laserXtens Extensometer

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

As a special development, the laserXtens stands out in the range of non-contact extensometers. It does not require specimen markings. The specimen is illuminated with laser light and the reflected laser beams generate a speckle pattern in the camera. The process is highly accurate and offers a wide range of evaluation options. Since no specimen marking is required, a lot of time is saved. 

Applications

Extensometers using laserXtens systems provide non-contact measurement of deformations on a wide range of materials.

The measuring principle eliminates the need to apply gauge marks, giving laserXtens systems a wide range of application.

  • Tensile, flexure and compression tests on metals and plastics.
  • Tests on components.
  • Tests on specimens where specimen contact is undesirable or not possible due to specimen condition or properties.
  • Deformation measurements on specimens prone to whipping at break which might damage a contact-type measuring system.
  • Testing in temperature chambers and at high temperatures.
  • Applications requiring biaxial deformation measurement.

With laserXtens high-resolution systems, even measurements on small specimen geometries are easy. Flexibility and ease of operation make laserXtens equally suitable for classical quality assurance applications or for use in research and development.

Key Advantages and Features

Simple operation

  • Easy to operate
  • Tamper-proof: anti-tamper paint for the housings for the complete system and nothing on the lenses can be adjusted. An important requirement for reliable test results.
  • Easy alignment to the specimen: laserXtens is centrally aligned to the gauge marks via the connection to the crosshead. This is a very quick operation via simple height adjustment (not with laserXtens 1-15 HP).
  • Compensation for different specimen thicknesses plus testing shear specimens.
  • Wear-free system = low-maintenance. The systems also feature 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.

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.

laserXtens versions

laserXtens 7-220 HP

laserXtens 2-220 HP

laserXtens 1-15 HP

Type

7-camera system: cameras in the measuring head have a fixed mounting; fields of view are combined into a single large image (array technology)

2-camera system: cameras in the measuring head are mounted on motorized carriages, used for L0 setting

1-camera system with telecentric lens for small to very small specimens, from 1 mm Ø Even smaller after pre-testing.

Initial gauge length

3 to 200 mm

3 to 200 mm
Max. measurement travel 50 mm

3 to 14 mm

Load frame

AllroundLine

AllroundLine

zwickiLine

Accuracy Class

Class 0.5 to ISO 9513 (Class B2 to ASTM E83)

Class 0.5 to ISO 9513 (Class B2 to ASTM E83)

Class 0.5 to ISO 9513 (Class B2 to ASTM E83)

Resolution

0.07 μm

0.07 μm

0.04 µm

Connection to crosshead

Yes

Yes

No

Typical applications

Sheet metals and flat steels to ISO 6892-1 Method A with strain-rate control

Sheet metals and flat steel to ISO 6892-1 Method A with strain-rate control

Mini and micro specimens: stents, fine wire, mini metal specimens

Strain-rate-controlled tests to ISO 6892­1 Method A1 (closed loop), suitable for gauge lengths ≥ 30 mm

Strain-rate-controlled tests to ISO 6892­1 Method A1 (closed loop), suitable for gauge lengths ≥ 50 mm

-

r&n-values to ISO 10113 and ISO 10275 (additional option required for change-in-width measurement)

r&n-values to ISO 10113 and ISO 10275 (additional option required for change-in-width measurement)

-

Use with ZwickRoell temperature chamber

Use with ZwickRoell temperature chamber

Special design required for use with temperature chamber

Options

Strain Distribution, Test Re-Run, Second Measurement Axis, 2D Dot Matrix, Flexure Test
videoXtens AddOn: option of switching to videoXtens mode

Second Measurement Axis, Flexure Test

Strain Distribution, Test Re-Run, Second Measurement Axis, 2D Dot Matrix, Flexure Test


Product designation:
1st digit: number of cameras
2nd digit: Min.field of view = max. gauge length (number applies to short mounting distance and is rounded down, so minimum field of view)
Additional designation HP if Accuracy Class 0.5 satisfied

laser_7-220HP_ImageArticle

laserXtens 7-220 HP

The overlapping fields of view of the seven cameras are combined into a single large image. The two virtual gauge marks are also tracked here during the loading process (speckle tracking). If a gauge mark reaches the edge of the field of view of one camera, it is transferred to the field of view of the adjacent camera. This process results in a large measuring range with maximum resolution.

Combined overall image of specimen

Flow mode can be switched to when one of the gauge marks approaches the edge of the overall field of view.

