With the high demand of electronic devices from last few decades, the electronic component manufacturing industry has also evolved a lot. To cope up with the demand the industry has also need to evolve with new tools and methodologies.

Surface Mounted Technology (SMT) for Surface Mounted Devices (SMD) are discovered as an answer to speedup the overall manufacturing process. These also helped improving the quality and reliability of the devices and most important by greatly reducing the size of devices. Due to this “SMT” and “SMD” terms are very popular in the electronic manufacturing and assembly business.

By definition, Surface Mounted Technology (SMT) is the method of placing components on the PCB board and Surface Mounted Device (SMD) is an electronic component that is mounted on a PCB board.

Before Surface Mounted Technology (SMT), through-hole technology (THT) construction method was widely used for adding components with their wire leads into the respective holes in the PCB. Now a days, both the technologies work hand-in hand to put SMDs as well as large transformers, control buttons, heat-sink on the same PCB.

During the earlier deployment phase of SMT, the production process speeds up, but due to less accuracy of SMT machines the risk of defects also increases due to smaller component and the denser packing on PCB. Detection of failures has become critical for any SMT manufacturing process which leads to further invention of various manual, semi-automatic and automatic testing machines which are currently an integral part of the entire manufacturing process.

A SMT component is usually smaller than its through-hole counterpart because it has either smaller leads or no leads at all. It may have short pins or leads of various styles, flat contacts, a matrix of solder balls (BGAs), or terminations on the body of the component.

ElectroTrail for SMT and SMD

ElectroTrail has complete setup for SMT for supporting our customers. We provide this process to deliver the highest-quality products at lowest possible cost by using the most efficient processes. We have two station Pick-and-place machine along with a eight-zones lead free reflow oven that brings even more accuracy and control to this highly-sensitive process.

At ElectroTrail, we strive hard to meet customer requirements to the fullest and meet the stringent quality targets. We achieve this using out state of the art setup with all required equipment’s and most important the trained man-power we have. We not only partner with our customer for assembly of electronic circuits (PCB) but also help customer for design and development of boards, procurement of components, support for box-build assembly as needed.

Electronics industry has seen a systematic shift from the through hole technology (THT) to surface mount technology (SMT) in past decade. This shift is mostly to induct automation, reduce dependency on skilled resources, increase through-put, achieve highest quality and reduce overall cost.

In a PCB assembly process, reflow oven is the most important machine to weld surface mount components to PCB. Currently, it is extensively used across all PCB assembly factories for building electronics devices such as mobiles, hand held devices, LED lights, automotive control units, aeronautics, defence sectors, control circuits in industrial automation, etc.

An ideal Surface Mount Technology (SMT) consist of four parts: solder paste printing machine, SMT machine, Reflow oven and testing machine at the end.

Solder paste printer apply solder paste to PCB as per required thickness and pass it to SMT machine for mounting SMD components. Post SMT process, the PCB is passed through the reflow oven where the magic of welding/soldering happens in a computer temperature controlled environment.

Lead and Lead free welding /soldering:

Soldering paste with lead (e.g. Sn63Pb37) has 63% tin and 37% lead and melting point of around 183°C (361°F). For a good weld the thickness must be in between 0.5 to 3.5 μm for the components. The inter-metallic compound formation happens at 195 (383°F) to 200°C (392°F) which is higher than lead based welding.

Due to the RoHS guidelines, there is a demand in the industry for lead free solder paste. However, lead free solder paste needs higher temperature for welding. The lead free solder paste (e.g.  Sn96.5/Ag3.0/Cu0.5) has melting point at 217-220°C (423-428°F).  The maximum temperature of electronic circuit designed to withstand is about 240°C (464°F). This makes the temperature difference gap very close when the board is passed though reflow oven.

Due to computer controlled temperature for all zones ensure that the welding process is achieved as required and not crossed the maximum withstand limit of components.

At ElectroTrail, we have a computer controlled temperature eight zone reflow oven attached with industry best SMT line.