Note: Descriptions are shown in the official language in which they were submitted.
Field o~ the Art
The i~ve~tion relates to the metal macnining by cutt-
ing~ and more particularly, to cutting members o~ rotary
tools.
The inve~tion may be most advantageously used in ma-
chining packed paper rolls of supercalenders at pulp a~d
papar-making factorie~.
'~he inve~tion ma~ al~o be used in machinin~ metals
and their alloys and also f or machining no~metals.
Back~round o~ the Invention
The clo~est prior art o~ the inve~tion is a cutti~
member of a rotary tool disclosed in the book by ~.G. Eo-
novalov, V.A. Sidorenkol A~V. Sous', 'tAdvanced Systems
~or Rotar~ Metal Cutting", Nauka i tekhnika Publishing
House 9 Mins~, 1972, p. 193, Fig. 79 e (in Russian).
The prlor art cutting member o~ a ro-tary tool compris-
e~ a rin~ having the outer periphery i~ the form of a bo
dy o~ revolution and end ~ace9 of which one ~unctions
a~ a mou~ting base and the ot~er, opposite end face, de-
fines a cutting edge.
Duri~ the machini~ wit~ t~e prior art cutting member
the re~ultant cutting force (mainly its radial component)
cause~ a radial de~ormatio~ o~ the cutting mem~er which
propagates on either side ~rom the poi~t o~ contact o~ the
cutti~g member with a workpiece. Since the radial rigidi-
ty o.~ thfl cutting member, whîch is determined by the ring
thicknes~, remai~ -the same along the perimeter, the ela-
stic deformations propagate symmetricall~ with respect
to the point o~ co~tact of the cutting member and the
workpiece and are directed toward one another along the
perimeter of the ring. ~he ri~ ~hickness means the di~-
~erence betwee~ the outside and inside diameters o~ the
rin~ in o~e and the same cross-seotion. Owing to a conti-
nuous rotation o~ the cuttin~ member durin~ the machining
and i~ viow o~ the permane~tly acting cutting ~orce, its
elastic deformation also occurs continuously and causes
the development of ~orced (~undamental) oscillatio~s o~
the cutting member whioh are also directed toward one ano-
ther along the perimeter o~ tha ring. The fundamental fre-
quency o~ the cutting member is always the same owing to
the constant rigidity o~ the ring so that the cutting mem-
ber is broken owing to the coincidence of fundamental fre-
~ue~cies (i.e. a resonance takas place). In order to pre-
vent the cutting member o~ such type from being broken,
its tnick~ess is to be increased thus bxinging about a
greater metal consumption and an increase in the co~sump~
tio~ o~ tool metal.
Summary of the Inve~tion
It is the mai~ objeot o~ the inve~tio~ bO provide a
cutting member which e~hibits a longer li~e oompared to
~imilar cut~in~ members us~d for the same pur~ose,
Another o`oject o~ the invention is to pxovide a cutt-
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ing me~ber whic~ requires less metal ~or its manufacture
compared to cutting members of this -type usecl for the same
purpose~
These a~d other objects are accomplished by t~at a
cutting member of a rotary tool, comprising a ri~g having
an ou-ker periphery in ~he form o~ a body of revolution
and end ~aces of which o~e end face functions as a mount-
ing base and the other end face opposite thereto de~ine~
a cu~ting edge, according to the i~ventio~, is made with
a radial rigidit~ var~in~ along the perimeter of the ring.
I~ ~achini~g with the cutting member of a rotar~ tool
having a radial rigidity varying along t~e perimeter o~ the
cutting member the resultant cutting ~orce also cau~es the
.radial elastic de~ormation o~ the rotary tool which pro-
pagates o~ either side from the point of contact o~ the
cutting member with a ~rorkpiece, Owing -to the non-uni~orm
radial rigidity of the cutti~g member, -the elastic defor~
mations propagate along its perimeter tow~rd one another
asymmetrically with respect to the point of contact of the
cuttin~ membe~ with t~e workpiece thus resulting in the de-
velopme~t of forced oscillations of the cuttin~ member,
i.e. o~ ~he ring. ~he ~requency of thess oscillatio~ vary.
'~a oscillatio~s propagatin~ alon~ t~e perimeter of the
ri~ toward one a~other dimin~h one another. I~ machin-
ing with ~uch cutti~g member, a coincidence of ~requencies
o~ oscillatio~s of its indi,vidual parts~ iOe. resonance
causing the breaklng of the cutting member~ is eliminated.