Typical application laserXtens 7-220 HP

Sheet metals and flat steel to ISO 6892-1

  • Specific advantages in this application
  • Strain-rate-controlled tests to ISO 6892­1 Method A1 (closed loop) (for gauge lengths ≥ 30 mm) are used.
  • Determination of strain at break, including specimens with high fracture energy - no damage due to hard impacts at break.
  • No specimen marking required - significant time saving.
  • No specimens are wasted due to break outside L0: 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: extensometer tracks via connection to crosshead. This also results in a larger measuring range and the system is automatically positioned centrally to the gauge length at all times.
  • Optional temperature chamber or connection for testing at high temperature.
  • High-accuracy testing in the ZwickRoell temperature chamber Temperature control and air distribution in the temperature chamber are optimized so that laserXtens resolution is only minimally affected, even at temperature.
  • 2D Dot Matrix option: measurements over the entire specimen, at different measuring points.
  • 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); flexible tunnel minimizes signal interference.

laserXtens 2-220 HP

The laserXtens 2-220 HP measuring head consists of two digital cameras mounted on motorized carriages. This allows the distance between the cameras to be varied, enabling different initial gauge-lengths.
laserXtens 2-220 HP is suitable for use with temperature chambers.
laserXtens 2-220 HP can also be used for strain-rate-controlled tests to ISO 6892-1 Method A1 (closed loop) (for gauge lengths ≥ 50 mm).

Typical application laserXtens 2-220 HP

Sheet metals and flat steel to ISO 6892-1

  • Specific advantages in this application
  • Strain-rate-controlled tests to ISO 6892­1 Method A1 (closed loop) (for gauge lengths ≥ 50 mm) are used.
  • Determination of strain at break, including specimens with high fracture energy - no damage due to hard impacts at break.
  • No specimen marking required - significant time saving.
  • Second Measurement Axis option: determination of change in width and r-value to ISO 10113.
  • Width measurement always centered: extensometer tracks via connection to crosshead. This also results in a larger measuring range and the system is automatically positioned centrally to the gauge length at all times.
  • Optional temperature chamber or connection for testing at high temperature.
  • High-accuracy testing in the ZwickRoell temperature chamber: temperature control and air distribution in the temperature chamber are optimized so that laserXtens resolution is only minimally affected, even at temperature.
  • Resistant to environmental influences (e.g. air currents); flexible tunnel minimizes signal interference.

laserXtens 1-15 HP

laserXtens 1-15 HP is a high-accuracy system for testing small and very small specimens. In addition to a camera and two laser light sources it possesses a special lens. A telecentric lens can compensate for lateral specimen movements (see below).

Due to the short distance from the specimen this laserXtens can only be mounted on zwickiLine. It is not tracked and therefore has no connection to the crosshead.

laserXtens 1-15 HP: compensates for lateral specimen movements
With many specimens or test assemblies there is a tendency for the specimen to move out of the test axis. This happens particularly often with small specimens. However, a change in the distance of the specimen from the camera results in an enlargement/reduction of the specimen in the trapezoid field of view, influencing test results. laserXtens 1-15 HP's telecentric lens compensates for these lateral specimen movements, minimizing measuring errors.

Typical application laserXtens 1-15 HP

Mini and micro specimens: stents, fine wire, mini metal specimens

  • Specific advantages in this application
  • Contact-type systems cannot be used for these as they are unable to access the specimen.
  • No influence on the specimen - no contact, no specimen marking.
  • Out-of-plane movement compensated for by telecentric lens.
  • Resolution: 0.04 µm - no comparable system for micro specimens.
  • Accuracy Class 0.5
  • Time-saving - no specimen marking required.
  • Our competitors have no comparable product with laser speckle technology.
  • Customizing - can be connected to special temperature chambers to test sensitive specimens at uniform temperature.
  • laserXtens 1-15 HP has no moving parts and is completely wear-free.
  • Option: 2D dot matrix over the entire specimen, at different measuring points or whole surface.

laserXtens 2-120 HP/TZ

The laserXtens 2-120 HP/TZ provides non-contact measurement of deformations on a range of materials in varying environmental conditions up to 2,000°C. The laserXtens 2-120 HP/TZ is equipped with two cameras, two green laser light sources for measurement at very high temperatures, and two telecentric lenses. The telecentric lenses make the laserXtens 2-120 HP/TZ resistant to distance changes between the lens and specimen. When using the laserXtens 2-120 HP/TZ in connection with temperature chambers and high temperature furnaces, the negative influence on the measurement signal due to changed optical conditions such as air currents, must be taken into consideration. With the laserXtens 2-120 HP/TZ these influences are minimized by means of an optical tunnel.

