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Extensometers for materials testing

Precision Optical Extensometers – Epsilon ONE

Breakthrough Performance  •  Incredibly Easy to Use  •  Works With Any Test Machine
Epsilon ONE high-precision optical extensometers measure axial strain with industry-leading resolution, accuracy, and speed. Innovative Instant Reset, Always On and Laser Alignment features maximize performance and increase testing throughput.

NEW PRODUCT

Patent Pending

Why Non-Contact:

  • One system for many different tests, measuring ranges, and gauge lengths
  • Test through failure with high-energy specimens
  • Test fine, delicate specimens without unwanted influence or contact stresses

Why Epsilon ONE:

  • Performance: industry-leading resolution, accuracy and ease of use
  • Instant Reset: ready to test in under 2 seconds
  • High Speed: cyclic testing up to 200 Hz and real-time data rates up to 3000 Hz
  • Precision by Design: better non-contact testing with Laser Alignment and Telecentric Optics

Product Videos

Overview – see Epsilon ONE in action

Faster testing – see how

Epsilon ONE optical non-contact extensometers perform high-accuracy, high-resolution, non-contacting axial strain and displacement measurement. These extensometers are suitable for testing high-modulus materials such as metals and composites, high-elongation materials, thin or delicate specimens, cyclic fatigue, strain controlled testing, deflectometer applications, and measuring crack opening displacements. Strain or extension is measured and output in real time.

Epsilon ONE’s high resolution and ISO 0,5 / ASTM B-1 accuracy classes make it suitable for non-contact measurement of a wide range of strain values, from very small strains required to measure modulus of metals, composites, ceramics and CMCs through elastomers and everything in between.

Class-leading accuracy and resolution are achieved by Epsilon’s comprehensive optical path optimization, a unification of several optical technologies and signal processing algorithms. Ultra-high camera resolution, real-time data rates up to 3000 Hz, minimization of optical error sources, and signal processing techniques provide high strain resolution and accuracy with the lowest noise. No other system on the market combines all of these technologies.

The Laser-Assist Alignment System provides an instant alignment and distance spot check. Epsilon ONE will project pre-aligned laser lines on the specimen before the test, revealing any misalignment. During the test, high precision telecentric lenses on the PT models eliminate errors due to out-of-plane movements – a common source of errors for many video extensometers. Epsilon ONE arrives factory calibrated – there are no calibration grids or gauge length bars, saving a great deal of time.

The system sets up for new specimen types in minutes and requires very little training or skill to use. The desktop user interface software and optional Touch Interface provide continuous digital readouts and status information.

Epsilon ONE was designed for the fastest specimen cycle times. Auto-start repetitive tests without any software interaction; Epsilon ONE is always running, and its Instant Reset and Automatic Mark Detection eliminate software start/stop interactions common with video extensometers.

Epsilon ONE fits all types of materials testing machines. The system may be used with environmental chambers that are equipped with a window – contact Epsilon.

Epsilon ONE is patent pending.

