1. It has been said, ‘‘Total quality control is superior to 100% inspection because inspection, like any other process, has its own defect rate. Some substandard product, therefore, is always likely to slip through.’’ Do you agree or disagree? Discuss.
2. The pulse-echo ultrasonic technique can be used to determine the thickness of a part or structure. By accurately measuring the time it takes for a short ultrasonic pulse to travel through the thickness of a material, reflect from the back or inside surface, and return to the transducer, the distance can be calculated by
d = thickness of the test piece
V = speed of sound in the material being tested
t = measured round-trip time
What are some alternative means of measuring thickness? Briefly discuss their relative pros and cons. Consider such features as geometric and material constraints, and the ability to measure from one side only.