Displacement Verification to ASTM E 2039

Why Verify Your Impact Testing Machine?

When you use an impact tester to determine the breaking energy of specimens, you need to have confidence that the data is sound. An Instron® calibration of your machine gives you a statement of how well your impact testing system is performing.

Pendulum Impact Testers (Metal & Plastics)

For Pendulum Impact testers, the ASTM & ISO standards testing methods stipulate that the impact testing machine needs to meet particular performance requirements and have a current calibration certification to show proof of compliance. Instron's pendulum impact calibrations are carried out against the appropriate international standard using traceable equipment and a fully trained and accredited calibration staff. Such calibrations provide a high integrity independent calibration report that fully meets ISO 9000 and ISO 17025 needs.

Drop Tower Impact Testers

At present, there are no ASTM or ISO calibration standards for these more modern drop-tower type Impact testers. However, Instron does provide a comprehensive calibration service for this equipment that verifies the critical parameters.

Instron has Unsurpassed Capability

When choosing an impact verification provider, it is essential to determine if that provider has all the equipment necessary to fully assess the capability of your system. Impact testing machines come in many different shapes and sizes from many different manufacturers. Variations include:
  • Pendulum impact testers for metals
  • Pendulum impact testers for plastics
  • Drop Tower impact testers
  • Capacities from 1 Joule up to 750 Joules (35 ft-lbf to 550 ft-lbf)
  • Compound/‘C’-shaped or ‘U’-shaped hammers
  • Manual/automatic hammer lift
  • Analogue/digital scales
  • Manual/automatic specimen insertion centering
  • Software controlled versions with either local or remote console controls

Some providers’ calibration equipment and methods may only be able to handle certain versions or capacities. Instron has a comprehensive range of Impact calibration offerings to cover most variations of machines and manufacturers.

Instron will Calibrate Your Tester to Meet Your Needs

There are four internationally recognized standard methods for verifying pendulum impact testing machines.

For Metals Verifying Charpy pendulum impact testing machines used for testing metals:

  • ISO 148-2 (EN 10045-2): Charpy impact test on metallic materials – Method for the verification of impact testing machines
  • ASTM E 23: Standard test methods for notched bar impact testing of metallic materials

For Non-metallic Materials Verifying Izod and Charpy pendulum impact testing machines for non-metallic materials such as plastics or rubber:

  • ISO 13802: Plastics - verification of pendulum impact testing machines - Charpy, Izod and tensile impact testing
  • ASTM D 256: Standard test methods for determining the Izod pendulum impact resistance of plastics

The choice of standard has to suit the client’s needs. As a general guideline in North America, most users require verifications to the ASTM methods and, in Europe, generally require EN or ISO verifications.

Direct verifications of impact testers provide a check on the soundness of the basic mechanical and geometrical properties of the machine, including measurement of windage and friction losses. This verification is most important when the machine is first installed or when a major part is replaced, but should also be performed as part of the periodic re-calibration and certification.

Indirect verifications are performed using reference specimens that have been carefully characterized by qualified labs as reference specimens. Many testing machine problems cannot be detected by a direct verification, so the indirect verification is an important additional check of the machine’s performance. The energy levels recorded are assessed for accuracy and repeatability, along with estimated uncertainty of measurement levels. This gives a high level of assurance that the machine is recording the breaking energy levels of specimens accurately. Indirect verification is only available for metals. Indirect verification per ASTM E 23 is performed using reference specimens from NIST. The broken specimens are then sent to NIST for evaluation and a formal report.