Download Data Sheet

  • Always on, always ready: Unlike DIC systems, software interactions are unnecessary when running repetitive tests.
  • Always real-time: Post-processing is never required, even at the highest data rates.
  • Faster throughput with Instant Reset: Auto-start repetitive tests without touching the extensometer or software.
  • Reliable, automatic mark detection: Robust tracking of bright or dark marks beyond 1000% strain and speeds >1500 mm/second.
  • Laser Assist Alignment System: Provides an instant visual spot-check for specimen alignment and optics positioning.
  • Precision Telecentric Design: Epsilon ONE’s telecentric lenses prevent common sources of error – Read this Tech Note.
  • Fully factory calibrated: Epsilon calibrates using the industry’s most comprehensive process to account for scaling, skew, lens distortion, and uneven lighting. A2LA accredited factory calibration, traceable to the SI; no grids or bars are required for calibration.
  • Cleaner workspace: No need for an additional computer and monitor; the included User Interface software has very low resource requirements and can run on the test machine’s computer.
  • Optional Touch Interface: Access and control the Epsilon ONE without a computer. (see a demo )
  • Retractable high-stiffness mounting: Industry-leading ease-of-use while maintaining maximum dynamic range and vibration rejection.
  • Selectable multi-line specimen marking: Automatically identify and report the region of highest strain concentration, in real time.
  • Wide range of selectable filter and optical settings enable high performance with many different materials and specimens.
  • Faster Testing: Save time with industry-leading 200+ Hz dynamic range and automatic gain compensation filters.
  • Admin/User Modes: Define, save and reload settings for specific specimens and test methods, then lock them in User Mode.
  • Real-time digital output: High-speed data stream including APIs for control and status, and examples for automation and integration.
  • Better Strain Control: Built-in high speed 16-bit analog output; not susceptible to unpredictable cyclic bias errors typical of DIC systems.
  • Strain Metrics: Report strain measures using five finite or small strain theories.
  • Applicable for testing with many ISO and ASTM standards, including:
    • ISO 6892-1, 527-2, 527-4, 527-5
    • ASTM E8, E9, D3039, D638, A370, D3552, E646
  • Turn-key: Each base package includes
    • Optics Package with laser-assist alignment system
    • Lighting Module
    • Sensor Controller
    • Mounting Interface Subassembly
    • Specimen Marking Kit
    • Cables and software
  • Includes high quality foam lined case.
  • Patent pending.

Key Applications

  • Testing of high-modulus materials – resolution and accuracy for very small strain measurements typical with these materials
  • Automated testing – no software interaction is required between repetitive tests
  • Fine / thin specimens – <Ø20 μm (0.001”) specimens
  • Elastomers and high-elongation plastics – best-in-class performance; >1000% strain and  >1.5 meters/second tracking speed
  • High speed cyclic testing – test frequencies up to 200 Hz and real time data rate up to 3000 Hz
  • Long-term creep testing – excellent thermal stability and automatic recovery in the event of a test interruption

Download Data Sheet

 

Field of View: 50-200 mm. Other ranges available – contact Epsilon

Working Distance: 150-300 mm. See specific optics packages

Real-Time Data Rate: 300-3000 Hz, >2000 Hz typical. Includes image frame rate, analog output, and digital output

Analog Output: ±10VDC, short-protected. Selectable units & range. Includes 2.4 m (8 ft) shielded output cable

Digital Output: 16-64 bit over RS232 with selectable units & data type; 2.9 kHz typical@32 bit. Includes 1.9 m (6 ft) shielded null modem cable

Resolution: <0.2 µm RMS typical at 1 Hz; <0.5 µm at 10 Hz; <1 µm at 100 Hz; <5 nm in low strain rate applications; Typical resolution at selected filter settings. Resolution is a function of the data rate and filter settings.

Extensometer Class: ISO 9513 Class 0,5 and ASTM E83 Class B-1 or better typical at ≥10 mm gauge length

Absolute Accuracy: <±1 µm or 0.2% of value, not exceeding ±5 µm with Precision Telecentric Optics

Thermal Drift: Room Temperature Stability <0.002%ε/°C (20 µε/°C  )

Minimum Specimen Size: < Ø20 μm (0.001”)

Gauge Length: 2 mm minimum, ≥4x specimen width or diameter recommended. For smaller sizes contact Epsilon

Maximum Elongation: >1000%, limited by field of view and gauge length

Maximum Tracking Speed: >1500 mm/second (90,000 mm/minute)

Cyclic Testing: >200 Hz cyclic test frequency, waveform independent

Strain Control: Suitable for monotonic and cyclic strain control applications

Out-of-Plane Sensitivity*: Allowable out-of-plane motion for ISO 9513 Class 0,5 @15 mm gauge length and ASTM E83 Class B-1: <1000 µm (0.040”) for ONE-PT-xx <25 µm (0.001”) for ONE-CE-xx *Understand this specification before you purchase any optical extensometer – see this Tech Note

Power Supply: 100-240 VAC, 50-60 Hz, 100W, IEC 320 C14 receptacle. Specify plug type when ordering

