Iso3408 3 2006 - Standard5104 Ballscrew

INTERNATIONAL ISO
STANDARD 3408-3
Second edition
2006-06-15
Ball screws —
Part 3:
Acceptance conditions and acceptance
tests
Vis à billes —
Partie 3: Conditions et essais de réception
Reference number
ISO 3408-3:2006(E)
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Copyright International Organization for Standardization © ISO 2006

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ISO 3408-3:2006(E)
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ii
Copyright International Organization for Standardization © ISO 2006 – All rights reserved
ISO 3408-3:2006(E)
Contents Page
Foreword............................................................................................................................................................ iv
1 Scope ..................................................................................................................................................... 1
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2 Normative references ........................................................................................................................... 1

3 Terms and definitions........................................................................................................................... 1
4 Test conditions and permissible deviations ...................................................................................... 2
4.1 Classification......................................................................................................................................... 2
4.2 Geometrical tests.................................................................................................................................. 2
5 Acceptance tests .................................................................................................................................. 6
5.1 General................................................................................................................................................... 6
5.2 Travel deviation and variation ............................................................................................................. 7
5.3 Run-out and location tolerances....................................................................................................... 12
5.4 Functional tests .................................................................................................................................. 22
Annex A (normative) Complementary tables ................................................................................................ 24
© ISO 2006 – All rights reserved

Copyright International Organization for Standardization iii
ISO 3408-3:2006(E)
Foreword
ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies
(ISO member bodies). The work of preparing International Standards is normally carried out through ISO
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. ISO collaborates closely with the
International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.
International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.
The main task of technical committees is to prepare International Standards. 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.
Attention is drawn to the possibility that some of the elements of this document may be the subject of patent
rights. ISO shall not be held responsible for identifying any or all such patent rights.
ISO 3408-3 was prepared by Technical Committee ISO/TC 39, Machine tools.
This second edition cancels and replaces the first edition (ISO 3408-3:1992), which has been technically
revised.
ISO 3408 consists of the following parts, under the general title Ball screws:
⎯ Part 1: Vocabulary and designation
⎯ Part 2: Nominal diameters and nominal leads — Metric series
⎯ Part 3: Acceptance conditions and acceptance tests
⎯ Part 4: Static axial rigidity
⎯ Part 5: Static and dynamic axial load ratings and operational lifetime
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iv
INTERNATIONAL STANDARD ISO 3408-3:2006(E)
Ball screws —
Part 3:
Acceptance conditions and acceptance tests
1 Scope
This part of ISO 3408 specifies the technical acceptance conditions for ball screws (see Figure 1) and, in
particular, the respective permissible deviations for the acceptance tests.
NOTE The actual design need not necessarily correspond to that shown in Figure 1.
The respective tests required will be agreed upon between the manufacturer and user.
2 Normative references
The following referenced documents are indispensable for the application of this document. For dated
references, only the edition cited applies. For undated references, the latest edition of the referenced
document (including any amendments) applies.
ISO 230-1:1996, Test code for machine tools — Part 1: Geometric accuracy of machines operating under no-
load or finishing conditions
ISO 286-2:1988, ISO system of limits and fits — Part 2: Tables of standard tolerance grades and limit
deviations for holes and shafts
ISO 3408-1:2006, Ball screws — Part 1: Vocabulary and designation
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 3408-1 apply.
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© ISO for
Copyright International Organization 2006 – All rights reserved
Standardization 1
ISO 3408-3:2006(E)
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4 Test conditions and permissible deviations
4.1 Classification
The tests are graded in six standard tolerance grades (see Table 1) in conformance with ISO 286-2:1988,
Table 1.
Table 1 — Standard tolerance grades
Standard tolerance grade 0