Owing to the elimination o~ the resonanc~ phenomeno~, the
8~E~3
SerYice life o~ the cutting member is prolo~ged a~d the
metal co~sumption for its manu~acture can be reduced.
~ he radial rigidity may be made varying along the
perimeter of the ring by varying the ring thickness, the
minimum thickness value amin being deterrnined by the
formula:
amin. ~ 5) ~ ~0.1 ~ mm,
wherein D is the outside diameter o~ the ring in mm~
In this manner, by increasing or reducing the ri~
thickness in a desired amount, a respective increase or
decrease in its radial riOidity ma~ be obtained. The above-
given relationship of the ~inimum ring thickness versus
the outside diameter o~ the cutti~g member makes it pos-
sible to determine the cutting ~orce. It is not recommend-
ed to choose the minimum thickness of -the riag smaller
t~an that mentio~ed above as it may result in the cu-tting
member being broken under the ac-tion o~ cutting forces.
In ca~e the ri~ thickness i~ greater t~an that de~ermined
by the above ~ormula, only an increase in the consumption
~ the ~ool metal a~d metal consumptio~ for the ma~ufac~
ture can take place~ but the life o~ the cutting member
cannot be improved, while the labour e~ort for re ~harp-
ening o~ the tool increases.
It is ver~ convenient from the manu~acturing stand-
point to provide varying radlal rigidi~y along the peri-
meter o~ the ri~g by making the outer and inner sur~aces o~
the ring eccentrical with respect to one another~
--5--
The provi~ion of the inner surface o~ the rin~ arra~g-
ed eccentrieally with respect to the outer sur~ace in the
direction of the of~set o~ the eccentricity makes it pos-
sible to have minimum thick~ess of the ring. It is to be
understood that t~e ring thic~ness i~ maximum in the direc-
tion opposite to the offset oP the eceen~ricity. T~e tran-
sition from the minimum ring thickness -to the maximum thick-
ness i5 made gradually, with a monotonous increase. In ma-
chining with sueh cutting member the elastic de~ormation
also vari~s monotonously. Maximum value of the elastic de-
~ormation occurs at -the point of minimum rigidit~, and v~i,-
ce ver~a. This cause~ the appeara~ee of forced (~u~dament-
al) oscillations o~ t~e ring the ~requency o~ which varies,
i~e. the possibility o~ coineidence of the ~orced (funda-
mental) ~requencies of the ring is eliminated so that the
durability of the cuttlng member is i~proved and metal con-
sumption for its manu~acture is reduced.
The radial rigidity may be made varying along the peri-
m~ter o~ the ring by making its inner sur~ace in the ~orm
of a~ ellipseO
Sueh eutti~g member has two portion~ with minimum ra-
dial rigidity whieh are disposed symm~trically with res-
peet to one another in the plane e~tendi~ throu~h t~e ma-
jor axis o~ the ellip~e~ Two portions with maximum radial
ri~ldity are also disposed symmetrieally wi~h respeet to
one another in the plane extendin~ -through the mi~or axis
oP the ellipse. During maehining, maximum deformation of
-6-
the cutti~g member occurs duri~g one revolutio~ about its
axis in the zo~es of its minimum rigidity and minimum de-
form~tion occurs also in the two zones of its ma~imum ra-
dial rigidity. The time o~ variation and mutual diminish-
in~ of ~re~u,~ncy o~ ~undamental oscillations of such cutt-
ing member during one revolution thereof is reduced twice
compared to the cut-ti~g member having eccentric outer a~d
inner ~ur~aces, i.e. having only one portion o~ minimum
a~d o~e portion o~ maximum ri~idity. Thi~ construction of
the cutting member also improves its durability. The fre-
quencies of ~orced (fundamental) oscillations o~ the ring
during machini~g vary a~d mutually dimini~h one another
every one ~ourth of its revolution. ~he time needed for va-
riation and mutual diminishing o~ ~re~uencies of ~orced os-
cillations of such CUbti~g member dul~ing one revolution abo-
ut its a~is is twice as ~hort as for the cutting member hav~
ing only one portion o~ minimum and one portion of ma~imum
rigidity. Such cut-ting member can be very ad~antageous for
machining sur~aces with an uneven allowance.
A~ annular radial projection is pre~erably provided on
the i~ner surf~ce o~ the ring adjacent to i~s base.
~ he axial elastic de~ormation o~ the cutting member
is also non uniform owing to it9 varying radial rigidity.
