Instron 2630-100 Series Clip-On...
Transcript of Instron 2630-100 Series Clip-On...
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M20-52630-1Issue C January 1997
Instron2630-100 Series Clip-On
Extensometers
Operator’s Guide
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PROPRIETARY RIGHTS NOTICE
This document and the information that it contains arethe property of Instron Corporation. Rights toduplicate or otherwise copy this document and rightsto disclose the document and the information that itcontains to others and the right to use the informationcontained therein may be acquired only by writtenpermission signed by a duly authorised officer ofInstron Corporation.
© Copyright 1997 Instron Corporation
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Amendment Incorporation Record
AMENDMENTNUMBER
BRIEF DESCRIPTION OFCONTENT
NAME OFPERSON
INCORPORATINGAMENDMENT
1Additional informationcovering Phase 2 andPhase 3 extensometers
Siân Oakes
2Wire clip information
amended. Issue raised toC, ECR35152
Siân Oakes
3
4
5
6
7
8
9
10
Preliminary Pages
iii M20-52630-1
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Amendment Incorporation Record
AMENDMENTNUMBER
BRIEF DESCRIPTION OFCONTENT
NAME OFPERSON
INCORPORATINGAMENDMENT
11
12
13
14
15
16
17
18
19
20
Preliminary Pages
iv
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GENERAL SAFETY PRECAUTIONSMaterials testing systems are potentially
hazardous!
Materials testing involves inherent hazardsfrom high forces, rapid motions and storedenergy. You must be aware of all moving andoperating components which are potentiallyhazardous, particularly the actuator in aservohydraulic testing system or the movingcrosshead in an electromechanical testingsystem.
Always be aware of the possible hazardsinvolved when operating and maintaining thesesystems. You must not operate any materialstesting equipment unless you are thoroughlyfamiliar with its functions and operation.Unfamiliarity with a materials testing systemcan lead to unexpected actuator or crossheadmotion with the consequent risk of injury anddamage.
Carefully read all relevant manuals and observeall WARNINGS and CAUTIONS. The termWARNING is used where a hazard may lead toinjury or death. The term CAUTION is usedwhere a hazard may lead to damage toequipment or to loss of data.
Ensure that the test set-up to be followed andthe actual test to be performed on materials,assemblies or structures constitutes no hazardto operating personnel.
Make full use of all mechanical and electroniclimits features. These are supplied for your
Preliminary Pages
v M20-52630-1
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safety to enable you to prevent movement ofthe actuator piston / moving crosshead beyondthe desired regions of operation.
The following pages detail various generalwarnings that you must heed at all times whileusing materials testing equipment. Morespecific warnings and cautions will be found inthe text whenever your attention needs to bedrawn to a potential hazard.
Your best safety precautions are to gain athorough understanding of the equipment byreading your instruction manuals and to alwaysuse good judgement.
WARNING
DISCONNECT THE ELECTRICALPOWER SUPPLY BEFOREREMOVING THE COVERS OFELECTRICAL EQUIPMENT
You must disconnect the equipment from theelectrical power supply before removing anyelectrical safety covers or replacing fuses. Donot reconnect the main power source while thecovers are removed unless you are specificallyinstructed to do so in the manual. Refit coversas soon as possible.
DISCONNECT POWER SUPPLIESBEFORE REMOVING THE COVERSOF ROTATING MACHINERY.
You must disconnect the equipment from allpower supplies before removing any cover
Preliminary Pages
vi
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which gives access to rotating machinery, e.g.belts, screws or shafts. Do not reconnect anypower supply while the covers are removedunless you are specifically instructed to do soin the manual. If the equipment needs to beoperated to perform maintenance tasks with thecovers removed, ensure that all loose clothing,long hair, etc. is tied back. Refit covers as soonas possible.
WARNING
SHUT DOWN THE HYDRAULICPOWER SUPPLY AND DISCHARGEHYDRAULIC PRESSURE BEFOREDISCONNECTION OF ANYHYDRAULIC FLUID COUPLING.
Do not disconnect any hydraulic couplingwithout first shutting down the hydraulic powersupply and discharging stored pressure to zero.Tie down or otherwise secure all pressurisedhoses to prevent movement during systemoperation and to prevent the hose fromwhipping about in the event of a rupture.
SHUT OFF THE SUPPLY OFCOMPRESSED GAS ANDDISCHARGE RESIDUAL GASPRESSURE BEFOREDISCONNECTION OF ANYCOMPRESSED GAS COUPLING.
Preliminary Pages
vii M20-52630-1
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Do not release gas connections without firstdisconnecting the gas supply and dischargingany residual pressure to zero.
WARNING
USE PROTECTIVE SHIELDS ORSCREENS IF ANY POSSIBILITY OFA HAZARD EXISTS FROM THEFAILURE OF A SPECIMEN,ASSEMBLY OR STRUCTURE UNDERTEST.
