Ensuring Optimal Performance through Test Machine Alignment

Ensuring Optimal Performance through Test Machine Alignment

There are direct connections between reliable test results and test machine alignment.  Machine alignment is integral to accuracy in measurement, regardless of the application.  Precise alignment prevents the risk of inaccurate measurements.  Increased stringency in quality evaluations of materials and components has led to tighter performance tolerances and an even greater emphasis on confidence in measurement results.  Ensuring the traceability of the geometrical alignment of materials testing machines has therefore become an important consideration in today’s test labs.  The concept of traceability refers to the full and complete documentation of a measured result. 

To ensure your testing complies with test methods that limit the permissible amount of misalignment, we recommend periodic alignment verification.  Zwick USA offers materials testing machine alignment services and is accredited by A2LA to provide these services.  These services are performance in accordance with ASTM E1012, Standard Practice for Verification of Testing Frame and Specimen Alignment Under Tensile and Compressive Axial Force Application.  In accordance with the standard, our team of professionals conducts a recorded inspection of test axis alignment.  The electronic measurement of bending influences that can arise as a result of the smallest angular errors or offset in the test axis is a requirement in the scope of services performed. 

Misalignment of the test axes causes non-uniform force application to the specimen.  This also creates bending stresses during the application of tensile and compressive forces, which can cause erroneous test results.  Misalignment also creates an increased risk of breakage near the point at which the specimen is clamped and therefore elevates the risk that the measurement result will be inaccurate. 
Misalignments can be especially common with brittle materials.  Stiff and brittle materials break with seemingly low tensile stress and strain in the area of the largest bending.  This is where Zwick's alignment services come into play.  A highly developed procedure enables visualization of the specific bending strain with the help of strain gages and reporting to initiate required measurements for alignment.

Based on ASTM E1012, strain-gaged alignment transducers, which preferably conform to the geometry of the specimen to be tested at a later time, are required.  An experienced Zwick service technician positions the strain-gaged alignment transducer in the test axis of your testing system and it is then loaded in the elastic range.

In the event of non-uniform force application to the specimen, the applied strain gages will register different strains.  These are digitized through a connected electrical measurement amplifier and transferred to a special testXpert II software test program.  Material properties are determined and logged in testXpert II according to standard specifications and specimen geometries.  A simple, structured evaluation in testXpert II enables a Zwick service technician to identify errors in the test axis on the basis of characteristic measurement results.  In addition, testXpert II provides adjustment recommendations for the alignment unit option, allowing detected alignment to be corrected easily and conveniently.

Key Benefits of Zwick Machine Alignment Services

  • By using standardized strain-gaged alignment transducers, Zwick guarantees a high degree of comparability with customer-specific specimen dimensions
  • Convenient testXpert II software with adjustment diagrams directly display the individual components of the alignment error and adjustment instructions for the operator
  • Complete, detailed recording of measurement results as required by the standards and beyond (incorporation of images possible)
  • Qualified Zwick experts guarantee professional and individualized support for questions and individual requirements.

Contact us for additional information on machine alignment services. 


Zwick USA
Tel.  +1 770 420 6555
E-Mail  info@zwickusa.com


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