It is at its minimu~ at points o~ ma~imum radial rigidity,
and YiCe ~er~a~ As the elastic de~ormation of the ring dur-
ing the machiniQg, which is due to the a~ial cutting force,
i~ direct~d awa~ ~rom the cutti~ edge to~ard the mounting
--7--
;
;
~5~
base, i.e. axially along t~e ri~g, forced (~undamental)
axial oscillations o~ the ri~a are caused under impact
loads, the frequency of -these oscillations being also no~-
uniform along the perimeter of the mounting base. There-
~ore 7 the axial force applied for ~ixing -the cutting memb-
er along the tool axis is also non-unifor~ during machin-
ing and varies along the perimeter of the mounting base.
I~ order to provide for a substantial reduction or elimi-
nation o~ the negative e~ect of no~-uni~orm forced (~un-
dame~tal oscillations o~ the rin~ on its mounting base,
an annular radial projèction is preferably provided on the
i~ner surface o~ the ring~ adjacent to its base. In the
zone o~ the projection the ri~g ha~ a thickness which is
greater than the ring thickness so that it9 radial rigidi-
ty is also greater~ Therefore, the ela~tic deformation of
the ring u~der the action o~ axial cutti~ ~orce is sub-
stantiall~ reduced in the zone adjacent to its mounting
base so that ~orced (fundamental) oscillations of the ri~
alo~g the perimeter thereo~ will al~o decrease substantl-
ally. Thi~ ~aGilitg improves the reliability of fasteni~g
oî the riu~; arld it~ d~rabilit;y.
The ratio o~ t~e i~side diame~er d of the a~nular
radial projection -to the outside diameter D of the ring
is pre~erabl~ withi~ ~he range
d = 0.2 ~ 0.8,
and the height h of the annular radial projection is pre-
--8--
~9~ ~
~.~
~erably deter~ined by the relationshiph = (0.05 ~ 2) ~ (O.lD)Z mm.
If the ratio of t~e inside diameter o~ the annular
radial pro~ectio~ to the outside diameter Or the cuttin~
member is greater thatl that giVeQ above7 this will result,
durin~ machining, in a radial deformation of the flat
mounting base t~us complicatiag the fastening o~ the cutt-
ing ~ember a~ially with respect to ~he tool. If the ratio
of the inside diameter oY t~e annular radial projection
to the out~ide diameter of the cutting member is smaller
tha~ that sPecified above, this will result in a greater
metal consumptio~ ~or makin~ the cutting member without,
however, improving its operating performanceO
With a~ increase i~ the diameter of the cutting memb-
er, the a~ial compone~t o~ the cuttin~ foIce also inoreas-
es. ~here~ore, i~ deter~ining the height h o~ the annul-
ar radial projection, the outside diameter D of the cutt-
ing member ~hould be ~aken into accou~t, which is reflect-
ed in th~ above~iven relationship. In case this value is
smaller tha~ recommended, negative e~fect o~ tlle a~ial forc-
ed tiundamental) oscillations o~ the ring is not diminishea.
I~ the value of h i5 a~eater t~an that given above, thi~
will only bring about a greater metal consumption ~or mak-
i~g the cutting member without, however, improving its ope-
rati~g per~orma~ce.
~ Ve have ~oun~ that in case the outer sur~aca of the
xln~r is made conical with a con~ angle betwee~ 15 and 45~
_g _ -
:,.^~'
the heig~t h o~ the annular radial projection should be
substantially equal to the minimum ring thickness amin.
During machining with the cutting member having the
outer surface which is made conical with an angle of cone
be-tween 15 and 45, the arm o~ actio~ o~ the axial ~orce
applied to the cutting edge of the rin~ with respect to
the moun-ting base increases with an increase in the bend-
ing mo~e~t acting on the ring. The experience has shown
that~ in order to avoid the ring breakage at t~e point o~
it~ conjugation with the a~nular radial projection~ the
hei~t o~ the a~nular radial projection should be substan-
tiall~ equal to the miaimum rin~ thickne~s.
~ he invention will now be described wit~ re~erence -to
a speci~ic embodiment illustrated in the accompanying draw-
ings~ in ~hîch:
Figur~ 1 is a general view, in lon~itudinal section, o~
a cutting member according to the invention having the inn-
er surface eccentrical with respect to the outer surface;
Fi~ure 2 is a plan view of Fiæo l;
Figure 3 is a gen0ral view, in longitudi~al section, o~
a cutting member having the interior in the form o~ an el-
lip~e;
Fi~l~o ~ is a plan view of Figure 3;
Figure 5 shows an embodiment, i~ longitudi~al section,
o~ a cutting member according to the invention, having an
annular radial projectio~ adjacent to the base;
Figure 6 is a plan view o~ ~igure 5.
