A The major parameters of a PCBA X-ray inspection machine include:
 
1. X-ray tube power and focus spot size
2. Image detector resolution and size
3. Magnification
● Geometric magnification, with the optical magnification
● The total magnification that can enlarge the photo digitally via the computer, followed by an in-depth observation.
 
4. Manipulator
● Anti-collision design
● The more the shafts, the better will be the precision
● 360-degree planar rotation
● Sample holder
 
5. Radiation protection to prevent leakage
● As per the international standards, the permissible level of radiation leakage will be less than 1µSv/hr.

A The below listed parts are required to assembly a basic PCBA X-ray machine:
 
● Microfocus X-ray tube to generate X-ray beams
● Vacuum System where the X-ray tube should be operated
● Loading table or sample operating table to place the sample and move them during testing
● High Voltage Generator to produce high voltage 90-130 KV and power to the entire system Overhead power line
● A shield cabinet having two layers of stainless-steel plate + 6 to 8 mm of the lead plate to prevent X-ray radiation
● Image Detector to determine the intensity of X-rays and produce black and white signal through the computer.

A PCBA X-ray machine can be used to inspect the following components:
 
● Electrical and electronic components for lifted ball bonds, broken wedge bonds die attach, and wire sweep
● Populated and unpopulated PCBs
● Find surface mount defects such as solder joint porosity, misalignments, as well as bridging Non-lead solders
● A detailed study of vias through multi-layer alignment and hole plating
● CSPs , BGAs, QFN, PoP and LED components soldering quality especially of the Soldering void rate

A The attributes such as an increase in density, size reduction, and intense complexity of PCBs and their components have made it nearly impossible for traditional inspection methods to detect intricate defects thoroughly. The traditional inspection methods such as optical, ultrasonic, and thermal imaging methods are relatively not effective in inspecting the components especially PCBs. This is where an X-ray inspection test can take detailed images, compared to other tests.
 
● The X-ray beam can penetrate every layer of PCB to check the inner layers and
packaging. Hence, it can accurately inspect the solder joints of complex PCB assemblies of the BGA,QFN, CSP and PoP components.
 
● X-ray inspection in PCBs helps you to take the final call in terms of the quality as well as measurement criteria.
 
● PCBA X-ray Inspection helps you to inspect BGA & QFN soldering voids and anomalies like non-wetting solder balls, and take measurements.
 
● Other applications of these X-ray test include the determination of the hole in solder joints with Non-destructive test like cross sectioning.
 
X-ray inspection tests can study the wetting features of solder on pads beneath a component as well as the characteristics that remain hidden due to the high density of the printed circuit board (PCB).

A Before understanding the importance of an X-ray test in PCBA inspection, you firstly need to know how X-ray inspection works.
All X-ray inspection devices are composed of four basic features:
 
● X-ray tube to generate X-ray beams to penetrate the samples
 
● Image detector located on the other side of the sample to capture and collect X-ray photons and convert them into visible image
 
● Manipulator platform to move the given sample in varied directions so that it can be inspected from all angles and magnitudes.
 
● Powerful software with cutting-edge algorithm to get the inspection result.
 
X-ray imaging test works with the help of X-ray photons, which are passed through the target material kept on the operation platform. The resultant rays will be collected on the other side through a detector, which results in an image formation. Based on the differential absorption principle, the X-ray photons pass through the target object in a differential manner depending on its physical properties, such as density, atomic weight, and thickness.
 
Usually, heavier objects absorb more X-rays, so that they can develop into an image, whereas lighter objects are more transparent. Since different objects has unique characteristics, different amounts of X-ray photons are collected on the other end of the target object, to form a final image.
 
Since the components in a PCB consist of heavier elements, it is easier to view their internal parts on an X-ray image.

A For the last few years, area array packages or devices such as QFNs, BGAs, CSPs, and flip chips are extensively used in all sectors like industrial, aerospace, military industry, communication, etc., where solder joints will get hidden under the package. Hence it will not be possible for traditional visual or optical inspection technology to inspect PCB devices with more accuracy. Additionally, the appearance of surface mount technology (SMT) that helps in making both leads and packages become smaller. Components on PCBs have got more density with their hidden solder joints and buried holes.
 
Hence, the already prevailing traditional inspection methods such as optical inspection (AOI) is not enough. This is where X-ray machines play a vital role to inspect the those electronics components like BGA, QFN, CSP and PoP in detail.
 
X-ray inspection technology is otherwise called as automated X-ray inspection. This technology can find unseen features in any target object. Starting from the medical sector to aerospace manufacture, X-ray inspection is widely used to detect manufacturing defects. Compared to other inspection methods, X-ray can effectively penetrate into the inner packages, and inspect the quality of those hidden solder joints.
 
When it comes to SMT PCBA inspection, X-ray test is vastly carried out during the PCB assembly process to test the quality of PCBA soldering. This is one of the major steps carried out by the PCBA contract manufacturers to assure its quality. It can quickly and accurately detect the hidden defects without causing any damage to the target object.
 
Hence with the rapid increase in miniaturization of semiconductor components, it’s better to consider an X-ray inspection system.

A 1. Inspect the defects in the IC package, such as wire bonding, layer peel, bursts, voids, and integrity testing of wire.
 
2. Detect the defects in the PCB process, such as poor alignment or bridging, and open circuits.
 
3. Detection and measurement of voids in SMT BGA QFN LED solder joints.
 
4. Tests the open circuits, solder bridge, BGA Head in Pillow (HiP), short circuits, defects, BGA void, PTH filling rate during electronics assembly process.
 
5. Integrity testing of solder balls for BGA and CSP during reflow soldering in EMS.
 
6. Detect cracks in higher density plastic material.
 
7. Measures chip size, marking and wire arc, and tin component area ratio.            
 
Unicomp was established in 2002 and has become a national high-tech X-ray equipment provider engaged in the research of microfocus X-ray technologies as well as the development and manufacture of X-ray intelligent inspection equipment. Our technology and equipment are widely used in testing SMT, BGA, CSP, Flip-Chip, IC semiconductor components, connectors, wire, photovoltaic components, lithium batteries, ceramic products, and other electronic products. Our manufactured equipment is ergonomic, easy to use, cost-effective, reliable, highly qualitative, long-lasting. Our equipment is used by many domestic and foreign companies, including PCB manufacturing companies for testing services.

A There are several quality-based risks while winding the pole pieces, welding the ears, spot welding into the shell, and welding caps. Hence, after completing the lithium battery cell, X-ray inspection is required to check whether the welding inside the battery is proper or not. If the rolls are aligned properly, the winding won’t undergo short-circuit which leads to an explosion. The internal image is visually displayed by the X-ray inspection equipment, and the defects are automatically judged by its software AI algorithm. This equipment improves the efficiency of Li-ion cell inspection and the quality of the lithium battery.
 
Unicomp Technology, as the national high-tech X-ray inspection solutions provider, has developed its Li-ion battery X-Ray inspection systems to inspect different type of lithium batteries like cylinder cell, laminated & stacked cell, Pouch cell for both consumable electronics and electric-vehicle. This X-ray equipment emits X-rays through an X-RAY generator, which penetrates the battery’s internal structure. The imaging system receives the X-rays of the lithium battery and takes pictures. The powerful software AI algorithm will automatically measure and alignment between the Anode and Cathode, and automatically recognize if a defective (NG) found.