Increasing requirements on accuracy and function
4.2 Geometrical tests
4.2.1 Tolerances
Tolerances on specified travel, ep, for the useful travel, lu (tests E 1.1 and E 1.2), are taken directly from
ISO 286-2:1988, Table 1. Values of ep for useful travel, lu, of greater than or equal to 3 150 mm were
calculated be linear extrapolation (see Table A.1).
Tolerances on travel variation, vup, in micrometres, within useful travel lu were evaluated using the following
equations:
⎯ Grade 0: vup = 0,0035 ⋅ lu + 2,4
⎯ Grade 1: vup = 0,0045 ⋅ lu + 4,6
⎯ Grade 3: vup = 0,009 ⋅ lu + 9,2
⎯ Grade 5: vup = 0,018 ⋅ lu + 18,4
where lu is the geometrical mean, in millimetres, of the extreme lengths of each step of measured travel
given in Table A.1:
lu = lu max ⋅ lu min
Run-out tolerance and orientation tolerances were determined from experience.
4.2.2 Evaluation of the measuring diagrams
4.2.2.1 General
To evaluate the actual mean travel deviation within the useful travel, either a mathematical method — precise
by its nature — or a graphical method — simple and quick and recommended as an approximation method
suitable for everyday evaluation — may be used.
NOTE The travel variation, vua, resulting from the mathematical method may not be the minimum travel variation.
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ISO 3408-3:2006(E)
The graphical method gives the minimum travel variation.
4.2.2.2 Mathematical (least square) method
The actual mean travel deviation, ea, is given by the formula
ea = a + bγ
with
∑ γ i2 ⋅ ∑ ei − ∑ γ i ⋅ ∑ γ i ⋅ ei
a=
n ⋅ ∑ γ i2 − ∑ γ i ⋅ ∑ γ i
and
n ⋅ ∑ γ i ⋅ ei − ∑ γ i ⋅ ∑ ei
b=
n ⋅ ∑ γ i2 − ∑ γ i ⋅ ∑ γ i
where
ea is the actual mean travel deviation in relation to the specified or nominal travel, as appropriate;
γ is the angle of rotation (specified or nominal travel, as appropriate);
γi is the angle of rotation (specified or nominal travel, as appropriate) corresponding to the ith
measuring point;
ei is the travel deviation (or travel) in relation to the specified or nominal travel for the angel of rotation
(or travel) corresponding to the ith measuring point;
n is the number of measuring points.
4.2.2.3 Graphical method [see Figure 3 a) and b)]
The evaluation of the actual mean travel deviation from the travel deviation diagram is carried out as follows:
a) draw the tangents to the actual travel deviation curve at two ore more upper peaks (l1, l2, ...) and repeat
this procedure for the lower peaks (l3, ...);
b) determine the largest respective deviations (e1, e2, e3, ...) parallel to the ordinate, and select from these
the smallest deviation (e2 in the example);
c) draw a straight line through this point of minimum deviation that is parallel to the corresponding peak line
(l′2 parallel to l2 in the example).
The actual mean travel deviation, ea, is the centreline between these parallel lines (l2 and l′2). The bandwidth
within the useful travel, vua, is the distance between these parallel lines, e2, measured parallel to the ordinate.
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Copyright International Organization for Standardization 3
ISO 3408-3:2006(E)
Key
1 ball screw shaft
2 ball
3 ball nut
Figure 1 — Ball screw
Key
1 ball nut
2 angular measuring instrument (permissible error = 10”)
3 measuring slide
4 travel measuring instrument (permissible error = 1 µm)
5 clamping device (e.g. chuck), drive
6 ball screw shaft
Figure 2 — Basic measuring principle
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ISO 3408-3:2006(E)
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a) Deviation esa related to specified travel ls
b) Deviation e0a related to nominal travel l0

NOTE For the excess travel, see Table A.3.
a Travel deviation.
Figure 3 — Determination of the actual mean travel deviation, esa or e0a

ISO 3408-3:2006(E)
5 Acceptance tests
5.1 General
The typical tolerance grades for positioning and transport ball screws are given in Table 2.
Table 2 — Typical tolerance grades for positioning and transport ball screws
Type of ball screw Standard tolerance grade
Positioning 0–1–3–5
Transport 0 – 1 – 3 – 5 – 7 – 10
The test according to Table 3 shall apply, depending on the type of ball screw considered [positioning (type P)
or transport (type T) ball screw].
The basic measuring principle is illustrated in Figure 2.
Table 3 — Travel deviation tests
Type of ball screw