Protective shields should be used whenever arisk of injury to operators and observers existsfrom the failure of a test specimen, assembly orstructure, particularly where explosivedisintegration may occur. Due to the widerange of specimen materials, assemblies orstructures that may be tested using materialstesting equipment, any hazard resulting fromthe failure of a test specimen, assembly orstructure is entirely the responsibility of theowner and user of the equipment.
PROTECT ELECTRICAL CABLESFROM DAMAGE ANDINADVERTENT DISCONNECTION.
The sudden loss of controlling and feedbacksignals which can result from a disconnected ordamaged cable causes an open loop conditionwhich may drive the actuator of crossheadrapidly to its extremes of motion. All electricalcables, particularly transducer cables, must be
Preliminary Pages
viii
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protected from damage. Never route cablesacross the floor without protection, nor suspendcables overhead under excessive strain. Usepaddings to avoid chafing where cables arerouted around corners or through wall openings.
WARNING
WEAR PROTECTIVE CLOTHINGWHEN HANDLING EQUIPMENT ATEXTREMES OF TEMPERATURE.
Materials testing is often carried out atnon-ambient temperatures using ovens,furnaces or cryogenic chambers. Extremetemperature means an operating temperatureexceeding +60 °C (140 °F) or below 0 °C(32 °F). You must use protective clothing, suchas gloves, when handling equipment at thesetemperatures. A warning notice concerning lowor high temperature operation must bedisplayed whenever temperature controlequipment is in use. You should note that thehazard from extreme temperature can extendbeyond the immediate area of the test.
TAKE CARE WHEN INSTALLING ORREMOVING A SPECIMEN,ASSEMBLY OR STRUCTURE.
Installation or removal of a specimen, assemblyof structure involves working inside the hazardarea between the grips or fixtures. Keep clearof the jaws of a grip or fixture at all times.Keep clear of the hazard area between the gripsor fixtures during actuator or crosshead
Preliminary Pages
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movement. Ensure that all actuator orcrosshead movements necessary for installationor removal are slow and, where possible, at alow force setting.
WARNING
BEFORE THE EXTENSOMETER ISUSED IN STRAIN CONTROL,CHECK THE FOLLOWING:
1. Ensure that the extensometeris securely attached to thespecimen.2. Ensure that the extensometeris calibrated.3. Set the Load, Position andStrain limits.4. Ensure that the testingmachine loop-shapingparameters are set correctly.
BEFORE REMOVING THEEXTENSOMETER FROM THESPECIMEN AT ANY TIME, ENSURETHAT THE MACHINE IS NOT INSTRAIN CONTROL!
Preliminary Pages
x
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Preliminary Pages
xi M20-52630-1
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Table Of Contents
Chapter Page
INTRODUCTION 1-1
GENERAL 1-1
BASIC FEATURES 1-2
EQUIPMENT SUPPLIED 1-4
OPTIONAL ACCESSORIES & SPARES 1-4
SPECIFICATION 2-1
ENVIRONMENTAL 2-1
OPERATION 3-1
GAUGE LENGTH SETTING 3-1
SPECIMEN ATTACHMENT 3-3
Wire Clip 3-3
Variable Pressure SpecimenClamp 3-5
Elastic Bands or O-Rings 3-7
Fitting to the Specimen usingBoth Hands 3-8
Fitting to the Specimen usingOne Hand 3-9
CABLE CLEAT AND EXTENSOMETERHOLDER 3-10
Preliminary Pages
xi M20-52630-1
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KNIFE EDGE CHANGING 3-12
Specimen Centering Stops 3-13
IMPORTANT SAFETY NOTE 3-14
CALIBRATION 3-15
Automatic ElectricalCalibration 3-15
Manual ElectricalCalibration 3-16
Manual MechanicalCalibration 3-18
VERIFICATION 3-19
APPENDIX ACLIP SIZES A-1
CLIPS FOR ROUND SPECIMENS A-2
CLIPS FOR RECTANGULARSPECIMENS A-4
Notes A-6
Preliminary Pages
xii
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LIST OF ILLUSTRATIONS
Figure Page1-1. Case Layout 1-5
3-1. Gauge Length Setting with thecone-latch released 3-1
3-2. Gauge Length Setting with thecone-latch engaged(gauge length set) 3-2
3-3. Insertion of Clips 3-4
3-4. Wire clips in use 3-4
3-5. Specimen attachment using theoptional Specimen Clampsand Pivot Knife Edges 3-6
3-6. Specimen attachment usingelastic bands 3-7
3-7. Two-handed Installation 3-8
3-8. Single-handed Installation 3-9
3-9. Extensometer suspended fromcleat post — T-slot machines 3-10
3-10. Extensometer suspended fromcleat post — steel coveredmachines 3-11
3-11. Knife Edge Replacement 3-12
Preliminary Pages
xiii M20-52630-1
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3-12. Specimen Stops 3-13
3-13. Extensometer mounted on anoptional calibration fixture(Cat. No. 2602-017) 3-17
List of Tables
Table Page1. Extensometer Gauge Lengths
and Travel 2-1
2. General Specification 2-3
3. Machine Compatibility 2-5
4. Extensometer PhysicalCompatibility with 3119 SeriesTemperature Chambers 2-8
Preliminary Pages
xiv
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INTRODUCTION
GENERALThe 2630-100 series extensometers convertthe mechanical displacement of a strainedtest specimen into an electrical signal. Whenused with the current range of Instrontesting machines, each extensometer isautomatically recognised, and is able to becalibrated at the touch of a button.
