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Title Material Behavior in Grinding with Single Modified Tool

Author(s) Kita, Yoshihiro; Ido, Mamoru

Editor(s)

CitationBulletin of University of Osaka Prefecture. Series A, Engineering and nat

ural sciences. 1973, 21(2), p.175-186

Issue Date 1973-03-31

URL http://hdl.handle.net/10466/8253

Rights

･175

Material Behavior in Grinding with Single

Modified Tool

Yoshihiro KiTA* and Mamoru IDo*

(Reseived November 15, 1972)

The grinding wheel has a numerous cutting edge in that surface. But for the sake

of analysing the action of abrasive grain. the phenomena of swell out residuals caused

by each cutting edge must be clarified. In order to investigate the materia! behavior

by abrasive grains, cutting test was perfbrmed using a modified cuttlng edge which was

deterrnined statistically. In this experiment the conical tool was used and profile of

groove produced by cutting perfbrmance was compared with that of cutting edge.

Mereover the infiuence of cutting conditions such as depth of cut, apex angle of cutting

edge and grinding fiuid on the swell out residual was investigated.

As a result, it was fbund that the profi!e and the roughness of cutting edge had

been transfered fairly well to the cutting gnoove, and the volume of 50.v70% to be cut

geometrica!ly remained as swell out residual at each side of groove. The height of swe!1

out residual was about 60% of depth of cut and the breadth of swell out residual was about

120% of cutting breadth, and its degree was not vaTied by changing the depth of cut･ But

the degree of swell out residua! was changed with different apex angle of cutting edge

and showed a smal! change by using grinding fluid. The flow of rnaterial in the cutting

direction was applicab!e large. These phenomena had significant difrerence from that of

turning, and such phenomena must play a great part for the surface forming of material

in grinding process.

1. Introduction

The mechanism of the grinding process is very complicate because of random

grinding tools and of complicate wheel structure. The number, the dimension and

the geometry of the cutting edge cannot be described complehensively by a

deterministic model. Besides, high cuttnig speed, small depth of cut, specific wear

behavior of cutting edge and high momentaly temperatures make more difeicult to

analyse the grinding mechanism. For above reasons, we cannot explain the

mechanism of metal by cutting elements of grinding wheel.

In order to make the grinding operation more usefu1 and more effective ways

of machining, many problems concerning grinding performance must be solved･ So

an investigation of fundamental grinding operation becomes more improtant. And

to get the information of cutting phenomena by means of single abrasive grain

･ will much contribute to analyse the mechanism of grinding process.

This paper concerns with the material behavior investigated by using modified

cutting edge.

* Department of Mechariical Engineering, Cbllege of Engineering.

276 Y. KrTA and M. IDo 2. Experimental Procedure

2-1. Cutting apparatus The experiment was proceeded by using surfa¢e grihding machine (OKAMOTO

CO. PSG-IAE). The basic apparatus consisted of a single modified cutting edge

fastened to an aluminum wheel mounted on a grinding wheel spindle is shown in

Fig. 1.

O cutting tool

f"

`i:

2s.4

@ tool holdef

li, ll

l

,

m

sss)lj

,

3 whbe1

Fig. 1. Cutting apparatus

The cuting edge operates at nominal grinding speeds on a workpiece mounted

on the surface grinding machine tab!e having some cross feed. In such way only

one cut groove with swell out residual at each side was produced.

2-2. The modified cutting edge and the specimen

An investigation of the profile of abrasive cutting edge had been caried out from

all approachesi)2) such as measuring the trace after scratching the material or determ-

ing the angle ofcutting edge from tangential and normal cutting forces or observing

the shape of cutting edge directly with microscope. From the experimental data

in the past3), the shape of cutting edge seems to be conical which has the apex

angle of 1200N1600 and in this experiment the conical edge having the apex angle

of 1000-v1600 was used: '

The materials of specimen and cutting edges used were listed in Table 1.