Travel deviations per reference length Positioning Transport
Test
Travel compensation c for useful travel lu Specified by user C=0
Tolerance on specified travel ep E 1.1 E 1.2
Permissible travel variation vup within useful travel E2 —
Permissible travel variation v300p within 300 mm travel E3 E3
Permissible travel variation v2πp within 2π rad E4 —
Tests and tolerances to the ball nut displacement are relative to the ball screw shaft.
A pitch-to-pitch measurement may be carried out using a measuring ball by touching the ball track of a non-
rotating ball screw shaft. For the measuring intervals, see Table A.2.
The travel variation v2π within 2π rad is determined over nine measurements (8 × 45°) per revolution, or
continuously within one thread (at the start, in the middle and at the end of useful travel), provided that this
has been the subject of special agreement.
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ISO 3408-3:2006(E)
5.2 Travel deviation and variation
Object: Positioning ball screw

E 1.1
Checking of the mean travel deviations, esa and e0a, within the useful travel, lu:
a) for the specified travel, ls;
b) for the nominal travel, l0.
Diagram
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a Actual travel deviation.

Permissible deviations Observations and remarks
Useful travel Tolerance on specified travel
lu ep
mm µm
Standard tolerance grade
> u 0 1 3 5 7 10 a)
0 315 4 6 12 23 — — esa = ________ µm
315 400 5 7 13 25 — —
400 500 6 8 15 27 — —
500 630 6 9 16 32 — — b)
630 800 7 10 18 36 — — The travel compensation c
800 1 000 8 11 21 40 — — shall be specified by the
1 000 1 250 9 13 24 47 — — user
1 250 1 600 11 15 29 55 — — c = ________
1 600 2 000 — 18 35 65 — —
e0a = ________ µm
2 000 2 500 — 22 41 78 — —
2 500 3 150 — 26 50 96 — —
3 150 4 000 — 32 62 115 — —
4 000 5 000 — — 76 140 — —
5 000 6 300 — — — 170 — —
Measuring instruments
See Figure 2.
Test instructions
See Figure 2.
Copyright International Organization for Standardization© ISO 2006 – All rights reserved 7
ISO 3408-3:2006(E)
Object: Transport ball screw

E 1.2
Checking of the mean travel deviation e0a, within the useful travel, lu:
Diagram
Tolerance on specified travel

ep
µm
0 1 3 5 7 10 e0a = ________ µm
lu
ep = ± ⋅ v 300p
300
See Figure 2.
Test instructions
See Figure 2.
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ISO 3408-3:2006(E)

E2
Checking of the travel variation vu within the useful travel, lu:
Diagram
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Useful travel Travel variation
lu vup
mm µm
> u 0 1 3 5 7 10
0 315 3,5 6 12 23 — —
315 400 3,5 6 12 25 — —
vua = ________ µm
400 500 4 7 13 26 — —
500 630 4 7 14 29 — —
630 800 5 8 16 31 — —
800 1 000 6 9 17 34 — —
1 000 1 250 6 10 19 39 — —
1 250 1 600 7 11 22 44 — —
1 600 2 000 — 13 25 51 — —
2 000 2 500 — 15 29 59 — —
2 500 3 150 — 17 34 69 — —
3 150 4 000 — 21 41 82 — —
4 000 5 000 — — 49 99 — —
5 000 6 300 — — — 119 — —
See Figure 2.
Test instructions
See Figure 2.
vua is the smallest distance, measured parallel to the ordinate, between two lines parallel to the mean travel
that envelop the actual travel deviation over the useful travel lu.

ISO 3408-3:2006(E)
Object: Positioning or transport ball screw

E3
Checking of the travel variation v300 within an axial travel of 300 mm:
Diagram

0 1 3 5 7 10
v300p
µm
v300a max = _______ µm
3,5 6 12 23 52a 210a
a Only for transport ball screws.
See Figure 2.
Test instructions
See Figure 2.
v300a is the smallest distance, measured parallel to the ordinate, found when a template is moved along the
actual travel deviation and parallel to the mean travel, which contains the actual travel deviation over any
300 mm length along the useful travel.
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ISO 3408-3:2006(E)

E4
Checking of the travel variation v2πp within 2π rad:
Diagram
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0 1 3 5 7 10
v2πp v2πa max = ________ µm
µm
3 4 6 8 — —
See Figure 2.
Test instructions
See Figure 2.
v2πa is the smallest distance, measured parallel to the ordinate, found when a template is moved along the
actual travel deviation and parallel to the mean travel, which contains the actual travel deviation over any
distance corresponding to one revolution, i.e. 2π rad along the useful travel.

