SMT Assembly

SMT Assembly is the precision process of mounting electronic components onto PCBs using automated, high-speed equipment to create reliable, high-density circuit boards. It encompasses solder paste application, chip placement at rates up to 180,000 CPH, reflow soldering, and multi-stage inspection (SPI, AOI, X-ray) to ensure zero-defect output. Our SMT lines feature modular pick-and-place systems, intelligent feeder management, and real-time process control—enabling seamless transitions between prototypes, medium runs, and high-mix configurations with minimal downtime. This delivers superior placement accuracy (±25 µm), consistent solder joints, and full traceability from reel to reel. Need fast, flawless SMT assembly for complex or high-reliability boards? We can get your design into production.

Manufacturing Metrics

All of our services have different metrics. We've aimed to unify and better present the capabilities of our manufacturing services through a standardized approach.

SMT Assembly

Screen Printing

Marked PCB boards are delivered in a raw state and put on racks by the surface mount technology (SMT) line operator. Automated loaders, then move the boards onto the SMT line. The PCB boards need to be delivered to the line in the proper quantity and flow. They begin to move on the conveyor, starting the screen-printing process. Once the SMT line has been programmed and the selected product programme has been confirmed, the solder paste printer is ready. The SMT operator applies the solder paste to the metal stencil. This paste is made of tiny pieces of metal solder and tacky flux that stick to the metal parts of the printed circuit board. The flux in the solder paste holds all the parts in place until the board is heated in the reflow oven. We use automatic screen printers, which are supplied with a machine vision system that ensures that the stencil and the printed circuit board are correctly aligned, allow to apply different squeegee pressure on the parts of the board and provides high accuracy screen printing of very small parts. Double lanes can simultaneously assemble both sides of the PCB board, which fastens the assembly process.

SMT Assembly

Solder Paste Inspection (SPI)

To ensure a proper electrical connection on the PCB board, solder paste must be applied correctly. Before the PCB assembly process starts, the solder paste is inspected to see whether it has been placed appropriately. Pasted PCB boards go straight to the solder paste inspection machine. It has a monitor which displays the inspection process and results. The machine shows printing trends and features and configurable statistic presentation. To determine if the proper quantity of solder paste is applied, and to ensure that there are no inconsistencies on the PCB contact pads, 2D and 3D images are taken. It is done by two projectors which use striped pattern light to project pictures of solder. The equipment also gives adjustments to the screen-printing machine based on data from inspection results. Additionally, it scans the PCB's barcode, allowing the inspection results to be recorded.

SMT Assembly

Pick and Place

We use highly productive pick and place machines for the component placement process, which begins as soon as the accuracy of the solder paste application is verified. Based on PCB board layout and bill of materials, the SMT programmer sets up the machine. Project-specific surface mount devices (SMD) are then loaded by the SMT operator to the feeders at the prescribed locations. SMD components arrive in reels or trays and are loaded to feeder magazines based on their size. Each component reel has a data matrix that is scanned and inserted into the SMT system. An automated system ensures accuracy by rejecting any incorrect reels. By scanning the next one, reels can be simply replenished. The pick-and-place machine receives the PCB board and places the components on the pasted panels. To pick up pieces and subsequently deposit them into the solder paste on the board, special nozzles employ vacuum. Small chips, large ICS, and other complex components can all be assembled by this precision machinery.

SMT Assembly

Reflow Soldering

Following the component placement, the assembled PCB board goes through the soldering oven, where the high temperature gradually melts the paste and attaches the electronic components to the board. These are long convection ovens with a process length of more than 6 meters, separated into 10 heating zones and cooling zones. Preheat, thermal soak, reflow, and cooling are the four stages into which the zones are split. Solder profiles can be optimized for each particular assembly job based on the component size and layout, layer counts on the PCB, and copper distribution on the board. The oven's heating zones are each set at a controlled temperature that corresponds to the solder profiles needed for assembly. After heating the component and its attachment to the board, follow the cooling process. The solder paste will harden as soon as the temperature decreases significantly, and the components are then attached to the circuit board. In the final areas of the reflow oven, where the processed board is cooling, the solder alloy solidifies and forms the solder joints. After reflow soldering, the PCB board goes to the loader, which performs two functions. It can act as a buffer for the boards that are waiting for checking, or it can be used to cool down the board after reflow soldering.

SMT Assembly

Automated Optical Inspection

After soldering, it is crucial to check the component placement quality. Since we focus on low-mix, high-volume electronics production, automated optical inspection (AOI) suits our needs. When the AOI starts, the operator prepares it with a designated program. The main purpose of it is to check printed circuit board assemblies for flaws. AOI uses cameras to scan PCBAs and finds two categories of defects: catastrophic failures, such as missing components, and quality failures, like crooked fillets or skewed components. We use an AOI machine, which has two conveyors for both sides of the PCB board. In the machine, there are sensors that detect the arrival of the PCB. Inside the machine, there is a camera that captures the whole cycle. Then the software determines if there are discrepancies. If there are no mistakes, the board enters the pass section, and if a single mistake is found, it enters the check section. Boards that have not passed the AOI inspection are additionally checked in designated stations. An expert in AOI scans the PCBs board's data matrix and reviews photographs taken. The programme shows the intended result of the component placement. AOI specialist decides if a small amount of soldering can fix the problem or if the board needs to be relocated to a rework station. If it's a small issue, the experts solder themselves. If incorrect flaws are discovered, AOI specialists can reprogram automatic optical inspection devices or alter currently running programmes.