The displacement is transmitted by a lightrigid frame to strain gauges bonded to aflexural element. The gauges are arranged ina fully active four-arm Wheatstone Bridgecircuit.
The 2630-100 series of extensometersincludes different gauge lengths/strain rangeoptions to suit a wide range of specimencharacteristics.
Robust construction provides accuracy andreliability. As with all measuringinstruments, rough handling, contaminationwith dirt and moisture effect calibration andshorten the life of the instrument.
The extensometer is supplied in afoam-lined presentation case, dimensions350 mm (13.8 in.) long, 260 mm (10.2 in.)wide and 85 mm (3.3 in.) deep. Theshipping weight is 0.9 kg (2 lbs).
When not in use, the extensometer shouldbe stored in the presentation case.
INTRODUCTION
1-1 M20-52630-1
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BASIC FEATURES• Ergonomic, lightweight,
cross-braced design with overloadprotection.
• Easy attachment and release fromthe specimen facilitatesingle-handed operation.
• Simple, cone latch gauge-lengthsetting method with automaticdisengagement.
• Precise, fixed gauge-lengths withautomatic recognition andcalibration capability.
• Available in metric and U.S.Customary versions to meetISO 9513 and ASTM E83standards of accuracy.
• Low operating-force arms withsingle-bevel, interchangeable knifeedges.
• Suitable for a wide range ofspecimen materials, geometry andsize with a choice of attachmentmethods.
• Combined cable cleat andextensometer holder withprovision for retaining cordattachment to the extensometer.
• High impact plastic storage casewith a contour moulded insert,securely retains the extensometer
INTRODUCTION
1-2
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and accessory parts together withits Calibration Certificate andcomprehensive operating manual.
INTRODUCTION
1-3 M20-52630-1
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EQUIPMENT SUPPLIEDRefer to Figure 1-1.
1 Extensometer
2 Cable cleat and extensometer holder
3 Allen key
4 11 pairs of wire clips
5 Specimen centering stops
6 Operator’s guide
7 Calibration certificate
8 Foam lined presentation case
OPTIONAL ACCESSORIES &SPARES
1 Variable pressure specimen clamps: see page 3-5.
2 Replacement knife edges, one pair, straightprofile. All purpose use on round and rectangularcross section specimens. Cat No. 2601-077.
3 Replacement knife edges, one pair. Three pointcontact for flat specimens that are not truly flat.Cat No. 2601-078.
4 Replacement knife edges one pair. Radiused edgefor flat specimens that are not truly flat.Cat No. 2601-079.
5 Digital Readout Extensometer Calibrator for manualspan setting. Cat No. 2602-017.
7 Wire clips (see Appendix A).
8 O-Rings, internal diameter 11 mm unstretched.(Instron Part No. T1351-1034).
INTRODUCTION
1-4
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CASE OPERATOR’S GUIDE
ALLENKEY
CLIPS FOR RECTANGULARSPECIMENS
CLIPS FOR ROUNDSPECIMENS
EXTENSOMETERCABLE CLEAT AND
EXTENSOMETER HOLDER
SPECIMENSTOPS
Figure 1-1. Case Layout
INTRODUCTION
1-5 M20-52630-1
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SPECIFICATIONTable 1. Extensometer Gauge Lengths and Travel
G.Lmm(in.)
Strain % Travel mm (in.)Cat.No.
*Class ISO 9513 (ASTM E83)Strain %
Overall Dimensionsmm (in.)