Typical application laserXtens 2-120 HP/TZ

Metals to ISO 6892-2

  • Specific advantages for this application:
  • Strain-rate controlled tests to ISO 6892-2 (high temperature) and to ISO 6892-1 (room temperature) Method A1 (closed loop).
  • Measurement of transverse strain and deflection without additional markings and without required hardware expansion (software option).
  • The adjustment of different gauge lengths is motor-driven.
  • The specimen is not affected by the laser light.
  • Even at elevated temperatures, sensitive specimens are not affected by the extensometer.
  • Sensor arms are maintenance-free and not prone to breaking.
  • Resistant to environmental influences (e.g. air currents); the flexible tunnel minimizes signal interference.
  • Temperature chambers and high temperature furnaces can remain completely closed. Openings are thermally sealed with glass windows.
  • Specimen markings are not required, saving time especially with high specimen throughput, as for example in the case of carousel solutions.

laserXtens 1-32 HP/TZ

The laserXtens 1-32 HP/TZ includes one camera, two green laser light sources for measurement at very high temperatures, and one telecentric lens for reduction of distance changes between the lens and specimen. The measuring principle eliminates the need to apply gauge marks.

The laserXtens 1-32 HP/TZ is intended for use with vacuum chambers, furnaces, and induction up to a temperature range of +2,000°C.

When using the laserXtens 1-32 HP/TZ in connection with temperature chambers and high temperature furnaces, it must be taken into consideration that the measurement signal may be negatively influenced due to changed optical conditions such as air currents. These influences are minimized by means of an optical tunnel.

Typical application laserXtens 1-32 HP/TZ

Metals to ISO 6892-2

  • Specific advantages for this application:
  • Strain-rate controlled tests to ISO 6892-2 (high temperature) and to ISO 6892-1 (room temperature) Method A1 (closed loop).
  • Measurement of transverse strain and deflection without additional markings and without required hardware expansion (software option).
  • Different gauge lengths can be set in fractions of a second.
  • The specimen is not affected by the laser light.
  • Even at elevated temperatures, sensitive specimens are not affected by the extensometer.
  • Sensor arms are maintenance-free and not prone to breaking.
  • Resistant to environmental influences (e.g. air currents); the flexible tunnel minimizes signal interference.
  • Temperature chambers and high temperature furnaces can remain completely closed. Openings are thermally sealed with glass windows.
  • Specimen markings are not required, saving time.

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 Re-Run module enables retrospective recalculation of strain using an image series recorded during a test but employing a different initial gauge-length (provided multiple marks 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.

The recalculated strain can naturally be synchronized retrospectively with the other measured 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

Video capture is a recording of the test (without retrospective recalcualation). The recording is synchronized with the measured curve, enabling the test to be viewed retrospectively. The option includes no hardware, as recording and synchronization take place entirely via the laserXtens system.
Please note: this option can only be operated via a camera. We should also point out that the speckle pattern, not the natural surface of the specimen, is visible on the specimen.
The option is supplied free of charge with all laserXtens versions from testXpert II V3.71 and testXpert III.

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 deflection in 3 or 4-point flexure tests. This can be measured at one point (displacement of one measurement location) or three points (relative displacement of the middle or two outer measurement locations) with a maximum measurement base of 15 mm (20 mm for laserXtens 7-220 HP).

Technical data

laserXtens 7-220 HP

Type

laserXtens 7-220 HP

Item No.

1043974

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

2[1]

Initialgauge length

3 to 200

mm

Measurement travel with speckle tracking

210 mm - initial gauge length

Measurement travel flow measurement

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

Strain rate control as per ISO 6892-1 Method A1

from 30[2]

mm

Resolution

0.07

µm to EN ISO 9513

Accuracy class

to EN ISO 9513.

0.5

FOV (L x W)

220 x 28

mm

Typical measurement frequency (adjustable)

70

Hz

Max. measurement speed at measurement point

500

mm/min

Specimen thickness

flat specimens, measured on the broad side

≤30

mm

flat specimens, measured on the specimen edge

>1[3]

mm

Round specimens

1 to 30[3]

mm

Specimen width

1 to 30

mm

Dimensions

Height

460

mm

Width

485 to 745

mm

Depth

140

mm

Minimum version

testXpert II V 3.71 and testXpert III

Scope of delivery:

measurement head with 7 high-resolution digital cameras plus lenses, 5 laser light sources (red), tunnel to minimize signal interference, INC module (RS module for tC), software license, accessory case with scaling aid

  1. No protective measures required.
  1. Not in ZwickRoell temperature chamber
  1. Pre-testing is required for specimens with thickness < 1 mm.

laserXtens 2-220 HP

Type

laserXtens 2-220 HP

Item No.

