Inspection, testing, and fault diagnosis

Inspection Techniques

Inspection techniques are used to detect faults and potential problems in mechanical systems or equipment.
Visual inspection is the simplest form: look for visible signs of damage such as wear, corrosion, fractures or leaks.
Aural inspection involves listening for irregular noises which could indicate a problem.
Tactile inspection involves using touch to locate unusual vibrations or heat.
Sensory inspection techniques, combining visual, aural, and tactile inspection, are often first-line checks.
Non-destructive testing (NDT) techniques include magnetic particle inspection and dye penetrant inspection.
Borescope inspection can be used to examine difficult-to-reach or internal areas of equipment.
Pressure testing checks the integrity of pressure systems to ensure they are safe to use.

Functional testing includes running systems or equipment to confirm they operate as required. If not, the characteristic faults help identify problem areas.
Testing equipment should be used where required, such as multimeters for electrical systems and tachometers for rotational speed.
Performance testing checks the system’s ability to perform its intended function under varying conditions.
Stress testing checks the system’s ability to function under heavy load situations, such as high temperatures or high pressure.
Endurance tests check how long a system can operate continuously without failure.
Testing should be performed following the manufacturer’s guidelines to ensure reliable, accurate, and safe results.

Fault diagnosis is the process of identifying the cause of any faults in a system or piece of equipment.
A structured approach, often known as root cause analysis, is usually taken, including defining the problem, identifying potential causes, testing hypotheses, and deciding on the most probable cause.
To diagnose a fault, it may be necessary to refer to technical manuals or diagrams, or to consult with colleagues or manufacturers.
Fault trees can be constructed as a method of visualising the potential causes of a system failure and how they may be related.
Basic principles of mechanics, such as the relationship between force, motion and energy, are always important when diagnosing problems.
Data logging and documentation of faults and their resolution are important for future reference and prevention of recurring faults.