No. 1, 1998 - Tribology in Industry

No. 1, 1998 - Tribology in Industry No. 1, 1998 - Tribology in Industry

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{rtcrial prclucral : l5 Cr08 K-70" For; i div. - ?0 N Avnrrry:0.3 nrnr.rot-l l, -' -6" v ( h.0rtit ) * 50 nnn . min-l |'tattritl sorla: SiAION gri Y--6" F*: t div. - 20 N Vittz-r: 30,1 m. nrin-l cr. - 60 For';1div.-4ON ,Lrirlru:irru: L5 nrnr r-0.Jmm - Expr'ii.rrtn lI E)pgicrd! I b Fig. 3. Erperintental cuwes obtained in stalic measuretnents in obliquc tuning of steels Avanco 0.2 nrfty'tr :FK:sB*38!iEi€rEF:FE Temps (0.001 s) Fig 4. Etptritrrcnta! curt'es oLttained dyuntic nlea^\urotrcnLr in oblique tunrittg of steels 1. - the friction coefficient on the flank sudace is assumed as known, it is approximately constant, with values behveen 0.1...1.9 [i3l; 2. - the values of the component (l7) on the flank surfa- .p LU sl arc r Fvncri U mentellrr rlot erminerl PL r rrrrLrrr(lrrj ur LUr lrrrrluu, /' "grvj r h.q €AY d /o- '-F-. 'f') .i't' / U Knowing the coefficientsA;, B;, C; and Nr1 (i=1, 2,3/, the friction force (F ) on the t-lank sur{ace or the friction coefficient p', and the components -Fo,,, Fr), Fo, experimentally obtainecl, after solving the systenr for one of twcr situations the components { F61 1 and F,y and the ratio between thern cun be calculated. sl'."- €r'd s-/."- \0, Iig 5. I'hysical-geotnalrical nrcdal for a cutlittg tool t2 TiiboktSyt irt iruhutry, Volunrc 20, No. l, 1998.

li Tool Charge amplifier typ€ 5001 (KArG) . ,1 * r x,'',F Fig. 6. Mcasurenrctrl, rccording and stalistical Ircottltctlt oJ'ilala clmitt 4. EXPERIMENTAL RESUI,TS. 4.1. Machining conditions In order to determine the friction force and the friction coefficient on the flank surface, tests were carried out in cylindrical external oblique turning, using different cutting speeds [3, 4]. The experinrents were made on tt modified lathe, with a 16 KW engine and an electronic variator for the rotation. The workpiece had a disk shape, mounted between chuck and dead centle, made fronl OLC 15 steel. Ttie tool used was a mineral-ceramic one (SiAlON CC 680 E), type SNUN, rvith the geometry k=70, y=6, 7:6, a:6.The measurement chain used was composed of a piezo-electrical clynamometer type 9527 A (I{istler), a charge amplifier, a recording apparatus and the PC computer. 4.2. Experimental results and interpretation =10 I a i I -r.-l i,l- \a r --,! -!-l l-a-F.v-loljm/tu | @ ]-^-F.e-re5.aEi l' I wdsidorcli I -t -..ti t !--'' i2 i . ] ) . I I I, -a-F.r.otns,/rer i -^- ts. r- 0.r nn' r tu' I wid sElol-c {51 IIIl +. -'-]_' -^*i--^ =z: --t' The experimental values obtained for the friction tbrce and friction coefficient on the flank surface as function of the cutting parameters allow to design the variation cuweslto=f(t,), ,u,.:f(f) ancl p,,--f(a) in figures 7,8,9. Analysis of these value-shows that force and the friction coefficient on the flank surface depend on the cutting parameters (rl .f c). For speeds vp to 250 rnlmirt, tlte temperature rises to 4()ffC, the mechanical characteristics r,,f the work-material are less affectecl. -40 I i=-;:,;;ii";.-l I-^-t.'1e1.r$/.MI *'61srel ol! 4J I I ,l)-/ I -_'--l- ,.'/'t' -za L- CulurS dcp{h. mm c l-ig. 7. Variatiatt oJ tlrc fiictiott Jor

li<br />

Tool<br />

Charge<br />

amplifier<br />

typ€ 5001<br />

(KArG)<br />

. ,1 *<br />

r x,'',F<br />

Fig. 6. Mcasurenrctrl, rccord<strong>in</strong>g and stalistical Ircottltctlt oJ'ilala clmitt<br />

4. EXPERIMENTAL RESUI,TS.<br />

4.1. Mach<strong>in</strong><strong>in</strong>g conditions<br />

In order to determ<strong>in</strong>e the friction force and the friction<br />

coefficient on the flank surface, tests were carried out <strong>in</strong><br />

cyl<strong>in</strong>drical external oblique turn<strong>in</strong>g, us<strong>in</strong>g different cutt<strong>in</strong>g<br />

speeds [3, 4]. The exper<strong>in</strong>rents were made on tt<br />

modified lathe, with a 16 KW eng<strong>in</strong>e and an electronic<br />

variator for the rotation. The workpiece had a disk shape,<br />

mounted between chuck and dead centle, made fronl<br />

OLC 15 steel. Ttie tool used was a m<strong>in</strong>eral-ceramic one<br />

(SiAlON CC 680 E), type SNUN, rvith the geometry<br />

k=70, y=6, 7:6, a:6.The measurement cha<strong>in</strong> used was<br />

composed of a piezo-electrical clynamometer type 9527 A<br />

(I{istler), a charge amplifier, a record<strong>in</strong>g apparatus and<br />

the PC computer.<br />

4.2. Experimental results and <strong>in</strong>terpretation<br />

=10<br />

I<br />

a<br />

i<br />

I<br />

-r.-l<br />

i,l-<br />

\a<br />

r --,!<br />

-!-l<br />

l-a-F.v-loljm/tu<br />

|<br />

@<br />

]-^-F.e-re5.aEi l'<br />

I wdsidorcli I<br />

-t<br />

-..ti<br />

t<br />

!--''<br />

i2<br />

i<br />

.<br />

]<br />

) . I I I,<br />

-a-F.r.otns,/rer i<br />

-^- ts. r- 0.r nn' r tu' I<br />

wid sElol-c {51<br />

IIIl<br />

+. -'-]_'<br />

-^*i--^<br />

=z:<br />

--t'<br />

The experimental values obta<strong>in</strong>ed for the friction tbrce<br />

and friction coefficient on the flank surface as function<br />

of the cutt<strong>in</strong>g parameters allow to design the variation<br />

cuweslto=f(t,), ,u,.:f(f) ancl p,,--f(a) <strong>in</strong> figures 7,8,9.<br />

Analysis of these value-shows that force and the friction<br />

coefficient on the flank surface depend on the cutt<strong>in</strong>g<br />

parameters (rl .f c). For speeds vp to 250 rnlmirt, tlte<br />

temperature rises to 4()ffC, the mechanical characteristics<br />

r,,f the work-material are less affectecl.<br />

-40<br />

I<br />

i=-;:,;;ii";.-l<br />

I-^-t.'1e1.r$/.MI<br />

*'61srel ol! 4J I<br />

I<br />

,l)-/<br />

I -_'--l-<br />

,.'/'t'<br />

-za<br />

L-<br />

CulurS dcp{h. mm<br />

c<br />

l-ig. 7. Variatiatt oJ tlrc fiictiott Jor

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