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i3
Detailed Descriptio~ o~ the Invention
A cutti~g member o~ a rota~ tool accordi~g to the in-
vantion (~i~uro 1~ comprises a ring 1 having a~ outer sur-
face 2 in the form oY a cone and end faces ~ and 4 o~
whi~h one end face 3 functions as a moun-ting base and the
o-ther end ~ace 4;t which is opposite to the first end face'
3, de~ines a cutting edge 5. The inner surface 6 o~ the
ring 1 is ecce~trically o~fset with respect to a geometric-
al a~es 7 of symme~ry (~igure 2~ o~ the outer sur~ace 2.
An axis o.f symmetr~ 8 of the inner sur~ace 6 i9 spaced
~rom the a~is 7 by the amount o~ the ecceR~rici-t~ "e"~
As a result~ the thickness 'latt o~ the ring 1 is non-u~i-
~orm~ ~linimum taick~ess amin ~ the ring 1 is o~ an a~-
is of symme~r~ 9 o~ the ring 1~ Maximum thickness ama~
of the rin~ 1 is also on the axis of symmetry 9 o~ the ring.
The rin~ thickness a monotoRously increases in the direc-
t:ion shown b~ arrows A~ Consequently, the radial rigidity
of the~cutti~ member o~ tnis construction is non-uni~orm
.
: alo~ the perimeter o~ the ring.
: The mi~imum -thickn~ss ami~ ~ the ring 1 can be de-
: : termined by the ~ormula
- ~/ 2
: : ami~. = (1 ~ 5) ~ (O~lD) mm,
wherei~ D is the ou-tside diameter of the ring i~ mm.
: Thus? ~or cuttin~ members with an outside diameter up
to 30 mm7 the minimum thick~ess o~ the ring will be
amin = (1 ~ 2~5) ~ ~Q.lD)2 mm.
~ .,. ;
i3
Ia case the outside diameter o~ the cutting member
does not e~ceed 50 mm :
3/ 2
aminO = (2~5 ~ 3 5) V (O..lD) mm.
In all other applications the minimum thickness o~ the
ring i~ de~ermined by t~e formula
amin. = (3-5 ~ 5) ~/ (O.lD)2 mm.
The cutting member of a rotary tool show~ in ~igure 3
comprises a ring 10 havin~ a c~lindrical outer surface 11
and end faces 12 a~d 13 o~ whic~ one end ~ace 12 ~unctions
as a mounting base and the other end ~ace 13, which is op-
p~site to the ~irst end ~ace, de~ines a cutting edge 14,
The interior 15 o~ the ring 10 i9 elliptical (Figure 4).
~his cutting member has two i.dentical port}ons o~ minimum
r.igidit~ with a thickne3s a~in which are disposed on
a major axis 16 of -the ellipse. ~wo portions o.~ maximum
rigidit~ with a thickness amaX are dis~osed on a minor
axis 17 o~ the ellipse. ~he thickness a o~ the ri~g 10
increases bet~ee~ minimum a~d maximum, i.e. between ami~
and ama~ in the directions shown by arrow B and C. The
radial rigi~ity o~ the ring 10 also varies in these direc-
tLons from its minimum value at points with the minimum
thLck~e~ amin ~ the ri~g 10 to its maximum value at
poi~ts with the maximum thickne~s ama~ f ~he ri~g 10.
The cuttin~ member of a ro-tar~ tool show~ in ~igure 5
comprises a ring 18 having a~ ou-ter surfacc 19 which i~
conical with a~ angle of cone ~ = 15 ~ 45 9 and end ~aces
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20, 21~ The end ~ace 20 is a mounting ba~e and -the e~d
~ace 219 which is opposite to the end face 20, de~ines
a cuttin~ edge 220 The inner sur~ace 23 o~ the ring 18
is eccentrically o~set with respect to the outer surface
19 by the amount el tFigure 6). T~e inner ~urface 2~
is provided, adjacent to the end face 20 de~ini~g the mo-
un-ting ba~e, with an an~ular radial projection 2~ of a
height h24 and an i~side diameter d24, which makes it
possible to substantiall~ reduce the dif~erence in a~ial
elastic de~ormations and dimi~ish -the ~requenc~ of forccd
(~u~damental~ o~cillations of the ring 18 caused thereby.
