Advancements sometimes come in funny twists. Progress in one area can throw clog, sludge, and a giant-sized spanner into the wheel of another part of the same thing.
The SMT (Surface Mount Technology) has brought some notable improvements in electronic assemblage technology.
This progress is seen in miniature electronic components as SMT affords designers the ability to reduce elements to tinier sizes. This technology also allows many other functionalities and gadgets as part of a single whole device.
However, this has created another challenge in quality assessment and control, which is a critical part of ensuring that users value money.
Let’s not get ahead of ourselves. Let’s have a little background story of how the SMT X-ray came into being.
- A background about SMT x ray
Ever since the SMT replaced the manual wave soldering technique for assembling electronic components, it has become the first choice assembling method, especially for Printed Circuit Boards (PCBs).
The reason is that SMT offers a faster way of assembling PCB elements, provides more structural integrity, and can save up to 50% of production cost when compared with traditional technologies like Through Hole Technology (THT). It also has a minimal defects rate, higher numbers of assembled parts, and can produce lightweight devices.
Most of the advantages that SMT offers is due to the high automation that accompanies it. SMT further facilitates other technologies like the BGA (Ball Grid Arrays), SMD (Surface Mount Devices), and SMC (Surface Mount Components) with efficiency within their installed environment.
However, the challenge of quality assessment persists, considering that the surface of Printed Circuit Boards are entirely packed with components and leave little or no room for conventional forms of quality inspection.
This situation was what necessitated the X-ray to check the conformance of SMTs to the required design specification. The usual inspection methods, including ultrasonic and optical techniques, became grossly inadequate, seeing that soldered components have become smaller and tightly fixed. Using the traditional quality inspection methods only leave a large room for errors and non-conforming parts as it became practically impossible to penetrate these components for proper inspection.
Nonetheless, SMT X-ray inspection has principles that make it easy for thorough and adequate quality inspection and component assessment to ensure design conformance.
- How does x-ray equipment work in SMT?
X-ray equipment provides a non-destructive method of testing SMT parts for soldering continuity and defects identification in the PCB components.
The X-ray equipment can also measure the ball diameter of BGAs and recognize the presence of anomalies like cracking solder voids or bridging.
But how does X-ray equipment achieve these feats?
The principle and process of detection
When the machine releases X-ray radiations, the sample material absorbs the energy based on the density of the material. Since materials with higher densities tend to absorb more X-ray radiation, they are easily visible. In contrast, less dense materials absorb less X-ray radiation and are less visible on the image screen.
When viewing an X-ray image of test material, on-screen materials with higher densities appear darker while lighter materials are lighter or even transparent.
When carrying out an SMT X-ray inspection, there must be an X-ray machine that has an X-ray tube to generate the X-ray radiation. Also, the platform for the sample needs a feature for rotating the platform so that X-rays can penetrate the sample from various angles for adequate inspection.
Finally, a detector allows the X-ray projection to form the image of the sample projected on the screen. Most X-ray inspection systems have magnification to ensure that the image is clear enough for analysis. However, if the magnification is not adequate, especially for tiny components, defects might be hard to identify.
Notwithstanding, an oblique angle gives the best view for a thorough inspection of the thickness and size of solder balls.
- The importance of SMT x-ray
You cannot speak enough about the importance of an SMT X-ray inspection in this modern era of electronic design, where components are becoming smaller, tinier, and lightweight. The best method that offers the best value for carrying out a quality assessment of these components is still SMT X-ray.
Probably the most important reason for using X-rays is the fact that they can detect various flaws accurately. But how varied are the number of flaws that it can check? Anomalies in soldering, including bridging, voids, missing soldering, and excess soldering, are accurately spotted using SMT X-ray.
In the case of faulty components and missing or misplaced parts, X-ray inspection can also identify these errors during the analysis of a well-magnified image of the test sample.
- Different types of X-ray machines in SMT
Proper consideration is often given to the type of X-ray machine needed to carry out certain SMT inspections. This requirement is necessary as the wrong kind of machine might be inadequate for the accurate generation and analysis of the sample image.
There are two main types of X-ray machines which are 2D and 3D X-ray machines. There is the possibility of carrying out a random offline inspection at any point during production, which enhances the early detection of defects without significant delay in production.
However, the choice of an online or offline machine will significantly depend on the quantity and the type of X-ray inspection required.
While a 2D X-ray machine will give you the image of the components installed on both faces of the PCB, a 3D machine can generate a more comprehensive image with the combination of several 2D images.
But that’s not all! The 3D machine can also use a technique called Laminographic construction to reproduce the image of an isolated component within the PCB using the combination of various 2D images.
The ability to check for defects and errors in electronic components installation is now very accessible because of the advent of SMT X-ray inspection.
You consider this method a breakthrough in the electronic manufacturing industry as it allows for a precise and very accurate quality inspection method. It has also enabled manufacturers to save costs on warranties incurred due to the manufacturing of faulty products.
However, the choice of the best X-ray machine will significantly depend on the quantity and specific application of the X-ray machine.