OperatingForceg (lbs)
+Weightg (lbs)
CodeType
+ve -ve +ve -ve 2630- Class 0.5 (B-2) Class 1 (C) Length Width Height
8 50 50 4 4 120 0, +50 30, +50 67 (2.64) 39 (1.5) 25 (1) 20 (0.04) 27 (0.06) Dual
(0.3) 50 50 (0.15) (0.15) 121 0, +50 30, +50 67 (2.64) 39 (1.5) 25 (1) 20 (0.04) 27 (0.06) Dual
10 10 10 1 1 101 -10, +10 67 (2.6) 39 (1.5) 25 (1) 160 (0.35) 27 (0.06) Single
10 50 50 5 5 102 0, +50 30, +50 67 (2.64) 39 (1.5) 25 (1) 20 (0.04) 27 (0.06) Single
(0.5) 10 10 (0.05) (0.05) 103 -10, +10 67 (2.64) 39 (1.5) 25 (1) 170 (0.37) 27 (0.06) Single
(0.5) 50 50 (0.25) (0.25) 104 0, +50 30, +50 67 (2.64) 39 (1.5) 25 (1) 20 (0.4) 27 (0.06) Single
25 10 10 2.5 2.5 105 -10, +10 100 (4) 39 (1.5) 52 (2) 55 (0.12) 56 (0.12) Single
25 50 10 12.5 2.5 106 0, +50 115 (4.5) 39 (1.5) 58 (2.3) 75 (0.17) 58 (0.13) Single
25 100 10 25 2.5 107 0, +70 0, +100 132 (5.2) 39 (1.5) 69 (2.7) 45 (0.1) 60 (0.13) Single
(1) 10 10 (0.1) (0.1) 108 -10, +10 100 (4) 39 (1.5) 52 (2) 56 (0.12) 56 (0.12) Single
2-1
SPEC
IFICA
TION
-
G.L
mm
(in.)
Stra
in%
Tra
velm
m(in
.)C
at.
No
.*C
lass
ISO
9513
(AST
ME8
3)St
rain
%
Ove
rall
Dim
en
sion
sm
m(in
.)O
pe
ratin
gFo
rce
g (
lbs)
+W
eig
ht
g(lb
s)
Co
de
Typ
e
+ve
-ve
+ve
-ve
2630
-C
lass
0.5
(B-2
)C
lass
1(C
)Le
ng
thW
idth
He
igh
t
(1)
5010
(0.5
)(0
.1)
109
0, +
5011
5(4
.5)
39(1
.5)
58(2
.3)
75(0
.17)
58 (
0.13
)Si
ng
le
(1)
100
10(1
)(0
.1)
110
0, +
700,
+10
013
2(5
.2)
39(1
.5)
69(2
.7)
45(0
.1)
60 (
0.13
)Si
ng
le
5010
105
511
1-1
0,+
1010
0(4
)39
(1.5
)72
(2.8
)45
(0.1
)60
(0.
13)
Sin
gle
5050
525
2.5
112
0, +
350,
+50
132
(3.2
)39
(1.5
)72
(2.8
)45
(0.1
)60
(0.
13)
Sin
gle
5010
010
505
113
0, +
700,
+10
018
1(7
.1)
39(1
.5)
72(2
.8)
37(0
.08)
70 (
0.15
)D
ua
l
(2)
1010
(0.2
)(0
.2)
114
-10,
+10
100
(4)
39(1
.5)
72(2
.8)
45(0
.1)
60 (
0.13
)Si
ng
le
(2)
505
(1)
(0.1
)11
50,
+35
0,+
5013
2(5
.2)
39(1
.5)
72(2
.8)
45(0
.1)
60 (
0.13
)Si
ng
le
(2)
100
10(2
)(0
.2)
116
0, +
700,
+10
018
1(7
.1)
39(1
.5)
72(2
.8)
37(0
.08)
70 (
0.15
)D
ua
l
8010
18
0.8
117
0, +
1011
6(4
.6)
39(1
.5)
101
(4)
60(0
.13)
60 (
0.13
)D
ua
l
8050
540
411
80,
+35
0,+
5018
1(7
.1)
39(1
.5)
101
(4)
45(0
.1)
70 (
0.15
)D
ua
l
100
505
505
119
0, +
350,
+50
181
(7.1
)39
(1.5
)12
1(4
.8)
37(0
.08)
70 (
0.15
)D
ua
l
*: +:
Wh
en
ca
libra
ted
usin
ga
pp
rop
riate
ca
libra
tion
ap
pa
ratu
sth
ese
ext
en
som
ete
rsa
reg
uara
n-
tee
dto
me
et
the
sta
ted
cla
ssifi
ca
tion
.Ou
tsid
eth
ese
sta
ted
ran
ge
sth
ee
xte
nso
me
ters
inc
om
pre
ssiv
em
od
eg
en
era
llyp
erf
orm
toIS
O 1
.0o
rAST
MC
cla
ssifi
ca
tion
.W
eig
ht
exc
lud
es
ca
ble
an
dc
on
ne
cto
r.2-2 M20-52630-1
SPECIFICATION
-
Table 2. General Specification
Creep (3 mins - 5 secs)
-
Effe
ct
of
Tem
pe
ratu
re o
nse
nsit
ivity
-0.0
06,2
0 to
100
°C(t
ypic
al)
-0.0
08,1
00 t
o15
0°C
(ty
pic
al)
-0.0
1, 1
50to
200
°C(t
ypic
al)
% /
°C
Me
tho
do
fa
tta
ch
me
nt
toSp
ec
ime
n
11ty
pe
so
fwire
clip
s.El
ast
icb
an
ds
(no
tsu
pp
lied
).O
ptio
na
lsp
ec
ime
nc
lam
ps
(re
fert
op
ag
e3-
5).
Imm
ers
ibili
tyN
on
-co
nd
uc
tive
/ n
on
-co
rro
sive
flu
ids,
i.e.
ac
eto
ne
,min
era
lan
dsil
ico
ne
oils
,alc
oh
ol,
etc
.
Ga
ug
e le
ng
th s
ett
ing
Co
ne
latc
h w
itha
uto
ma
tic re
lea
se
Ro
un
d s
pe
cim
en
siz
es
<15
,(0.
6 in
.)a
nd
20
(0.8
in.)
mm
Re
cta
ng
ula
r sp
ec
ime
nsiz
es
Wid
th<
40(1
.6 in
.)Th
ickn
ess
<15
,(0.
6 in
.)m
m
Kn
ifee
dg
eg
ripp
ing
forc
e30
0to
600
(0.6
6 to
1.32
lbs)
, su
bje
ct
toth
e c
orr
ec
tse
lec
tion
of
clip
sg
ram
s
Ma
xim
um
wid
tho
fsp
ec
ime
nw
ith s
pe
cim
en
sto
ps
fitte
d18
mm
(0.
71in
.)
NO
TEFS
—Fu
llSc
ale
.All
valu
es
rela
teto
ate
mp
era
ture
of2
2°C
un
less
oth
erw
isest
ate
d.
2-4 M20-52630-1
SPECIFICATION
-
Table 3. Machine Compatibility
The extensometer connector plugs contain codes which are used by the testing machine to define gauge length, traveland calibration points. The extensometers are fitted with either a single code or dual codes, as shown in Table 1.
Machine Series AutomaticElectrical CalibrationManual Electrical
Calibration
ManualMechanicalCalibration
Comments
8000 All Not available All
Via user-definedtransducer setupusing first codeonly.
8500 prior to V21 Single code only Single code only Single code only Versions may beidentified via thefront panel orMDC board label.
8500 V21 All except 2630-119,120, 121All except 2630-119,
120, 121All except 2630-119,
120, 121
8500 Plus All All All
2-5
SPEC
IFICA
TION
-
Ma
ch
ine
Se
ries
Au
tom
atic
Ele
ctr
ica
l Ca
libra
tion
Ma
nu
alE
lec
tric
al
Ca
libra
tion
Ma
nu
al
Me
ch
an
ica
lC
alib
ratio
nC
om
me
nts
6000
All
No
ta
vaila
ble
All
Via
use
r-d
efin
ed
tra
nsd
uc
ers
etu
pu
sing
first
co
de
on
ly.
4500
prio
rto
V2.
25M
S04
Sin
gle
co
de
on
lyA
llA
llV
ers
ion
ma
yb
eid
en
tifie
dvi
ath
eM
ast
erb
oa
rdla
be
l.
4500
po
stV
2.25
MS0
4A
lle
xce
pt
2630
-120
,12
1A
llA
ll
4500
Po
stV
2.25
MS0
5o
rla
ter
All
All
All
4200
/430
0 C
PU
ca
rdw
ith P
RO
Ms
prio
rto
A47
4-71
7,71
8, 7
19, 7
20Si
ng
lec
od
eo
nly
All
All
Ch
ec
kC
PU
ca
rd.
4200
/430
0 C
PU
ca
rdw
ith P
RO
Ms
A47
4-71
7,71
8, 7
19, 7
20
All
exc
ep
t 26
30-1
20,
121
All
All
2-6 M20-52630-1
SPECIFICATION
-
Ma
ch
ine
Se
ries
Au
tom
atic
Ele
ctr
ica
l Ca
libra
tion
Ma
nu
alE
lec
tric
al
Ca
libra
tion
Ma
nu
al
Me
ch
an
ica
lC
alib
ratio
nC
om
me
nts
4200
/430
0 C
PU
ca
rdw
ithP
RO
MS
A47
4-73
6,73
7,73
8,73
9o
rla
ter
All
All
All
Ch
ec
kC
PU
ca
rd.
2180
/216
0N
ot
ava
ilab
leA
llA
ll
1100
No
All
All
4400
All
exc
ep
t26
30-1
20,1
21A
llA
ll
4400
PR
OM
A47
4-74
0o
rla
ter
All
All
All
5500
Pre
-De
c 9
3A
lle
xce
pt
2630
-120
,12
1A
llA
ll
5500
Po
st-D
ec
93
All
All
All
2-7
SPECIFICATION
-
ENVIRONMENTALThe extensometer’s simple and easyattachment method make it ideal for usein a temperature chamber.
The extensometer’s temperaturecapability is stated in Table 2.
High relative humidity may altercalibration and it is advisable to confirmthe calibration using a suitablecalibration fixture at the test condition.
CAUTION:
Contamination bycondensation, electricallyconducting fluids, dirt orcorrosive substances maydamage the extensometer.
Table 4.Extensometer Physical Compatibility with
3119 Series Temperature Chambers
ChamberCat. No. Suitable Extensometers
3119-005 All except 2630-113, 116, 118 and 119
3119-006 All except 2630-113, 116, 118 and 119
3119-007 All
3119-008 All
3119-009 All except 2630-113, 116, 118 and 119
SPECIFICATION
2-8 M20-52630-1
-
OPERATION
GAUGE LENGTH SETTINGBefore strain can be accurately measuredthe extensometer arms must be spaced toset the knife edges at gauge length. Theextensometer features an integral conelatch arm locating system.
To set gauge length press the two roundbuttons with index finger and thumb ofeither left or right hand. Ensure the conelocates in the cone-seat. The extensometerknife edges are now held at the correctgauge length. The extensometer is readyfor attaching to a test specimen (refer toFigures 3-1 and 3-2).
with the cone-latch released
CONE SEAT
CONE PIN
Figure 3-1. Gauge Length Setting
OPERATION
3-1
-
Verification of gauge length may beconfirmed by engaging the gauge lengthcone latch and checking the distancebetween the knife edges using eithercallipers or a slip gauge.
with the cone-latch engaged(gauge length set)
Figure 3-2. Gauge Length Setting
OPERATION
3-2 M20-52630-1
-
SPECIMEN ATTACHMENTFor accurate results, effective attachmentof the extensometer to the specimen isessential. Test results may be altered if theknife edges press too firmly into thespecimen. A sign of excessive knife edgepressure is breaking of the specimen at theknife edge point of contact. At the otherextreme, with low knife edge pressure,slippage may occur. This can be identifiedfrom a stress v strain graph by a rapidchange in strain for a small change instress. If a test is to involve strains greaterthan 10%, a higher clamping force may berequired.A number of different attachmentmethods are available offering theflexibility to suit a wide range of testingconditions. Care during attachment shouldavoid any difficulties and permit theoptimum knife edge pressure to beachieved.Knife edges should be replaced if blunt,as described on page 3-12.
Wire ClipClips are available in two profiles toaccommodate round and rectangularspecimens. It is important for good resultsto select the clip that best suits thespecimen. Appendix A gives full sizescale diagrams of the available clips withinformation on the optimum workingrange for each clip. The clips mount intothe extensometer arms from either side,
OPERATION
3-3
-
using the technique shown in Figure3-3. Figure 3-4 shows the wire clip inoperation holding the extensometer to atypical specimen.
Once the wire clip is selected and a testspecimen is correctly installed in thetesting machine grips the extensometercan be attached.
Figure 3-3. Insertion of Clips
Figure 3-4. Wire clips in use
OPERATION
3-4 M20-52630-1
-
Variable Pressure Specimen ClampIf preferred, the instrument may bechanged to use variable pressure specimenclamps as supplied on earlier 2630 seriesinstruments. This requires optional notchpivot knife edges to permit the use ofspecimen clamps.
Specimen clamps are an optional extraand can be ordered from Instron using thefollowing Catalogue Numbers:Cat No. 2601-081, specimen clamp andknife edges — Small, minimum gaugelength 10 mm. Accommodates roundspecimens 1 to 9 mm in diameter or flatspecimens to 9 mm wide and 1 to 10 mmthick.Cat No. 2601-082, specimen clamp andknife edges — Medium, minimum gaugelength 25 mm. Accommodates roundspecimens 1 to 15 mm in diameter in di-ameter or flat specimens to 14 mm wideand 1 to 18 mm thick.Cat No. 2601-083,specimen clamp andknife edges — Large, minimum gaugelength 25 mm. Accommodates roundspecimens 1 to 10 mm in diameter or flatspecimens to 25 mm wide and 1 to 10 mmthick.
To fit the Extensometer to the Specimen
Hold the extensometer with the GaugeLength cone-latch engaged and positionthe knife edges against the test specimen.Holding a specimen clamp, straddle the
OPERATION
3-5
-
specimen above the knife edges of theextensometer. Press the clamp againstthe specimen to compress the springloaded plunger and hook the specimenclamp on the knife edges. Ensure thatthe knife edge seats properly in thespecimen clamp notch pivot. Repeat thesame operation on the lower specimenclamp.When testing round specimens, align the“V” groove of the spring-loaded plungerbefore straddling the specimen.
