ISO 3685:1993

INTERNATIONAL IS0
STANDARD
Second edition
1993-11-15
Tool-life testing with single-point turning
tools
Essais de d&e de vie des outils de tournage 9 partie active unique
Reference number
IS0 3685:1993(E)
IS0 3685:1993(E)
Contents
Page
1 . 1
Scope
2 Normative references .
3 Definitions .
4 Workpiece . 2
......................................................................... 2
41 . Work material
.................................. 2
42 . Standard conditions for the workpiece
5 Tools . 3
. . 3
51 Tool materials
52 . Tool geometry .
53 . Standard conditions for the tool .
............................................................................... 8
6 Cutting fluid
..................................................................... 8
7 Cutting conditions
71 . Standard cutting conditions .
72 . Other cutting conditions . 9
......................................................................... 9
73 . Cutting speed
......................... 9
8 Tool-life criteria and tool wear measurements
81 . Introduction .
....................................................................... 9
82 . Tool-life criteria
83 . Tool wear measurements .
Equipment . 13
......................................................................... 13
91 . Machine tool
92 . Other equipment .
Tool-life test procedure . 14
............................................ 15
11 Recording and reporting results
11.1 Tool-life tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
0 IS0 1993
All rights reserved. No part of this publication may be reproduced or utilized in any form or
by any means, electronic or mechanical, including photocopying and microfilm, without per-
mission in writing from the publisher.
International Organization for Standardization
Case Postale 56 l CH-1211 Geneve 20 l Switzerland
Printed in Switzerland
ii
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.2 Data sheets and diagrams
Evaluation of tool-life data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
11.3
Annexes
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
General information
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Reference work materials
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tool wear and tool-life criteria
Data sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
Preliminary tool-life test
Evaluation of tool-life data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Chip characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Bibliography . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
. . .
III
IS0 3685:1993(E)
Foreword
IS0 (the International Organization for Standardization) is a worldwide
federation of national standards bodies (IS0 member bodies). The work
of preparing International Standards is normally carried out through IS0
technical committees. Each member body interested in a subject for
which a technical committee has been established has the right to be
represented on that committee. International organizations, governmental
and non-governmental, in liaison with ISO, also take part in the work. IS0
collaborates closely with the International Electrotechnical Commission
(I EC) on all matters of electrotechnical standardization.
Draft International Standards adopted by the technical committees are
circulated to the member bodies for voting. Publication as an International
Standard requires approval by at least 75 % of the member bodies casting
a vote.
International Standard IS0 3685 was prepared by Technical Committee
ISO/TC 29, Small tools.
This second edition cancels and replaces the first edition
(IS0 3685:1977), of which it constitutes a technical revision.
Annexes A, B, C, D, E, F and G form an integral part of this International
Standard. Annex H is for information only.

IS0 3685:1993(E)
Introduction
The adoption by both industry and testing bodies of the recommendations
contained in IS0 3685:1977 created a demand for the publication of simi-
lar recommendations for other commonly used cutting processes.
is covered in IS0 8688-l :1989 and
Tool-life testing in milling
IS0 8688-2:1989. During the final stages of their preparation, it was rec-
ognized that there was a need to update the recommendations for
single-point turning tools.
This International Standard contains recommendations which are appli-
cable in both laboratories and manufacturing units. These recommen-
dations are intended to unify procedures in order to increase reliability and
comparability of test results when making comparisons of cutting tools,
work materials, cutting parameters or cutting fluids. In order to come as
close as possible to these aims, recommended reference materials and
conditions are included and should be used as far as is practical.
In addition, the recommendations can be used to assist in finding rec-
ommended cutting data or to determine limiting factors and machining
characteristics such as cutting forces, machined surface characteristics,
chip form etc. For these purposes in particular, certain parameters, which
have been given recommended values, may have to be used as variables.
The test conditions recommended in this International Standard have been
designed for turning tests using steel and cast iron workpieces of normal
microstructure, with solid high-speed steel tools or tools with cemented
carbide or ceramic indexable inserts. However, with suitable modifi-
cations, this International Standard can be applied, for example, to turning
tests on other work materials or with cutting tools developed for specific
applications.
The specified accuracy given in the recommendations should be con-
sidered as a minimum requirement. Any deviation from the recommen-
dations should be indicated in detail in the test report.

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INTERNATIONAL STANDARD
IS0 3685:1993(E)
Tool-life testing with single-point turning tools
based on this International Standard are encouraged
1 Scope
to investigate the possibility of applying the most re-
cent editions of the standards indicated below.
