What Is X-Ray Machine PCB Inspection?
With so many electronics on the market today, reliable functionality is what separates quality products from the competition. Everyday consumers count on their gadgets to work when they need them to. But for professionals in medicine, aerospace, and military operations, properly functioning electronics can quite literally be a matter of life and death.
To ensure that electronics work as intended, x-ray inspections of printed circuit boards are performed throughout the assembly process. While different classes of circuit boards have different inspection standards, x-ray inspection is a widely adopted method to detect defects that visual inspection can’t.
What Is PCB?
A printed circuit board (PCB) is essential in modern electronics. Whether a simple board used in a tv remote control or a sophisticated high-density board used in a laptop computer, all other electronic components of a device depend on PCBs to function.
In simple terms, a printed circuit board is a structure consisting of electric circuits made of various traces and planes soldered together to create a board. The metal components of PCBs are typically made of copper while the dielectric material is usually a composite material called FR-4.
PCBs have a variety of applications, including:
- Medical devices
- Security equipment
- Heavy machinery
- LED lighting
- Automotive parts
- Aerospace components
- Telecommunications equipment
- Consumer electronics
Some PCBs are made to be flexible so circuits can be bent into shape, but most PCBs are rigid boards with a solid structure that doesn’t bend. Printed circuit boards can vary in complexity from a single layer of circuitry to dozens upon dozens of layers.
Because printed circuit boards are fundamental to the functionality of most electronic devices, they need to be as reliable as possible. In order to precisely gauge the quality of PCBs in the manufacturing and assembly process, x-ray inspections are performed.
X-Ray Printed Circuit Board (PCB) Inspection
An x-ray inspection is a popular method of identifying defects in manufactured parts and components, especially in printed circuit boards. While highly specialized automated visual inspections can be effective at recognizing flaws and irregularities, x-ray machines are particularly well suited for analyzing electronic parts.
X-rays allow for comprehensive PCB inspection that reveals defects unable to be detected through strictly visual means. X-rays provide access to the internal geometries and structures of a circuit board without the need for physical disassembly. Defects can be identified and tested by an x-ray machine without damage to the PCB.
As technology continues to advance, x-ray inspections are increasingly necessary. Parts and components are becoming smaller and more complex, along with solder joints required to connect them. As such, manufacturing and assembly errors are not always visibly apparent, and traditional inspection methods aren’t always applicable.
But x-ray inspection technology allows for a detailed view of printed circuit boards that accounts for even the smallest voids and cracks. And as such, other inspection methods like ultrasonic and thermal imaging simply can’t compare.
Since even the smallest solder joint deviations and faults can compromise the functionality of electronics, automated x-ray inspection systems are highly important in the PCB assembly process.
Why X-Rays Are Important in PCB Assembly
First and foremost, x-ray machines are important in printed circuit board assemblies because they can pinpoint any irregularities on the circuit board, ensuring process control and facilitating proper failure analysis. Images of different PCBs can be compared for consistency, ensuring quality solder joints before moving forward in assembly.
Broken or missing solder joints can be identified, which may help to determine issues in the production or design process.
And for circuit boards using solder balls, an x-ray inspection system is especially useful. The shape of the solder balls can be compared to a standard reference image, ensuring that each ball has been placed and connected correctly.
X-ray inspection has earned its place as one of the most popular quality assurance methods in PCB assembly. The accuracy and power of x-rays are undeniable in the inspection process, but there are a host of other benefits that make x-ray inspection so important for PCBs.
Non-Invasive
X-ray inspections can be performed without risking damage to a PCB or its components.
Fast
Compared to an involved visual inspection, x-ray inspections are much faster.
Comprehensive
Several different types of qualities can be inspected at once using x-ray inspection technology. Solder bridges, solder joints, pin-hole fills, solder voids, and more can all be analyzed at the same time.
High-Resolution
A quality x-ray image taken at high resolution allows for the most accurate view of PCBs.
Comparable
Different x-ray images of the same object can be easily compared to identify alterations and irregularities.
How X-Ray Inspection Works
X-ray inspection works by measuring x-ray photons passed through a given material. Different materials have different elemental compositions with corresponding atomic weights, and x-ray photons behave differently when they come in contact with certain elements.
Heavier elements usually appear darker while lighter elements appear more transparent, resulting in a dynamic x-ray image. Since PCBs are generally composed of heavier elements, detailed visuals are easily generated through x-ray imaging.
PCB x-ray inspection devices typically have three fundamental parts:
- X-ray tube
- Platform
- Detector
The x-ray tube is the component responsible for generating x-ray photons. Sometimes called a Roentgen tube, an x-ray tube works by accelerating electrons to high velocity and forcing them to collide with a target.
The platform of an x-ray machine is used to move the PCB sample in various directions, allowing x-ray inspection to be performed from all necessary angles.
The detector collects x-ray photons on the opposite side of the sample PCB and converts them into an image. This can either be a 2D rendering or a detailed 3D image depending on the particular software being used.
X-Ray Inspection from 3D Engineering Solutions
At 3D Engineering Solutions, we’re dedicated to providing state-of-the-art engineering metrology services to partners in virtually every industry. Anywhere that precision x-ray imaging or 3D modeling is required, our team’s detail-oriented approach and abundant experience will deliver the highest quality results.
We’re happy to work with you to expand your x-ray inspection systems capabilities. Whether you’re installing new x-ray inspection equipment or streamlining your current process, our staff of degreed engineers will support you at every step of the way.
