For over the past 30 years Time-Of-Flight Diffraction (TOFD) technique of the UT method of NDT has been developed swiftly and has become an irreplaceable one when carrying out welded joints testing. TOFD assures a great accuracy for comfortable measuring the critical size of defects. The accuracy of better than ±1mm can be obtained in a wide range of material thickness.
TOFD Man ultrasonic weld testing equipment
The system is designed for testing long welded joints of pipes, tanks, vessels, cisterns, ship hulls, bridges, etc. using TOFD technique. Circumferential welds with a diameter from 12 in (300 mm) can be inspected on cylindrical objects. On cylindrical, spherical, as well as complex shaped objects with a radius of surface curvature from 16 ft (5 m) to flatness, the system is capable of testing long welds in any direction. Objects with wall thickness from .25 to 12 in (from 6 to 300 mm) can be examined with the help of appropriate probes. Depending on the inspection task, the TOFD MAN TM system can be complemented with another scanner. The number of probe pairs can vary from 1 to 4. For good coupling, it is advisable to use an external couplant supply system. In this case, a water hose is attached to the scanner. But if absolute mobility is needed, coupling media can be applied to the object before testing, or a test piece can be continuously showered with water
All the equipment is placed in the operator's utility vest, which does not impede the movement, also when performing an inspection at height (climbing, rope access). The standard system kit comes with an 8 to 10-hour battery to be placed in the vest. The scanner is lightweight and easy to operate. It ensures a handy probe setup.
During setup and testing, all setup data are transferred to a remote PC (laptop or tablet) via Wi-Fi. A system for protecting the integrity of test data is provided, while they are fully stored inside the TOFD module and transferred to PC at the end of testing. If required, it is possible to use a wire connection to transmit data to PC.
Key Features:
- Quick, accurate and highly reproducible weld inspection.
- Wireless operation. An NDT inspector with a data acquisition PC can work anywhere within Wi-Fi range.
- The ultrasonic weld tester can operate with any type of Windows based computer: Laptop, Desktop, Tablet, etc. Its interface is both mouse- and finger-friendly.
- Select, do not setup! - Really quick and comprehensive setup due to the element libraries: Geometry library, Material library, Scanner library, Probe library, etc.
- Automated water supply individually under each probe.
- Electronics protected against a mechanical shock by scanner design.
Main advantages of TOFD are:
- Defect detection regardless of their orientation, in contrast to the pulse echo technique
- In contrast to the radiography method, planar defects and cracks, which are not perpendicular to the measured surface can be detected
- High degree of repeatability
- Precise defect sizing capability
- Fast scanning only along the weld. Full volume inspection in a single run.
- Immediate results and permanent digital records with graphic images
- Amplitude insensitive – acoustic coupling less critical
- Set-up independent of weld configuration
The TOFD Man is a compact and reliable test system, which guarantees stable scanning results. Magnetic wheels and spring-loaded probe carriers with a self-positioning system ensure transducer stability on the object surface which results in good coupling necessary for reliability of test results. The scanner is easy to drive and does not fall from the object even when upside down. The System is composed of the elements that are placed in the utility vest: - TOFD Ethernet module, - Wi-Fi module, - rechargeable battery pack. The cases of the TOFD module and the battery pack are shockproof. All the equipment has a protection rating of IP65. The scanner design ensures that if the scanner falls down, the main impact will come to the scanner structure elements saving the electronics. The storage battery provides 8-10 hours of TOFD Man system operation.
TOFD system software consists of a queue of tabs guiding the inspector through step-by-step setup procedure, data acquisition and analysis. Software is both mouse and finger friendly, so it can be used on various types of computers – tablets, laptops, desktops, monoblocks, etc. The setup process is greatly facilitated due to a wide usage of setup element libraries – Geometry library, Material library, Scanner library, Probe library, etc. Thus, the setup procedure is reduced to selecting proper elements from the libraries. Complete setup packs suitable for particular testing tasks can be saved and then loaded at any time.
Main software functions are distributed among the following tabs:
«Object» tab:
- selecting the test object geometry and setting up its dimensions;
- selecting the test object material;
- selecting the type of a weld bevel and setting up all its dimensions.
«Scanner» tab:
- selecting the scanner;
- setting up the scanner type: manual, motor-operated;
- setting up the spatial position of TOFD transducers pairs relative to the origin of the coordinate system;
- using up to 4 TOFD transducer pairs;
- carrying out encoder calibration.
«TOFD setup» tab:
- selecting the type of TOFD probes, TOFD wedges, or setup of their parameters;
- setting up the PCS – the distance between the index points of TOFD transducers and their shift relative to the welded joint axis;
- calculation and graphic display of the following parameters using TOFD Calculator:
- Spatial resolution (R);
- Scanning-surface dead zone (D);
- Backwall dead zone (D);
- Locus curve;
- Beam Spread.
«TOFD Calibration» tab:
- setting up the main UT parameters;
- carrying out the real-time TOFD calibration;
- real-time checkup of reflectors detection in calibration block;
- saving the calibration results.
«Data acquisition» tab:
- A-Scan + TOFD-Scan display during the testing process;
- carrying out the testing and data acquisition;
- displaying the current scanner position and the scanning speed;
- data synchronization by lateral wave during the testing process;
- considering the scanning direction and capability to rescan the regions with the acoustic coupling loss;
- saving test results.
