Choosing a reputable contract electronics manufacturing company is vital to your project’s success and there are certain criteria on which you should base your decision, including their product testing capabilities.
A CEM must carry out different types of testing to ensure product reliability for every PCB manufactured including environmental, functional and stress testing, and 3D AOI testing and inspection.
A rigorous electronics quality assurance process ensures the PCBs are of a high quality, reliable and in alignment with your business’s goals.
Product testing in electronics manufacturing promotes durability and safety, with functional tests checking performance, safety tests preventing hazards, environmental tests simulating usage conditions and stress tests assessing durability under extreme conditions.
Importance of functional testing
Functional testing of PCB assemblies is an integral part of the manufacturing process, as it confirms that a product operates according to its design specifications. The days when testing meant simply checking for errors have long gone.
Printed circuit boards today are increasingly complex, with intelligent components, so as well as checking for manufacturing errors, it’s necessary to verify that the PCB is working efficiently and safely.
Functional testing means simulating the PCB in its end use to ensure everything functions in line with requirements. The PCB manufacturer will complete tests using state-of-the-art equipment, capturing any error trends and allowing problem parts or design issues to be identified and improved. This type of testing will also provide full traceability back to the component level and operator where the fault occurred to identify if there are likely to be any similar problems in future.
Environmental testing
Electronics manufacturing testing should also include environmental considerations, simulating the conditions in which the PCBs will be used. This includes conditions such as moisture, temperature extremes and altitude to verify that the products will continue to function effectively. The process allows PCBs to continue to operate reliably in their intended environment, whether this means extreme weather conditions, vibration, thermal stress, damp and any other variables.
The PCB assembler will expose their applications to simulated conditions and make sure they are 100% safe and efficient before they are passed to the client. This is vital in every sector and especially so when the printed circuit boards are being used in critical industries, such as military and defence, aerospace and at sea.
Water absorption tests are common for PCBs that will operate in wet and humid environments.
Stress testing
Stress tests help to identify product weaknesses and are a vital process for evaluating PCBs and whether they can withstand parameter strains and other forces: they determine the range at which the board can maintain its functionality and structural integrity. Manufacturers can then spot potential failures or weaknesses before the board is integrated into the final application.
Various methods, techniques and processes are used to perform the stress testing, with the majority classified as electrical, mechanical or thermal:
- PCB interconnect stress testing simulates the mechanical and thermal stresses that a PCB may encounter when operational.
- Burn-in testing involves operating the board under low and high temperature and voltage ranges for a few days.
- Electrostatic discharge tests establish how well the PCB assembly can withstand these events.
Safety testing
Safety testing plays a crucial role in electronic product design and test procedures.
HiPot safety testing, also known as electrical safety flash testing, is the standard procedure to ensure electronic equipment complies with electrical safety standards. It involves the direct application of a high voltage to the unit in test conditions.
The voltage applied is commonly much higher than the components’ usual operating voltage, causing stress to the device’s dielectric properties. The test determines whether the assembly is safe, including whether the leakage current remains within the test parameters.
Leakage current measurements are crucial because every electrical system consists of a grounding technique that shields against shock hazards in the event of an insulation fault. A shock hazard occurs if the ground or earth connection is intruded, with the chance of a shock potentially being greater than envisaged if leakage of currents takes place.
The safety testing in contract electronics manufacturing is essential to ensure that all products meet electrical, environmental and mechanical safety standards. Should an assembly fail any of the fault-finding procedures, a full suite of tools and equipment will isolate any fault down to component level.
By collecting and analysing data, the cause of the fault can be rectified. The PCB will then be inspected and retested, ensuring preventative action is taken to prevent the issue from recurring.
3D AOI testing
Modern PCB inspection capabilities are further enhanced with the use of 3D AOI solutions. This is something we have invested in heavily, with our Zenith Alpha HS+ from Koh Young, which is a true 3D AOI solution powered by artificial intelligence and machine learning.
Combining the best opt mechatronics and vision technologies to deliver outstanding performance and accuracy, it takes our testing capabilities to the next level. A state-of-the art, one of a kind AOI machine, it uses light metrology to take incredibly precise, 100% 3D measurements of a PCB up to 25mm in height.
Suitable for demanding production lines, the Zenith Alpha HS+ significantly improves process yields, making it ideal for the quick turn-around prototype assembly and low volume/high mix production demands in which we specialise.
If you would like any further information, please do not hesitate to contact us.