ASTM E2658-11

Standard Practices for Verification of Speed for Material Testing Machines

SIGNIFICANCE AND USE
Material testing requires repeatable and predictable testing machine speed. The speed measuring devices integral to the testing machines may be used for measurement of crosshead speed over a defined range of operation. The accuracy of the speed value shall be traceable to a National or International Standards Laboratory. Practices E2658 provides procedures to verify testing machines, in order that the indicated speed values may be traceable. A key element to having traceability is that the devices used in the verification produce known speed characteristics, and have been calibrated in accordance with adequate calibration standards.  
Verification of testing machine speed at a minimum consists of either or both of the following options:
Verifying the capability of the testing machine to move the crosshead at the speed selected.
Verifying the capability of the testing machine to adequately indicate the speed of the crosshead.
Where applicable, determine the testing machine's ramp-to-speed condition. This condition can be significant especially when verifying fast speeds or testing conditions with very short testing durations.
This procedure will establish the relationship between the actual crosshead speed and the testing machine indicated speed and or selected setting. It is this relationship that will allow confidence in the reported displacement over time data acquired by the testing machine during use.
Note 1—Many material tests never reach the desired test speed. Unless the actual data from the material test is examined, it is often impossible to know if the test speed has been reached or is repeatable from test to test.
SCOPE
1.1 These practices cover procedures and requirements for the calibration and verification of testing machine speed by means of standard calibration devices. This practice is not intended to be complete purchase specifications for testing machines.
1.2 These practices apply to the verification of the speed application and measuring systems associated with the testing machine, such as a scale, dial, marked or unmarked recorder chart, digital display, setting, etc. In all cases the buyer/owner/user must designate the speed-measuring system(s) to be verified.
1.3 These practices give guidance, recommendations, and examples, specific to electro-mechanical testing machines. The practice may also be used to verify actuator speed for hydraulic testing machines.
1.4 This standard cannot be used to verify cycle counting or frequency related to cyclic fatigue testing applications.
1.5 Since conversion factors are not required in this practice, either SI units (mm/min), or English [in/min], can be used as the standard.
1.6 Speed measurement values and or settings on displays/printouts of testing machine data systems-be they instantaneous, delayed, stored, or retransmitted-which are within the Classification criteria listed in Table 1, comply with Practices E2658.
1.7 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.

General Information

• Status: Historical
• Publication Date: 31-Jan-2011
• ICS: 19.060 - Mechanical testing
• Technical Committee: E28 - Mechanical Testing
• Drafting Committee: E28.01 - Calibration of Mechanical Testing Machines and Apparatus

Relations

• Referred By: ASTM E9-19 - Standard Test Methods of Compression Testing of Metallic Materials at Room Temperature
• Effective Date: 01-Feb-2011
• Referred By: ASTM E8/E8M-22 - Standard Test Methods for Tension Testing of Metallic Materials
• Effective Date: 01-Feb-2011

