Acceptance and re-verification tests for

Coordinate Measuring Machines.

A brief introduction.
 ISO 10360

Acceptance and re-verification Tests for A brief introduction

Coordinate Measuring Machines (CMMs)
Since 1994 the ISO 10360 Acceptance and
Consisting of: re-verification Tests for Coordinate Measur-
ing Machines is in force. This standard
ISO 10360-1 (2000): describes the procedures to verify the perfor-
Vocabulary 1) mance of Coordinate Measuring Machines
(CMMs).
ISO 10360-2 (2001):
CMMs used for measuring size Before purchasing a CMM, it is important to
get familiar with the basics of this standard.
ISO 10360-3 (2000): The following pages are intended as a guide
through the ISO 10360. Some terms and
CMMs with the axis of a rotary table as
definitions have been simplified for a more
the fourth axis
easy understanding.

ISO 10360-4 (2000):

Although the ISO 10360 is an international
CMMs used in scanning measuring mode accepted standard, there are still CMM
makers who specify their CMMs according to
ISO 10360-5 (2000): other outdated national standards, such as
CMMs using multiple-stylus probing VDI/VDE 2617 (German) or B89 (American).
system
Only if customers insist on specifications
ISO 10360-6 (1999): based on ISO 10360, they can compare the
Estimation of errors in computing Gauss- performance of CMMs made by different
ian associated features (1) manufacturers.

(1)
Not dealt with in this introduction The original ISO standards can be obtained
for example through publishing house Beuth
at www.beuth.de.

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ISO 10360-2 CMMs used for measuring size

Volumetric Length Measuring Error E Volumetric Probing Error P

(Form Error of the CMM)

Test procedure
A set of 5 length gauges is measured 3 times A reference sphere is measured with 25
in 7 spatial positions. evenly distributed points.

Total number of measurements: 5 x 3 x 7 = 105 P = (Rmax - Rmin = Sphere form)

Form error of the CMM
100% of results must be within the specifica-
tion.

General remark:
The ISO 10360 also uses the terms MPEE, MPEP, MPETHP etc.
MPE stand for Maximum Permitted Error. In CMM metrology the specifications
are colloquially referred to as just E, P, THP etc.

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 ISO 10360-2 Where do E and P apply?

Volumetric Length Measuring Error E

describes the CMM error when measuring

Distances

Diameters

Position Tolerance

Volumetric Probing Error P

describes the CMM error at all form inspections

Free Form Tolerances

Straightness

Flatness

Roundness

Cylindricity

in single point modus.

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ISO 10360-3 CMMs with the axis of a rotary table as the fourth axis

Rotary table Errors are:

Radial Error FR - Tangential Error FT - Axial Error FA

Test procedure 6. Rotary table error - Radial

1. Fix spheres A and B on RT. FR = Max. range in X (A or B)
(recom.: h = 400, r = 200mm).(1)
2. Measure sphere B and set center- Rotary table error - Tangential
point to zero (0,0,0). FT = Max. range in Y (A or B)
3. Measure sphere A in 14 positons:
7 positions from 0 to 720 Rotary table error - Axial
7 positions from 720 to 0. FA = Max. range in Z (A or B)
4. Measure sphere B in 14 positions:
7 from 0 to 720
7 from 720 to 0
At the last position (28) measure
sphere A one more time
5. Calculate range of X, Y and Z for
A and B.

The errors of a rotary table generally increase

1)

with h, radius r and table load.

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 ISO 10360-3 CMMs with the axis of a rotary table as fourth axis

Evaluation of a rotary table test according to ISO 10360-3

Position Angle Measured Coordinates for

No. Test sphere A Test sphere B
XA YA ZA XB YB ZB
0 0 401.6647 0.0000 -398.276 0,0000 0,0000 0,0000
1 103 401.6632 0.0011 -398.2285 - - -
2 206 401.6631 -0.0016 -398.2270 - - -
3 309 401.6625 -0.0014 -398.22 92 - - -
4 412 401.6652 0.0012 -398.2285 - - -
5 515 401.6648 0.0009 -398.2290 - - -
6 618 401.6660 -0.0011 -398.2270 - - -
7 721 401.6646 -0.0018 -398.2263 - - -
8 618 401.6658 -0.0015 -398.2273 - - -
9 515 401.6635 0.0006 -398.2265 - - -
10 412 401.6623 0.0003 -398.2260 - - -
11 309 401.6649 -0.0011 -398.2264 - - -
12 206 401.6640 0.0009 -398.2278 - - -
13 103 401.6638 0.0004 -398.2285 - - -
14 0 401.6655 -0.0013 -398.2277 0.0012 -0.0011 0.0015
15 -103 - - - -0.0005 0.0005 0.0007
16 -206 - - - -0.0011 0.0009 -0.0003
17 -309 - - - 0.0014 0.0014 -0.0010
18 -412 - - - 0.0020 0.0000 0.0002
19 -515 - - - 0.0001 -0.0019 0.0012
20 -618 - - - -0.0010 -0.0010 0.0012
21 -721 - - - 0.0017 0.0016 0.0009
22 -618 - - - -0.0003 0.0003 0.0013
23 -515 - - - -0.0009 -0.0003 -0.0008
24 -412 - - - -0.0017 -0.0018 -0.0003
25 -309 - - - 0.0011 0.0004 0.0006
26 -206 - - - 0.0018 0.0015 0.0004
27 -103 - - - 0.0005 0.0004 0.0014
28 0 401.6628 0.0020 -398.2290 -0.0018 -0.0009 -0.0007
Rotary Table Error FRA FTA FAA FRB FTB FAB
3.7m 3.8m 3.2m 3.8 3.5 2.5

