Identifying electronic components with T&M in mind

Before their electronic product can enter production, designers and manufacturers must identify their electronic components based on how they fare in the T&M phase of their production. Components that have a particular need for ‘stress testing’ are of course the screens and enclosures of devices. Correspondingly, this article focuses on smartphones, their touchscreens, and their chassis – and how applying the correct T&M instruments and practices to these technologies can help both manufacturers and consumers to identify the right electronic parts.

T&M to achieve durable devices and components

Test engineers must ensure that the device under test’s (DUT) phone screen (namely the touchscreen) is unlikely to become cracked even after being subjected to multiple types of damage. The process of identifying electronic components is heavily informed by this stress test phase, which involves dropping the DUT from various heights, twisting it, and subjecting it to various amounts of water.

These elements draw on two key elements of smartphone T&M: testing for damage resistance (crucial for the touchscreen), and testing for water and dust resistance (crucial for the chassis). The following sections consider each of these two areas before moving on to discuss how these facets inform how manufacturers – and even consumers – can identify optimal electronic components for smartphones and other devices.

Testing for damage resistance

There are of course many machines that could recreate the instance of a user damaging a device, but two major examples are the tumble test machine and a horizontal impact test system (HITS). The former is a cylindrical container that rotates multiple times so that the DUT is constantly made to hit each side of that container; and the latter is rather like a powerful motorised conveyor belt that forces the DUT along a long, flat railing and straight into the stopper at the end.

The tumble test machine and the HITS respectively simulate a user dropping a device and a user allowing the device to slide and bump into obstacles. The latter is particularly applicable to when the DUT is in transit; in fact, a horizontal impact test system is primarily used to determine how the test device will withstand any wall-to-wall bumps that may occur when a delivery driver is transporting it to warehouses, customers, and so on.

Testing for water and dust resistance

When it comes to damage resistance from water, the T&M machinery for a smartphone is often known as ingress protection test equipment, which is the umbrella term for any instrument that subjects a DUT to water or dust to help determine what the device’s IP rating should be.

The IP rating, short for ingress protection rating, is a measure of a device’s ability to keep out liquid and solid contaminants (we’ll continue to use water and dust as the chief examples of which) and therefore protect its internal components in various use cases, e.g. taking a smartphone out in the rain or using a smartphone on a building site where there is a high concentration of particulates in the air.

Examples of water IP test equipment and dust IP test equipment are respectively a depth pressure chamber and a dust test chamber.

Depth pressure chamber

A depth pressure chamber is a vessel of water that contains the DUT and uses air pressure to simulate the stress the device will receive in certain submarine conditions. For example, if the manufacturer wants a smartwatch won’t break when submerged 30 feet underwater, test engineers can use the depth pressure chamber to imitate 30 feet of water pressure on the device.

Dust test chamber

A dust test chamber is essentially a large electronic cabinet that subjects the enclosed DUT to dust that is either blown straight onto the test device or left to settle onto it over time (blown dust and settled dust are supposed to simulate outdoor and gradual indoor dust damage respectively).

More on T&M for product IP ratings

The result of test and measurement in ingress protection is that the DUT will be assigned a two-digit IP rating that respectively refers to, on a scale of 0 to 6, how well the device’s internal components will be shielded from solid and liquid contaminants. Solid ingress protection is represented by the initial character (for example, 6) and liquid ingress protection is represented by the secondary character (e.g. 4).

Using the above examples, a smartphone that has the ingress protection rating of IP64 would be ideal for a person who needs to use their phone in harsh outdoor conditions, as their device would be fully protected from both blowing dust and splashes of rainwater. Smartphone and other device manufacturers must ensure that the results of their T&M inspections are communicated effectively with potential customers, particularly those who will need to identify electronic components (e.g. a resilient touchscreen) that will suit harsh applications such as in the above example.

In view of this, identifying the right electronic components is, again, not always the job of test and measurement engineers and manufacturers alone: there can also be a duty of device consumers to bear in mind what T&M goes into their device’s component specifications. After all, doing so could help to inform them of how that technology received its IP rating in the first place. By identifying and testing electronic components with the optimal specifications, not only can manufacturers offer the right tech for the right use cases – but consumers may even be able to learn how to best utilise and repair their own devices.