ISO 3408-3:2006(E)
5.3 Run-out and location tolerances
Object: Transport or positioning ball screw

E5
Measurement of radial run-out, t5, of ball screw shaft outer diameter for ascertaining straightness related to
AA′ per length l5:
Diagram
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Nominal diameter Standard tolerance grade
d0 l5
mm mm 0 1 3 5 7 10
t5a = _______ µm
> u l5p, µm, for l5
6 12 80
12 25 160
25 50 315 16 20 25 32 40 80 t5max a = ________ µm
50 100 630
100 200 1 250
l1/d0 l5max p, µm, for l1 > 4l5
> u
— 40 32 40 50 64 80 160
40 60 48 60 75 96 120 240
60 80 80 100 125 160 200 400
80 100 128 160 200 256 320 640
Dial gauge and V-blocks
Test instructions Reference to test code ISO 230-1:1996, 5.612.2
Place ball screw in identical V-blocks at points A and A′.
Set dial gauge with measuring shoe at the distance l5 perpendicular to the cylindrical surface.
Rotate the ball screw slowly while recording the changes in the measurements at specified measuring
intervals.
NOTE 1 Optionally, measurement by supporting the ball screw shaft at both centres can be used by agreement.
NOTE 2 If l1 < 2l5 take the measurement at l1/2.
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ISO 3408-3:2006(E)

E 6.1
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Measurement of redial runout, t6.1, of bearing seat related to AA′, per unit length l:
For l6 u l (l see table)
l
For l6 > l to be valid t6.1a u t6.1p 6
l
Diagram
Key
1 bearing seat

d0 l
mm mm 1 3 5 7 10
> u t6.1p, µm, for l Diameter t6.1a
6 20 80 10 12 20 40 63 ______ mm _____ µm
______ mm _____ µm
20 50 125 12 16 25 50 80
______ mm _____ µm
50 125 200 16 20 32 63 100
______ mm _____ µm
125 200 315 — 25 40 80 125
Place the dial gauge at the distance l6 perpendicular to the cylindrical surface.
Rotate the ball screw slowly and record the dial gauge readings.

ISO 3408-3:2006(E)

E 6.2
Measurement of radial runout, t6.2, of bearing seat related to the centreline of the screw part:
Diagram
Key
1 bearing seat

d0
0 1 3 5 —
mm
> u t6.2p, µm
— 8 3 5 8 10
8 12 4 5 8 11
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12 20 4 6 9 12
20 32 5 7 10 13 —
32 50 6 8 12 15
50 80 7 9 13 17
t6.2a = ________ µm
80 125 — 10 15 20
Dial gauge and V-blocks (assembled nut or jig for exclusive use)
Support a screw shaft at near both ends of threaded part, using the plural number of balls of the same size
as the balls used.
Place the dial gauge at the outside diameter of the ball bearing seat of the screw shaft.
Rotate the screw shaft one revolution and record the dial gauge readings.
NOTE This test can be used on an agreement between user and manufacturer. If used, it replaces test E 6.1.
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ISO 3408-3:2006(E)
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E 7.1
Measurement of radial run-out, t7.1, of journal diameter related to the bearing seat by determining the
difference:
for l7 u l (l see table)
l
for l7 > l to be valid t7.1a u t7.1p 7
l
Diagram
Key
1 bearing seat

d0 l
1 3 5 7 10
mm mm
Diameter t7.1a
> u t7.1p, µm, for l
_____ mm _____ µm
6 20 80 5 6 8 12 16
_____ mm _____ µm
20 50 125 6 8 10 16 20
_____ mm _____ µm
50 125 200 8 10 12 20 25 _____ mm _____ µm
125 200 315 — 12 16 25 32
Place the dial gauge at the distance l7 perpendicular to the cylindrical surface.
Rotate the ball screw slowly and record the dial gauge readings.