Test result:
Rotary table error in radial direction FR = 3.8m
Rotary table error in tangential direction FT = 3.8m
Rotary table error in axial direction FA = 3.2m

Marked with are the maximum deviations.

Remark: Rotary table errors are always specified for Rotary table and CMM. The same rotary table
used on different types of CMMs will have different specifications.

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ISO 10360-4 CMMs used in scanning measuring mode

Scanning Probing Error THP Test procedure

A reference sphere, 25 mm, is scanned at
4 defined lines.

THP is the range of all radii (spere form, i.e.

Form Error of the CMM in scanning mode).

Important:
2 3 The scanning measuring error depends on the
scanning speed. Therefore the CMM maker has
1 to specifiy the THP-value with the correspond-
4 ing total measuring time, for example THP =
1.5 m at t = 45 sec.

Where does THP apply?

THP defines the measuring error of the CMM

for Form Measurements:

Straightness

Flatness

Roundness

Cylindricity

Free Form Tolerances

when the CMM is used in scanning mode.

Note: THP means scanning on a Predefined

path, collecting a High density of points. The
ISO 10360-4 describes also test procedures
for TLP, THN and TLN. But they are usually not
specified in CMM metrology.

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 ISO 10360-5 CMMs using multiple-stylus probing system

Multiple Stylus Errors of Location, Size and Form

Fixed probing system Articulating probing system

Test procedure
Qualify 5 orthogonal styli of length L. Qualify 1 stylus (length 20 mm) with extension
LE in 5 orthogonal positions.

A high precision reference sphere is measured with each stylus resp. with each qualified position.
Every sphere measurement takes 25 probings, total number of probings is 5 x 25 = 125.

Evaluations(1):
Multiple Stylus Location Error
ML resp. AL = Max. Range of the 5 centre coordinates in X, Y or Z.

Multiple Stylus Size Error

MS resp. AS = Deviation from the calibrated diameter (all 125 points).

Multiple Stylus Form Error

MF resp. AF = Form error of the calculated sphere (all 125 points).

A stands for articulating probe system

1)

M stands for fixed probe system

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ISO 10360-5 CMMs using multiple-stylus probing system

Multiple Stylus Errors of Location, Size and Form: Evaluations

Multiple Stylus Size Error AS / MS (1)

over 125 points
from 5 different styli (fixed head) or 5 dif-
ferent orientations (articulating head).

Multiple Stylus Form Error AF / MF (1)

over 125 points
from 5 different styli (fixed head) or 5 different
orientations (articulating head).

Multiple Stylus Location Error AL / ML (1)

Biggest axial distance in X, Y or Z between the
5 measured center points.

A stands for articulating probe system

1)

M stands for fixed probe system

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 ISO 10360-5 Where do AL, AS and AF apply?

Multi Stylus Probing Errors for CMMs with Example:

articulating probe system CMM specs:
AL (Location), E = 2.4 + L / 300; P = 2.8m
AS (Size) and AL = 4.8m; AS = 1.9m
AF (Form) AF = 8.6m

have to be considered, if for a measurement of

Measuring feature:
a feature the probe system has to be articu-
lated. Distance 500 0.030

Max. CMM measuring error for this feature:

= AL + E
= 4.8 + 2.4 + 500 / 300
= 4.8 + 2.4 + 1.7
8.9m

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ISO 10360-5 Where do ML, MS and MF apply?

Multi Stylus Probing Errors for CMMs with a Example:

fixed probe system CMM specs:
ML (Location), E = 0.9 + L / 600; P = 0.9m
MS (Size) and ML = 1.9m; MS = 0.5m
MF = 3.0m
MF (Form)
have to be considered, if for a measurement of Measured feature:
a feature more than 1 stylus is used.
Distance 500 0.030

Max. CMM measuring error for this feature: Max. CMM measuring error for this feature:
= ML + E =E
= 1.9 + 0.9 + 500 / 600 = 0.9 + 500 / 600
= 1.9 + 0.9 + 0.8 = 0.9 + 0.8
3.6m 1.7m

In this case the multiple styli error ML has to be considered.

