Non-Contacting Laser Extensometers for Strain Measurement in Materials Testing

The Non-Contacting Laser Extensometers are high precision non-contacting units designed for strain measurement in materials testing. They have a high speed laser scanner that is used to measure the spacing between reflective tape strips on the sample.

The measurement range is from 8 to 127 mm (0.3 to 5”) for the LE-05 and 8 to 381 mm (0.3 to 15”) for the LE-15. The gauge length is determined by the user. This allows high elongation measurements when shorter gauge lengths are used. The high resolution also enables accurate measurements of smaller strains.

There are 36 extensometer models available in several thousand variations. The company’s focus is on helping customers has led to the development of models to cover almost any test process

With 20+ years of service to the materials testing community, Epsilon will be there to stand behind their products when the users critical application requires it

Epsilon extensometers are compatible with virtually every brand of test equipment and can be supplied with the correct connector to plug in directly, or supplied with an independent conditioner and amplifier

The self-contained extensometer uses sophisticated laser diode technology, and a digital display is included. The analog output may be used to connect to current test controls. The RS-232 serial communications interface allows two way communications, and operation may be remote or local.

The scanning beam is always perpendicular to the specimen, unlike many other laser extensometers, eliminating errors when viewing through windows in chambers. It also reduces sensitivity to the distance between the sample and the extensometer. As the unit measures reflected light, a receiver is not required behind the sample.

Easy to Use

The visible laser light is simply aimed at the specimen, which has small reflective tape strips set at the desired gauge length. The extensometer shows the actual measured gauge length. If preferred, the zero button can offset the output to zero. As the specimen is tested, the display will then directly read the elongation.

The RS-232 interface and analog output are easily connected to current controls or data acquisition systems. High temperature clip-on reflectors may be used as an substitute to tape reflectors. The reflective tape can be used at maximum temperatures of 300 °F (150 °C). These are re-useable and available as an option. They are rated for use to 800 °F (425 °C).

Features

The main features of the Non-Contacting Laser Extensometers are given below:

Non-contacting optical design only requires reflective tape marks on the specimen, or clip-on reflectors

Ideal for use in chambers-calibration not affected by aiming through viewing windows

High resolution of 1 micron

Full 127 mm (5”) or 381 mm (15”) measuring range allows high elongation measurements (e.g. 200% on a 25 mm gauge length).

Specifications

The main specifications of the Non-Contacting Laser Extensometers are given below:

Measurement range: LE-05: 8 to 127 mm (0.3 to 5”); LE-15: 8 to 381 mm (0.3 to 15”)

Maximum resolution: LE-05: 0.001 mm (0.0001"); LE-15: 0.01 mm (0.001”)

Maximum scan rate: 100 scans/second

Linearity¹: LE-05: ±0.01 mm (±0.0004”); LE-15: ±0.04 mm (±0.002”)

Repeatability¹: LE-05: ±0.005 mm (±0.0002”); LE-15: ±0.04 mm (±0.002”)

Target distance: Two selectable factory preset values between 254 and 457 mm (10 and 18”) Default values are:

LE-05: 305 and 381 mm (12 and 15”)

LE-15: 381 and 457 mm (15 and 18”)

Scan line orientation: Vertical

Scan averaging: Moving window averaging over a selectable number of scans

Zero suppression: Reading may be set to zero anywhere in measuring range

Analog output: 16 bit, ±10 VDC standard

Full scale ranges:

0.1, 0.2, 0.5, 1.0, 2.0, 5.0, 10.0, or 20.0” (model dependent)

Optional 2.0, 5.0,10, 20, 50, 100, 200, or 500 mm (model dependent)

Mounting provisions: 1/4-20 UNC tapped holes in base (4)

Selectable Baud rate: 9600, 4800, 2400, or 1200

Display: 2 line, 16 character digital display, backlit LCD

Digital communications: RS-232 serial communications, standard 3 wire

Power input: 115 VAC ±10%, 50/60 Hz standard; 230 VAC ±10%, 50/60 Hz optional

Weight: LE-05: 4.5 kg (10 lbs), LE-15: 20.4 kg (45 lbs)

Size: LE-15: 668 L x 457 H x 196 W mm (27 L x 18 H x 7.7 W inches)

Laser source: Diode laser, 670 nm, CDRH Certified Class II laser instrument

Options: Reflective clips for high temperature use

¹Over optimum displacement range at calibrated distanceNote: Specifications measured at 25 °C and 50% relative humidity.

Non-Contacting Laser Extensometers for Strain Measurement in Materials Testing

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