RSWA

1. RSWA Training Course Alex Denisov

2. Outline • Overview • Basic Theory • RSWA Components • RSWA Software

3. Overview • Ultrasonic Testing • Visual Inspection • Pry Chisel Test • Ultrasonic Spot Weld Inspection

4. Ultrasonic Testing Ultrasonic testing is intended to replace or reduce the pry chisel tests. : • Reduction of scrap • Reduction in physical effort • Reduction in possible injury • Faster/easier checks of spot weld gun & controller adjustments

5. Visual Inspection Still an important part of the inspection. Can identify an unacceptable or defective weld. The inspector should always visually examine the welds for: • Coloration of the weld area • Excessive indentation • Edge and radius welds • Surface cracks and pits • Deformed metal, misaligned electrodes • Electrode deposits (brassing) If the weld can be rejected visually, there is no reason to do the ultrasonic check.

6. Pry Chisel Test • Used as necessary along with the ultrasonic inspection. Whenever a “no read” situation is encountered with the ultrasonic method, the suspect weld must be pry tested. This may be occasionally necessary because of: • Burn through (a hole through the metal) • Deep cavities/pits/pin holes

7. Ultrasonic Spot Weld Inspection • Can be used to identify weld quality without destroying the part. The advantages of ultrasonic inspection over other inspection methods include: • Inspection of welds that are difficult to chisel • Verification of stick welds • Parts do not have to be destroyed • Quick inspection of welds after servicing or repair procedures • Lower production costs • Less downtime • Better indication of weld quality

8. Basic Theory • Velocity, Frequency, Wavelength, and Amplitude • Piezoelectric Effect • Pulse-Echo Method • Reflections Inside the Weld • Mechanical and Electronic Scanning • Matrix Transducer

9. Velocity & Frequency • Sound is a mechanical energy transmitted by pressure waves in a medium. Every sound wave is associated with cyclic motion of particles from which the medium is composed. • Velocity of sound indicates how fast a sound wave travels through a material. The velocity depends on mechanical properties of the material (elasticity, density) and also on mode of vibration. • Frequency of sound is a rate at which material particles oscillate when a sound wave propagates through it. Frequency is measured in oscillations per second, or hertz (Hz). • Sound frequencies relative to the human hearing range are: • Subsonic – below 20 Hz • Sonic – 20 Hz to 20 kHz (the range of human hearing) • Ultrasonic – greater than 20 kHz

10. Wavelength & Amplitude • Wavelength indicates how far a wave travels during one oscillation; wavelengths are measured in meters or other length units. • Amplitude characterizes the range of oscillation of particles inside the material when a wave passes through it. Waves with larger the amplitudes, transfer more energy.

11. Sound Velocities

12. Transmit: Mechanical sound is produced when electrical energy is applied Receive: Electrical energy is produced when mechanical sound is applied Piezoelectric Effect • Certain piezo-ceramics and piezo-compozite materials generate mechanical energy when electrical energy is applied and vice versa. The frequency of the wave depends on material properties and the thickness of the material. • The ultrasonic probe is also called transducer because it transforms electrical pulse into ultrasonic wave and back.

13. Pulse-Echo Method

14. Energy Distribution

15. Reflections in Welded Parts

16. Mechanical vs. Electronic Scanning

17. Mechanical vs. Electronic Scanning

18. Matrix Transducer

19. RSWA Components • Matrix Transducer • CPU • DSP Board

20. Matrix Transducer  Sensor Protective case Delay Coupler

21. Matrix Transducer • Transducer specifications: • Frequency: 15 MHz • Number of Channels: 52 • Elementary pitch: 1.25 ± 0.05 mm • Inter-element spacing: 0.1 ± 0.05 mm • Stainless housing • 2 m cable made of 52 separate coaxial cables in a common ground shield, protective cover

22. CPU • The CPU unit is a fully functional computer, a tablet PC, which runs Windows 2000 operating system and RSWA software. • Processor: Pentium III with Intel Speed Step technology 600/300 MHz • Main RAM: 256MB • Hard disk drive: 2.5” 15GB IDE • Digitizer: Resistive • Display: 8.4” TFT/VE-TFT Color SVGA 800 × 600 pixels, 8 levels of brightness

23. DSP Board

24. RSWA Software • Common Features • On-Screen Keyboard • Login • Launcher • Array Explorer

25. On-Screen Keyboard

26. Login

27. Launcher

28. Launcher Turning Off Switching Between Applications Current User

29. Array Explorer

30. Buttons • New Inspection – starts new inspection file • Open Inspection – opens previously stored inspection • Settings – allows changing various application settings • Setup – measures front plate thickness • Get • push to take a measurement • push and hold to enter continuous mode • Size indicator – shows nugget diameter

31. C-Scan Area • Green – fused area • Red – no fusion • Dotted circle – estimation of weld nugget • Small squares – push to switch between elements • Spinning wheel – show minimum size indicator • Hand button – manual circle sizing • “IND: ” – indentation indicator

32. A-Scan Area

33. Settings – Cont. Mode

34. Settings – User Interface

35. Typical Welds

36. Problems

37. Thank you