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ASTM D575 - Rubber Compression Testing

astm d575 compression platens
Universal Grip ASTM D575 specimen cutter for universal testing machines

Standard Test Methods for Rubber Properties in Compression - PDF

ASTM D575 Specimen Cutter – Universal Grip Data Sheet (PDF)

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ASTM D575 uses the same button specimen as ASTM D395. For 95% of people we recommend jumping straight to the ASTM D395 page. The Method B Fixture is most popular.

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ASTM D575 is the standard test method for determining the compressive properties of unvulcanized or vulcanized rubber materials. It’s commonly used to measure a rubber compound’s ability to resist deformation under a compressive load. The test provides data such as compressive stress-strain behavior, modulus, and hysteresis (energy loss).

There are two main procedures under this standard:

  • ASTM D575 Method A: Compression to a specified deflection, measuring the force needed

  • ASTM D575 Method B: Compression under a specified force, measuring the resulting deflection

Common Applications of ASTM D575

  • Evaluating rubber seals, bushings, mounts, pads, and gaskets

  • Material selection for applications involving compressive loads

  • Quality control during rubber manufacturing

  • R&D for comparing different rubber compounds

  • Measuring force-deflection behavior in compressionss (compression set is measured with ASTM D395)

What Does ASTM D575 Measure?

The primary properties measured include:

  1. Compressive Stress at Given Strain

  2. Modulus in Compression (e.g., stress at 10%, 20%, or 30% strain)

  3. Deflection under a specified force (Method B)

  4. Hysteresis / Energy Loss (difference between loading and unloading curves)

  5. Permanent Set after compression

These results give insight into a material’s stiffness, energy absorption, and long-term behavior under compression.

Equipment Required

To perform ASTM D575 testing accurately, the following equipment is required:

1. Universal Testing Machine (UTM)

  • Load cell capacity: Typically 10 kN to 100 kN, depending on rubber stiffness

  • Precise crosshead speed control (especially important for Method A)

  • Capable of recording load vs. displacement data

2. Compression Platens

  • Hardened steel platens with smooth, parallel surfaces

  • Flatness tolerance: within 0.025 mm

  • Lubrication (e.g., talc or soap solution) may be used to reduce friction

  • Alignment must be precise to avoid off-axis loading

3. Deflection Measuring Device

  • Dial gauge, LVDT, or extensometer to measure the change in thickness

  • Resolution: at least 0.01 mm or better

4. Deflection Control

  • Crosshead position or a deflectometer to stop or record compression at each specified deflection

ASTM D575 Specimen Dimensions

Standard Specimen for Both Methods:

  • Cylindrical Rubber Specimen

    • Diameter: 28.6 mm ± 0.13 mm (1.13 in)

    • Thickness: 12.5 mm ± 0.13 mm (0.5 in)

  • Ends must be parallel and flat

ASTM D575 Method A: Compression at a Specified Deflection

Objective: Find the force needed to compress the specimen to set deflections, for example 10%, 20% and 30% of its original thickness.

Procedure:

  1. Condition the specimen at standard laboratory temperature (23 ± 2 °C).

  2. Center the specimen between the compression platens.

  3. Compress at a constant speed of about 12 mm/min (0.5 in/min).

  4. Record the force at each specified deflection.

  5. Report compressive stress (force divided by the original cross-sectional area) at each deflection.

ASTM D575 Method B: Compression under a Specified Force

Objective: Find how far the specimen compresses under set forces.

Procedure:

  1. Use the same specimen, platens and speed as Method A.

  2. Apply force up to each specified value.

  3. Record the deflection at each force as a percentage of the original thickness.

Notes: Results depend on specimen shape and on friction at the platens, so only compare results from the same specimen geometry and platen surface. Compression set, where the specimen is held at a fixed deflection with spacers and then released, is a different test: ASTM D395.

Data Reporting Requirements

An ASTM D575 test report should include:

  • Specimen dimensions

  • Rubber type and cure state

  • Environmental conditions (temperature, humidity)

  • Load and displacement data

  • Stress at specified strain levels (e.g., 10%, 20%, 30%)

  • Force at each specified deflection (Method A)

  • Deflection at each specified force (Method B)

  • Percent hysteresis

  • Notes on bulging, failure, or anomalies during test

Related and Similar Standards

Best Practices for Accurate ASTM D575 Testing

  • Ensure platens are parallel and well-aligned to avoid bending or eccentric loading.

  • Use lubrication to reduce friction and prevent bulging or sticking.

  • Avoid over-tightening clamps or fixturing tools which can induce pre-stress.

  • Use digital displacement measurement tools for high-precision deflection data.

  • Always condition specimens in the testing environment for at least 16 hours.

  • Perform multiple tests to validate results and assess consistency across batches.

Summary

ASTM D575 is the foundational test method for evaluating rubber under compression. It offers insights into the stiffness, deformation behavior, and energy dissipation properties of elastomeric materials. Whether you're developing new rubber compounds or performing routine QC testing, understanding the nuances of both Method A and Method B will help you ensure accurate and repeatable results.

ASTM D575 FAQ

What is the difference between ASTM D575 and ASTM D395?

D575 measures how much force it takes to compress rubber, or how far it compresses under a given force. D395 measures compression set: how much permanent deformation remains after the rubber is held compressed for a set time and temperature.

What specimen does ASTM D575 use?

A cylinder 28.6 mm (1.13 in) in diameter and 12.5 mm (0.49 in) thick, the same size as the D395 Type 1 button.

What is the difference between Method A and Method B?

Method A compresses the specimen to specified deflections and records the force. Method B applies specified forces and records the deflection.

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