MTS Series 311 Load Frame - Manual (Page 45)

Installing a Specimen
Series 311 Load Frame Operation 45
Note Always lower the crosshead to where you want it. The pressure
remaining in the lift cylinders after raising the crosshead can slightly shift
its alignment. Lowering the crosshead to its final position removes this
pressure and improves alignment.
C. Use the Crosshead Lift/Lock Controls to move the crosshead
to a point where you can install the specimen (or specimen
fixture) into the upper grip or fixture without obstruction.
Set the control to the stop position “O” before proceeding.
D. Use the Crosshead Lift/Lock Controls to clamp the
crosshead to lock it in its current position. Wait 30 seconds
for the locks to fully clamp the columns.
3. Install the specimen into the grips or fixtures.
Specimen installation will vary according to the type of grip or fixture being
used. If grips are not used then the specimen is installed in a special fixture
designed for a specific specimen to be installed in a specific load frame.
See the appropriate grip manual or fixture drawings for installation
instructions. MTS manufactures a variety of grips:
Note Hydraulically controlled grips require a Series 685 Hydraulic Grip Supply.
• The Series 641 Hydraulic Wedge Grips (hydraulically controlled) are
specifically designed for static or fatigue testing applications. They are
available with a self aligning feature.
• The Series 643.6X Tension/Compression Grips (mechanical) are used
for testing threaded-end and button-end specimens in tension,
compression, or tension/compression.
• The Series 646 Hydraulic Collet Grips (hydraulically controlled) are
designed to perform in a wide variety of testing applications (for
example, high and low cycle fatigue, tension, and compression).
• The Series 647 Hydraulic Wedge Grips (hydraulically controlled) are
specifically designed for static or fatigue testing applications. There are
a variety of configurations of this grip.
• The Series 649 Wedge Grips are specifically designed for static or
fatigue testing applications. These are a mechanical version of the
Series 647 Hydraulic Wedge Grips.
Each type of grip requires the specimen or specimen fixture to fit properly
into the grip.