Note that the notch pivot slots in thespecimen clamp should always pointaway from the gauge length, as shownbelow.
VARIABLE PRESSURESPECIMEN CLAMP
PRESSURE ADJUSTER RING
NOTCH PIVOT
NOTCH PIVOT SLOTSPOINTING OUTWARDS FROM
THE GAUGE LENGTH
Figure 3-5. Specimen attachmentusing the optional Specimen Clamps
and Pivot Knife Edges
OPERATION
3-6 M20-52630-1
-
Elastic Bands or O-RingsHooks for elastic bands or O-rings are anintegral part of the knife edges, althoughelastic bands and O-rings are not suppliedwith the extensometer. Refer to page 1-4for O-ring details.
Hold the extensometer with the gaugelength cone latch engaged and positionthe knife edges on the test specimen.
Stretch good quality elastic bands orO-rings around the specimen and loop theends over the two knife edge hooks, asshown in Figure 3-6.
Figure 3-6. Specimen attachmentusing elastic bands
OPERATION
3-7
-
Fitting to the Specimen using BothHands
When testing soft or delicate materials,two-handed installation reduces thepossibility of marking the specimen.
Hold the extensometer with either handand engage the gauge length cone-latch.Using the other hand open the wire clipsto clear the specimen, as shown inFigure 3-7. Position the extensometer inline with the specimen and graduallyrelease the clips. Once the extensometeris attached to the specimen the gaugelength cone-latch can be released. If theextensometer is not held firmly onto thespecimen select a smaller clip.
PRESS TO SETGAUGE LENGTH
CLIP PRONG
Figure 3-7. Two-handed Installation
OPERATION
3-8 M20-52630-1
-
Fitting to the Specimen using One HandSingle handed installation is useful forworking in temperature cabinets whereaccess is limited.Hold the extensometer with either handand engage the gauge length cone-latch.Hook the wire clip prongs behind thespecimen as shown in Figure 3-8. Pull theextensometer to open the wire clips toclear the specimen. Slide the clip againstthe specimen bringing the extensometer inline with the specimen and graduallyrelease the clips so the knife edges gentlytouch the specimen. Do not slide the knifeedge against the specimen as thespecimen may be marked or the knifeedge blunted. Once the extensometer isattached to the specimen, release thegauge length cone-latch. If theextensometer is not held firmly onto thespecimen select a smaller clip.
PRESS TO SETGAUGE LENGTH
CLIP PRONG
Figure 3-8. Single-handed Installation
OPERATION
3-9
-
CABLE CLEAT ANDEXTENSOMETER HOLDER
A combined cable cleat andextensometer holder is provided, and isshown in Figures 3-9 and 3-10.
The magnetic base of the cleat can beattached to steel parts of the testingmachine e.g. the column covers. For “T”slot machines with aluminium columncovers the special keeper assembly willslide into the “T” slot and then the cleatwill attach to the keeper.
The slot in the base of the cleat is usedto support the extensometer cable. Thecleat should be positioned to reduce theeffects of cable tension on theextensometer.
KEEPER NUT
SLIDE INTOT-SLOT
Figure 3-9. Extensometer suspendedfrom cleat post — T-slot machines
OPERATION
3-10 M20-52630-1
-
When the extensometer is not in use but isstill required to be connected to the testingmachine, it may be secured to a cleat postusing the hole provided in theextensometer cover.
Ensure the cleat is returned to thepresentation case, with the magnetattached to the keeper plate when not inuse.
ATTACH TOSTEEL
SURFACE
SLOT FORCABLE
Figure 3-10. Extensometer suspendedfrom cleat post — steel covered
machines
OPERATION
3-11
-
KNIFE EDGE CHANGINGRefer to Figure 3-11 below. Loosen thesocket head cap screw using thesupplied allen key.
Position replacement knife edge withthe bevel side of the knife edge furthestfrom the cut-out in the extensometerarms. Secure with socket head capscrew ensuring alignment faces of theknife edge and extensometer touch.
SOCKET HEAD CAPSCREW
KNIFE EDGE
BEVELLEDEDGE
ALIGNMENT FACES
Figure 3-11. Knife Edge Replacement
OPERATION
3-12 M20-52630-1
-
SPECIMEN CENTERING STOPSPrecise alignment of the extensometer isnecessary to ensure the correctmeasurement of strain in a specimen andto enable rapid, precise attachment to thespecimen. To achieve this a pair ofoptional stops are supplied to assist withaligning the extensometer relative to thespecimen. Graduations are marked on thesurface of the stops to allow equal setting.
The installation of a specimen stop isshown below in Figure 3-12.
