No. 4, 1998 - Tribology in Industry

lnL
!8p:=lt'--_
-
'"-"r'
2'
or vaiues rcd t if the diagramg ir: Figilres 5 and 7,
'llhe r;r:;.; rii energies sperll on fricricn between
'rhe clearirg,
i-rc; anrl ihe machined piece, aud the energy of
irr,rrirrn beiv,':gn ihe rake face anci ihc chip, can be
ir ir:imined accore',ing to expression (Figure 8):
'1": '^-'. =' - | i '"-"'r-- |!.i';Lsq,'.(n!.p:i).:4 '':- .o-.fl.s9!.r
'=-'" -,, =l(trapt,a,tr) -
;;';,8;i
4", fir
-' : ''bi\/'))'6,('t) n
0,5
q
6
1,25
rvhere:
or by' using ciiagrams in Figures 12 ta i5.
As the total energy- A can be represented approximately
as the sum of energies of the internal and external frictions:
where:
. ) - sirt],
""'
Q=rr,c(:rtl'
cosy
A = Afi+ Ast
Arr=A'tiA"t
thus the ratio is:
t's! a nt A, ( t'tl A,, \
-::- - l,
,r, A, .1, _ A" I
\)
EXAMPLE: For the cLrtting,Jepth of n:0. 5 mm andthe
tool with the rake angle y=5", the clearing atgle a:6o,
and the rounding radius of the bladep 1=0.020 mm, and
for the chip slenderness ratio A=2.5,we have:
^
.a-L 1
V= o'2sszg
*=t,t,'
t=
ZU
!:igure 9- Diagr:ttlr lor detentinaiiott o! ilrc ralio betv'een
:!i enrry)' ccnsuttrcd on fricliort bi:Iv,cctl
the chip and tle rake lace and tlrc total
enetyl co,tsutned in ti:'e cuttitit pocess
Figure 11. Contact of tlrc hlaCe and tlrc active pan
o.f thc kto! cbaring fuce
A1
-.'.;
I
t--
I
I
.1,2C
I
. .1 q
li"iit
i-! i-:!
I!
L_
!
:
I
i
I
;--
I
'
t--
I
i
!
t_
t
t!
J0
2A
*{.1=t,i)y=const.
I
JU
v-- 'l,/
t/
)" = 0",'
r = lflo
I
40
I
50
j^ ].
OU
0
: 'qt,ta i ii. ):a.grr;stt for dtler:tiinatiott of tlrc rctio L>ef,vcur
!!.i: ei!e t-q.,' i't'tnsi;t;ic:i otr fiictiott ltaI*'ectt
t|rc chip and rhr nke face linl the tolal
.Jtet4' coir::!l,rttd ii't tltc culling prccess
Figure 12. Aaxiliary Juitction gt for deternination of tlte
ratio befpeen errctgies cortsunteri ott fiictktrt
betvteettlrc clearirg face and ilrc trwclrined
picce, and bctti'{:ett tlu: chip attd tlre rake face
;.'-r'lri,i ,3r, li; i;ttitistry- !'oiusre 2*, No. ,1, 1998.
131