~ he ratio o~ the i~side diameter d24 f the a~nular
radial ~rojection 24 to the out~ide diameter ~ o~ the
rin~ 18 is witAin the range
~ _ 0.2 ~ 0.8,
and the heig~t h24 ~ the a~nular radial projection 24
r~ is determin~d by the for~ula 2
h24 = ( ~ ~ 2) ~(0.1~) mm~
Such an~ular radial projection may also be provided
in t~e cu~ting memb~r sho~n i~ Figures 3 and 4.
For machi~i~g the materials characterized by impact
loads~ t~e ratio of d~D a~d the value of h of the cu-tt-
ing ~ember are pre~erably determined by the ~ormulae:
d _ 0.z ~ 0.~
3 r 2
h = (1~ 2) V (O-lD) mm.
~13-
~9~
For a semifinish machining of 0aterials:
dD = 0-4 ~ 0.6
h = (0.5 ~ m.
For finishing:
d = o.~ ~ 008.
h = (OrO5t ~ 0.5) ~ (O.lD)2 mm.
In case the outer conical sur~ace 19 has an a~gle o~
cone ~ - 15~45, t~e height h2L~ f the annular radial
projection 24 should be substantially equal to the minimum
thickness of th~ ring 18.
Operation
~ he cutting member of a rotary tool accordi~g to the
inventio~ shown i~ Figures 1,2 ~unctio~s i~ the follo~;ling
manner.
As a result o~ rotation O:e a workpieca a~d lo~ feed
Of a machine tool slide, the cutting member of a rotary
tool, comprising the rin~ rotates about the a~is o~ sym-
metry 7 o~ t~e outer sur~ace 2. The cutting ~orce, a~d main-
ly its radial component, causes a radial elaqtic de~ormati-
on o~ the rin~ 1 which propagates on either side from the
point of co~tact between the ring a~d the workpiece (not
~hown)~ 'When the cutting member is in contact ~itn -the work-
piece sur~ace at the point of it~ minimum radial ri~idit~,
which is determined by the minimum thickness ami~ f the
rlng 1, elastic dQformations of the ring 1 pxopagate in the
-14-
directions o~ arrows A on either side from the point o~minimum thickness amin of the ring l. '~he ~orced (fun-
damental) oscillations o~ the ring 1 caused by its elas-
tic deformations also propagate in these directions, At
the next moment, owing to the rotation o~ the cutting memb-
er, the radial componen~ o~ the cuttin~ ~orce causes an
elastic deformation o~ the ring l at the point o~ its ma-
ximum rigidity ama~ ~ i.e, at the point where the radial
rigidity of the rin~ is at its ma~imum. ~he elastic defor-
mations at this poi~t and the forced (~unda~ental) oscilla-
-tions of the ring l caused by such de~ormations also pro-
pa~ate along the perimetor o~ the ring 1 toward one ano-
ther. ~Iowever, the frequency o~ the forced ~fundamental)
oscillations of the ring l at this point is diI~erent
from t~e frequency of oscillation9 o~ the ring 1 at the
point of its minimum thickness amin ~ i~e. at the point
o~ its minimum radial rigidity since the values of elastic
deformation~ at these points are di~ferent.
In machi~i~g with such cutting~ member the coincidence
o~ ~requencies o~ forced (fu~damental) oscillations o~ the
deformed parts, i,e. the reso~ance phenomeno~ causing the
destruction of the ring l is eliminated. This is achieved
o~Jin~ to the provision o~ a radial ri~idity varyin~ alon~
the perimeter of the ring.
All other embodiments of the cu~tin~ me~bers of a ro-
tary tool will ~unction in th~ same manner. The cutting
member of a rotary -tool acoording to the invention e~ui-
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~9~363
bits an improved durability since the operating-condi~
-tions of the cutting member are more favourable compared
to those of the prior art cutting members of rotar~ tools.
The embodiments of cutting members of rotary tools accord-
ing to the invention fea-ture easgm~nufacturing process
and simplicity of design. The dimensional proportioning o~
various parts o~ the cutting member makes it possible to
ensure its optimum dulability and minimum metal consump-
tion ~or its manufacture and also a reduction o~ the con-
sumpi~ion of tool metal at the stage o~ development and de-
~ign.
:,
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I
,:,:
