Technical data MFA 2

Accuracy class EN ISO 9513 0.2

Measuring principle Strain gauge full bridge
Measuring path for tensile test MFA 2 2 mm (3 mm)
Measuring path for pressure test to be agreed
Indication error * 0.2 %
Indication error * 0.6 m
Error in initial measuring instrument length < 50 m
Sensitivity 2 mV/V
Rated resistance of bridge 350 Ohm
Max. voltage input 10 V
Actuation force 10 - 60 cN
Standard initial instrument measuring length 30 (25)** and 50 mm
Attachments for initial instrument measuring length 30 to 300 mm
Standard temperature range +1 °C to + 60 °C
Type for temperature chamber +1 °C to + 200 °C
Weight of single-side MFA 190 g
Weight of double-side MFA 260 g
* The greater value is permissible
** By turning the blades through 180 degrees

Adjustable for following test pieces cross sections***

circular 0 to 30 mm
flat 0 to 30 x 30 mm
circular with adapter 0 to 60 mm
flat with adapter 0 to 60 mm thickness and
60 mm width
Cable length 5m
***Others on request

MFA 2
Hand clamped extensometer

M e s s - & F e i nw e r k t e c h n i k Gm b H P r e c i s i o n t e s t i n g o f l i n e a r s t r a i n

With validity of this issue all others lose their validity. All informations are not-binding. Misprints and errors reserve. Review 01.2013
Area of application Delivery scope
The MFA 2/05 linear strain gauge is The extension arms can be changed Single - side linear strain gauge
suitable for virtually all tests above an quickly and without tools. The basic
initial instrument measuring length equipment comprises the extension 1 MFA 2 with 5 m cable
(L0) of 25 mm. Its measuring accuracy arms for L0 30 (25*) mm and L0 50 1 Extension arm, L0 30 (25*) mm
exceeds all requirements set down by mm. The clamping device facilitates
1 Extension arm, L0 50 mm
standard EN ISO 9513. Its design, quick and easy clamping.
which has been tried and tested over The top moving measuring arm is 1 Clamping device with cylindrical
many years of use, guarantees a high held in its zero position by a stop, backing rollers
level of reliability and a long service which means that it does not need to 2 Spare fixing screws, M3 T10
life, even under difficult operating be adjusted or released. The pressing 1 TORX screwdriver, T10
conditions. The MFA is particularly force and the opening width of the
suitable for determining the module of MFA are infinitely variable. 1 Test Specification Sheet
elasticity, proof stress and ultimate Rectangular knife edges, specially 1 Storage case
strain. The MFA is fast, designed for thin circular test pieces
straightforward and easy to use, and and the averaging double - side MFA
therefore enables large numbers of version, can be supplied.
tests to be carried out.
Operation Spare parts and accessories
Design and function To use the MFA, the clamping device Single - side linear strain gauge
Picture2 : MFA 2 double - side - extensometer
A lever mounted in ball bearings, is opened with the thumb and Extension arms L0 25 mm to 300
which have been tensioned to prevent forefinger. Care must be taken when mm (cannot be adjusted)
play, and housed in a casing of a positioning the device on the test Delivery scope Spare parts and accessory Calibration
Adapter for test pieces of up to 60 1. Set levers to “ m “ on double side
high-strength aluminium alloy is used piece, that the bottom edge contacts Double - side linear strain gauge Double - side linear strain gauge
mm x 60 mm and 60 mm diameter MFA 2.
to take up the clamping forces. The with the test piece first. The clamping
Knife edge fixing screw, M3 T10 1 Double - side MFA 2 with 5 m Pair of extension arms for double- 2. Bring unclamped MFA 2 in
path of the test elongation is device should be positioned on the
Circular knife edge, 9.5 mm cable side MFA 2, L0 25 mm - 300 mm measuring position and adjust the
transferred to the measuring spring MFA casing so that the backing rolls
Rectangular knife edge, 9.5 x 10 mm 2 Extension arm, L0 30 (25*) mm (cannot be adjusted) amplifier to “ Zero ”.
through this lever. If the measuring are symmetrically opposite the knife
Clamping device Pair of adapters for test pieces of up 3. Push movable knife edge gentle
distance (path) is exceeded or the test edges. Where L0 is above 60 mm, the 2 Extension arm, L0 50 mm
to 60 mm width and 60 mm diameter towards its upper stop.
piece breaks prematurely when the clamping device is screwed directly 1 Double clamping device
MFA is in use, the measuring spring is onto the extension arm. The Holder with cylindrical backing rolls 4. Calibrate measuring amplifier in
* By turning the knives on the extension arm 30 3 Spare fixing screws, M3 T10 for clamping one MFA only
fully protected by stops. The extension arms themselves can be mm and on the MFA housing a gauge length
this position to the value which is
measuring spring is applied with a inserted without danger of twisting of 25 mm can be set. 1 TORX screwdriver, T10 Knife edge fixing screw, M3 T10 documented in the test
temperature-compensated strain once the coupling ring has been Circular knife edge, 9.5 mm specification sheet
1 Test Specification Sheet
gauge full bridge, which is calibrated released. On the double-side MFA, diameter 5. To make sure that the calibration
1 Storage case Rectangular knife edge, 9.5 x 10 has been carried out correctly, re-
to 2 mV/V for the nominal measuring the lever should be set to "Zero"
path. before clamping and then to mm peat steps 2 to 5 and readjust if
The L0 of the measuring instrument "Measure" to facilitate clamping Clamping device necessary.
can be equipped for all required without initial tension.
lengths from 25 to 300 mm. With that the calibration of the MFA 2
is brought to its end.

Recommendation
The following calibrating instruments
can be used for high calibration
requirements:
KMF3 for sensitivity calibration
KMF1 and KMF01 for sensitivity cali-
bration and for checking linearity.

Picture 1: MFA 2 - Dimensions Picture 3: MFA 2 with L0 50 mm Picture 4: Wiring