Standards Content (Sample)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
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Designation:E2658 −11
StandardPractices for
Verification of Speed for Material Testing Machines
This standard is issued under the fixed designation E2658; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 2. Referenced Documents
1.1 These practices cover procedures and requirements for 2.1 ASTM Standards:
the calibration and verification of testing machine speed by E2309 Practices for Verification of Displacement Measuring
means of standard calibration devices. This practice is not Systems and Devices Used in Material Testing Machines
intended to be complete purchase specifications for testing
3. Terminology
machines.
3.1 Definitions:
1.2 These practices apply to the verification of the speed
3.1.1 percent error,, n—in the case of a speed measuring
application and measuring systems associated with the testing
system, the ratio, expressed as a percent, of the error to the
machine, such as a scale, dial, marked or unmarked recorder
reference value of the applied speed.
chart, digital display, setting, etc. In all cases the buyer/owner/
3.1.1.1 Discussion—The speed, as measured by the testing
user must designate the speed-measuring system(s) to be
machine, and the speed, as computed from the readings of the
verified.
calibration devices, shall be recorded at each verified speed.
1.3 These practices give guidance, recommendations, and
The percent error, shall be calculated from this data as follows:
examples, specific to electro-mechanical testing machines.The
Percent Error 5 TMsp 2 Refsp /Refsp 3100 (1)
@~ ! #
practicemayalsobeusedtoverifyactuatorspeedforhydraulic
testing machines.
where:
TMsp = speed measured by the machine being verified,
1.4 This standard cannot be used to verify cycle counting or
mm/min [in/min], and
frequency related to cyclic fatigue testing applications.
Refsp = reference value of the measured speed, mm/min
1.5 Since conversion factors are not required in this
[in/min], as determined by the calibration device.
practice, either SI units (mm/min), or English [in/min], can be
Not all testing machines have available indicated speed
used as the standard.
values. In such cases, the verification of the testing ma-
1.6 Speed measurement values and or settings on displays/
chine’s speed setting is applicable. The percent error for the
printouts of testing machine data systems-be they
testing machine speed settings, shall be calculated as fol-
instantaneous, delayed, stored, or retransmitted-which are
lows:
within the Classification criteria listed in Table 1, comply with
Percent Error 5 TMsps 2 Refsp /Refsp 3100 (2)
@~ ! #
Practices E2658.
where:
1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
TMsps = testing machine speed setting, mm/min (in/min),
responsibility of the user of this standard to establish appro-
and
priate safety and health practices and determine the applica- Refsp = reference value of the measured speed, mm/min
bility of regulatory limitations prior to use. (in/min), as determined by the calibration device.
These practices are under the jurisdiction of ASTM Committee E28 on
Mechanical Testing and is the direct responsibility of Subcommittee E28.01 on For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Calibration of Mechanical Testing Machines and Apparatus. contact ASTM Customer Service at [e-mail]. For Annual Book of ASTM
Current edition approved Feb. 1, 2011. Published February 2011. DOI: 10.1520/ Standards volume information, refer to the standard’s Document Summary page on
E2658–11. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
E2658−11
3.1.2 ramp-to-speed condition, n—during a speed verifica- allow confidence in the reported displacement over time data
tion run, it is the time and or change in displacement required acquired by the testing machine during use.
to achieve a constant speed condition.
NOTE 1—Many material tests never reach the desired test speed. Unless
3.1.3 reference standards, n—devices used to verify either the actual data from the material test is examined, it is often impossible to
know if the test speed has been reached or is repeatable from test to test.
the speed of a testing machine or the speed indicated by a
testing machine.
5. Calibration Devices
3.1.4 speed measuring system, n—a device or set of devices
5.1 Reference standards used for verification of speed
comprising of a speed transducer and associated instrumenta-
measuring systems shall have estimated measurement uncer-
tion or a displacement transducer with associated timer and
tainties. The measurement uncertainty of verification results,
instrumentation.
contain the combination of the uncertainty of the displacement
3.1.5 tolerance, n—theallowabledeviationfromareference
calibration device and time indicating device. The combined
value.
estimate of uncertainty for the reference standards shall be
3.1.6 speed, n—displacement divided by time expressed in
equal to or less than ⁄3 the allowable error for the measuring
terms of millimeters/minute, inches/minute, etc.
system. The estimated measurement uncertainty of the refer-
ence standards should have a confidence level of 95% (k=2).
3.1.7 verification speed, n—a speed with traceability de-
rived from national standards of length and time, with a
5.2 It is recommended that the testing machine have its
specific uncertainty of measurement, which can be applied to
displacement measuring systems verified in compliance with
speed measuring systems.
Practices E2309 prior to performing this verification. Often the
same displacement calibration devices can be used to perform
Practices E2309 and this practice. It may be possible to attach
TABLE 1 Classification of Speed Application Measuring Systems
the Displacement Calibration Device one time and perform
B
Classification Resolution Percent Error
A
both verification practices.
% of Reading
Class A ±0.25 ±0.5
5.3 Displacement Calibration Devices:
Class B ±0.5 ±1.0
Class C ±1.0 ±2.0 5.3.1 Digital Linear Scales and Displacement Measuring
Class D ±2.5 ±5.0
Transducers—These devices typically have sufficient resolu-
Class E ±5.0 ±10
tion and accuracy to perform verification of all speed settings.
Class F ±10 ±20
It is important to assess the minimum measurement capability
A
Resolutionisnotcriteriaforclassificationwhenspeedapplicationonly,isverified.
B
of the device. At very slow speeds it may take considerable
Percent Error of application or indication of speed.
timetoreachanenddisplacementvaluethatisadequateforthe
use of the device.
5.3.1.1 These devices may also have the capability to be
4. Significance and Use
automated.
4.1 Material testing requires repeatable and predictable
5.4 Time Indicating Devices—
testingmachinespeed.Thespeedmeasuringdevicesintegralto
5.4.1 Time pieces such as quartz wrist and stop watches can
the testing machines may be used for measurement of cross-
be used for slower speed settings. The time piece shall have a
head speed over a defined range of operation. The accuracy of
calibration traceable to a national metrology institute. For most
the speed value shall be traceable to a National or International
