Surface Mount Technology (SMT) is necessary for electronics manufacturing. It mounts components onto the surface of printed circuit boards (PCBs), supporting compact designs, high-speed assembly, and reliable performance.
At PCBONLINE, we provide fully automated SMT PCB assembly services from prototypes to large-volume productions. Each of our SMT lines is built with comprehensive surface mount technology machines, including dual-AOI.
In this article, you will see the surface mount technology machines one by one.
On-line Surface Mount Technology Machines
From the first machine that loads bare PCBs to the final stacking of the PCBAs for subsequent THT assembly or functional testing, every SMT assembly step is automated and quality-controlled with our complete and advanced surface mount technology machines.
PCB Loader
The SMT process begins with the PCB loader, also known as the PCB loading machine. Its role is to feed bare PCBs onto the production line automatically, ensuring smooth and continuous operation.
Instead of relying on manual operators to place PCBs one by one, the loader reduces handling time and prevents contamination or damage to the bare PCBs. It can hold multiple PCBs stacked vertically or horizontally and transfer them onto the conveyor system with precision alignment.
At PCBONLINE, our loaders are compatible with PCBs of various sizes and thicknesses, making them suitable for diverse applications from consumer electronics to industrial control PCBs.
2. Solder Paste Printer
Once a PCB enters the line, the next machine is the solder paste printer. This step is crucial because it directly determines the quality of solder joints.
The machine uses an SMT stencil and a squeegee to apply solder paste precisely onto the exposed copper pads of the PCB. The solder paste contains a mixture of fine solder powder and flux, which holds the components in place before reflow soldering and ensures strong electrical connections.
Our solder paste printers feature high-accuracy alignment systems, ensuring that even 0.3mm-pitch BGAs and micro components are printed with exact consistency. They also integrate automatic cleaning systems that keep the stencil free of paste residue, guaranteeing reliable deposition throughout the production run.
4. Two High-Speed Pick-and-Place Machines – YAMAHA YSM20R
Once the solder paste is confirmed to be accurate, the PCBs move into the high-speed pick-and-place (PNP) stage.
At PCBONLINE, each SMT line includes two YAMAHA YSM20R high-speed pick-and-place machines. These are the workhorses of the line, capable of placing small-footprint surface-mount devices (SMDs) at extremely high speeds.
Each YSM20R has dual-side feeders with 70 slots per side, totaling 140 slots per machine.
- With two machines in sequence, our line supports 280 feeder slots dedicated to small components such as resistors, capacitors, diodes, and small ICs.
- High-speed heads capable of placing over 90,000 components per hour with sub-50 micron accuracy.
By distributing the workload across two YSM20R machines, PCBONLINE achieves both speed and redundancy, ensuring consistent placement even for PCBs with thousands of components.
5. Functional Pick-and-Place Machine – YAMAHA YSM10
After the high-speed placement of smaller parts, larger and more complex components are mounted using our YAMAHA YSM10 functional PNP machine.
The YSM10 is optimized for flexibility and large-footprint SMDs. It features: Dual-side feeders with 48 slots per side, totaling 96 slots.
- Support for larger and heavier components such as BGAs, QFNs, connectors, sockets, and shielding frames.
- Advanced vision alignment systems to ensure perfect orientation and placement.
This step ensures that even the most complex assemblies with diverse package sizes can be completed in a single line without manual intervention.
6. Pre-Reflow 3D AOI (Automated Optical Inspection)
Before the PCBs enter the reflow oven, PCBONLINE adds an extra layer of quality control by using a 3D AOI system.
This AOI machine inspects component placement in three dimensions, checking component presence and polarity.
- Placement accuracy (X, Y, rotation)
- Coplanarity of leads to ensure they will solder correctly during reflow.
By catching misaligned or misplaced components before soldering, we prevent defects such as tombstoning or cold joints, saving significant costs in rework.
7. Reflow Oven (10-Zone, Lead-Free)
The heart of SMT assembly is the reflow soldering process, performed in our 10-zone lead-free reflow ovens.
