Almost everything that is manufactured needs to be tested. This allows manufacturers to confirm that it is capable of the task it’s designed for. For instance, that could help you decide if you need to see the difference between 304 vs 316 stainless steel for machining or you may need to switch to another type of production all together like rubber injection. It also ensures that it is strong enough to withstand specific environments and other important criteria. The exact nature of the tests will depend on the environment it’s going to and it’s usage.
There are two main ways of testing something.
- Destructive
As the name suggests, this type of testing will destroy the object being tested. You’ll find destructive testing is used in factory environments where the manufacturing conditions can be carefully controlled, ensuring every product is the same specifications.
It doesn’t matter if a product is destroyed in testing, you’ll find out its limits and know these apply to all the other products.
- Non-destructive
However, if you are producing unique pieces or have particularly expensive products you may not want to destroy it during testing. In these cases, you’ll want to use non-destructive techniques and the very best non-destructive testing equipment.
This will find the limits of the product within a defined safety margin, and allow the product to remain functional.
There are several frequently used methods of non-destructive testing:
Acoustic Emission Testing
In effect, short bursts of ultrasound waves are sent into a component. Sensors are placed around the component to detect if it comes through minute cracks in the component instead of going around it.
This is an effective way of testing for cracks in nearly any type of material.
Electromagnetic Testing
This type of ndt sends an electric current through a conductive piece of equipment or creates a magnetic field. This then allows the monitor to assess whether there is any impedance affected the flow of the current.
It’s a very effective way of testing pipes to ensure they are structurally sound.
Ground Penetrating Radar
This is effective on solid materials like rock, ice, soil, or even water. The radar pulses are sent through the material and will move uniformly through unless they encounter another object. They are then refracted and you can work out the size and shape of the foreign object.
Laser Testing
There are actually three different types of laser testing:
- Holographic testing which reveals changes in the surface of a material after stress has been applied.
- Laser profilometry detects corrosion through a high speed rotating laser, reveal surface defects invisible to the naked eye.
- Laser shearogrphy creates an image of the surface, this is done before the product is stressed. The laser image is then repeated to find out what deviations have occurred.
Microwave Testing
Transmitting a microwave frequency through dielectric materials allows changes in the dielectric properties to be ‘seen’. This is another test that reveals cavities, pores, and even cracks.
Liquid Penetration
Simply lace low viscosity fluid on a surface and see if it seeps into the material, this will highlight any defects, especially once the developer is applied and the defects effectively show themselves.
It’s important to note that this is not an exhaustive list of non-destructive testing techniques, this is simply the most commonly used ones.