purposes, a time piece with an accuracy of 60.02% (approxi-
Standards Laboratory. Practices E2658 provides procedures to
mately 2 second in 3 hours) is sufficient.The uncertainty of the
verifytestingmachines,inorderthattheindicatedspeedvalues
calibration of the time piece shall be at most ⁄3 the accuracy of
may be traceable. A key element to having traceability is that
the time piece and shall not significantly contribute to the
the devices used in the verification produce known speed
uncertainty of the speed measurement. See NIST Special
characteristics, and have been calibrated in accordance with
Publication 960-12. With automated computer software, ac-
adequate calibration standards.
curacies of 60.01 seconds may be achieved. However, care
4.2 Verification of testing machine speed at a minimum
must be taken in designing such systems to avoid errors due to
consists of either or both of the following options: things such as timer resolution, programming language
4.2.1 Verifying the capability of the testing machine to
limitations, competing interrupts and processes, etc. Third
move the crosshead at the speed selected. party software is available to track and adjust the computer
4.2.2 Verifying the capability of the testing machine to
clock referenced to NIST.
adequately indicate the speed of the crosshead.
6. System Verification
4.3 Where applicable, determine the testing machine’s
6.1 Speed measuring systems shall be verified as a system
ramp-to-speed condition. This condition can be significant
with the speed sensing and measuring devices in place and
especiallywhenverifyingfastspeedsortestingconditionswith
operating as in actual use.
very short testing durations.
4.4 This procedure will establish the relationship between
the actual crosshead speed and the testing machine indicated
Gust, J.C., Graham, R.M., Lombardi, M.A. Special Publication 960-12 Stop-
speed and or selected setting. It is this relationship that will watch and Timer Calibrations National Institute of Standards and Technology 2004
E2658−11
6.2 System verification is invalid if the speed sensing 8. Selection of Verification Speed Values
devices are removed and checked independently of the testing
8.1 Many testing machines have a selection of preset
machine.
crosshead speeds, typically ranging from .025mm/min to
10,000mm/minute (.001in/min to 400 in/minute). It is difficult
6.3 The verification shall consist of at least two verification
and very time consuming to verify every selectable setting
runs of speed derived data per selected testing machine speed
available with testing machines. Additionally, it is often
setting.
impossible to adequately verify the fastest speed selections
6.3.1 If the initial verification run produces any percent
because displacement calibration devices are typically not long
error values outside applicable specifications, the “as found”
enough to accommodate the displacement necessary. For these
data may be reported and may be used in accordance with
reasons, at a minimum, speeds most commonly used should be
applicable quality control programs.
selectedforverification.Aminimumoftworunsofverification
6.3.2 Adjustments may be made to improve the accuracy of
data for each speed is required.
the system. They shall be followed by one additional verifica-
8.1.1 In some cases a testing machine might only be used at
tion run, and issuance of a new verification report. Typically,
one speed with one clutch selected. In such a case only one
making adjustments to improve testing machine speed will
speed with two runs of data are all that is required to meet this
influence all speed settings. If an adjustment is made, all tested
standard.
speeds must be re-verified unless it can be demonstrated that
the adjustment did not affect other speed settings.
8.2 Many testing machines have multiple clutch selections.
6.3.3 Quality control programs may require evidence of If the testing machine is used with multiple clutch settings,
repeatability, reproducibility and reversibility. In such cases it speeds for each clutch setting shall be verified even if the
is recommended that a minimum of one speed be verified for selected speed is the same as a selected speed verified with a
repeatability, reproducibility, and reversibility. different clutch setting.
8.3 In selecting speeds to be verified, consideration of the
6.4 The testing machine is verified with the crosshead
total displacement and time must be considered. The total
configured to free run with no specimen installed.
displacement must be great enough to allow for the displace-
NOTE 2—Testing machine compliance under loading conditions may
ment calibration device’s measurement uncertainty. If the
introducesmallerrorsinthedisplacementmeasurementdataduringactual
calibration devices are automated, time is not as critical to the
materials testing. This error is considered insignificant relative to this
overall measurement uncertainty. But, if a manual Start and
verification. There are also testing machines where the crosshead speed
slows when force is applied. In such cases where it is necessary to verify
Stop method is employed, the duration of the verification run
speed of the testing machine under loaded conditions, higher accuracy
must be long enough to minimize error due to human action.
displacement calibration devices such as laser interferometer measuring
The manual Start and Stop method also requires that the total
systems, or extensometer type displacement reference standards must be
displacement and duration of the verification run be long
used due to the very small displacements being verified.
enough to start beyond the ramp to speed condition. See
Appendix X1.
7. Methods of Verification
8.4 It is not normal to experience a difference in the speed
7.1 Start and Stop Method:
indication of the testing machine when the crosshead moves in
7.1.1 Thismethodrequiresthatasetofstartingandstopping
the opposite direction. However, gravity may contribute to a
displacement and time readings be recorded from the displace-
difference in the ramp to speed condition when the crosshead
ment and time calibration devices.
is operated in the descending mode. The testing machine
7.1.2 In order to obtain data within expected tolerances an
should be verified in the mode of operation normally used
assessment of the ramp-to-speed condition may be necessary
during testing.
so the test run can be started after the crosshead has reached a
constant speed condition.
9. Preliminary Procedure
7.1.3 It is best to have testing machine software that can
9.1 Alignment:
easilyacquireandreportdisplacementandtimedataduringthe
9.1.1 When attaching the displacement calibration device, it
verification run for each selected speed.
is important to minimize any misalignment. Significant errors
7.1.4 The comparison of the reference start and stop values
can be induced due to misalignment. Gauge blocks or a square
and the data reported by the testing system provides the basis
may be used to ensure that the displacement calibration device
for verification of speed using this method.
operates perpendicular to the crosshead in electro-mechanical
7.2 Continuous Acquisition Method: testing machines, or in-line or parallel, to the a
...