This International Standard specifies recommended
Members of IEC and IS0 maintain registers of cur-
procedures for tool-life testing with high-speed steel,
rently valid International Standards.
cemented carbide and ceramic single-point turning
tools used for turning steel and cast iron workpieces.
IS0 185:1988, Grey cast iron - Classification.
It can be applied in laboratory testing as well as in
production practice.
IS0 229:1973, Machine tools - Speeds and feeds.
In turning, cutting conditions may be considered un-
IS0 468:1982, Surface roughness - Parameters,
der two categories:
their values and general rules for specifying require-
conditions as a result of which tool deterioration is men ts.
a)
due predominantly to wear;
IS0 513:1991, Application of hard cutting materials
for machining by chip removal - Designation of the
b) conditions under which tool deterioration is due
main groups of chip removal and groups of
mainly to other phenomena such as edge fracture
application.
or plastic deformation.
This International Standard is solely concerned with
IS0 683-l : 1987, Heat-treatable steels, alloy steels
recommendations for testing which results predomi-
and free-cutting steels - Part I: Direct-hardening
nantly in tool wear.
unalloyed and low-alloyed wrought steel in form of
different black products.
Testing for the second category of conditions above
is to be subject to further study.
IS0 841 :1974, Numerical control of machines - Axis
and motion nomenclature.
This International Standard establishes specifications
for the following factors of tool-life testing with
IS0 883: 1985, Indexable hardmetal (carbide) inserts
single-point turning tools: workpiece, tools, cutting
with rounded corners, without fixing hole - Dimen-
fluid, cutting conditions, equipment, assessment of
srons.
tool deterioration and tool life, test procedures and the
recording, evaluation and presentation of results.
IS0 1940-I : 1986, Mechanical vibration - Balance
quality requirements of rigid rotors - Part 1: Deter-
Further general information is given in annex A.
mina tion of permissible residual unbalance.
NOTE 1 This International Standard does not constitute
an acceptance test and should not be used as such. IS0 2540:1973, Centre drills for centre holes with
protecting chamfer - Type B.
IS0 3002-I :1982, Basic quantities in cutting and
grinding - Part 1: Geometry of the active part of
cutting tools - General terms, reference systems,
2 Normative references
tool and working angles, chip breakers.
The following standards contain provisions which,
IS0 4957:1980, Tool steels.
through reference in this text, constitute provisions
of this International Standard. At the time of publi-
IS0 5610: 1989, Single-point tool holders for turning
cation, the editions indicated were valid. All standards
and copying, for indexable inserts - Dimensions.
are subject to revision, and parties to agreements
IS0 3685:1993(E)
IS0 9361-l :1991, Indexable inserts for cutting tools
4.2 Standard conditions for the workpiece
- Ceramic inserts with rounded corners - Part 1:
Dimensions of inserts without fixing hole.
All mill scale or casting skin shall be removed by
clean-up cuts before testing, except when the effect
IS0 9361-2:1991, Indexable inserts for cutting tools
of the scale is being tested.
- Ceramic inserts with rounded corners - Part 2:
Dimensions of inserts with cylindrical fixing hole.
The plastic formed surface of the shoulder, i.e. “the
transient surface ”, and any other burnished or abnor-
mally work-hardened surface on the workpiece which
can come in contact with the test tool shall be re-
3 Definitions
moved with a sharp clean-up tool prior to testing in
’
order to reduce as much as possible the residual
Fo r the purposes of
this Internation al Sta ndard , the
sub-surface deformations due to the previous test.
fol lowing definitions a
PPlY*
However, this does not include removal of the
normally work-hardened surface on the test bar pro-
3.1 tool wear: The change of shape of the tool from
duced by the previous passes of the tool.
its original shape, during cutting, resulting from the
gradual loss of tool material or deformation.
The length/diameter ratio of the workpiece shall be
not more than the minimum ratio at which chatter
3.2 tool wear measure: A dimension to be meas-
occurs. The test shall be stopped when chatter oc-
ured to indicate the amount of tool wear. curs. A length/diameter ratio greater than 10 is not
recommended.
3.3 tool-life criterion: A predetermined threshold
The hardness of the work material shall be deter-
value of a tool wear measure or the occurrence of a
mined over the complete cross-section of one end of
phenomenon.
each test bar or tube.
3.4 tool life: The cutting time required to reach a
Where hardness variations are expected to be signifi-
tool-life criterion.
cant, measurements shall be taken to ascertain that
values fall within the prescribed limits.
The locations of measurement points and the method
4 Workpiece
of measurement should be noted in the test report.
It is recommended that the deviation within one batch
of material be as small as possible. A realistic hard-
ness value for the reference materials and similar
4.1 Work material
materials is + 5 % of the mean value.