System Environment: 10-40°C (50-100°F), for use and storage; 20-80% relative humidity non-condensing environments

Host PC (optional): Requires Windows 7 or 10 PC, 900×550 minimum display, one serial or USB port

ce-certified

Download Data Sheet

 

  • Mounting Systems for testing machine base mount, T-slot column mount, or cylindrical column mount
  • ONE-TI-1 Touch Interface (see a demo )
  • ONE-LBI-1 Light Beam Interlock
  • Customized specimen marking templates
  • Connectors to interface to nearly any brand of test equipment

Download Data Sheet

Composites, Metals, Ceramics

Foil, Wire, Polymer Films

Plastics, Elastomers

Non-Contact COD Gage

Applications

Can Epsilon ONE be used for my application?

Advantages

What sets Epsilon ONE apart from other non-contacting extensometers?

Resolution, Accuracy, Speed

Telecentric Design

Always On, Always Real Time

Laser Alignment System

Ordering Information

Epsilon ONE Optical Extensometer Systems

The Epsilon ONE system includes an Optics Package, lighting, Laser Assist Alignment System, Sensor Controller, cables, mounting interface, standard specimen marking kit (see a marking video ) and software. The included user interface software will run on your testing machine’s existing computer.

Select an Optics Package that meets your range of gauge length and elongation requirements. Start with the largest gauge length that you will need and determine which Optics Packages have enough elongation range for that gauge length. Repeat this process for the smaller gauge lengths in your range of applications. Telecentric lenses are superior to conventional lenses, especially for applications involving strain measurements <~2%. Learn more about telecentric lenses here.

Epsilon ONE will work with any gauge length that is within the stated range for the Optics Package. Indicated maximum tensile strain values are approximate.

Precision Telecentric Lens Systems i

Model Number: ONE-78PT-System

ONE-78PT-System Premium performance. Precision telecentric lens. 78 mm field of view and 200 mm working distance. Any gauge length between 2 mm and 65 mm may be used. See table for the maximum tensile elongation that is available for a specific gauge length. Maximum elongations shown are estimates and actual values may vary significantly. Learn more about selecting the field of view for your application.

Gauge Length Maximum Strain Maximum Elongation
2 mm >1000% 66 mm
5 mm >1000% 63 mm
10 mm 580% 58 mm
12 mm 470% 56 mm
20 mm 240% 48 mm
25 mm 170% 43 mm
50 mm 35% 18 mm
65 mm 5% 3 mm

Precision Telecentric Lens Systems i

Model Number: ONE-52PT-System

ONE-52PT-System Precision telecentric lens. 52 mm field of view and 150 mm working distance. Any gauge length between 2 mm and 40 mm may be used. See table for the maximum tensile elongation that is available for a specific gauge length. Maximum elongations shown are estimates and actual values may vary significantly. Learn more about selecting the field of view for your application.

Gauge Length Maximum Strain Maximum Elongation
2 mm >1000% 40 mm
5 mm 740% 37 mm
10 mm 320% 32 mm
12 mm 250% 30 mm
20 mm 110% 22 mm
25 mm 68% 17 mm
40 mm 5% 2 mm

Conventional Entocentric Lens Systems i

Model Number: ONE-200CE-System

  • Conventional entocentric lens – suitable for high elongation applications and for measuring strain values of ~2% or greater
  • 200 mm field of view and 220 mm working distance
  • Any gauge length between 2 mm and 181 mm

ONE-200CE-System Conventional entocentric lens for high elongation applications and for measuring strain values of 10% or greater. 200 mm field of view and 220 mm working distance. Any gauge length between 2 mm and 181 mm may be used. See the table for the maximum elongation that is available for a specific gauge length. Maximum tensile elongations shown are estimates and actual values may vary significantly. Learn more about selecting the field of view for your application.

May be used for strain measurements less than 10% strain in some applications – contact Epsilon.

