OUR SERVICES
SMT Assembly
Are you in need of high-quality Surface Mount Technology (SMT) assembly services for your printed circuit boards (PCBs)? Look no further than ELIPCB. With our state-of-the-art facilities and experienced team, we offer comprehensive SMT assembly solutions tailored to meet your exact specifications.
What is SMT Assembly?
SMT (Surface Mount Technology) assembly is the process of mounting surface-mount components directly onto PCB pads and soldering them to form electrical connections. It is the dominant assembly method for modern electronics, enabling high density, small form factor, and automated mass production.
Basic Process Flow
Solder Paste Printing — Solder paste is stenciled onto the PCB pads; paste volume and alignment set the foundation for joint quality.
Component Placement — A pick-and-place machine mounts SMT components onto the pasted pads with high speed and precision.
Reflow Soldering — The entire board passes through the reflow oven; the controlled profile melts the paste, wets pads and leads, and forms metallurgical bonds.
Cooling — The board exits the oven and cools at a controlled rate, solidifying the joints.
Inspection — AOI and X-Ray verify joint quality, checking for defects such as bridging, tombstoning, voids, and shift.
Key Process Elements
| Element | What It Covers | Why It Matters |
|---|---|---|
| Stencil & paste printing | Aperture design, paste type, print pressure/speed | Determines paste volume; the root cause of most defects |
| Pick-and-place | Placement accuracy, feeder setup, nozzle selection | Affects offset, missing/misplaced parts |
| Reflow soldering | Profile control, oven uniformity, atmosphere | Forms the actual solder joints |
| Inspection & test | AOI, X-Ray, ICT, FCT | Catches defects and verifies function |
| DFM review | Pad design, thermal balance, panelization | Prevents problems before production |
Quality and Inspection Capabilities
AOI: Full inspection after reflow; detects tombstoning, bridging, shift, missing components.
X-Ray: BGA/QFN bottom-side joint void rate inspection, benchmarked against IPC-A-610 Class 2/3.
ICT/FCT: In-circuit test and functional test.
Cross-sectioning: IMC layer thickness and internal solder joint structure analysis.
Pull/shear testing: Solder joint mechanical strength verification.
SPC: Batch trend monitoring for peak temperature, TAL, and first-pass yield.
Types of SMT Assembly
Single-sided SMT: Components on one side only; simplest and most common.
Double-sided SMT: Components on both sides; second reflow requires securing bottom-side heavy parts.
SMT + THT mixed assembly: SMT reflow first, then wave/selective soldering for through-hole parts.
High-density assembly: Fine-pitch QFN, BGA, CSP, 01005 components; demands precision and X-Ray verification.
Flex/rigid-flex assembly: Thin, bendable substrates; low-stress profiles and handling required.
LED/aluminum substrate assembly: Thermal management is critical; reflow profile must protect the LED.
SMT Assembly vs. Through-Hole Assembly
| SMT Assembly | Through-Hole Assembly | |
|---|---|---|
| Component type | Surface-mount (SMD) | Through-hole (THT) |
| Mounting | On pad surface | Inserted through holes |
| Soldering | Reflow | Wave/selective/manual |
| Density | High | Lower |
| Typical use | ICs, resistors, capacitors, BGA, QFN | Connectors, electrolytic capacitors, pin headers |
Mixed-technology boards combine both: SMT reflow first, then THT wave or selective soldering.
Process Capability Parameters
| Item | Capability Range |
|---|---|
| Minimum component size | 01005 / 0201 |
| Finest lead pitch | 0.3 mm (QFP/QFN), 0.4 mm BGA pitch |
| Maximum PCB size | Depends on line configuration (e.g., 510 × 460 mm) |
| PCB layer count | 1–16 layers (including HDI) |
| Board thickness range | 0.4–4.0 mm |
| Component types | Resistors, capacitors, inductors, ICs, BGA, CSP, QFN, connectors, odd-form components |
| Placement accuracy | ±0.05 mm (fine pitch) |
| Reflow soldering | Multi-zone forced convection; nitrogen/vacuum optional |
| Double-sided assembly | Double-sided SMT reflow supported |
| Mixed assembly | SMT + THT (wave/selective soldering) |
Process Control and Traceability
Profile records: Measured profiles archived by batch/product for traceability.
Solder paste management: Records of batch, warm-up, and usage time.
First-article confirmation: Triple confirmation via X-Ray + AOI + profile.
Board-level traceability: QR code/batch number traceable to solder paste, pick-and-place machine, and operator.
DFM up front: Pad, stencil, and thermal balance recommendations provided at the prototype stage.
Certifications and Systems
ISO9001 / IATF16949 / ISO13485 (selected according to business needs)
RoHS / REACH compliance
IPC-A-610 Class 2/3 acceptance standards
Need SMT Assembly?
ELIPCB is your trusted partner for high-quality SMT assembly services. With our advanced equipment, experienced team, and commitment to quality, we guarantee superior results for all your PCB assembly needs. Contact us today to learn more about our SMT assembly capabilities and how we can help bring your PCB projects to life.
Why Choose ELIPCB for SMT Assembly?
Advanced Equipment: At ELIPCB, we utilize the latest SMT assembly equipment to ensure precision and efficiency in every step of the assembly process.
Experienced Team: Our team of engineers and technicians are highly skilled and experienced in SMT assembly techniques, ensuring that your PCBs are assembled with the utmost care and attention to detail.
Quality Assurance: Quality is our top priority at ELIPCB. We adhere to strict quality control measures throughout the assembly process to ensure that your PCBs meet the highest standards of reliability and performance.
Custom Solutions: We understand that every project is unique. That’s why we offer custom SMT assembly solutions tailored to meet your specific requirements, whether you need a prototype or large-scale production.