2-3. The measurrnent of degree of replication between cutting edge and

grooved profiIe

In order to have the information how much the.cutting edge prorne was

replicated to the groove, the profiles of cutting edge and groove were compared

with each other. For this measurment, the profile ofcutting edge had been

photographed before cutting was performed and it was enlarged as large as 500

times of its actual size. Then the profile of the groove was recorded by Talysurf

Mhterial Behavior in, Grinding with SVhgle Mbdijied 7lool

-.,. Table･ 1. Specimens and cutting tools

(a)' Msterials of Speeirnen

W7

Material.Heattreatmentannealed

intheVacuumHardness(Hv)

S15CS55CAI

Cu

gooec6omin.7goec6omin.

350℃30min.500℃30min.

102

,185

･32

44

(b) Cutting tgols

Shape Conical

Apexanglee 100"--1600

Cuttingtool

materiaIs

Diamond.

Cementeddarbide.

Highspeedsteel

Abrasivegrain2A

IV at the magnification as large as 500 times of its actual size in both horizontal

and vartical direction.

And also the roughness of the flank of the cutting edge and the groove were

measured by Talysurf IV and compared with each other.

2-4. The measurment of swell out residuals

The swell out residual at each side of the groove produced by cutting is

shown schematically in Fig. 2. To represent the extent of defbrmation, the height

and the breadth of swell out residual were measured from the profile, and fo11owing

two coethicients were denoted.

z y

y

x Xl

L

h

la

£ bu

.ha

e

02 x va 1 1 x-x

Fig. 2. Swell out residual produced by cutting

Hight coeMcient of swell out residual rh :

Breadth coethcient of swell out residual rb :

The profile of the groove was recorded at the

direction. To measure the profile at aceurately spaced

the groove, the specimen was set on the cross

dx

sectlon

and measured terms

rh = (h, + h,) 12d

rb == (bi + b2) !2be

center of groove in the cutting

section along the length of ,

table which could be moved,

178 Y. KiTA and M. IDoaccurately by the screw with dial indicator. By summing those all profiles, the

volume of swell out residuai can be caluculated and also the volume which is to

,be removed by the cutting edge geometrically can be obtained as following.

Now, we set the Z-coordinate along the length of groove and describe the

area of profile of groove as Wlx and the area of swell out tesidual as W>z. Then

VVI2-Il4iz represents the area of material removed in that section and denoted

(VVIx-I4,Za)IWIz to removal ratio and also %z/IJVIx to residual ratio. And describing

the distance between adjacent two sections as dZi ll2>adZ represents the volume of

swell out residual at that sections. So the total volume of swell out residual

around thLe groove is .:LL.i W2zdZ and total volume of the groove to be cutLis .>L:..],VVIzdZ

So that .Z.-,{ (Wlz- W>a) 1.Wlz} repre.sents the removal volume ratio and .Z.-, (VVLz/Wl.)

represents the rsidual volume ratio respectively. In this experiment dZ was taken

as 250pt and the relation between the length and the depth ofcut is listed intable 2.

' , Table 2. The relation between the depth of cut and the

!ength of groove

･ 3. Results and Discussion tt3-1. The degree of replication between cutting edge and groove profile.

To represent the degree of rep!ication, the angle of profile of cutting edge e

and the angle of groove e' were measured and compared with each other. Then

the ratio e'/e was caluculated and p!otted fbr the various depth of cut (d) in Fig.

3. Fig. 3 (a) shows the result for the materials Al, S15C, S55C taking the apex

angle of cutting edge as patameter. Fig. 3 (b) shows the effect of speed on the

1-degree of replication and Fig. 3 (c) is the similar exprimental result when the

diamond cutting edge is used. According to these results, we can realize easily

that the profile of cufting edge is replicated fairly well to the groove.

Then the replication of surface roughness of cutting edge on the groove was

investigated and its results are shown in Table 3. Table 3 (a) is the results tested

by various cutting tool materials such as Cemented carbide, High speed steel and

Abrasive grain (2A). And Table 3 (b) is the results examined in various cutting

speeds such as 1700, 600, 400 and 240 m/min.

From these results it becomes clear that the surface roughness of cut groove is

the same order as the roughness of cutting edge in perpendicular to the cutting

direction but it is very small in the cutting direction. And there is a tendency

that the surface roughness is smaller for the hard material than the softer one.

