Force Comparison Protocol,
50 kN to 200 kN
Force testing machines calibration,
Compression mode
SIM
Cárdenas Moctezuma, Alejandro
Torres Guzmán, Jorge C.
Force and Pressure, CENAM
June 2013
Content
1.
2.
3.
4.
5.
6.
7.
8.
INTRODUCTIÓN
OBJETIVE
SCOPE
REQUIREMENTS
ORGANIZATION
CRITERIA FOR EVALUATION OF RESULTS
PRESENTATION OF RESULTS
DATES OF TESTS
Force Comparison Protocol
SIM
3
3
3
3
3
6
6
6
June 2013
Sheet 2 of 6
1.
INTRODUCTION
To support the NMIs CMCs comparisons in force, at SIM area was proposed by the Centro Nacional de
Metrología (CENAM). A comparison in calibration of force testing machines, in compression mode,
within the interval of (50.0 to 200.0) kN was organized, where CENAM is the reference laboratory.
2.
OBJECTIVE
This comparison has the objective to determine the compatibility of results for the calibration of force
testing machines. The reference values will be the results of the reference laboratory (CENAM). The
values to be determined in this comparison are the average error and the uncertainty, for each point of
force calibrated.
3.
SCOPE
The force testing machine will be calibrated in the interval from 50 kN to 200 kN in compression mode,
using direct comparison method, according to the procedure described in this protocol.
4.
REQUIREMENTS
The laboratory must have technical competition to do calibrations of force testing machines, using a force
transducer calibrated, to cover the points of force indicated in this protocol
5.
5.1
ORGANIZATION
Contacts
Logistics Coordination: CENAM
Name
Jorge C. Torres Guzmán
e-mail
jtorres@cenam.mx
Reference Laboratory: CENAM, Force Laboratory.
Name
e-mail
Alejandro Cárdenas Moctezuma
acardena@cenam.mx
5.2
Phone
442-2110500, ext. 3 741
Fax. 442-2110568
Phone
442-2110500, ext. 3 749
Participants
Laboratory
(Country)
Contact person
1
INDECOPI (Peru)
Leonardo de la Cruz García
2
INM (Colombia)
Aristides Dajer Espeleta
adajer@inm.gob.co
3
Lanamme (Costa Rica)
Humberto Tioli
jose.tioli@ucr.ac.cr
Force Comparison Protocol
SIM
e-mail
ldelacruz@indecopi.gob.pe
June 2013
Sheet 3 of 6
5.3
Description of equipment
The arrangement of force testing machine, including force transducer, used as Transference Standard (TS)
is showed in table 1.
Table 1. Transfer Standard data (TS).
Testing Machine
Manufacturer Model
Serial Number
Satec Systems 60 HVL
1393
5.4
Manufacturer
HBM
Transducer
Model
Serial Number
C3H3
G01639
Comparison procedure
To realize the comparison, the TS will be calibrated by the reference laboratory and the participants. At
the end of the measurements, each laboratory will deliver the readings and results. The reference
laboratory will produce a report with the results obtained. The reference laboratory will calibrate the TS
before and after the participation of the other laboratories.
5.4.1
Installation
To install the participating laboratory calibration standard on the TS: Connect the participating
laboratory standard and turn on the TS at least 1 hour before beginning the calibration.
5.4.2
Measurement Process
Initiate the measurements applying three pre-loads, up to 200 kN.
To perform the first round of measurements by increasing force, with the participant standard in
initial position (0°). To do measurements in zero force and then the 5 target force points (50 kN, 75
kN, 100 kN, 150 kN, and 200 kN).
The second round consists in rotating the participant standard 120° with respect to the initial
position, to apply one preload and measure the zero force and then the 5 target force points (50 kN,
75 kN, 100 kN, 150 kN, and 200 kN).
For the third round, rotate the participant standard 240° respect to the initial position, apply one
preload and measure the zero force and then the 5 target force points.
The next diagram describes the measurements process:
Force Comparison Protocol
SIM
June 2013
Sheet 4 of 6
Pre-cargas
Toma de lecturas
100 %
100 %
Corrida 2 120 °
Corrida 1 0 °
0%
0%
100 %
Corrida 3 240 °
0%
5.4.3
Calculations
Each participant laboratory will carry out the necessary corrections to its measurements as it find
suitable.
5.4.4
Uncertainty
To estimate the combined uncertainty of the TS, the minimum components to consider are:
The standard uncertainty due to the calibration system.
The standard uncertainty due to reproducibility.
The standard uncertainty due to resolution.
The standard uncertainty due to zero error.
The expanded uncertainty (U) of the measurements will be reported using a coverage factor of k = 2.
The laboratory should report the uncertainty according to its CMCs declared (or the ones to be
declared).
Force Comparison Protocol
SIM
June 2013
Sheet 5 of 6
6.
CRITERIA FOR EVALUATION OF RESULTS
The criteria to evaluate the compatibility of results for the comparison are:
Normalized Error (En), as shown in the next model.
En 
xlab  xref
2
2
U lab
 U ref
Where:
xlab is the error of the TS, determined by each participant laboratory.
xref is the error of the TS, determined by the reference laboratory.
Ulab is the expanded uncertainty, estimated by each participant laboratory.
Uref is the expanded uncertainty, estimated by the reference laboratory.
And according to the normalized error model:
if |En| ≤ 1 the results are satisfactory,
if |En| > 1 the results are not satisfactory.
7.
PRESENTATION OF RESULTS
The report of the results will be edited by CENAM and distributed among the participants firstly as report
B and ones an agreement have been reached among all participants the final report (report A) will be
edited. The final report will be sent to SIM and to BIPM for inclusion in their data bases.
8.
TEST DATES
The measurements are to be performed by each participating laboratory according to the scheduled
presented in the following table.
Table 2. Measurements dates.
Laboratory (Country)
Contact person
Measurements date
1
CENAM (Mexico)
Alejandro Cárdenas Moctezuma
2013-06-17
2
INDECOPI (Peru)
Leonardo de la Cruz García
2013-06-18
3
INM (Colombia)
Aristides Dajer Espeleta
2013-06-19
4
Lanamme (Costa Rica)
Humberto Tioli
2013-06-20
5
CENAM (Mexico)
Alejandro Cárdenas Moctezuma
2013-06-21
Force Comparison Protocol
SIM
June 2013
Sheet 6 of 6