Why Component Level Testing Is So Important

Let’s explore component-level testing, the process followed for selecting and testing good quality and reliable components for your product, and the various benefits you’ll get by testing components during the product design and development process.

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What is the difference between component-level and product-level testing?

Any product is composed of a number of components. For instance, electronics are made from PCBs, each filled with different components that are soldered onto them, all within a casing. So product-level testing is where we test the product as a whole as the user would see it after purchase. Businesses that produce a finished component may also test those as their ‘product,’ too, and those in turn may be made up of different components and materials that might be tested individually separately.

Component-level testing is not the same and can be divided into 2 areas:

PCB testing – where we check how it functions by hooking it up to analyzers to see that it is working to specification, especially in different environmental tests.
Component testing – a single component that would ultimately be on the PCB is taken in isolation and tested to specification, for example, you may test two similar components where one is more expensive than the other to see if the cheaper one’s performance is good enough for the product.

There could be a lot of component testing to do because you will need to test different options for every component in your product to make sure that they hit performance and specification goals; so if your product is made up of 100 components you may be testing 200+ components in total before making a final decision about what goes into the BOM. (01:21)

What’s the component qualification process?

The design engineer requests a type of component from purchasing. They will source samples from different suppliers and let the designer engineer know when they will arrive and how much they cost and will try to get volume pricing at the same time.

Then component engineers will go through the data sheets for each component and make sure that they match what is required per specification for the product design. They will also check that the components can be produced in high volumes by the supplier and will often do an on-site audit of the supplier’s factory to assess that they are capable and can meet the price, quantity, and quality requirements.

If the factory passes, the engineer requests samples of the components which could be in the hundreds of pieces. The samples are used for testing in the test lab, kept for evidence, and broken down for cross-section analysis to evaluate what is inside, how it is made, etc. Then the sample components are given a temporary part number and the design engineer will test them on the PCB to check their performance against specification.

The component engineer then does a component pilot run to create numerous PCBs with the various components from different suppliers and the design engineer tests them and selects which ones they’re happy with and discards the others, perhaps because they don’t meet the necessary specifications.

The components that pass then go into further testing, including reliability, quality, and manufacturing testing in order to qualify them. Qualified components are then assigned an official part number so that if they’re used in any product in future, you know exactly which component is which. (08:14)

The 10-point component testing and evaluation process.

Component Selection – includes sourcing suppliers and components, testing them against specification and selecting the right options, assessing availability and volumes, etc.
Component Datasheet Analysis – includes specs, charts, graphs, etc, which is important to know when sourcing. Design engineers need to check them in depth per product to gain assurance that the component is suited to the intended product, environment, etc. If tey get this wrong and miss something in the datasheet it could badly affect and delay the entire project later on, so design engineers’ impact here is often underrated.
Visual Inspection – components have often been cut and put together before you buy them, so someone needs to visually inspect that everything is in alignment, has no physical damage or manufacturing defects, etc, before they go into the product design or manufacturing.
Continuity Check – some samples are taken from incoming components and they’re checked to make sure that everything remains within spec, such as resistance in resistors. If it is not this could lead to defective products.
Functional Testing – components are plugged in and simply checked that they are working.
Performance Testing – critically checks that components are not only functional but also operating within your required specifications for voltage, current, temperature, frequency variation, etc.
Environmental Testing – related to reliability as the components are tested in different environments to assess their ability to operate normally with different temperatures, humidity, vibration, shock, and transportation testing to evaluate if components will remain securely on PCBs during transit.
Ageing and Life-cycle Testing – components need to be able to work for a certain amount of time without breaking down. In a car, this could be 10-20 years. Components are put through accelerated testing to simulate use over many times or a relatively long period of time to provide assurance that they will reach your reliability goals, for example, that products will last for longer than the warranty period.
Compliance Testing – components will probably need to be compliant with the intended market’s safety regulations, so batteries will need to be tested to UN38.3 to demonstrate that they’re safe to transport. Wireless products that emit RF radiation may have, for example, Bluetooth-enabled components and these would have to be FCC-tested for sale in the USA. If you include non-compliant components in your product this will result in not being permitted to sell the finished products in your market, or worse, it may lead to costly returns, lawsuits, or even jail time if someone is injured.
Documentation – databases for qualified components and suppliers are needed and include the component, its part number, and the different approved suppliers who provide it (and maybe some reserve options that are not yet approved). One supplier is preferred for most components, but for CTQ components that are essential for the operation and manufacturing of the product, a backup is also in place. The suppliers on the approved supplier list may be audited once or twice a year and also continually updated to include new suppliers for new products or those added as backups.
Approved datasheets may also be collected, and your internal datasheet will spell out your specifications and requirements. Non-approved components may also be collected in a spreadsheet, too, as these are perhaps yet to be tested and approved, but may be in future. (15:59)

Why businesses and entrepreneurs bringing a new product to market shouldn’t be expected to have the testing expertise in-house and what we do to help.

Businesses that work with us to develop and bring a new product to market use our engineers’ expertise to go through the sourcing and component selection and testing process outlined above. Once the product has been put together, we utilize our own testing lab, RSQ-Labs, to do a full range of product-level testing including HALT, HASS, drop testing, package testing, etc. Failures will be investigated and fixed before the product moves on towards mass production and we also handle the compliance testing at this point once the design has been frozen, and then it can go into mass production. Component testing is not only done on electronic components, either, it will be done on mechanical parts and materials, too. (36:13)

A few examples of problems that might occur if component testing is not done properly.

There are cases where airplanes have crashed due to a single screw not being up to specification and those surely could have been avoided if good component testing had been done.
Closer to home is the case where a coffee mug cracks as soon as boiling water is poured into it, and in this case the mug was not tested adequately to assure that it could withstand the likely use case scenario of hot liquids being added.
The Titan submersible is another recent failure in the news and it was found to have been using untested components that were not suitable for deep-sea exploration, such as a commercial game controller for steering the vehicle. (40:18)

Do YOU need to decide on and do all types of component-level testing?

In the design phase engineers usually rely on the component supplier having done most of the component-level design testing that would be done during its manufacture and they usually focus on component limit testing that would confirm that what the datasheet says about the component is correct, for instance, its ability to handle a certain temperature. Your focus will usually be testing components to assure that they are appropriate for the environment/s their product will be used in and reach the necessary reliability level. (43:37)

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