ISO 3408-3:2006(E)

E 7.2
Measurement of radial run-out, t7.2, of the journal diameter related to the centreline of the bearing seat:
Diagram
Key
1 bearing seat

d0
0 1 3 5 —
mm
> u t7.2p, µm
— 8 3 5 8 10
8 12 4 5 8 11
12 20 4 6 9 12
t7.2a = __________ µm
20 32 5 7 10 13 —
32 50 6 8 12 15
50 80 7 9 13 17
80 125 — 10 15 20
Support a screw shaft at its supporting bearing seats horizontally using V-blocks.
Put the dial gauge at the outside diameter of the journals.
NOTE 1 This test can be used on an agreement between user and manufacturer. If used, it replaces test E 7.1.
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ISO 3408-3:2006(E)

E 8.1
Measurement of axial run-out, t8.1, of shaft (bearing) faces related to AA′:
Diagram
t8.1a u t8.1p − |∆|
where ∆ is the deviation of straightness.
Key
1 bearing seat

d0
1 3 5 7 10
mm
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Diameter t8.1a
> u t8.1p, µm
_____ mm _____ µm
6 63 3 4 5 6 10
_____ mm _____ µm
63 125 4 5 6 8 12
125 200 — 6 8 10 16
_____ mm _____ µm
Test instructions Reference to test code ISO 230-1:1996, 5.632
Place ball screw at points A and A′ on V-blocks.
Secure the ball screw shaft in the axial direction against movement (e.g. by placing a ball between the
centres of the ball screw shaft and the mounting surface).
Place the dial gauge perpendicular to the end face of the journal and to the cylindrical surface of the
corresponding diameter.

ISO 3408-3:2006(E)

E 8.2
Measurement of axial run-out, t8.2, of the shaft faces related to the centreline of the screw shaft:
Diagram
Key
1 bearing seat
d0
0 1 3 5 —
mm
> u t8.2p, µm
— 8 2 3 4 5
8 12 2 3 4 5
12 20 2 3 4 5
t8.2a = ___________ µm
20 32 2 3 4 5 —
32 50 2 3 4 5
50 80 3 4 5 7
80 125 — 4 6 8
Support a screw shaft horizontally by the V-blocks at the supporting bearing seats while butting one end of
the screw shaft to the fixed face.
Place the dial gauge at its supporting bearing seat end face.
NOTE 1 This test can be used by agreement between user and manufacturer. If used, it replaces test E 8.1.
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ISO 3408-3:2006(E)

E9
Measurement of axial run-out, t9, of ball nut location face related to AA′ (for preloaded ball nuts only):
Diagram

Flange diameter Standard tolerance grade
D2
mm 0 1 3 5 7 10
> u t9p, µm
16 32 8 10 12 16 20 t9a max = ___________ µm

32 63 10 12 16 20 25
63 125 12 16 20 25 32 —
126 250 16 20 25 32 40
250 500 — — 32 40 50
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System preloaded. Place the ball screw on V-blocks at points A and A′.
Secure the ball screw shaft in the axial direction against movement (e.g. by placing a ball between the
centres of the ball screw shaft and the mounting surface).
Place the dial gauge perpendicular to the flange face at the outer rim of the inspection diameter D2.
Secure the ball nut against rotation on the ball screw shaft.
Rotate the ball screw shaft and record the dial gauge readings.

ISO 3408-3:2006(E)

E 10
Measurement of radial run-out, t10, of ball nut location diameter related to AA′ (for preloaded and rotating
ball nuts only):
Diagram
a Fixed.
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Ball nut body outer Standard tolerance grade
diameter
D1 0 1 3 5 7 10
mm
> u t10p, µm
16 32 8 10 12 16 20
32 63 10 12 16 20 25
63 125 12 16 20 25 32 — t10a max = ___________ µm
125 250 16 20 25 32 40
250 500 — — 32 40 50
System preloaded. Place the ball screw on V-blocks at points A and A'.
Place the dial gauge perpendicular to the cylindrical surface of ball nut location diameter D1.
Secure the ball screw shaft.
Rotate the ball nut body slowly. Record the dial gauge readings.
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ISO 3408-3:2006(E)

E 11
Deviation of parallelism, t11, of rectangular ball nut related to AA′ (for preloaded ball nuts only):
Diagram
a Fixed.