In principle, testing bodies are free to select the work
The cutting test shall be conducted only in the range
materials according to their own interests. However,
of diameters where the hardness lies within the limits
in order to increase the comparability of results be-
given by the original hardness specification.
tween testing bodies, the use of one of the reference
materials, steel C 45 in accordance with IS0 683-l or
Quantitative metallography (as micro-
regards
cast iron grade 25 in accordance with IS0 185, is
structure, grain size, inclusion count, etc.) of the work
recommended. Detailed specifications of these ma-
material is recommended but when this is not practi-
terials are given in annex B. Within these specifi-
cal, photomicrographs shall be included in the test
cations, materials may vary with a resulting effect on
report. The magnification shall be in the range x 100
machinability. To minimize such problems the pro-
to x 500.
vision of a closer specified work material should be
discussed with the supplier.
In machining tests carried out on production com-
ponents, the fixing devices normally employed in the
It is recommended that information concerning the
process shall be utilized.
work material such as grade, chemical composition,
physical properties, microstructure, hardness, com-
plete details of the processing route of the work ma- The chuck and the spindle shall be stable and well
terial (e.g. hot rolled, forged, cast or cold drawn) and balanced (for a method of evaluating the balance, see
any heat treatment be given in the test report (see 4.2 IS0 1940-l). When fixing the workpiece between a
chuck or a faceplate and a centre, special care shall
and annex B).
be taken to prevent any bending loads on the
In order to be able to compare results over reasonably
workpiece.
long periods of time, it is recommended that testing
bodies procure sufficiently large quantities of refer-
For diameters above 90 mm, the use of a faceplate is
ence work material to cover their long term needs.
recommended.
IS0 3685:1993(E)
A centre hole of 6,3 mm diameter with 120” protect- 5.1.3 Ceramics
ing chamfer, in accordance with IS0 2540, is rec-
ommended. These shall be of commercially available grades and
the composition and physical properties shall be
noted in the test report in as much detail as possible.
5 Tools
The reference ceramics shall be
In principle, testing bodies are free to select testing
tools according to their own interests. However, in
a) A&-O,-based, with min. 70 % AI,O, and additions
order to increase the comparability of results between
of other hard materials such as ZrO,, titanium
testing bodies, the use of one of the reference tool
carbide (TIC) or titanium nitride (TIN);
shapes and tool materials, as specified hereafter, is
recommended.
b) S&N,-based, with min. 90 % S&N, and additions
of Y,O, and/or AI,O,.
5.1 Tool materials
5.1.4 Other tool materials
In all cutting tests in which the tool material is not it-
self the test variable, the investigation shall be con-
When the tool material is the test variable, the ma-
ducted with an appropriate reference tool material to
terial classification and, if possible, the chemical
be defined by the testing body.
composition, hardness and microstructure shall be
noted in the test report.
In principle, testing bodies are free to select the tool
materials according to their own interest. However, in
order to increase the comparability of results between
5.2 Tool geometry
testing bodies, the use of one of the reference ma-
terials, specified in this subclause, is recommended.
5.2.1 Cutting tool geometry
Within these specifications, tool materials may vary
with a resulting effect on performance. To minimize
The cutting tool geometry is defined in accordance
such problems, the provision of a closely specified
with IS0 3002-l.
tool material should be discussed with the supplier to
ensure as much uniformity as is practical.
Figure 1 illustrates those angles which are necessary
to define the orientation of the cutting edges, face
In order to be able to compare results over reasonably
and flank of a single-point cutting tool.
long periods of time, it is recommended that testing
bodies procure sufficiently large quantities of refer-
ence tool materials to cover their long term needs.
5.2.2 Standard tool geometry
Reference tool materials should not have any coating
All cutting tests in which the tool geometry is not the
or surface treatment.
test variable shall be conducted using one of the tool
geometries given in table 1. In the case of sintered
If the tool material itself, coating or surface treatment
carbide and ceramic tools, these shall be of the
is the test variable then the material classification,
clamped insert type. Brazed or adhesive-bonded in-
physical properties, microstructure hardness and pro-
sert tools shall not be used as reference tools.
cessing route should be reported in detail.
The tool shall be set on the machine correctly. This is
51.1 High-speed steel
accomplished by setting the corner on centre and
setting the tool shank perpendicular to the axis of ro-
The high-speed steel reference tool material should
tation of the workpiece. For carbide cutting tools used
be uncoated non-cobalt alloyed (S 2 and S 4) or cobalt
for machining steel and similar alloys only, the cutting
alloyed (S 8 and S 11) all of which conform to
edge shall have a radius m such that,
IS0 4957.
if rE = 0,4 mm, then m = 0,02 mm to 0,03 mm;
5.1.2 Sintered carbide
if r, > 0,4 mm, then r” = 0,03 mm to 0,05 mm.
