laserXtens 7-220 HP Extensometer

The laserXtens is a non-contact extensometer that performs tests with the highest accuracy, without the need for gauge marks.

The laserXtens 7-220 HP provides high-accuracy, non-contact measurement without the need for gauge marks for tensile, compression and flexure testing on metals. Due to the patented laserXtens array technology it has a wide measurement range and full view of the entire specimen, which allows for the collection of much more information from the specimen than just the elongation between two gauge marks.

  • The laserXtens does not require specimen markings, which provides significant cost and time savings, especially in the case of high specimen throughput.
  • The patented laserXtens array technology is unique. It allows the laserXtens 7-220 HP to measure in a wide measurement range with high accuracy. In addition, the extensometer has full view of the entire specimen, which allows for the collection of even more information from the specimen. For example, the setting of up to 100 measuring points on the specimen or the automatic determination of the break point, which prevents breaks outside the L0 and considerably minimizes specimen waste.


Extensometers from the laserXtens systems series measure without contact and with the highest level of accuracy. The measuring principle eliminates the need to apply gauge marks. This allows the laserXtens systems to be used for a wide range of applications:

  • Tensile, flexure and compression testing preferably on metals or other materials that disperse the laser light on the surface.
  • Testing on contact-sensitive specimens or specimens with high fracture energy.
  • Highly accurate testing in temperature chambers and high-temperature testing
  • Applications in which more than two measuring points are used, e.g. biaxial deformation measurements or strain distribution.
  • Measurements on small specimen geometries or components.

Due to its flexibility and easy handling the laserXtens is ideal for applications in the field of quality assurance, as well as in research and development.

Key Advantages and Features

Testing without specimen marking

  • Testing without specimen marks
  • laserXtens' unique technology eliminates the need for specimen marking.
  • Significant time and cost savings, particularly with high specimen throughput.
  • The advantages are especially apparent with options covering multiple measuring points or entire specimen surfaces.
  • Easy to use in temperature chambers, where environmental conditions can make gauge mark application really difficult.
  • Ideal for automated systems - no manual specimen preparation required.

Simple operation

  • Easy operation
  • Tamper-proof: The housing of the complete systems are lacquered; nothing can be adjusted on the lenses. This is an important requirement for reliable test results.
  • Simple alignment to the specimen: Through the connection to the crosshead, the laserXtes is aligned centrally to the gauge marks. This can be done very quickly due to the ease of height-adjustment. (not for laserXtens 1-15 HP).
  • Compensation of various specimen thicknesses and testing of shear specimens.
  • Wear-free system, and as a result also low-maintenance. The systems have an extremely long service life.

High accuracy

  • High accuracy down to the last detail
  • laserXtens possesses high precision in the micro and macro measurement ranges.
  • ZwickRoell extensometers exceed the requirements of the standards and are calibrated over the entire measurement range to Accuracy Class 0.5, ISO 9513.
  • Calibration in Accuracy Class 0.5 to ISO 9513 with first calibration point from as early as 20 µm.
  • Industrial-quality cameras and high-quality, low-distortion lenses.
  • Specimens from 1 mm in width/diameter can be tested; even smaller specimens may be possible following pre-testing.
  • In contrast to contact-type extensometers or pure video instruments, laserXtens can measure strain on short specimens (gauge lengths from 3 mm) with high accuracy.
  • Extensometer mounted using stable, low-vibration mounting arms.
  • Housing provides protection against dirt and dust and inadvertent loss of adjustment of components.
  • Exact synchronization of all measurement channels.
  • A tunnel minimizes environmental influences such as air currents.

Automatic centering

  • Automatic centering increases measurement travel and measuring accuracy.
  • laserXtens tracks at half crosshead speed via the connection to the crosshead, keeping the testing operation automatically in focus and making optimum use of the measuring range.
  • This results in increased system accuracy; the gauge marks shift less in the image and are captured in the (more accurate) center of the lens.

laserXtens 7-220 HP

The laserXtens 7-220 HP extensometer features seven fixed high-resolution cameras and five laser light sources. The overlapping fields of view of the seven cameras are pooled into one large picture. Both virtual gauge marks are also tracked here during the loading process (speckle tracking). If a gauge mark makes hits the edge of a camera’s field of view, it will be transferred to the field of view of the adjacent camera. This method results in a large measurement range with high resolution.

