When you’re planning a PCB assembly project, it can be tempting to focus first on components, lead times and production requirements. Testing may only enter the conversation once the first assemblies are approaching manufacture.
However, its a much better idea to think about it sooner! Considering your inspection and test requirements earlier can help identify practical challenges, support more effective fault detection and reduce the risk of having to make changes later in the project which can cost you time and money.
At Active-PCB Solutions, we have skilled and experienced colleagues who can support and advise our customers. We have access to a wide range of inspection and testing methods, from AOI and X-ray inspection to flying probe and functional testing, although the most appropriate approach depends on the assembly, the stage of the project and the specific requirements of the application.
Why Consider Testing Early?
The decisions made earlier in a project can affect how straightforward an assembly is to inspect and test later.
For example, test access, fixture requirements, available test points, customer-supplied equipment and acceptance criteria may all influence the most suitable approach. Discussing these requirements before production begins can help establish what is practical and identify any additional equipment, procedures or documentation that may be needed.
Early planning can also help avoid a situation where a preferred test method is difficult to implement once the design and manufacturing process have already been finalised.
Testing During Prototype and NPI Builds
Prototype and New Product Introduction builds often require a different approach from established repeat production.
At this stage, the objective may include verifying the assembly process, identifying unexpected issues and building confidence before increasing the production volume. The most suitable inspection and test methods will depend on the complexity of the board and the specific risks associated with the build.
Depending on project requirements, this may involve:
- Manual inspection
- Automated Optical Inspection
- X-ray inspection
- Flying probe testing
- Functional testing
- Customer-specific test procedures
Using the right combination of methods can provide greater visibility during the early stages of manufacture and help support a smoother transition into ongoing production, and save time, money and hassle down the line.
Does Every PCBA Need the Same Test Strategy?
No two PCBA projects are ever identical, so applying the same test approach to every PCB assembly is unlikely to be appropriate.
A relatively simple assembly produced in low volumes may require a very different strategy from a dense, complex PCBA containing BGAs or other components with hidden solder joints. An assembly intended for a demanding or high-reliability application in defence, aerospace or the medical sector may carry different risks from one used in a less critical environment.
Production volume is another important consideration. A method that works well during prototype or low-volume manufacture may need to evolve as quantities increase and repeatability, throughput and process efficiency become more significant.
The purpose of the test strategy should therefore be to select appropriate methods for the product and project rather than simply applying every available process.
Planning for Future Production Volumes
Testing requirements can change as a product moves from prototype and NPI into repeat production.
For example, flying probe testing may be appropriate for certain lower-volume requirements because it can offer flexibility without the need for a dedicated fixture. In other cases, a more production-focused approach may become suitable as volumes increase.
Functional testing may also require more formalised procedures as a product matures. Clear work instructions, acceptance criteria and repeatable processes can become increasingly important when assemblies are being produced regularly.
Considering this progression earlier in the production process can help customers and their manufacturing partner plan for both immediate requirements and future production needs.
The Role of Functional Testing
Functional testing is used to assess whether an assembled PCB performs as intended under defined conditions.
At Active-PCB Solutions, we can support a mix of customer-supplied functional testing and standard bench testing using equipment such as power supplies, digital multimeters and oscilloscopes, depending on project requirements.
Our experienced engineering team can also advise on appropriate testing approaches and support the development of customer-specific test procedures and Standard Operating Procedures.
This can be particularly valuable where a customer has a clear functional requirement, but needs support establishing how that requirement should be implemented consistently within the manufacturing process.
Inspection and Testing for Complex Assemblies
Some assemblies present inspection challenges that cannot be addressed through visual inspection alone.
For example, BGAs and other components with hidden solder joints may require X-ray inspection to provide visibility beneath the package. AOI using our Koh Young machines can support the automated inspection of visible features, while flying probe testing can provide electrical test coverage without the need for a dedicated bed-of-nails fixture.
Each method has a different role, and the most appropriate combination depends on factors such as board complexity, component type, production volume and customer requirements.
This is why test and inspection planning should be considered as part of the wider manufacturing strategy rather than as a single final-stage activity.
Testing for High-Reliability Applications
For PCBAs intended for demanding or high-reliability applications, inspection and test requirements may be influenced by product complexity, customer specifications, traceability requirements and the consequences of failure in the field.
In sectors such as aerospace and defence, confidence in the manufacturing process is hugely important. Early discussion around inspection and testing can help ensure that the project requirements are understood before production begins and that appropriate processes are considered from the outset.
The exact approach should always reflect the needs of the individual product rather than relying on assumptions based solely on sector.
Work With Your PCBA Partner Earlier
Discussing test requirements with your PCBA manufacturing partner early in the project can help establish what is practical, what equipment or documentation may be required and how the test approach could evolve as production volumes change.
At Active-PCB Solutions, we support customers across prototype, NPI and ongoing production with a range of inspection and testing capabilities. Our engineering team can advise on appropriate methods for your project and work with you to develop customer-specific procedures where required.
To discuss your PCB assembly, inspection or testing requirements, contact us! We’d be happy to talk to you.