The sintered carbide reference tool material shall be-
long to the IS0 groups of application P 10 for ma- The conditions of the cutting edge for ceramics shall
chining steel or K 10 for machining cast iron in be in accordance with the magnified view in figure 1.
m values shall be those obtained by grinding and shall
accordance with IS0 513.
be noted in the test report.
Since carbide grades for the same group of application
can vary between producers and are unlikely to be All other cutting tools shall be used with the normally
comparable, it is recommended to select a particular sharp edge produced by the grinding or finishing
supplier’s grade as a reference grade. operations indicated in 5.3.5.

IS0 3685:1993(E)
Dimensions in millimetr
-es
View on tool orthogonal plane 1 P,)
N-N
View on cutting edge normal plane 1 P,)
IL
SC
/
A
8n (negative)
Edgeroundness
Ceramic
Edgeroundness
----
Carbide
egative)
Corner radius rE
Minor cutting
edge
I/ -Minor flank
View on tool cutting edge plane 1 P,)
fl - w LMajorflank
Figure 1 - Illustration of tool angles
Table 1 - Standard tool angles
Angles in degrees
Cutting edge
Cutting tool material Rake ’) ClearanceI) Cutting edge angle Included angle
inclination
a
Y & Kf &f
High-speed steel 25 8 0 75 90
+6 5 0 75 90
Sintered carbide
-6 6 -6 75 90
Ceramic -6 6 -6 75
1) The tool rake and tool clearance angles may be measured in either the cutting edge normal plane (P,) or the tool
orthogonal plane (P,). The appropriate subscript shall be added to y and a to denote the plane of measurement, i.e. yn or
yO and a, or a,.
5.2.3 Other tool geometries
Alloys unusually difficult to machine, such as nickel
base and refractory materials, may require a departure
from the standard tool geometry, but such a departure
shall only be made when it is impossible to employ
the standard tool geometry. In such a case or where
tool geometry is the test variable, the following infor-
mation shall be indicated in the test report:
a) values of the tool angles and the corresponding
working angles (specified for the condition where
the feed speed is zero as shown in table I);
b) condition of the cutting edge: normally sharp,
rounded to a specified radius or chamfered (the
Blend angle
w--L-
widths and angles of any lands on the face or
flank).
Figure 2 - Details of rounded corner
5.3 Standard conditions for the tool
practice, this requirement is met when the corner is
5.3.1 Tool type and size
on centre within + 0,25 mm and the infeed of the tool
past a stationary reference point produces a deviation
A straight roughing tool shall be used.
of the top surface (parallel to the supporting plane)
and the side surface (parallel to the plane P ) of the
The shank cross-section h, x b for tool holders, in ac-
tool shank not in excess of & 0,4 mm per 58 mm of
cordance with IS0 5610, shall be
infeed motion (see figure 3).
25 mm x 16 mm for solid high-speed steel tools;
The tolerances of sintered carbide and ceramic inserts
shall correspond to IS0 1832 class G, except as indi-
25 mm x 25 mm for carbides; and
cated above.
32 mm x 25 mm for ceramics.
5.3.3 Tool finish
The distance from the corner of the tool to the front
The roughness, R,, of the face and flank of the tool
of the lathe tool post holder (overhang) shall be
25 mm. shall not exceed 0,25 pm (measured in accordance
with IS0 468).
Sintered carbide inserts shall be 12,7 mm square and
with a thickness of 4,76 mm for negative rake and The deviation from flatness of the supporting face of
3,18 mm for positive rake (see IS0 883). an insert, except in the immediate vicinity of its
edges, shall not exceed 0,004 mm.
Ceramic inserts, in accordance with IS0 9361-I and
IS0 9361-2, shall be 12,7 mm square and with a The cutting edge on high-speed steel tools shall have
thickness of 4,76 mm. neither burrs nor feather edge. These may be re-
moved by careful light honing of the face and flank
surfaces of the tool.
5.3.2 Tolerances
Each cutting edge to be used in testing shall be
Tolerances for all tool angles shall be & 0,5” (30 ’) for
examined at a minimum magnification of x 10 for
the complete cutting tool.
visual defects such as chips or cracks. These defects
shall be corrected if possible, otherwise the tool shall
The angle between a tangent to the rounded corner
not be used.
and the major or minor cutting edges at the point
where these blend shall not be greater than 5” (see
figure 2). 5.3.4 Tool holders for inserts
The tolerance for the corner radius &) shall be
For cutting tests, tool holders shall meet the following
+ 0,l x rc.