«Data analysis» tab:
- review and analysis of saved data in a form of А-Scans and TOFD-Scans;
- quick and detailed analysis of test results using two measuring gates (type: normal, hyperbolic, manual hyperbolic);
- for all indications, the following parameters can be measured:
- their position in the object (X and Y-coordinates);
- their length (ΔX);
- their depth and height (Z, ΔZ);
- their type: “volumetric”, ˝top-surface breaking˝, ˝bottom-surface breaking˝ or ˝inner˝;
- building the defect table and saving it.
«Reports» tab:
- Sorting and filtering test results in the database;
- TOFD scan scaling for printout;
- Report preview;
- Printing reports.
- Transmitter;
- Receiver;
- Wedges;
- Internal crack.
- lateral wave;
- back wall echo;
- diffracted signal from the top tip;
- diffracted signal from the bottom tip.
TOFD transducers specification:
| Catalog number | Frequency, MHz | Element dia. | Object thickness | ||
| in | mm | in | mm | ||
| TWS10-3-TOFD 3/8" | 10 | .125 | 3 | .390-.600 | 10-15 |
| TWS10-6-TOFD 3/8" | 10 | .250 | 6 | .600-1.4 | 15-35 |
| * TWS5-6-TOFD 3/8" | 5 | .250 | 6 | 1.4-2.0 | 15-50 |
| TWS5-12-TOFD M16 | 5 | .500 | 12 | 2.0-4.0 | 50-100 |
| TWS3-12-TOFD M16 | 3 | .500 | 12 | 4.0-8.0 | 100-200 |
| TWS2.5-12-TOFD M16 | 2.5 | .500 | 12 | 8.0-6.0 | 200-300 |
| TWS2.25-12-TOFD M16 | 2.25 | .500 | 12 | 8.0-6.0 | 200-300 |
| TWS3-8-TOFD M16 | 3.0 | .325 | 8 | 4.0-8.0 | 100-200 |
| TWS2.5-8-TOFD M16 | 2.5 | .325 | 8 | 4.0-8.0 | 100-200 |
| TWS2.25-8-TOFD M16 | 2.25 | .325 | 8 | 4.0-8.0 | 100-200 |
TOFD wedges specification:
| Catalog number | Thread diameter | Refracted angleo |
| WS45 L-3/8"-TOFD | 3/8" | 45 |
| WS60 L-3/8"-TOFD | 3/8" | 60 |
| * WS70 L-3/8"-TOFD | 3/8" | 70 |
| WS45 L-M16-TOFD | M16 | 45 |
| WS60 L-M16-TOFD | M16 | 60 |
| WS70 L-M16-TOFD | M16 | 70 |
* included in the standard kit
| Testing objects parameters | |
| Thicknesses | per one path .25 - 2 in (6 - 50 mm); with probe replacement per several paths 50 – 300 mm |
| Diameter for cylindrical objects | from 12 in (300 mm) to flat |
| Diameter for spherical objects | from 16 ft (5 m) to flat |
| Profile types | any |
| Scanner TOFD 2.2 Lite | |
| Dimensions (L×W×H) | 450 × 240 × 120mm |
| Weight | 2.8 kg |
| Number of TOFD pairs | 1 |
| Coupling liquid supply | individually for each probe |
| Compatible probes and wedges | |
| Frequencies | 1-15 MHz |
| Angles (L-wave) | 45°, 60°, 70° |
| Measurement | |
| Number of cursors | 2 |
| Types of cursors | Conventional (cross) Hyperbolic |
| Manual positioning | ✔ |
| Automatic positioning | ✔ |
| Absolute measurements | ✔ |
| Relative measurements | ✔ |
| Indications table | ✔ |
| Indications parameters | X, X1, X2, dX Z, Z1, Z2, dZ Type (Point, Top, Bottom, Middle, Volumetric) Amplitude |
| Units | mm / in / us |
| Output fields | 5 |
| Unit connectors | |
| Pulser and Receiver | 2 × BNC |
| Encoder | ✔ |
| Power | ✔ |
| RS485 | ✔ |
| LAN | ✔ |
| Sync input | ✔ |
| Trigger output | ✔ |
| Pulser | |
| Type | SWP |
| Voltage (SWP) | 20 V, 30 V, 40 V, 50 V, 80 V, 100 V |
| Energy (SWP) | 20 ns to 500 ns with 10 ns step |
| PRF | from 15 to 2000 Hz |
| Receiver | |
| Range | Up to 100 us |
| Delay | Up to 100 us |
| Gain | 0 to 110 dB, with 0.1 dB step |
| Max signal input | 20 V p-p |
| Bandwidth | 0.2 MHz - 27 MHz |
| Filters | 1 MHz, 2-3 MHz, 4-5 MHz, 10 MHz, 15 MHz, Full band |
| Rectification | Full Wave |
| Signal Average | 2x / 4x / 8x / 16x / 32x |
Standard kit:
- TOFD 2.2 Lite scanner (with transducers)
- TOFD unit
- Wi-Fi Module
- ammunition vest
- Software for MS Windows laptop/tablet
- Charger
- Battery
- Instruction manual (hard copy)
- Hard case
- Portable water tank with a motorized pump.
Available options:
- Rugged Notebook or Tablet PC with pre-installed TOFD Software;
- Additional transducers (see tab "Transducers");
- Extra battery.
