Platens are flat plates or disks used to enact a compressive force on a sample. These fixtures are designed to be used in conjunction with a Universal Testing Machine for compression testing. There are many sizes of platens but only a few types. These compression grips can be either circular or square, can have holes drilled in them, and also could be spherically seated. By using a combination of 1 fixed platen and 1 spherically seated platen, a sample specimen can be self-aligned during a compression testing procedure. LVDTs can be mounted through the platen to provide increased position data accuracy.
Fixed Platen
The fixed platen is the most ordinary and can be square or circular. There are tiny concentric rings which help to expel air during the test. Most quality engineers will opt for a spherically seated self aligning test setup to ensure the uni-axial force is properly aligned.
Foam Testing Platen
The foam testing platen has a pattern of drilled holes in it in order to let the air escape freely during testing. Threaded holes can also be drilled into the platen in order to attach additional fixtures and grips. The Platen for ASTM D3574 must be 8in. circular w/ swivel joint for static tests and 10in. w/ fixed joint for the I3 Constant Force Pounding Tests.
20kN Spherically Seated Platen
This type of compression fixture rests atop two spherical joints which allows it to self-align during a compression test. Platens with spherically seated joints are required for many ASTM tests for different materials including concrete, rubber, and wood.
1,000 kN Spherically Seated Platen
The 1 Meganewton steel platen is commonly used for concrete compression testing and can support up to about 300 kip. It is designed to fit on the base table of the universal testing machine and act as the bottom plate. The design allows 20 degrees of freedom. ~125 lbs. wt.
Compression Cage
Compression Cages are used to test boxes, shipping containers, packaging, large closed cell foams, and furniture such as chairs. 4 guide bars are used to help to avoid any damage to the load cell from trans-axial forces. These cages are machined to order and are highly customizeable.
Compression Ball
The compression ball is used in special, user-defined tests. The ball is an exact hemisphere, and can be sized according to request. The ball platen is machined as a custom item.
Guided Compression Platen
The guided compression platen is very similar to the compression cage and is basically a scaled down version. The two guides help to balance the load and eliminate any transverse forces which could damage the load cell. A reinforced ball bearing guide bushing is used to ensure even pressure and low friction.
Compression Probe Holder
The compression probe holder is a modified torque chuck which can hold pins from 3-16mm. This chuck can hold many different designs of compression probes. A myriad of different probes are used in food testing, depending on what the exact food is.
Heated Compression Platen
The heated compression platen is a great solution for testing at elevated temperatures. The package ships complete with a temperature controller. The apparatus plugs into the wall and can be wired for US or international power. The heated platen is usually place on the bottom.
Compressometer - LVDT
A compressometer is a type of compression fixture which is a combination of standard platens and position sensors. Linear Variable Displacement Transducers (LVDTs) are embedded in the platen and can send extremely precise data signals back to a DAQ controller unit.
300kN High Capacity Platens
Compression tests at high loads require special platens. An extra thick piece of heat treated steel is used to crush the sample. These size platens are used when testing geological rock samples as well as compression testing on metal pipes used in the oil & gas industry.