-
conditions.
The tolerance on parallelism between the tool refer-
The geometry shall be as indicated in table I.
ence plane P, and the tool back plane P, (see
IS0 3002-l :I 982, subclauses 4.1 .I and 4.1.3) and the The tolerance on the angles for tool holder plus in-
fixed setting axes Xm and Zm (see IS0 3002.2:1982, serts shall be + 0,5” (30 ’) and for the tool holder
subclause 2.2) of the machine tool, shall be + 0,5 ”. In alone + 0,2” (12 ’).
-
IS0 3685:1993(E)
Dimensions in millimetres
-ym i3;
cv
A d
t
Plane P,
L
-
A
z
d
I
t
V
-xn
A
1 -
In
d
t
k
u!
I
Figure 3 - Tolerance on parallelism
The angle for locating the indexable insert in the tool
The faces on the tool holder or the shim supporting
holder shall be as specified in figure4.
the insert shall be flat to within 0,Ol mm.
The underside of the indexable insert shall not project
over the supporting face of the tool holder by more
than 0,3 mm (see figure5).
The chip breaker height and chip breaker distance and
the method of clamping the insert shall be noted in
the test report. (See 5.3.7.)
Indexable insert
5.3.5 Tool grinding of high-speed steel
The sequence of operations, types of grinding wheel,
Tool holder
cutting data and recommended procedures should be
7-
obtained from the grinding wheel manufacturers.
For tools having a positive rake, each subsequent
Figure 4 - Tolerances on squareness of insert
corner shall be lower than the preceding one. The
and tool holder location
decrease in tool corner height shall not exceed
5 mm, otherwise a new rake face shall be ground at
the original height.
The tool holder material shall be steel with a tensile
The cutting direction of the active periphery of the
strength not less than 1 200 N/mm* (1 200 MPa).
grinding wheel should be approximately perpendicular
The flatness of the base of the tool holder shall be
to the tool major cutting edge and in a direction away
within 0,l mm over the length and width of the tool
from the major cutting edge across the tool surface
holder.
being ground.
fD
-h
-.
n
ii
a
-0’
D
CT 0
;;: -VI -. 3
--t
P SF-
F
-b
al
n
ii.
z
-.
IS0 3685:1993(E)
When using a plain grinding wheel the direction of For ceramic tools, the distance lBn may not be too
feed motion may be either in the same direction or small with regard to the risk for crushing the edge.
opposite to the cutting direction of the wheel relative
NOTE 2 Particular attention should be paid to the fact
to the surface being ground.
that the crater can be different when turning with or without
There is a danger of overheating, especially when the a chip breaker.
grinding machine does not permit a perfect control of
depth setting and feed. Overheating is usually fol-
lowed by oxidation colours but when colours are not 6 Cutting fluid
obvious, overheating may still influence the hardness.
Therefore, a hardness check shall be made. Cutting fluid shall be used when cutting steel
workpieces with high-speed steel tools unless the
After grinding, the hardness of the tool shall be
high-speed steel tools are being tested to catastrophic
measured on the flank or face as near as possible to
failure (see 8.2.1).
the cutting edge. The hardness shall correspond to
the previously measured hardness of the tool ma- When cutting steel workpieces with carbides or cer-
terial. If this hardness value is not obtained after
amics cutting fluid normally should not be used.
grinding, further grinding or cutting back shall be per-
When cutting cast iron the use of cutting fluids is not
formed until the desired hardness is achieved.
recommended.
be restored after testing
The profile of the tool shall
The cutting fluid shall be clearly specified either by
and table 1.
as s Ihown i n figures 1 and 2
trademark or composition of the active elements, the
When regrinding, the tool shall be ground back at
actual concentration, hardness of water (when used
least 2 mm beyond the wear marks. The tool ge-
as a diluent) and the pH value of the solution or
ometry has to be maintened as specified in figures 1
emulsion.
and 2 and table 1. Care shall be taken to ensure that
When using cutting fluid the flow should “flood” the
the tool corner has not been displaced sideways.
active part of the tool. The flow-rate should not be
less than 3 I/min or 0,l I/min for each cubic centi-
5.3.6 Carbide, ceramic
metre per minute of metal removal rate, whichever is
the larger. The orifice diameter, flow-rate and reser-
These inserts shall be used in the manufacturer ’s de-
voir temperature should be noted in the test report.
livery condition and shall not be reground.