1043978

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

2[1]

Initial gauge length

3 to 200

mm

Measurement displacement with speckle tracking

  • Initial gauge length: 3 to 25 mm; max. measured displacement: 25 mm - initial gauge length (measurement with camera)
  • Initial gauge length: 20 to 180 mm; max. measured displacement: 50 mm
  • Initial gauge length: 180 to 200 mm; max. measured displacement: 220 mm - initial gauge length

Measurement displacement for flow measurement

After measurement displacement via speckle tracking, laserXtens switches to flow measurement

Strain rate control compliant to ISO 6892-1 Method A1

from 50[2]

mm

Resolution

0.07

µm to EN ISO 9513

Accuracy class

To EN ISO 9513

0.5

Typical measurement frequency (adjustable)

70

Hz

Speed at measurement displacement, max. at the measurement point

500

mm/min

Specimen thickness

Flat specimens, measured on the side

≤30

mm

Flat specimens, measured on the specimen edge

>1[3]

mm

Round specimens

1 to 30[3]

mm

Dimensions:

Height

460

mm

Width

485 to 745

mm

Depth

140

mm

Ambient temperature

+10 to +35

°C

Minimum versions

testXpert II V 3.71 / testXpert III

Scope of delivery

Measuring head with motorized gauge length adjustment (automatic L0 setting), 2 digital cameras including lenses F=75mm, 2 red laser light sources, software for image acquisition, evaluation of the cross correlation and transfer to testXpert III, accessory case with scale aid.

  1. No safety measure required.
  1. Not in ZwickRoell temperature chamber
  1. Pretests are required for specimens with a specimen thickness < 1 mm.

laserXtens 1-15 HP

Type

laserXtens 1-15 HP

Item No.

1043981

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

2[1]

Initialgauge length

3 to 14

mm

Measurement travel with speckle tracking

15

mm - initial gauge-length

Measurement travel flow measurement

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

Resolution

0.04

µm to EN ISO 9513

Accuracy class

to EN ISO 9513.

0.5

Typical measurement frequency (adjustable)

70

Hz

Max. measurement speed at measurement point

250

mm/min

Specimen thickness

flat specimens

≤30

mm

Round specimens

0.5 to 30[2]

mm

Dimensions

Height

175

mm

Width

306

mm

Depth

91

mm

Ambient temperature

+10 to +35

°C

Scope of delivery

measuring head with 1 digital camera incl. telecentric lens, two red laser light sources, software for image acquisition, evaluation of cross-correlation and transfer to testXpert II, accessory case with scaling aid

  1. No protective measures required.
  1. Pre-testing is required for specimens with diameter < 1 mm.

laserXtens 2-120 HP/TZ

Type

laserXtens 2-120 HP/TZ

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

2[1]

Initial gauge length

Measurement with one camera

1.5 ... 25

mm

Measurement with two cameras

25 ... 120

mm

Measured displacement with speckle tracking[2]

1.5 ... 25 mm

32 mm - initial gauge length

25 ... 120 mm

30 mm (for fixed assembly)

60 mm (for automatic entrainment)

Measurement displacement flow measurement

After reaching the max. measurement displacement, switch to flow measurement mode

Resolution

0.11

µm

Accuracy class to EN ISO 9513

0.5

Temperature range

-150°C ... +2,000°C

Measurement frequency for standard setup

70

Hz

Max. measurement speed at measurement point

500

mm/min

Scope of delivery

Measuring head with motorized gauge length adjustment (automatic L0 setting), two digital cameras incl. high resolution telecentric lenses, two green laser light sources, high temperature tunnel for reduction of environmental influences, software for image acquisition, evaluation of cross-correlation and transfer to testXpert II (Version 3.71 or higher) or testXpert III, accessory case with scaling aid, INC module (for tC: RS module). Incl. connection to crosshead; the extensometer tracks at half test speed.

  1. No protective measures required.
  1. If necessary, restriction implemented via furnace or temperature chamber

laserXtens 1-32 HP/TZ

Type

laserXtens 1-32 HP/TZ

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

2[1]

Initial gauge length

1.5 … 25

mm

Measured displacement with speckle tracking[2]

For fixed assembly

32 mm - initial gauge length

For automatic entrainment

2 * (32 - initial gauge length)

Measurement displacement flow measurement

After reaching the max. measurement displacement, switch to flow measurement mode

Resolution

0.11

µm

Accuracy class to EN ISO 9513

0.5

Temperature range

-150°C ... +2,000°C

Measurement frequency for standard setup

70

Hz

Max. measurement speed at measurement point

500

mm/min

Scope of delivery

Measuring head with one digital camera incl. high resolution telecentric lens, two green laser light sources, high temperature tunnel for reduction of environmental influences, software for image acquisition, evaluation of cross-correlation and transfer to testXpert III, accessory case with scaling aid, INC module (for tC: RS module). Incl. connection to crosshead; the extensometer tracks at half test speed.

  1. No protective measures required.
  1. If necessary, restriction implemented via furnace or temperature chamber

High-accuracy testing in the temperature chamber

The testing machine including temperature chamber features convenient, intuitive operation via the testing software. All components (materials testing machine, extensometer, and testing software) are developed in-house at ZwickRoell.
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