Compression Fixtures for Universal Testing Machines

Compression Jigs and Fixtures are the most varied type of grip. Universal Grip has an extensive offering of compression, bend, puncture, and shear fixtures as well as food testing fixtures for texture profile analysis. These fixtures attach onto a Universal Testing Machine using a clevis style adapter and locking pin.

Compression Platens

Platens are common with pipe tests and other compressive tests like foam. Platens can be machined to all different sizes, slotted for easy sample placement, and either be fixed or self-aligning with a spherically-seated joint.

Universal Grip offers custom engineered compression platens for applications that require unique solutions. Most platens are either square or circular and attach to the machine via a female clevis coupling.

Bend Fixtures

Bend fixtures can either be adjustable or fixed. The bottom two span points can move and the third loading point contacts the sample to bend it. The 4 point bend test is slightly different and has 2 top loading points. The Serpentine 4 point bend test is also available.

Universal Grip carries 3 main sizes of bend fixtures that customers can then customize with special supports or ASTM specific contact points.

Puncture Fixtures

Puncture fixtures are used to test films and membranes. The sample is secured before the puncture element comes down. The diameter of the hole vs. the puncture plunger is critical.

Sample specimens for puncture tests can sometimes take a long time to switch in and out. Universal Grip offers pneumatic puncture fixtures for production environment testing where high throughput is necessary.

Shear Fixtures

Shear grips are used to induce a stress that is parallel to the surface of the material. Most shear fixtures are uniquely designed for a specific ASTM or ISO test. Universal Grip has a wide variety of shear grip designs and can meet any specification or customer request.

Platens

Food Testing Fixtures

Texture Profile Analysis (TPA) is a specialized mechanical testing discipline that uses controlled compression cycles—typically performed with compression platens, probes, or purpose-built jigs—to replicate the forces and deformation experienced during mastication. By compressing a specimen once or multiple times, TPA quantifies key material properties such as hardness, cohesiveness, springiness, adhesiveness, and chewiness, making it widely used in food science and consumer product development. Universal Grip offers a range of application-specific grips and fixtures for Texture Profile Analysis, including the Ottawa Cell, which is commonly used to evaluate pasta extrusion quality by measuring firmness and structural integrity under standardized compressive loading conditions.

Catalyst Crush Strength Fixture

The Catalyst Crush Strength Fixture compresses individual catalyst pellets, extrudates and beads between hardened platens to measure single-pellet crush strength, the kind of test described in ASTM D4179 and D6175. A collection cup catches the fragments for easy cleanup.

Fiber Compression Fixture

The Fiber Compression Fixture uses a plunger in a clear cylinder to compress loose fibers, fill materials and powders, so you can measure compression resistance and recovery of fiberfill, batting and similar bulk materials.

Compression Fixtures by Type and Standard

Compression platens: fixed or spherically seated, round or square, for ASTM D695 plastics, ASTM D575 rubber, ASTM D1621 rigid foam and ASTM D3574 flexible foam. See compression platens.
Composite compression fixtures: ASTM D3410 shear loading and ASTM D6641 combined loading.
Bend fixtures: three- and four-point flexure for ASTM D790 and ASTM D7264. See bend fixtures.
Puncture fixtures: films, geomembranes and textiles. See puncture fixtures.
Shear fixtures: block shear, lap shear and composite shear. See shear fixtures.
Food and texture fixtures: texture profile analysis and the Ottawa cell. See food testing fixtures.
Catalyst crush and fiber compression fixtures: single-pellet crush strength (ASTM D4179, D6175) and loose fiber compression.

Compression Fixture FAQ

Fixed or spherically seated platens?

Fixed platens are rigid and simple. A spherically seated platen tilts to sit flat on a specimen whose faces are not perfectly parallel, which spreads the load evenly. Most foam, rubber and concrete tests use one spherically seated platen.

How do compression fixtures attach to my machine?

They attach with a clevis adapter and locking pin. Our grip adapters fit most universal testing machines.

Can you build a custom fixture?

Yes. We design and machine custom platens, jigs and fixtures to your standard or drawing. Contact us for a quote.