5.3.7 Chip breaker
7 Cutting conditions
A chip breaker shall not be used on high-speed steel
tools unless the chip breaker is itself a test variable
7.1 Standard cutting conditions
or if chipbreaking is necessary. The use of a chip
breaker is permissible when testing with sintered
For all tests in which feed,f, depth of cut, aP, or corner
carbide and ceramic tools. A chip breaker is often re-
radius, rE, are not the prime test variables, the cutting
quired when using these tool materials as a safety conditions shall be one or more of the combinations
factor.
listed in table 2.
The chip breaker, if used, shall rest flat on the
indexable insert. The deviation in flatness of the face Table 2 - Standard cutting conditions
of the chip breaker in contact with the insert shall not
B
Cutting condition A C D
exceed 0,004 mm.
The chip breaker angle es,, (see figure51 is the angle
a1 0,25 0,4 0,63
Feed, f, mm/rev
between the line of intersection of the chip breaker
Depth of cut, ap, mm 1 2,5 2,5 2,5
and the tool face and the straight portion of the major
Corner radius, rt, mm 0,4 0,8 0,8 I,2
cutting edge. The angle @BY can be varied with differ-
ent work piece materials so that an acceptable chip
form is achieved and in order to guide the chip direc-
The tolerance on feed shall be Tz % (in accordance
tion to or from the work piece, see IS0 3002-I :I 982,
with IS0 229).
subclause 7.5. The chip breaker wedge angle (os), i.e.
the angle between the active face of the chip breaker
The tolerance on depth of cut shall be + 5 %.
and the tool face shall be between 55” and 60 ”.
The edge geometry on corner radius is defined in
The chip breaker distance lsn shall be chosen so that
5.3.2.
an acceptable chip form is achieved (see figure 5). The
actual chip breaker distance shall be noted in the test
NOTE 3 Designations in accordance with IS0 3002-3
report. have been used.
7.2 Other cutting conditions
8 Tool-life criteria and tool wear
measurements
When it is not possible to choose one of the standard
cutting conditions, or when the feed, the depth of cut
or the corner radius is the test variable, it is rec-
ommended that only one parameter be altered at a
time and that the values chosen be at the intersection
8.1 Introduction
of designated feeds and depths of cut within the tri-
angular areas shown in figure6. The limits of the tri-
In practical/workshop situations, the time at which a
angular areas are defined in table3.
tool ceases to produce workpieces of the desired size
and surface quality usually determines the end of
useful tool life. The period up to the instant when the
Table 3 - Limits of other cutting conditions
tool is incapable of further cutting may also be con-
sidered as useful tool life. However, the reasons for
Minimum depth of cut 2 times corner radius ’)
which tools may be considered to have reached the
Maximum depth of cut 10 times feed
end of useful tool life will be different in each case
Maximum feed 0,8 times corner radius
depending upon cutting conditions etc.
I) A smaller depth of cut may make measurements of
To increase reliability and comparison of test results,
tool wear more difficult and less accurate.
it is essential that tool life is defined as the total cut-
ting time of the tool to reach a specified value of
tool-life criterion.
7.3 Cutting speed
Depending on where at the cutting edges the de-
The cutting speed, in metres per minute (m/min), shall
terioration occurs different values can be accepted.
be determined on the surface of the workpiece to be
cut, i.e. the work surface and NOT on the diameter
This International Standard recommends that tool de-
resulting from the cut, i.e. the machined surface.
terioration in the form of wear shall be used for de-
Furthermore, the cutting speed shall be measured af-
termining tool life.
ter the tool has engaged the workpiece to take into
account any loss of cutting speed resulting from the
Where more than one type of wear becomes
cutting action.
measurable, each type should be recorded and when
any one of the wear phenomena limits has been at-
At least four different cutting speeds shall be chosen
tained, then the end of tool life has been reached.
for each cutting condition, except for ceramics, when
a limitation to three speeds is practical with regard to
The numerical value of tool wear used to determine
the material consumption. In general, the cutting
tool life governs the quantity of testing materials re-
speeds shall be chosen such that the tool life at the
quired and the costs of testing. If the limiting value is
highest speed is not less than 5 min, for ceramics not
too high, the cost of establishing results may exceed
less than 2 min.
the worth of these results. If the limiting value is too
low, the established result may be unreliable since it
When machining expensive materials, a shorter tool
may be determined during the initial stages of wear
life may be chosen, but shall not be less than 2 min.
development under the test conditions.
In order to obtain adequately spaced points on the
cutting speed tool-life curve, it is recommended that
successive cutting speeds bear a ratio which will re-
sult in an approximately double tool life. The ratios can
8.2 Tool-life criteria
be chosen from a geometrical series of preferred
numbers given in IS0 3 and/or IS0 229.
