NDT

The requirement for accurate thickness measurements is found across many industries including aerospace, oil and gas, pharmaceutical and food processing.  Either for quality control in manufacturing or in-service verification often access is only available from one side and speed is critical.  The wall thickness from most materials can be measured ultrasonically including metals, composites, plastics and glass using a simple hand-held digital gauge.

In certain environments, a coating of paint or other non-metallic material may have been applied to protect the part.  A common application would be a painted pipe used in the petrochemical industry.  In this case a conventional ultrasonic gauge would give measurement errors from the presence of the paint.  However, with the correct gauge with through paint mode, measurement through the paint is possible resulting in the correct wall thickness measurement underneath.

NDT Systems offers a range of standard and high-resolution thickness gauges with features including A-trace display, B-scan, automatic probe recognition, data logging and much more. Furthermore, large area thickness mapping (C-scan) can be achieved using our Raptor imaging flaw detector and range of scanners.

Transducer (Probe) Type

Contact transducer – probes which transmit a pulse of compressional sound into the specimen at the right angles (normal) to its surface. It is the most common used transducer type for thickness measurement.

Delay Line transducer – in order to facilitate the complete inspection of thin plate sections it is necessary to eliminate the effect of the probe units dead zone and the earlier part of its near filed in which those areas of the interfering sound pressures exist. A normal angle probe is mounted on a plastic, epoxy or fused silica known as a delay block between probe element and test specimen

Immersion transducer – special waterproofed probes used in immersion testing which allow thinner and higher frequency crystals without face wear plates can be used with less chance of damage caused by probe handling encountered during contact scanning

Dual Element (Twin Crystal) transducer – comprises two crystals act as transmitter and receiver respectively which gives good sensitivity to near surface defects and measurement.

Shearography is an optical Non-destructive testing method that provides fast and accurate information about internal anomalies in different materials. Sherography is being extensively used in production, research and development and in-field within the aerospace, automotive, marine and wind industry.

Applications:

The main applications for shearography are for quality assurance of composite and other materials. Depending on the material strength and depth of defects within a sample, Shearography can detect most discontinuities that occur in composite structures, including disbonds; delaminations; cracked core; crushed core; kissing bonds; wrinkling; fluid ingresses; porosity; cracks; repair defects; and impact damage (BVIDs). Additional structural information such as ply drops, bulkheads, overlaps, splices, stringers, ribs can also be detected.