Bram Stoker—the author of the classic novel Dracula—noted that “We learn from failure, not from success.” Perhaps he was right. Success is never a sure guarantee in life. Experiencing failure is an inevitability at one time or another. Many people do anything to avoid this sense of negativity and worthlessness, even ceasing to attempt anything new.
Modern innovators and engineers, however, are not these kinds of people.
Even though not everything they create is perfect, these designers know endeavor is still worthwhile. Discovering a genuine solution is one of the greatest thrills of all time, especially for the creators of electronic products. These products need to be tried and tested numerous times before nailing objectives and performance demands on the head. The PCB testing method is an integral part of the modern manufacturing process for this very reason: eliminating the cost of failure.
But how do PCB assemblers test for a flawless design? We’ve compiled a list of the main seven types of PCB testing methods used throughout stages of the assembling process. Here’s what you need to know about inspection and testing in the PCB industry today.
Testing Methods: Setting Industry Standards
When considering the seven types of PCB testing methods and what you need to know about them, keep function and form in mind. A failed PCB function is problematic for companies that use it in their products. Electronics that malfunction after they hit the market are harmful to businesses’ reputations and consumers alike. Without proper and thorough testing beforehand, significant risks linger. Testing and inspection is a strategy to ensure PCBs efficiently meet current standards.
PCB testing during manufacturing builds up a pillar of confidence in circuit board design and capability. Manufacturers can choose a wide array of common methods to use. The application and board type of your PCB are the core factors that impact the decision. Let’s explore and compare these different testing methods and specializations further.
Visual Testing
Visual inspection is a general method of testing that’s relatively cost-effective and easy to set up. This basic process involves a technician visually inspecting the board for noticeable defects. These defects typically include soldering mistakes, irregular component orientation, circuit board stains, or missing parts.
While most of these major defects are identifiable via bare eye inspection of magnification, the process is subject to human error. Depending on the complexity of the board, this method can have possible inconsistencies which are time-consuming to fix.
In-Circuit Testing: ICT
This popular testing method is preferable for the majority of PCB manufacturers—due to its robust ability to find over 90 percent of faults, that is. As a form of automated testing, you’ll find this method most employed on larger batches or mature products—not prototypes or low-volume productions. During this process, technicians use specialized equipment, including an in-circuit tester system of sensors, a fixture of sensor points, and software that dictates pass or fail parameters.
Manufacturers can test individual components with this method to measure their specific performance. ICT is best for measuring resistance, capacitance, and analog measures to finalize stable products.
Flying Probe Testing: FPT
Flying probe testing is an enhanced form of ICT that uses needles to read board components. This popular method uses an innovative flying probe machine and programming to identify design efficiency—and it’s generally more cost-effective for the test coverage. FPT checks overs PCBs for shorts, transistor orientation, diode issues, resistance, capacitance, and inductance. Keep in mind that flying probe testing doesn’t power up a PCB like other common methods.
Automated Optical Inspection: AOI
Another automation method is known as AOI. This process involves 2D or 3D cameras taking high-resolution images of the PCB to compare with a template board. Basically, AOI inspects the PCB and determine how accurately it matches the original design schematics. This type of machine might be directly at the end of the mass production line for quality assurance. If something doesn’t add up, the board gets flagged and sent back for technician review.
Automated X-Ray Inspection: AXI
What makes AXI testing technology unique from other common optical methods is the use of X-rays. This inspection method can directly penetrate the PCB and component bodies to examine the quality of solder joints. Hence, this valuable tool is ideal for PCBs with hidden joints, chip components, or underside pads.
When manufacturers use this technology during the production process, they can detect defects early on and make the necessary adjustments to save costly repairs. X-ray inspection is time-consuming but remains a smart option for varied-size production batches or complex prototypes.
Burn-In Testing
Burn-in testing is a method revolving around early failure detection during manufacturing. Unlike other common inspection processes, this testing directly simulates extreme operating conditions and subjects PCBs to them to test load capacity. Collected data helps engineers understand defect causes and optimize the design to eliminate premature failures in the field. Manufacturers can test the operating conditions of printed circuit boards—temperature, voltage, or frequency—by sending a high-powered current through the circuit.
The process is intense and not necessary for every type of electronic product. Burn-in testing is best for those designing products that require top-notch reliability. A word of caution—this method can shorten the product’s lifespan if tested for too long.
Functional Testing: FCT
Traditional functional testing is a flexible method that’s typically the last phase of the production process. As a quality control procedure, FCT ensures the device under testing operates exactly as it’s intended to. Essentially, manufacturers verify the product will effectively power up in its end-use environment.
The exact requirement of this testing depends on the complexity of the PCB design Overall, FCT is ideal for detecting functional and parametric failures and pairs well with other PCB assembly testing types. No matter the production batch size, product quality assurance can be yours.
Quick-Turn Printed Circuit Board Assembly
If you need reliable PCB assembly services in the USA, turn to our expert team at Advanced Assembly. We’re the leading pioneers of quick-turn circuit board manufacturing. Our efficient assembly services and cutting-edge tech will help your business or company save time and money.
Advanced Assembly is here to take the hassle and headaches out of the PCB assembly process by building your project right the first time. Contact us with any questions about our capabilities and testing methods or start a quote today. Let’s get your boards produced with speed, accuracy, and quality in mind.