The type of wear that is believed to contribute most
As a guideline, the following speed ratios can be to the end of useful tool life in a specific series of
used: tests shall be used as a guide to the selection of one
of the tool-life criteria specified hereafter. The type
and value of the criterion used shall be noted in the
high-speed steel tool: 1,06
test report. If it is not clear which type of wear will
carbide tools: 1 ,12
predominate, it is possible to use either two criteria,
resulting in two v,-T, curves, or a mixed criterion, re-
ceramic: 1,25 sulting in a broken V& curve (see figure7).

IS0 3685:1993(E)
Cornerradii,mm
6.3
3,s
=
Standard cutting conditions
g 2s
.
0" 2
I I I
5 1 ‘25
I I I I
n 1
0,63
OS
0,4
r
Y
0,32
I
,. , , , , I I I
0,25
.
I I I I 1 1 I I
Ln
In 2 g ~s,Zs*m~a,
9 9 r
.
0 0 d d d d d 0‘ d d d d 0 T
Feed f, mm/rev
Figure 6 - Limits of cutting conditions
IS0 3685:1993(E)
\
.-
\
\
E
.
\
I2
\ 7 Criterion : depth of crater KT
\
aJ
G
.- v
d
\
I=
Resulting curve
<
Criterion : width of flank wear land i@B
\
\
Cutting speed vc, m/min
Figure 7 - Broken V& curve, combined flank and crater wear (Logarithmic scales)
8.2.1 Common criteria for high-speed steel tools
KT = 0,06 + 0,3f
(see figure 8)
wheref is the feed expressed in millimetres per rev-
The criteria most commonly used for high-speed steel
olution. For standard feeds, this leads to the values
tools are as follows:
of KT given in table4 when KT applies as a criterion.
a) the maximum width of the flank wear land
Table 4 - Values of KT
VB, max. = 0,6 mm if the flank wear is not regu-
/
larly worn, scratched, chipped or badly grooved in
Feed J mm/rev. 0,25 0,63
0,4
zone B;
Crater depth KT, mm 0,14 0,18 0,25
b) the average width of the flank wear land
VB, = 0,3 mm if the flank wear land is considered
to be regularly worn in zone B;
d) the crater front distance reduces to a value of
c) catastrophic failure. KF = 0,02 mm (see figure 8);
e) the crater breaks through at the minor cutting
edge, causing a poor finish of the machined sur-
8.2.2 Common criteria for sintered carbide tools
face.
(see figure 8)
NOTES
The criteria most commonly used for sintered carbide
tools are as follows:
4 It should be recognized that notch wear is normally due
to chemical action and occurs outside the area of physical
contact between tool and workpiece both along the major
a) the maximum width of the flank wear land
cutting edge and to a lesser extent along the minor cutting
VB, max. = 0,6 mm if the flank wear land is not
edge. In both instances notch wear affects both the face
regularly worn in zone B;
and the flank simultaneously.
b) the average width of the flank wear land
5 Notch wear, which in some cases can cause cata-
VB, = 0,3 mm, if the flank wear land is considered
strophic failure , should be distinguished from abrasive wear
to be regularly worn in zone B;
VB, which occurs along the cutting edge coincident with the
work surface. Notch wear is often caused by work harden-
c) the depth of the crater KT given, in millimetres,
ing effects in the workpiece by the previous pass of the
by the formula tool.
IS0 3685:1993(E)
Dimensions in millimetres
I A-A
a”
Flank wear land
Crater
max.
m--------w
Notch
wear
KF = crater front distance
KB = crater width
KM= crater centre distance
KT = crater depth
(see clause C.4)
Figure 8 -
Some types of wear on turning tools
8.2.3 Common criteria for tools of ceramics (see
9 Equipment
figure 8)
The criteria most commonly used for ceramics are as
9.1 Machine tool
follows:
The lathe on which the test is carried out shall be of
a) the maximum width of the flank wear land
stable design and in such good condition that no
VB, max. = 0,6 mm if the flank wear land is not
tendencies to vibrations or abnormal deflections can
regularly worn in zone B;
be observed under the test conditions (balance quality
grade G 6.3 in accordance with IS0 1940 is rec-
b) the average width of the flank wear land
ommended).
= 0,3 mm if the flank wear land is considered
VBB
to be regularly worn in zone B. The machine tool used for testing shall be equipped
with an infinitely variable speed spindle drive covering
the range of spindle speeds to be used.