The PCBs travel through a conveyor belt that passes sequentially through:
- Preheat zones – gradually raise PCB temperature to prevent thermal shock.
- Soak zones – stabilize the temperature and activate flux in the solder paste.
- Reflow zones – reach peak temperatures above the solder alloy's melting point, forming permanent joints.
- Cooling zones – solidify solder joints in a controlled manner to avoid thermal stress.
At PCBONLINE, our reflow ovens are nitrogen-compatible, allowing us to switch to nitrogen reflow soldering when working with sensitive or oxidation-prone components. This flexibility ensures reliable solder joints across all PCB designs, including double-sided assemblies.
8. Post-Reflow 3D AOI
After reflow, every PCB is inspected again by a 3D AOI machine.
AOI checks the quality of solder joints, verifying criteria such as solder fillet shape, wetting, and bridging. With 3D analysis, hidden defects like insufficient solder height or voiding can be detected.
By combining both pre-reflow and post-reflow AOI, PCBONLINE ensures that every defect is caught early, leading to a near-zero defect rate in shipped assemblies.
Finally, the PCBs reach the end of the SMT line, where a robotic arm stacks them into carriers for subsequent processes, like Through-Hole Assembly (THT), conformal coating, or functional testing.
Off-line Surface Mount Technology Machines
At PCBONLINE, besides the four full SMT lines (online machines), we also equip a first-article inspection (FAI) machine and two X-ray inspection machines to ensure the SMT assembly quality.
- First article inspection (FAI) machine – for checking the first sample PCBA before mass production.
- X-ray inspection machine – for inspecting hidden solder joints such as BGA, QFN, and CSP.
Choose the Turnkey PCBA Manufacturer PCBONLINE for SMT Assembly
Unlike semi-automated setups, PCBONLINE's SMT production lines are fully automated end-to-end, combining speed, accuracy, and consistency. We provide not only SMT assembly, but also PTH assembly, PCB fabrication, component sourcing, fixtures, enclosures, box-build assembly, value-added services, testing, and shipping the finished devices you can sell.
PCBONLINE is an OEM PCB source factory manufacturer founded in 2005. It has two large advanced PCB manufacturing bases independently fabricating all types of PCBs, one EMS (electronic manufacturing service) PCB assembly factory with two component warehouses, stable supply chains, and an R&D team. Besides, it keeps long-term cooperation with the top 3 mold/enclosure manufacturers in China to provide the molds, jigs, and enclosures for full box-build solutions.
Each SMT line at PCBONLINE is equipped with three advanced pick-and-place machines, supporting up to 376 SMD placements per PCB, enabling us to handle all types of SMT assembly, including high-density and large-format PCBs.
Our SPI and dual AOI systems perform 3D surface scanning, offering thorough and accurate inspections for superior quality control throughout the process.
We conduct first-article inspections both before prototype assembly and before mass production to ensure the highest PCBA quality and prevent costly issues.
Our experienced R&D and engineering teams provide one-on-one support, solving technical and non-technical challenges while offering optimization suggestions to ensure your project runs smoothly from start to finish.
High-quality PCBA manufacturing certified with ISO 9001:2015, ISO 14001:2015, IATF 16949:2016, RoHS, REACH, UL, and IPC-A-610 Class 2/3.
When your project enters the bulky production stage, PCBONLINE refunds the fees of prototyping, including its value-added services.
PCBONLINE supports clients across industries, including automotive, aerospace, IoT devices, industrial controls, LED lighting, and consumer electronics. To get a quote from the SMT PCBA manufacturer PCBONLINE, contact info@pcbonline.com.
Conclusion
It's important to visit an SMT line before choosing a PCBA manufacturer. Complete surface mount technology machines include PCB loaders, solder paste printers, 3D SPI systems, high-speed and functional pick-and-place machines, multiple AOI stages, reflow ovens, an X-ray inspection machine, and an FAI machine. The turnkey PCBA manufacturer, PCBONLINE, has these complete SMT lines and rich PCB assembly experience. To ensure the success of your PCB/PCBA projects, send the quote request to work with PCBONLINE.
PCB assembly at PCBONLINE.pdf
