such as cutting speed, feed
and depth of cut were selected based on earlier research work in this field.
A systematic procedure must be laid out to arrive at a better combination of cutting
parameters.
Experiments are to be designed to explore the possibility of arriving at a set of
fluid application parameters (with a particular thrust to the direction of fluid
application and the number of jets used) to achieve better cutting performance.
The preliminary investigations revealed that the jet configuration that facilitates
fluid application at the tool-work interface has got an edge over the one that
facilitates fluid application at the tool-chip interface and both these directions can
promote improvement in cutting performance. Attempts must be made to arrive at
a jet configuration which can facilitate fluid application at both these directions.
Finally the operating as well as the fluid application parameters are to be fine tuned
to make them more suitable for industrial applications.
A model is to be established to simulate hard milling with minimal fluid
application and an attempt must be made to develop a performance enhancer that
can further improve the cutting performance.