8.2.4 Other criteria
This is particularly important in turning in order to be
able to maintain the same cutting speed as the diam-
The criteria specified in 8.2 are usually sufficient when
eter of the workpiece is reduced by successive cuts.
turning steel and cast iron.
Furthermore, a variable speed drive allows precise
The reasons for the selection and choice of other cri-
predetermination of cutting speeds and reduces the
teria for special cases are discussed in annex C.
time required to obtain the data for a complete tool
life curve.
8.3 Tool wear measurements
9.2 Other equipment
Particles adhering to the flank directly under the wear
land can give the appearance of a larger width of the
The following equipment is needed for specific
wear land. Also a deposit in the crater results in lower
measurements and shall be of sufficient resolution to
values of the crater depth. Loose material shall be
discriminate the tolerances specified in this Inter-
removed carefully but chemical etchants shall not be
national Standard
used except at the end of the test.
- a device for measuring tool geometry accurately;
For the purpose of the wear measurements, the
major cutting edge is considered to be divided into
- a profile projector for inspection of the tool cor-
four zones as shown in figure8.
ners;
Zone C is the curved part of the cutting edge at the
- a stopwatch for recording the cutting time;
tool corner.
Zone B is the remaining straight part of the cutting - a toolmaker ’s microscope, or a microscope
edge between zone C and zone A. equipped with a filar eyepiece, for measuring flank
wear;
Zone A is the quarter of the worn cutting edge length
b farthest away from the tool corner.
- a dial indicator with a contact point approximately
0,2 mm in diameter for measuring crater depth;
Zone N extends beyond the area of mutual contact
between the tool and workpiece for approximately
- an X - Y table is recommended to obtain more ac-
1 mm to 2 mm along the major cutting edge. The
curate tool wear measurements;
wear is of notch type.
- a profile recorder if registration of the crater profile
The width of the flank wear land VBB shall be meas-
is desired;
ured within zone B in the tool cutting edge plane Psl)
perpendicular to the major cutting edge. The width of
- hardness testing equipment for the determination
the flank wear land shall be measured from the pos-
of hardness of the workpiece and the tool;
ition of the original major cutting edge.
- a portable roughness measuring apparatus for
The crater depth KT shall be measured as the maxi-
measuring workpiece roughness while the
mum distance between the crater bottom and the
workpiece is mounted on the lathe;
original face in zone B.
Further details are given in annex C.
- an instrument for measuring cutting speed;
I) The tool cutting edge plane P, is the plane containing the major cutting edge and the assumed direction of primary motion.
IS0 3685:1993(E)
- a slide caliper for measuring workpiece diameter The machine shall be set to the required cutting con-
and for setting the chip breaker distance; ditions. If necessary, a preliminary tool-life test as de-
scribed in annex E shall be carried out.
- equipment for measuring the flow-rate of cutting
Tool wear measurements shall be made at suitable
fluids (this can be done by measuring the time to
fill a barrel of known volume). intervals. All data shall be recorded on the “Wear
versus time measurements” data sheet as shown in
annex D. The readings shall be plotted on a tool wear
10 Tool-life test procedure
(ordinate) versus time (abscissa) diagram (see figures
9 and 10).
It is only possible to describe tool-life test procedure
in general terms, as conditions will vary with each
Such diagrams shall show at least five experimental
situation.
points for each curve so that the time at which the
value that is selected as the tool-life criterion is
The method to follow is the same as that used for
reached can be assessed with sufficient accuracy.
good machine tool operation, except that great care
and observation must be exercised and that certain
Under no circumstances shall the tool life be deter-
measurements must be taken.
mined by extrapolating the tool wear versus time dia-
gram.
Most details of the measurements and the pre-
cautions to be taken have already been covered else-
Finally, the results of a series of tests shall be re-
where in this International Standard.
corded on the “Tool life versus cutting speed
Before starting the test, ascertain that the lathe,
diagram” data sheet as shown in annex D.
workpiece and tools fulfil all the requirements of this
International Standard. Complete the data sheet The evaluation of the tool-life data is dealt with in
“General conditions” (see annex D). clause 11.
Tool-Life criterion
-
Cutting time t, min
Approximately equal to the edge
roundness (rn in figure 1)
Figure 9 - Development of flank wear for different cutting speeds, v,~-v~~ (Linear scales)

IS0 3685:1993(E)
Tool-life criterion
r
T
c4
Cutting time t, min
Figure 10 - Development of crater depth for different cutting speeds, vcl-vc4 (Linear scales)
If catastrophic failure is used as a criterion, the tool
11 Recording and reporting results
life, Tc., is plotted directly against the cutting speed,
vc, whrch will provide tool-life curves.
11 .I Tool-life
...