EXTENSOMETERARM
SPECIMEN STOP
SOCKET HEADCAP SCREW
Figure 3-12. Specimen Stops
OPERATION
3-13
-
IMPORTANT SAFETY NOTE
WARNING
BEFORE THE EXTENSOMETERIS USED IN STRAINCONTROL, CHECK THEFOLLOWING:
1. Ensure that theextensometer is securelyattached to the specimen.2. Ensure that theextensometer is calibrated.3. Set the Load, Positionand Strain limits.4. Ensure that the testingmachine loop-shapingparameters are setcorrectly.
BEFORE REMOVING THEEXTENSOMETER FROM THESPECIMEN AT ANY TIME,ENSURE THAT THE MACHINEIS NOT IN STRAIN CONTROL.
OPERATION
3-14 M20-52630-1
-
CALIBRATIONThe extensometer and machineconditioning electronics must becalibrated before use. Three parametersmust be defined: full scale, calibrationpoint and gauge length.
Three methods of calibration are possible:
Automatic Electrical CalibrationThis is the normal method of calibrationfor current Instron testing machines. Theextensometer is self-identifying via itscode resistors. These are interrogated bythe testing machine which has thecalibration parameters stored within itsmemory. If the extensometer is to be usedon an older Instron machine checkcompatibility with automatic calibration,refer to page 2-5.
To operate the automatic electricalcalibration, refer to the operatinginstructions or user’s guide supplied withthe testing machine.
Note: Ensure that theextensometer is set atgauge length, and iscorrectly attached to thetest specimen. Refer topages 3-1 to 3-8.
OPERATION
3-15
-
Manual Electrical CalibrationThis method can be used if your testingmachine is unable to use theself-identifying feature or if you wish tomodify the calibration parameters.
To operate manual electrical calibrationrefer to the operating instructions oruser’s guide supplied with the testingmachine.
Note: Ensure that the exten-someter is set at gaugelength, and is correctly at-tached to the test speci-men. Refer to pages 3-1to 3-8.
OPERATION
3-16 M20-52630-1
-
Figure 3-13. Extensometer mounted onan optional calibration fixture
(Cat. No. 2602-017)
OPERATION
3-17
-
Manual Mechanical CalibrationThis method must be used on oldertesting machines that are unable toperform any other type of calibration. Itis also a way of confirming the electricalcalibration.
A calibration fixture is required formanual mechanical calibration (refer topage 1-4 — Optional Accessories andSpares). The fixture consists of a digitalmicrometer head, mounted on a standframe, with two knurled collets forholding various calibrator spindlescorresponding to types and sizes ofspecimens to be tested. It enables theextensometer to be exercised over itsmechanical displacement range and thespan to be checked or set.
Note: Ensure that the exten-someter is set at gaugelength, and is correctly at-tached to the Calibrator.Refer to pages 3-1 to 3-8.
OPERATION
3-18 M20-52630-1
-
VERIFICATIONThe achievable ISO or ASTMclassification is given in Table 1 on pages2-1 and 2-2. Certification of the strainmeasurement system which includes theextensometer, conditioning electronicsand readout to the international standardsshould be arranged through accreditedcalibration services. Your local Instronarea office will be able to arrangeverification.
NOTE It is advisable to check theaccuracy of theautomatic/manualelectrical calibration atleast once per year.
OPERATION
3-19
-
APPENDIX ACLIP SIZES
Use the full-scale diagrams on the followingpages to identify the various clips suppliedwith the extensometer.
CLIP SIZES
Appendix A A-1 M20-52630-1
-
CLIPS FOR ROUND SPECIMENS(Supplied in pairs)
T1696-1390Ø0 to 3 mm
Ø 0 to 0.12 in.
T1696-1391Ø3 to 6 mm
Ø 0.12 to 0.24 in.
T1696-1392Ø6 to 9 mm
Ø 0.24 to 0.35 in.
CLIP SIZES
Appendix A A-2
-
T1696-1393Ø9 to 12 mm
Ø0.35 to 0.47 in.
T1696-1394Ø12 to 15 mm
Ø0.47 to 0.59 in.
T1696-1388Ø20 mmØ0.79 in.
CLIP SIZES
Appendix A A-3 M20-52630-1
-
CLIPS FOR RECTANGULARSPECIMENS
(Supplied in pairs)
T1696-1395SQR 0 to 3 mm
SQR 0 to 0.12 in.
T1696-1396SQR 3 to 6 mm
SQR 0.12 to 0.24 in.
T1696-1397SQR 6 to 9 mm
SQR 0.24 to 0.35 in.
CLIP SIZES
Appendix A A-4
-
T1696-1398SQR 9 to 12 mm
SQR 0.35 to 0.47 in.
T1696-1399SQR 12 to 15 mm
SQR 0.47 to 0.59 in.
CLIP SIZES
Appendix A A-5 M20-52630-1
-
NOTESCLIP SIZES
Appendix A A-6