A printed circuit board (PCB) on which all the electrical components have been soldered is called the Pcb assembly (PCBA). The assembly is ready to go into a slot inside an electronic device to handle inputs and outputs that make multifunction devices convenient gadgets. It makes the timer in your coffeemaker click on to start brewing your early morning cup. Its various components keep the brew hot or automatically turn off the machine according to a pre-set program.
As electronic devices become more complex and multifunctional like automated coffee makers and smartphones, PCBAs have turned into complex layers of insulating substrate and copper foil layers to which large numbers of electrical components like diodes, resistors, LEDs, switches, and capacitors are mounted. These components are all integrated in a circuit that flawlessly executes your commands when buttons are pressed or when you tap the screen with a flick of your finger.
The increased demand for greater functionality in small-sized devices has revolutionized the industry to come up with better methods of mounting electrical components on the PCB. EMS providers have gone a long way from the early years of employing Through-Hole devices (THD) to the currently preferred Surface-Mount Technology (SMT) wherein electronic components are assembled with automated machines. To understand better how technology has progressed in Pcb assembly operations, a comparison of these technologies is worth looking into.
Thru-hole technology (THT) is the conventional method of processing semiconductors wherein the electrical components have lead wires that are led through holes that have been previously bored in a multilayer PCB. The components are then soldered to fix the mounting. The large size of the leads and the bored holes limit the number of components that can be mounted per surface area of the PCB.
Surface mounting became the dominant process in the production of PCBAs when OEMs demanded for greater numbers of pins and reduced board weight and size. This is necessary for the production of multifunctional devices in smaller sizes. In surface mounting, the leads are directly soldered onto the surface of the PCB. It eliminated the process of boring holes through PCB layers and the use of large-sized leads, resulting to an increase in pin count per unit surface compared with THT. And since there are no holes to contend with, pins can be mounted on both sided of the board, almost doubling pin density.
The THT method has suffered a decline over the past years, leading many to believe that the more advanced SMT process has made it obsolete. However, leading suppliers of PCB assemblies such as pcbnet.com maintains both SMT and THT operations to give customers the option to choose the technology they prefer.
Through-hole mounting has remained resilient because it has captured a niche and remains the preferred Pcb assembly process for high-reliability products. Compared with SMT, THT processed PCBAs provide stronger connections for electrical components because these are soldered through the board. THT PCBAs can better withstand environmental stress and are preferred by industries engaged in the manufacture of military, aerospace, and products that are exposed to high temperatures, accelerations, and collisions.
Prototyping is one of the applications wherein the THT method has a definite advantage over SMT. The development of prototypes usually involve adjustments in the design and the placement of electrical components. Adjustments and replacements are better done manually using a through-hole device, which means THT will remain in use for testing and prototype applications.
On the other hand, SMT is more suitable for high volume production of PCBAs with reduced size and higher circuit speeds. The advanced technology employed in this process allowed the use of much smaller components that can be mounted on both sides of the board, making the production of smaller, denser, and higher performing PCBAs possible.
On the part of EMS providers, SMT requires a substantia –
Investment in machinery and greater skills for the engineering staff in design and production. The advantages of the automated SMT system are faster production time, lower cost, and a more reliable and repeatable process. By investing in state of the art SMT equipment, PCB assembly suppliers like pcbnet.com are able to process orders in thousands of units within a shorter time frame. This is a definite advantage for manufacturers of electronic devices that experience periodic surges in market demands and for manufacturers of high volume electronics.
Innovative PCBA suppliers offer clients both THT and SMT options because some electrical components are available only for through-hole operations. The cost of components can also vary, with some through-hole components being less expensive than SMD packages. From a business point of view, clients who require higher volumes of PCBAs within shorter time frames can opt for SMT, while manufacturers of products exposed to environmental stress can opt for the stronger mounting provided by THT.
In choosing your Pcb assembly supplier, you should look at the capability to produce the volumes you need as well as the company’s compliance to industry standards. This ensures that you get deliveries on time and the quality and reliability of the PCBAs remain consistent in both high volume deliveries and smaller orders.