Creep Machine Calibration

Instron Calibration Laboratories are accredited to calibrate and verify creep machines to the internationally recognized ISO7500-1 and ISO7500-2 standards.

These are the verification standards specified for those customers undertaking testing to ISO 204, the uni-axial creep testing in tension specification.

When You Need to Verify Creep

When you use a creep testing system, you need to have confidence that the data is sound. An Instron verification of your machine gives you a statement of how well your system is performing to particular performance requirements and has current calibration certification to show proof of compliance. Instron creep calibrations are carried out against ISO standards using traceable equipment and a fully trained and approved calibration staff. Such calibrations provide a high integrity independent calibration report that meets ISO 9000 and ISO/IEC 17025 demands.

This verification is most important when the machine is first installed or when a major part is replaced. It is also highly recommended to be performed as part of a creep machine’s periodic maintenance program. To ensure compliance with your testing and quality plans, creep verification needs to be undertaken prior to the commencement of a creep test if the predicted test life exceeds the date of expiry of the verification certificate.

Which Standard to Use
ISO 7500-1

This standard applies to testing machines with a force measuring system comprised of a load cell plus conditioning and indicator.

ISO 7500-2

This standard applies to testing machines of the following types:

  • Deadweight machines with or without guides
  • Overslung or underslung lever machines
  • Jockey weight machines, either with overslung or underslung lever
  • Any combination of the types mentioned above

All of our calibration certificates provide comprehensive uncertainty of measurement data as needed for any testing laboratory required to comply with ISO/IEC 17025.

Instron’s Comprehensive Service

The verification shall only be carried out if the machine is in good working order. The Instron Service Engineer will perform a general inspection of the testing machine prior to calibrating the applied load, ensuring that the system is not affected adversely by significant wear of knife edges, supporting points, bearings, grips, or pull rod guides. This inspection will include:

  • Checks for looseness on column mounting and fixed crossheads
  • Checks that the lever system can swing freely over its operating range
  • Checks that the machine is not adversely affected by environmental conditions, such as vibrations or local temperature variations
  • Checks that as far as possible, the line of action of force runs through the center of the knife-edges or ball seatings of the load train
  • Checks that the structure and gripping systems will permit the force to be applied axially

Having confirmed these points, the load applied by the testing machine can be verified. Some providers’ calibration equipment and methods may only be able to handle certain versions or capacities. Instron undertakes to cover all variations of machines offering a “design and manufacture service”  for any additional jigs or fixtures that may be required.