An X-ray is a valuable tool in PCB Assembly, providing insight into the PCB assembly process and detecting flaws that are not visible to the naked eye.
We will establish the significant X-Ray applications in PCB assembly, the common errors being sought after, and the benefits of using x-rays in PCB assembly. Continue reading to understand how x-rays are used during PCB assembly and what they offer to help improve your product quality.
X-rays are a non-destructive and easy way to inspect your circuit boards and detect any errors in the PCB assembly. It is a cost-effective way to reduce, rework, and improve product quality. They collect very detailed images while other commonly used methods of inspection cannot. X-rays penetrate multiple layers of PCB to inspect the packaging and the inner layers.
The two major classifications of x-ray machines are:
2D x-ray systems: These provide 2D images of the PCB assembly. The images can be compared side-by-side to see any differences between them and reveal issues in the solder joints on both sides of the board.
3D x-ray systems: These are an upgrade to the standard x-ray machines, and they provide more detailed images of solder joints on all sides of a board. This is useful in detecting any errors that may not be visible from one side only.
As noted, x-rays are used to inspect solder joints for any defects. The images from PCB x-ray inspections can compare the quality of solder joints in different builds and are instrumental when performing a multi-board build where multiple PCBs have been placed on one board. This way, you ensure that every joint has the same level of quality before going ahead with your production run.
X-rays can detect missing or broken solder joints. If you see any defects in the images taken, there are likely issues with production and/or design.
X-rays can help detect other sorts of errors, such as bad connections between conductors on a board, faulty components mounted where they should not be, and more.
This is a key application of x-ray machines. Solder balls are used for joints with too many pins to be placed on one pad, and they ensure a strong electrical connection between solder pads, which can otherwise fail due to thermal fatigue during the soldering process.
These irregularly shaped objects are inspected with x-rays because it can capture an image of each ball which can then be compared to a reference image. This way, you know if the solder balls have been properly placed and connected with other components on your PCB assembly.
The inspection of plated through-holes is another important application of x-ray machines. The holes are inspected to ensure no defects in the plating and that they have been properly filled with solder paste before being placed on a soldering board.
X-rays can detect cracks or voids present in the hole. If these issues are current, solder paste will not fill the hole completely, and a connection cannot be established.
X-ray imaging is a non-destructive method. It does not require samples to be sent away for analysis and only requires the sample to move through the machine once. This ensures that there is no damage done to it.
The x-ray won’t damage the PCB and its components, which means you can use this method for several inspections without worrying about damaging your board.
In comparison to solvent testing or visual inspection, an x-ray is much faster.
Some of the qualities that a PCB inspector can inspect at a time include solder bridges, pin-hole fils, solder voids, and more.
BGA inspection is another important application of x-ray machines. X-rays are helpful because they can capture an image of the BGA chip, which is then used to verify that it has been placed correctly on a board and no defects have occurred during processing.
PCB x-ray images can be taken at different resolutions, which can be used for various applications.
X-ray imaging is used to compare different images of the same product. This lets you check if any changes have been made in a production run that might impact quality. It also enables comparisons between products from different manufacturers at different stages in their life cycle.
Some of the common problems that x-rays help detect include:
Solder voids: Soldering voids are caused when gas or flux is trapped within the solder, usually due to water contaminating the solder paste. Solder voids create a buildup of insulation that lowers heat conductivity and might lead to physical flaws and much-reduced reliability. Soldering voids are easily detected with x-rays, which is one of the few methods to do so.
Solder bridges: This is a typical problem with circuit boards. It arises when solder joints are too close or form a connection where there should not be any. These solder issues are often hidden by other components, making optical inspections ineffective in detecting them. X-rays, on the other hand, readily identify them.
Pin-hole fills: Insufficient pin-hole filling for through-hole connections is a severe problem in printed circuit boards. X-rays can be used to spot these flaws and even help quantify the missing fill using coordinate measurements.
At Qtech, we provide various printed circuit board services, including assembly, inspection, and error-proofing. Our x-ray imaging services can be applied to the entire production process, from incoming inspection and sorting of components, through circuit board assembly.
Our goal is to help your business improve quality by finding defects before they become a problem for you or your customers. Contact us today to find out more about how we can help you.