0 1 3 5 7 10
t11p, µm, for each 100 mm (cumulative) t11a = ___________ µm
14 16 20 25 32 —
System preloaded.
Place ball screw on V-blocks at points A and A′.
Place the dial gauge perpendicular to the inspection surface and probe along the specified inspection
length l.
Record the dial gauge readings.
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ISO 3408-3:2006(E)
5.4 Functional tests

E 12
Measurement of dynamic preload drag torque, ∆Tp:
Diagram Tp = F × l without end seals
Tt = Ft × l with end seals
ln = ball nut length
Key
X travel
Y dynamic preload drag
torque
1 force indicator

Tp0 Standard tolerance grade Without end seals
Nm 0 1 3 5 7 10
> u ∆Tpp,% of Tp0, for lu / d 0 u 40 ; l u u 4 000 mm l = ____________ m
0,2 0,4 30 35 40 50 — — F =___________ N
0,4 0,6 25 30 35 40 — —
0,6 1,0 20 25 30 35 40 — Tpa = _________ Nm
1,0 2,5 15 20 25 30 35 —
∆Tpa = ± _______ Nm
2,5 6,3 10 15 20 25 30 —
6,3 10 — — 15 20 30 — ≈ ± _______ % of Tp0
> u ∆Tpp,% of Tp0, for 40 < l u / d 0 u 60 ; l u u 4 000 mm
0,2 0,4 40 40 50 60 — —
0,4 0,6 35 35 40 45 — — With end seals
0,6 1,0 30 30 35 40 45 —
Ft = ___________ N
1,0 2,5 25 25 30 35 40 —
2,5 6,3 20 20 25 30 35 — Tta = __________ Nm
6,3 10 — — 20 25 35 —
> u ∆Tpp,% of Tp0; lu > 4 000 mm ∆Tta = ± _________ Nm
— 0,6 Not specified
≈ ± _______ % of Tp0
0,6 1,0 — — 40 45 50 —
1,0 2,5 — — 35 40 45 —
2,5 6,3 — — 30 35 40 —
6,3 10 — — 25 30 35 —
Test bench with recorder for force value measured.
Test instructions
System preloaded (with or without end seals).
For the recording of the radial preload force, couple the ball nut body to a load cell at the distance l from the
axis of rotation.
Take recordings of the force indicator at a rotational speed 100 min-1 in both directions of rotation a.
For lubrication, use a lubricant of ISO viscosity grade 100 a.
a Other rotational speeds, lubricants and measuring instruments may be used by agreement between the user and the
manufacturer.
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ISO 3408-3:2006(E)

E 13
Measurement of axial rigidity, Rnu:
Diagram
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Key
X elastic deformation, ∆l
Y load, F
a Fixed against rotation.
b Axially fixed.
Not specified Fpr = ___________ N
F1 = ___________ N
F2 = ___________ N
∆l1 = ____________ µm
∆l2 = ____________ µm
Rnu1 = __________ N/µm
Rnu2 = __________ N/µm
Dial gauges and load cell.
Test instructions
Fix the preloaded ball nut axially in both directions and secure the ball screw shaft against rotation.
Place the dial gauge supports on the ball screw shaft and touch the measuring stylus against the face of the
ball nut body, as near as possible and as parallel as possible to the ball screw shaft axis.
Apply the axial load F1 = 0,5Fpr or F2 = 2Fpr to the ball screw shaft in tension and in compression.
Fpr is the preload and ∆l1 or ∆l2 are the elastic deformations (reversal range) caused by the axial test loads
± F1 and ± F2 respectively.
2 ⋅ F1 Fpr
Rigidity in the ranges ± F1: Rnu1 = =
∆l1 ∆l1
2 ⋅ ( F2 − F1 ) 3 ⋅ Fpr
Rigidity in the range + F1 to + F2 and − F1 to − F2: Rnu2 = =
∆l 2 − ∆l1 ∆l 2 − ∆l1
Other test loads F may be used by agreement between the user and the manufacturer.