Gauge Length Maximum Strain Maximum Elongation
2 mm >1000% 188 mm
12 mm >1000% 178 mm
25 mm 660% 165 mm
50 mm 280% 140 mm
75 mm 150% 115 mm
100 mm 90% 90 mm
150 mm 25% 40 mm
181 mm 5% 9 mm

Touch Interface (Optional)

Model Number: ONE-TI-1

The optional full-color Touch Interface provides all functions necessary to set up and use an Epsilon ONE system. May be mounted on the column of the testing machine near the Epsilon ONE.

  • Continuous display of two digital measurements and the live image
  • One-touch instant reset
  • System status indication
  • Setup functions, filter and sensor settings, analog and digital output settings
  • Digital readouts are configurable to show strain, length, and more in a variety of engineering units
  • Configurable, continuous data trend chart
  • Mounting for any ONE-MS-xx mounting system or test frame T-slot

The optional full-color Touch Interface provides all functions necessary to set up and use an Epsilon ONE system. May be mounted on the column of the testing machine near the Epsilon ONE. See a demo.

Touch Interface demonstration

High-Stiffness Mounting Systems

Epsilon ONE is a high-precision optical extensometer and requires rigid load frame mounting.

Other configurations than the ones shown below are available – contact Epsilon.

Further details are in the Epsilon ONE Mounting System Selection Guide.

Model Number: ONE-MS-01

For testing machines with integral T-slots on the column

  • Mounts to the vertical T-slots of the testing machine
  • Provides rigid mounting for any Epsilon ONE Optics Package
  • Swing-away and retraction features make it easy to move the Epsilon ONE out of the way when not in use or between tests
  • Repeatable placement provided by reference stops
  • See Epsilon ONE Mounting System Selection Guide for additional information

ONE-MS-01 For testing machines with integral T-slots on the left column

Model Number: ONE-MS-02

Universal base mounting for all testing machines

  • Mounts to the horizontal surface of the stationary baseplate / lower crosshead on most any testing machine
  • Provides rigid mounting for any Epsilon ONE Optics Package
  • Swing-away and retraction features make it easy to move the Epsilon ONE out of the way when not in use or between tests
  • Repeatable placement provided by reference stops
  • Includes design by an Epsilon engineer to ensure that ONE-MS-02 fits your specific testing machine
  • See Epsilon ONE Mounting System Selection Guide for additional information

ONE-MS-02 Universal base mounting for all testing machines

Model Number: ONE-MS-03

For servohydraulic or electrodynamic testing machines with cylindrical columns

  • Mounts to a cylindrical column on a servohydraulic or electrodynamic testing machine
  • Provides very rigid mounting for any Epsilon ONE Optics Package
  • Swing-away and retraction features make it easy to move the Epsilon ONE out of the way when not in use or between tests
  • Repeatable placement provided by reference stops
  • See Epsilon ONE Mounting System Selection Guide for additional information

ONE-MS-03 For servohydraulic or electrodynamic testing machines with cylindrical columns

Model Number: ONE-MS-04

For servohydraulic or electrodynamic testing machines with cylindrical columns

  • Mounts to a cylindrical column on a servohydraulic or electrodynamic testing machine
  • Provides rigid mounting for any Epsilon ONE Optics Package
  • Retraction feature makes it easy to move the Epsilon ONE out of the way when not in use or between tests
  • Designed to put the Epsilon ONE in a fixed position; this model does not have the swing-away feature
  • See Epsilon ONE Mounting System Selection Guide for additional information

ONE-MS-04 For servohydraulic or electrodynamic testing machines with cylindrical columns (without swing-away feature)

Example: ONE-78PT-System, ONE-MS-01, and ONE-TI-1: Precision Telecentric Lens, 78 mm Field of View, mounting for vertical T-slots on column of the testing machine, and the Touch Interface.

Repairs/Service

If your unit is in need of service, calibration or repair, initiate the RMA process with us and we will be happy to assist.

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Our 2018 Extensometer Catalog, Version 110 is now available! Not finding something you’re looking for? Ask us about a custom quote.