Combined overall image of the specimen

Typical application laserXtens 7-220 HP

Sheet metals and flat steel to ISO 6892-1

  • Specific advantages for this application:
  • Strain-rate controlled tests to ISO 6892-1 Method A1 (closed loop) (for gauge lengths ≥ 30 mm).
  • Determination of strain at break, including specimens with high fracture energy - no damage due to hard impacts at break.
  • No specimen marking required, therefore significant time saving.
  • No specimen is wasted due to breaks outside L0: the strain distribution option automatically sets L0 around the area of highest strain and the break location.
  • Second measurement axis option: determination of change in width and r-value to ISO 10113.
  • Width measurement always centered: the extensometer tracks via connection to the crosshead. This results in a larger measuring range and the system is automatically positioned centrally to the gauge length at all times.
  • High-accuracy testing in the ZwickRoell temperature chamber: temperature control and air distribution in the temperature chamber are optimized so that the laserXtens resolution is only minimally affected, even at temperature.
  • 2D dot matrix option: measurements over the entire specimen, at different measuring points.
  • The laserXtens 7-220 HP has no moving parts and is completely wear-free.
  • Patented unrivaled array technology.
  • Resistant to environmental influences (e.g. air currents); the flexible tunnel minimizes signal interference.

Extension measurement with the non-contact laserXtens

Measuring completely without measuring marks and with highest precision

laserXtens Extensometer

Ideal for tensile tests, compression tests and bending tests on metals, plastics, components; at room temperature and under temperature.

Software Options 

testXpert III testing software offers various options for precise, traceable non-contact extension and strain distribution measurement. 

Test re-run

The optional Test ReRun module enables subsequent recalculation of strain on the basis of an image series recorded during a test, using a different initial gauge-length (provided multiple markings are present). This can be particularly advantageous in component testing, for example, when it is necessary to evaluate local strain at different locations, or in standard tensile tests when specimen necking has occurred outside the original initial gauge-length.

Automatic symmetrical adjustment of strain around necking to ISO 6892-1, Annex I

The recalculated strain can, of course, be synchronized subsequently with the other measurement values via the testXpert testing software.

Strain distribution

The Strain Distribution option enables determination of local strains at multiple measuring locations along the specimen gage-length. Evaluation of up to 16 measuring locations is possible. This option also allows automatic real-time symmetrical adjustment of the initial gage-length around the necking (as per ISO 6892-1, Annex I).

Video Capturing

2D dot matrix

This option allows two-dimensional measurement of dots on a planar specimen surface. This enables determination of local strains and inhomogeneities of the specimen under load. X and Y co-ordinates plus the distances between dots are available as measured values.
Up to 100 measurement dots can be measured in any desired arrangement or in matrix form.
Display in testXpert III is limited to 15 channels.

Second measurement axis option 

This option allows local transverse strain to be measured simultaneously with determination of longitudinal strain.

Deflection measurement 

laserXtens also determines the deflection for 3- or 4-point flexure tests. Measurement can be performed at one point (displacement of a measuring point) or at three points (relative displacement of the middle measuring point to the two outside measuring points) with a maximum measurement basis of 15 mm (laserXtens 7-220 HP 20 mm).

Technical data

laserXtens 7-220 HP


laserXtens 7-220 HP

Item No.


Initial gauge length

3 ... 200


Measurement travel with speckle tracking

210 mm - initial gauge length

Measurement travel for flow measurement

After measurement travel via speckle tracking, laserXtens switches to flow measurement.

Strain rate control to ISO 6892-1 Method A1

From 30[1]




µm to EN ISO 9513

Accuracy class

To EN ISO 9513




Field of view, FOV (L x W)

220 x 28


Typical measurement frequency (adjustable)



Measurement speed, max. at the measuring point



Specimen dimensions

Flat specimen, thickness

1 ... 30


Round specimen, Ø

1 ... 30







485 ... 745





Minimum version

testXpert II V 3.71 and testXpert III

Laser safety class to DIN EN 60825-1 (11-2001)


Scope of delivery:

Measuring head with seven high resolution digital cameras including lenses, five red laser light sources, tunnel for minimizing signal interference, INC module (for tC: RS module), software license, accessory case with scale aid.

  1. Not in temperature chamber
  1. No safety measures required.

ZwickRoell supplies testing machine to the Jiangsu Shagang Group

The Jiangsu Shagang Group is one of the largest national industrial enterprises, and the largest private steel enterprise in China, headquartered in Zhangjiagang City, Jiangsu Province. The company’s assets total RMB150 billion, and the number of employees is over 30,000.