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 Attention should also be paid to the following restrictions

1. Styli
For which styli are the stated measuring errors For example the specification for the length
valid? measuring error E is given by 3 different CMM
For information on that please check the fine makers for the following styli:
print in the data sheets.
Regarding this important subject there are big
differences between the various CMM makers.

CMM maker A: CMM maker B: CMM maker C:

scale 1 : 3
Attention:
If the data sheet does not clearly specify, for which styli length and diameter the stated measuring
errors are valid check with the manufacturer.

2. Environment, throughput and part material

When evaluating the measuring errors of a CMM, it is also important to know:
For which temperature range and temperature gradients are the stated specifications valid?

For which machine dynamics (probing frequency, acceleration and moving speed) are the stated
specifications valid?

For which part material are the stated specifications valid?

For steel (coefficient of expansion 11.5m/m/K) or only for Invar/Zerodur (coefficient of expansion
close to 0m/m/K)

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Ratio of CMM measuring error to tolerance

CMM Capability Charts

This chart is used to determine which CMM specification E is required in order to measure a distance
or a diameter with a given tolerance.

Tolerance Distance or diameter [mm]

[mm] 50 100 200 400 600 1000 2000
0.003 0.3+L/1000
0.005 0.5+L/900 0.4+L/1000 0.3+L/1000
0.007 0.7+L/700 0.5+L/500 0.5+L/1000 0.3+L/1000
0.010 0.9+L/400 0.8+L/500 0.6+L/500 0.5+L/800 0.4+L/1000
0.015 1.3+L/300 1.2+L/350 0.9+L/350 0.7+L/500 0.6+L/800 0.4+L/900
0.020 1.8+L/200 1.6+L/250 1.3+L/300 0.9+L/350 0.8+L/500 0.6+L/700
0.030 2.8+L/200 2.6+L/250 2.2+L/250 1.7+L/300 1.5+L/400 1.0+L/500
0.050 4.7+L/150 4.3+L/150 4.0+L/200 3.0+L/200 2.6+L/400 1.7+L/300 1.0+L/500
0.070 6.5+L/100 6.0+L/100 5.7+L/150 5.0+L/200 4.0+L/200 2.0+L/200 2.0+L/400
0.100 9.5+L/100 9.0+L/100 8.0+L/100 6.0+L/100 6.0+L/150 5.0+L/200 4.4+L/350

Example: A diameter of 400 mm has a tolerance of 0.010 mm.

For the inspection of this feature a CMM with a length measuring error of
E = 0.5 + L / 800 [m] or better is required.

CMM Capability Analysis

By entering all critical features in the Excel chart below, the ratio of CMM error to tolerance for all
features can be easily determined

CMM type Leitz Reference 15.9.7

Measuring error according to ISO 10360-2 E= 0.9 + L / 400 [m]
No. feature nom. value upper tol. lower tol. CMM error % of the ratio
[mm] [mm] [mm] [mm] tolerance
1 diameter 8 0.010 -0.010 0.0009 9% 1 : 10.9
2 distance 985 0.015 -0.015 0.0034 22 % 1 : 4.5
3 distance 38 0.010 -0.010 0.0010 10 % 1 : 10.1
4 diameter 320 0.010 -0.010 0.0017 17 % 1 : 5.9
5 diameter 336 0.020 -0.020 0.0017 9% 1 : 11.5
6 diameter 86 0.000 -0.024 0.0011 9% 1 : 10.8
7 distance 168 0.025 0.000 0.0013 11 % 1 : 9.5
8 distance 70 0.012 -0.012 0.0011 9% 1 : 11.2

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 Example: Test report according to ISO 10360-2

Volumetric length measuring error E

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Example: Test report according to ISO 10360-4

Volumetric scanning probing error THP

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 Leitz
The Leitz brand as part of Hexagon Metrology
stands for high accuracy coordinate measuring
machines, gear inspection centers and probes.
Leitz measurement systems master quality as-
surance tasks equally well both in metrology labs
as well as on the shop floor. The development
and production are located in Wetzlar, Germany.
For more than 30 years Leitz has been offering
its customers the best innovative measurement
technology available. The primary goal remains
offering modern solutions for demanding mea-
surement tasks.

Hexagon Metrology
Hexagon Metrology is part of the Hexagon group
and brings leading brands from the field of
industrial metrology under one roof.

Hexagon Metrology GmbH

Leitz Division
Siegmund-Hiepe-Strae 2 12
35578 Wetzlar
Germany

E-mail contact.leitz@hexagonmetrology.com
Phone +49 (0) 6441 207 0
Fax +49 (0) 6441 207 122

www.leitz-metrology.com
www.hexagonmetrology.com

M42-510-004-231

2010 Hexagon Metrology GmbH

780148

All right reserved.

Printed in Switzerland. February 2010.

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