Thedepthofcut(d)pt 10 20 30 40 50

Thelengthofgroove(L)mm 2,5 3.6 4.4 5.0 5.6

Mlriterinl Behavior in orinding wih'ic sttrgle A`fodZtied 7bel 'tro

1.2

Ri.ott Lct' " ' '

O. 8 o

1. 2

as'is 10

O. 8 o 1,. 2

cts.

NLO " O.8 o

'

S15C

tttt ttt .ttt-tt - J'.. ;tt.t.. t.t. tt. /ttt .t

10 2Q･ id(pt).

30

r･-1

S55C

..}

tt-

'

10 20d(pt)

30

(a) Thg, etfqct g.f .. materials tQ'.be cut. ..

' V-t1700mhnitu

40 cemented carbide tool

' o esi 160q･ '

e ez l4oo ･･ o B,Ei li20" . ,)

4o O e= looo .

Al

10 20d(pt)-

30 40

1. 2

"is'1. 0

o. 8o

ct, 1･2

tsqb 1.0

O.8 o

1. ･2

"N1.0" O. 8

1.2cb 'li.o

' O.8 o

=･- .ttt

S15C'.t

'''

'

10 20･d(pt)

･ 30 40

'

S55C

10 20{ ･ ' 30 ttt t t.ttd(pt)･ 1.

'40

It tt

sls6

o1020d(.).39 40'5Q'

tt

･S55C

t

(b) The:e.ffegt.p.f,--.,

cntting speed.:' ...'

' o V = 1700mimini･ .

e .'V .- 600 m/inin.

V =,oo. Omhnin. ..

o V = 200 mimin.

-/.' l ",, l ' ･･ :/'Cc5 The effect of

cutting edge matetial

, V= 17POmhnin.

diamond too1 '

O e; 16oe e e=.14oe o ei= IQoe

10 20 30 4Q 510 1. d(") .. ･i Fig. 3. degree of replication between cuttihg edge and groove profile . ' /-

3-2. The swell out residuals

The coeficient of swell out residual was caluculated and listed in Table 4,andi

the results are shown in Fig. 4. rh, rb and r'h, r'b are the coethcients inithe

'conditions of dry and wet grinding.rcspectively, This rcs.ult indicate that the s .eff;ect of depth of cut on the gpethciehi･' i=s 'a little. . ' ''' ･

To investigate the profile. o/f swell out residual more detail similar experiments

were carried out for different ･materials 'in various' depthes of cut.

For normarizing the size of swell out residual the profile was expressed in the

two-dimensonal standerd coordinate X, Y:that is' '

X =xlb.e where x is abscissa represents the distance from the center of groove

and b, is the breadth of cutting edge at the heightd '･ Y=orld where y is ordinate represents the height of swell out residual and d

is the depth of cut. ･

-1eo

(a) The effec't

Y; K!zz ptrd- M. Ibo.

Table 3. The replication of surface roughness

of cutting .mater'ial

Surfaeercnlglmessof

grooveS15CRmaxIt

Surfaceroughnessof.

grooveS55CRmaxFtCuttingedge

e=-14oo

Sur.face

roghness..Qf

cuttingedge,

(Rmax)g

Parallpltocuttmgdirection'

Rectangular.tocuttmgdirection Parallglto

cuttmgdirection

Rectangular.tocuttmg

direction

.Cemented

caride(G2)

Highspeedsteel

Abrasivegrain(2A)

O.34

O.45

O.38

O.08

O.05

O.10

O.30

O.52

O.40

O.05

e.so

O.07

O.20

O.47

O.30

(6) The effect of cutt'm' g speed

Surfaceroughnessofgroove

CuttingedgeCuttingspeed

Vmlm'inParallelto

cuttingdirectionRectangularto

cuttingdirectiontt

Abrasive

grain

e-14oe

RmaxO.38pt

1700

600

400

240

O.07

O.07

O.09

O.10

O.30

O.31

O.32･

O.42

Table 4. The height coeMcient in dry ('rh) and wet (rh') condition

'