ISO 3408-3:2006(E)
Annex A
(normative)
Complementary tables
Table A.1 — Tolerance values on specified travel, ep, for a band width per 300 mm (v300)
and for a mean travel deviation, e, and for the standard tolerance grades
according to ISO 286-2:1988
Measured travel Standard tolerance grade

mm
0 1 3 5 7 10
Tolerance on specified travel, ep
> u
µm
— 315 4 6 12 23 52 210
315 400 5 7 13 25 57 230
400 500 6 8 15 27 63 250
500 630 6a 9 16 32 70 280
630 800 7a 10 18 36 80 320
800 1 000 8a 11 21 40 90 360
1 000 1 250 9a 13 24 47 105 420
1 250 1 600 11a 15 29 55 125 500
1 600 2 000 13a 18 35 65 150 600
2 000 2 500 15a 22 41 78 175 700
2 500 3 150 18a 26 50 96 210 860
--`,,```,,,,````-`-`,,`,,`,`,,`---
3 150 4 000 32 a 62 a 115 a 260 a 1 050 a
4 000 5 000 39 a 76 a 140 a 320 a 1 300 a
5 000 6 300 48 a 92 a 170 a 390 a 1 550 a

a These values were calculated by linear extrapolation from the IT values in accordance with ISO 286-2 for sizes above 500 mm and
less than or equal to 3 150 mm.
24
ISO 3408-3:2006(E)
Table A.2 — Minimum number of measurements over 300 mm (measuring intervals)
Specified tolerance grade

Lead
Ph 0 1 3 5 7 10
mm
Minimum number of measurements
2,5 20 15 10 6 3 1
5 20 15 10 6 3 1
10 15 10 5 3 1 1
20 6 5 4 3 1 1
40 — — 2 1 1 1
Table A.3 — Maximum excess travel

Dimensions in millimetres
Lead, Ph 2,5 5 10 20 40
Maximum excess travel, lmax 10 20 40 60 100
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ISO 3408-3:2006(E)
ICS 25.060.99
Price based on 25 pages
--`,,```,,,,````-`-`,,`,,`,`,,`---
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INTERNATIONAL ISO

Copyright International Organization for Standardization © ISO 2006

2 Normative references ........................................................................................................................... 1

© ISO 2006 – All rights reserved

⎯ Part 1: Vocabulary and designation

⎯ Part 2: Nominal diameters and nominal leads — Metric series

⎯ Part 3: Acceptance conditions and acceptance tests

⎯ Part 4: Static axial rigidity

ISO 3408-1:2006, Ball screws — Part 1: Vocabulary and designation

3 Terms and definitions

4 Test conditions and permissible deviations

Table 1 — Standard tolerance grades

Standard tolerance grade 0

Standard tolerance grade 1

Standard tolerance grade 3

Standard tolerance grade 7

Standard tolerance grade 10

4.2 Geometrical tests

⎯ Grade 0: vup = 0,0035 ⋅ lu + 2,4

⎯ Grade 1: vup = 0,0045 ⋅ lu + 4,6

⎯ Grade 3: vup = 0,009 ⋅ lu + 9,2

⎯ Grade 5: vup = 0,018 ⋅ lu + 18,4

Run-out tolerance and orientation tolerances were determined from experience.

4.2.2 Evaluation of the measuring diagrams

The graphical method gives the minimum travel variation.

4.2.2.2 Mathematical (least square) method

The actual mean travel deviation, ea, is given by the formula

γ is the angle of rotation (specified or nominal travel, as appropriate);

n is the number of measuring points.

4.2.2.3 Graphical method [see Figure 3 a) and b)]

© ISO 2006 – All rights reserved

Figure 1 — Ball screw

Figure 2 — Basic measuring principle

b) Deviation e0a related to nominal travel l0

Figure 3 — Determination of the actual mean travel deviation, esa or e0a

© ISO 2006 – All rights reserved

Type of ball screw Standard tolerance grade

The basic measuring principle is illustrated in Figure 2.

Table 3 — Travel deviation tests

Type of ball screw

Travel compensation c for useful travel lu Specified by user C=0

Tolerance on specified travel ep E 1.1 E 1.2

Permissible travel variation vup within useful travel E2 —

Permissible travel variation v300p within 300 mm travel E3 E3

Permissible travel variation v2πp within 2π rad E4 —

5.2 Travel deviation and variation

Object: Positioning ball screw

a Actual travel deviation.

Object: Transport ball screw

a Actual travel deviation.

Permissible deviations Observations and remarks

Tolerance on specified travel

Object: Positioning ball screw

© ISO 2006 – All rights reserved

Object: Positioning or transport ball screw

a Actual travel deviation.

Permissible deviations Observations and remarks

Object: Positioning ball screw

a Actual travel deviation.