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GreensTone provides SMT PCB assembly services in China for prototype and production projects. Our manufacturing partner supports 01005 components, with SPI and AOI used as routine process checks. We coordinate the project’s assembly files, material requirements and inspection scope before production.
For projects requiring component sourcing, through-hole assembly or additional production steps, our PCB assembly services can combine these requirements within the agreed manufacturing scope.
Our SMT assembly capabilities cover small-component placement, reflow soldering and inspection, with the production route reviewed against your board design. The production lines and facility figures below belong to our manufacturing partner.
| Capability | Available Support |
| SMT production lines | 3 SMT lines at our manufacturing partner. |
| Through-hole production lines | 2 DIP lines at our manufacturing partner. |
| Partner facility area | 5,000 m². |
| Small-component placement | 01005 components, subject to design and process review. |
| BGA assembly capability | 0.25 mm-pitch BGA where required, subject to project review. |
| Routine SMT inspection | Solder paste inspection (SPI) and automated optical inspection (AOI). |
| X-ray inspection | Mainly used for first-article checks, rework inspection and batch sampling. |
| Functional testing | Based on customer-provided test procedures and agreed acceptance criteria. |
For 01005 components and fine-pitch packages, the review considers pad design, component spacing, stencil requirements, placement access and inspection needs. Share the relevant board files and component package information so the assembly requirements can be assessed for your design.
The SMT PCB assembly process follows solder paste printing, inspection, component placement, reflow soldering and post-assembly verification. Materials, board design and testing requirements determine the detailed production route.
We review the BOM, PCB manufacturing files, placement data and assembly drawings. Board dimensions, panelization, component footprints, polarity, stencil requirements and test access are considered before the build. PCBs and components are prepared according to the agreed sourcing arrangement.
Solder paste is printed onto the PCB pads through a stencil. SPI checks paste thickness, volume and alignment before component placement, allowing printing defects to be identified at this stage.
Surface mount components are placed according to the assembly data and soldered through the reflow process. The assembly setup is reviewed against the PCB design, component packages and soldering requirements.
AOI checks the assembled board for missing or displaced components and visible solder defects. X-ray inspection is applied according to the inspection plan for hidden joints. Identified defects are reviewed, and reworked assemblies are reinspected before release.
Programming and functional testing are performed where included in the project, using customer-provided firmware and test instructions. Outgoing quality checks and record review are completed before the PCB assemblies are packed for shipment.
SMT inspection combines checks at different production stages. SPI examines the printed solder paste, AOI examines component placement and visible solder joints, and X-ray is used where hidden-joint inspection is required.
| Inspection or Test | What It Checks | How It Is Applied |
| SPI | Printed solder paste thickness, volume and alignment. | Routine check after solder paste printing and before component placement. |
| AOI | Component presence, placement and visible solder defects, including offset and tombstoning. | Routine check following reflow soldering. |
| X-ray inspection | Hidden solder joints, including BGA and QFN joints and voiding. | Mainly used for first-article checks, rework inspection and batch sampling, according to the project inspection plan. |
| Functional testing | Powered operation, programming and specified circuit functions. | Applied using customer-provided test procedures, firmware and agreed acceptance criteria. |
Please specify required inspection coverage, test connections, fixtures and acceptance criteria during project review. Where aging or burn-in testing is needed, the conditions and duration are agreed for the product.
Inspection results and quality records are reviewed before release. Assemblies requiring repair or rework return for the applicable inspection and testing before shipment.
Manufacturing Process
SMT PCB Assembly: Uses automated pick-and-place machines to mount components directly onto the surface of the PCB. Soldering is done through reflow soldering.
Through-Hole Assembly: Components have leads inserted into pre-drilled holes on the PCB and are soldered using wave or hand soldering.
Component Types
SMT: Uses small, lightweight surface-mounted components, making it ideal for compact designs.
Through-Hole: Uses larger components with leads, which provide stronger mechanical bonds.
Reliability and Strength
SMT: Suitable for high-density circuits but may have weaker mechanical connections.
Through-Hole: Provides stronger connections, making it better for high-stress applications.
Cost and Production Speed
SMT: Faster production and lower costs due to automation.
Through-Hole: More expensive and time-consuming due to manual labor.
Application Suitability
SMT: Ideal for consumer electronics, communication devices, and compact gadgets.
Through-Hole: Used in industrial equipment, aerospace, and military applications where durability is crucial.
Your SMT assembly order can include component procurement, customer-supplied parts, through-hole assembly and prototype or production quantities. The scope is agreed against your BOM and product requirements.
We can purchase components against your BOM while you supply the items identified as customer-provided. Proposed component substitutions require your confirmation by email and internal ECR/ECN review before replacement. Our turnkey PCB assembly service explains the available sourcing arrangements.
For boards containing both surface mount and through-hole components, SMT assembly can be combined with hand soldering or wave soldering as required. Our through-hole PCB assembly service supports the additional insertion and soldering operations.
Our prototype PCB assembly service starts from 5 pieces. Typical prototype delivery is 4–6 weeks from receipt of complete project files and order placement, when material procurement begins. Long lead-time components can extend this schedule. Production-order delivery is assessed against quantity, material availability and assembly and testing requirements.
All orders include a one-year repair warranty. GreensTone also provides engineering change management and after-sales support for delivered PCB assemblies.