Fig. 5 shows the swell out residuals represnted using X-Y coordinate, and it is

evident that the profile of swell out resklual produced by the same cutting edge

are the same although the depth of cut is diflbrent. But as shown in Fig. 4 the

･profile of swell out residual is rnore influenced by the cutting edge having larger

apex angle. And at the region of small apex angle it is much influenced by the

'S55C Al Cu

eo dpt 7h 7fi 7h '7fi .7h 7h'

10 O.65 O.49 O.61 O.53 O.56 O.51

100 20 O.68 O.51 O.65 O.55 O.61 O.53

30 O.64･ O.54 O.60 O.53 O.61 e.57

10 O.64 O.'54 O.67 O.60 O.58 O.54

120 20 O.64 O.54 O.59 O.50 ･O.64 O.62

30 O.65 O.57 O.60 O.53 O`63 O.60'

10 O.60 O.58 O.57 O.51 O.39 O.35.

140 20O.60l

O.55 O.61 O.54 O.39 O.3430 O.67 O.61 O.64 O.55 O.42 O.39

'

10 O.47 O.43 O.45 O.42 O.48 O.46

16e ee O.52 O.49 o." O.43 O.37 O.36''

30 O.49 O.44 O.'35 O.35. O.31 O.30

-aj

Nft

1,O

'ct5･

o o

Fig. 4.

1. 0

N

o

1.0

N

o

1.0

N

p

zo

N

o

dry1vetd=lopteAd=120AO.tsd=so"oA

/ -L-.- -"----"-1-'~"-'

' NN

(a

The

Mbten'al Bchaviar in (]rimling with Si,rgle MbdViee Ibel 18S

l.5

g

1.5 wet

d=le"e. -£ d;.co:.O-.in: .f,7fff X

･ 1.0

). Tlje height coefficient, ･< rh, ?th･ and e) '

coeMcient of swell out residual in -dry and wet grinding (V== 1700 m/min. S55C)

{a.) Cu e= 127e

e d= 4o pt O d= 34# Od=20pt e d== 13"

x LO l.5 2.0 (b) Al e= lslo

e d-- 3s pt O d= 17pt

dry

d=le#e-d;20.#O-.-=30re---

"Nt.1./

>s"!N-`NNe･'

Sliib`N.-.--'

O. 5

O. 5 1.Q L5

Cc) S55C o = 1,ooe

e d= 26 pt

Od=44"

2. 0 X

X

Fig.5. Smell out coordinate

residuals in X-Y(V ma 1700 m/min.)

O. 5 1.0 1.5

(d) S55C

e o

e== 16oe

d== 9"

d== 20"

2. 0

X

't

O.5 1.0 l.5 Z･ o

'182 ･ Y. KrrA and M. IDogrinding fluid. In,Fig. 4 the 'coeMcient of rn decrease progrssively as apex angle

increase from 100e to 1400 and it decrease abruptly at the apex angle between

1400-1600 in dry grinding. On"the other had, in wet grinding tb.e coeMcient

increase as.the apex angle between 1200"vl400.but it chainges the trend and

g:2geawSeerghaenaaPiyesXeda:sglfai?oewtX.negeP i400'yi600･ inorder to make.ciear this tenq,.p, cy

f"s Fig. 6 (a) show the differerce of the coeMcient of swell out residual (rh>"'

between dry and wet grinding on Al, Cu, S55C and the relation among rhi.pa. e.;

(apex angle of cutting edge) are represented. We can recognize that the diffbrence

of coeMcient (rh) increases as apex angle of cutting edge becomes small and this

tt ttt

'

O.2

£O.1

o 100 1eo ･140 1oo (t7)e (a) The relation hetween ili and e O. 3

O. 2 s' x･ R:

O. 1

o, '100 120 140 1oo <e)o (b) The relation hetween.I'Ulva and e O.2

R.

SO.1 ' N lt . "

NstO , l /1･

--o.i 1 110 (e)130 150 r (c) The ratid dn,fdad7i:!de and e i,

Fig. 6. The effect of fluid on the swell out residual (V=17oo mlmin.)

