Rigid-Flex PCB Testing: Ensuring Reliability and Performance

Rigid-Flex PCB Testing: Ensuring Reliability and Performance

A rigid flex PCB combines the best of both worlds as it has traits present in a rigid circuit board and properties seen in a flex circuit board. While they are more challenging to design compared to their non-combined counterparts, this board has plenty of advantages in store for the user. However, to secure these advantages, the rigid-flex circuit requires to be tested to ensure that they’ll work as planned.

In this article, we’ll be exploring the world of rigid-flex PCB testing and how manufacturers ensure that they are going to be reliable and have optimal performance.

Why should a rigid-flex PCB undergo tests?

Before we explore the practices that a rigid-flex PCB manufacturer uses to ensure reliability and optimize the performance of the board, let’s understand first why PCBs have to undergo tests. Rigid-Flex PCB Testing: Ensuring Reliability and Performance. Here are the reasons why rigid-flex circuit boards should undergo tests before packaging and shipping to the clients:

  • Error prevention – Your partner manufacturer conducts PCB tests to prevent problems and errors. They will do what they can to identify and fix problems in the early stages of fabricating the boards you requested from them. As a result, they will be able to work with the PCBs more efficiently and the final expenses won’t be as pricey compared to constantly replacing parts due to defects.
  • Pre-emptive defect prevention – Take note that rigid flex PCBs also require to be tested during the manufacturing process. The intent for mid-production tests is to allow your manufacturer to apply adjustments and optimizations before they go forward with the true fabrication process.
  • Detection of defective circuits and solder joints – Your manufacturer will also check the PCB if there are any signs of short circuits and defective solder joints. The reason why they want to check for those issues is to ensure that the rigid-flex circuit board will be safe for use, work as intended, and won’t break down once you are using it.

Practices done by the manufacturer during tests to ensure PCB performance and reliability

Now that we’re oriented to the reasons why your manufacturer would like to conduct tests on your rigid-flex PCB, let’s explore what are the practices that they use to ensure that the boards will perform as planned and maintain their reliability. Rigid-Flex PCB Testing: Ensuring Reliability and Performance. Here are some of the approaches that your manufacturing might be using to ensure that your boards will work according to design.

1. Utilizing in-circuit tests

The first practice that a rigid flex PCB manufacturer can utilize on their boards is the in-circuit testing method. It is by far the most reliable and potent approach to ensure that the rigid-flex circuit boards are working as intended. Your manufacturer will conduct tests that measure the performance of the PCB based on capacitance, resistance, and open circuits. This test is also a way for the manufacturer to detect if the board they created for you has short circuits.

2. Fixtureless in-circuit tests for your PCB

The next approach in testing your circuit boards by your manufacturer is known as the fixtureless in-less circuit test. It is quite similar to the previous type of test we’ve just discussed but with the use of a flying probe that will move around and test pins and check specific points on your printed circuit board quickly and efficiently.

This method of testing is also a means to check the PCB’s electrical performance and if there’s a possibility that they have short circuits.

3. Visualize with the automated optical inspection tool

The AOI or automated optical inspection tool is an electronic instrument used for inspecting PCBs that requires no human contact. Instead, what your manufacturer will do is they’ll employ the use of cameras and microscopes present in the inspection tool to take images of the PCB. The software in the tool will cross-examine the images that your rigid flex PCB manufacturer has taken and compare them to a reference material – which is the board’s schematic.

Your manufacturer’s technicians might take their time to thoroughly inspect the board to see if there are underlying issues that they can fix. The issues that this practice can remedy are gaps during soldering, missing components, and misaligned parts.

4. An intense assessment with burn-in tests

The next approach that your manufacturer could go for when examining the PCB’s performance and reliability is through a burn-in test. This intense type of testing is made to check the rigid flex PCB’s load capacity and to see if there are any errors early on. The printed circuit boards during this type of testing are exposed to electricity or heat continuously – for example, a PCB could be exposed to electric currents for 40 hours.

However, while it does help the manufacturer detect issues in terms of handling heat and electricity, this approach has the drawback of potentially lowering the PCB’s average working lifespan due to this test’s intense nature.

5. See through components and layers with an X-ray scanner

X-ray tests or AXI tests for your circuit boards are another means for your rigid flex PCB manufacturer to detect any issues in your PCBs. This method is handled by an X-ray technician who will scan the boards and see whether there are signs of defects, excess solders, and other potential issues that can reduce your rigid-flex circuit board’s performance.

The main perk of utilizing this test to detect issues that can affect the PCB’s performance is that the technician can detect, identify, and remedy issues that are concealed by the PCB’s outer layers. However, this method of checking your PCB’s reliability is a time-consuming and expensive process.

6. To repair or to remanufacture?

Last but not least, your manufacturer could either repair or remanufacture your PCB after tests have been conducted. This practice is important as this is the penultimate step before you can receive your rigid flex PCB.  What your manufacturer will do here is they’ll determine whether the defective parts can be still repaired or does they need replacements.

If to repair – they’ll just remove the defective parts and replace them with functioning components. If the underlying issues are too much for just a simple repair to handle, your manufacturer may resort to remanufacturing the circuit board – disassembled and built again.

Detect and resolve errors early with rigid-flex PCB tests

To sum up what we’ve discussed – rigid flex PCBs require testing by their manufacturer before they are shipped to your business address. The intent is to ensure that the boards are working as intended and there are no underlying issues. The tests tend to take place throughout the manufacturing process to ensure that the board can modified and tweaked to optimize its performance.

After all, the last thing you’d want to see arriving on your business address’s doorstep are packages of rigid flex PCBs that can’t properly work.