Il/

OS55C"AlACU

･I･

-/- L--- --.N <

"A- N

Mif20

--x- .t. .N

30

20 tsk"X

--10

;.--. -- -L--

'. 10

't-.

ts

d=10p20"30ptS55CQOO

AIaoCu･A･A

-×'x. '-

- .

-..---

N.N"-.

-..-...

'

S55Cdrywetd=lopteAd=20ptOLd==30pt.OA

,

tttt

v-t'/t

'?r==-t-bec".

Mdten'al Behavinr in Grihcting with Single MbdZtied 7'bol 183

tendency. is significant on S55C. Considering that the m4terial flows along the

cutting edge face, it is intuitive that the height of swell out resldual decrease

geometrically as the apex angle of cutting adge increases although the volume to

be swollen out is equall and conseqently the 'diflbrence of cdeM'cient (rh) will

decreases as the apex angle of cutting edge increases. So the ratio of rh to rh

and also the derivative of rh or r'h with respect to appex angle (drh/Ae, ztrh'IAe)

were calculated fbr each apex angle, and their results are schown in Fig. 6 (b)

and (c). According to Fig. 6 (b) theldiffbrences of the coeMcient of swell oUt

residual between rh and rh' are S55C, Al, Cu in the order of decreasing with each

other except the region of large apex angle of cutting edge. . Taking the fact that the terr}Per,ature of grinding point of cutting edge reaches

10000C into consideration, it is int6rest that the order of S55C, Al, Cu is as reverse

order of thermal conductivity, that is O.18, O.53 and O.94 (cal. cm"t sec"" OC"t) for

eagh other. Estimating the heat produced by friction according to equation

led by BOWDEN5), frictional heart is S55C, Al, Cu in the decreasing order. These

results mean that the grinding fluid give's the significant effect on the process of

producing swell out residualls. . , Fig. 6 (c) shows the efuct of apex angle of cutting edge on the swel! out residual.

It is evident that the variation of swell out residual is signiMcant at 1500 of apex

angle of cutting edge and this means that the height of swell out "residual decreses

abruptly during the apex angle increases from 140e to 1600. Mulhearn6) studied

the deformation of material by indentation test using conical and another type of

indenter, and reported that the mechanism of the deformation was the cutting at

small apex angle of indenter but it chainged to compression mechanism at the apex

angle beyond 1360.

So in the machining by abrasive grains which have large apex angle, the same

phenomina as mentioned above must be'appear so that the flow of materia!

should be much in the grinding.' ' . '' The breadth coeMcient of swell out residual is not so diflbrent whether the

cutting fluid is used or not used. And it is large at large at large apex angle of

cutting edge.

Fig. 7 indicates the variation of swell out residua! along the length of groove.

The abscissa is normarized by taking Z/L (Z:the distance from the beginning of

the groove in longitudinal direction L: the length of the groove). Fig. 7 (a) is

the result fbr diflbrent apex angle in the same depth of cut and Fig. 7 (b) is the

result for different depth of cut by the cutting edges having the same apex angle.

From this result it is evident that the swell out residual increases in the latter half

of the groove and the ratio of sweli out residual reaches about 200 % at the end.

As the apex angle of cutting edge increases, such trend becomes more signiMcant

and the tendency is invariable although the depth of cut chainged.

Fig. 8 shows the relation between remova} ratio (Wiz-W2a)/Wiz and depthof cut. The results stands fbr that removal ratio is rather small as 20-50 % and

184

A"v

Eg

am

20Q

150

1oo

50

o

e

Y. Ki rA and M. Ico

oe=1oo'

e-e=14ee

.

o

o

aso

,A 2QeX."N

v

EE

O O.2 O.4 O.6 O.8 1.0 ZIL(a)The effect of e･on removal ratia(d='ggA)

Fig. 7. The variation of residual ratio along

150･

1co

5Q

d

the

4pt

Od=14"'

ed=28#'Od=44B,

o e

.'

e 'e. 2' or4 o.6

ZIL(b)The effect of depth of

groove (V=17oo mlmin.

O. 8'

cut( e =

S55C)

1.0

14o")

,

'

a=N>sL

g

Fig. 8.

60

50

40

30

ee

10

o

ee

o oe e

o o'

oQ

otto

o

oe==16ooee=ls2"oe=14oe

o

The effect

ratio (V

10 20 30 40 crd(.pt)

of apex angle of cutting edge

=1700 mlmin. S55C cemented

50

O. 4

e. s

O. 6

O. 7

O. 8

O. 9

1. 0

gek

on the removalcarbide tool)

AYN>sL

E

.. Fig.

･40

so

20

10

o

O･ 40 80 120 R(pt)

9. The eflbct of radius (R) on the

d==20pt S55C cemented carbide

o

o

16e 200

removal ratio (V==tool e==ls4o)

240

O. 6

O. 7

O.8 S

g

O. 9

LO

1 7oo m/min.

Mbterial Behavior in Gbuinding evith Siagle MbdZtied 7lool 185

almost of material remains as swell out resldual at each side of the groove The

effect of radious of cutting cdge (R) on the removal ratko was investigated and its

result is shown in Fig. 9. In the limit ef this experiment (d=20st, R==10"v200pt),

the removal ratio decreases as the radious of cutting edge increases. In another

words swell out residual becomes large by daN cutting edges, and this means ifthe

radious of cutting edge reaches characteristic value by the cause of wear, all mate-

rial to be cut remains as sw,ell out residual. In the agtual grinding process the

geastitdeunaeidmduUsiti bCeUtitoi?.g edges piay a great part, and consc¢quentiy the swep out

' ' Fig. 10 represents the effect of inteerencg angle (a) on the removal ratio andthis result indicates that the removal ratio is larger when cuttihg is performed at

smaller interference angle and it is not so infiuenced by the depth of cut.

60 O.4 A "60 O.5 = it･ 40 O.6 S･30 O.7S N- 2o o.s v

-10 O.9 O LO 'O 10 '20 ,30 40 50 d(p)

Fig. 10. The effect of interference angle on the removal ratio (V== !700 mlmin. S55C cemented cabride tool e= 1540)

To promoting grindining machinings, the most effective condition must be

constructed and this is a important subject for a future study. This experiment

will be usefu1 in solving iater problems.

4. Conclusion

From this basic expreiment, fbllowings were made clear

l. The profile and the roughness of cutting edge are replicated fairly wel! to

the cut groove.

2. The swell out residuals are influenced by using grinding fluid significuntly at

the apex angle of cutting edge between 1000tvl400. But at the larger apex angle

of cutting edge beyond 1400, the deformation by compressign mechanism play a

great role in the process of producing swell out residuals.

3. The depth of cut has not significant aflbct on the swe!1 out residuals. The

height coethcients of swell out residual are O.4-vO.7 and the breadth coeMcients are

1.0N2.0 in the limit of this experiment on Al, Cu and S55C.

4. The removal ratio is 20Ay50% and almost of material remains as swell out

residual at each side of the groove. And its ratio is afl}ected by the radious of

o o

o

o

o.

ge

o oole-e

oI

oe

ea=3eOa=13oOa=230

･186 Y. KiTA and M. IDo

cutting edge and the interference angle.

5. In the cutting by abrasive grain, the material fiow into cutting direction is

signficant and swell out residual becomes large at the lattcr half of the groove.

Referenees

1) K. Okamura, Jour. Soc, Prec. Mech. Japan, 27, 333 (1961).

2) A. Kobayashi, Jour. Soa Prec. Mech. Japan, 24, 95 (1950).

3) M.' Matui, Jcrur. Sci. Mach. Japan, 2eq 1611 (l971).

4) J. O. Oatwater and M. C. Show, Tran. ASME, U, 73 (1952).5) E P. Bowden and O. Tabor, The friction and lubrication of Solids, p. 31 Oxfbrd (1954).

6) T. O. Mulhearn, Jour. Mech. Pech. Phys. Solid, 7, 85 (1959).