PCB Assembly Services
GreatPCB provides printed circuit board assembly services for prototypes, pilot builds and production orders. Bring PCB fabrication, component sourcing, SMT and through-hole assembly into one project, with programming, inspection and testing defined around your board requirements.
Send your Gerber files, bill of materials and build quantity to discuss the assembly scope, material availability and next steps.
Assembly Capabilities
From surface-mount components to connectors, cables and enclosures, the assembly route depends on what your product needs. Share the board layout and component list so we can review package compatibility, assembly access and any special handling before production.
SMT and BGA Assembly
Surface-mount technology (SMT) places components onto solder-paste deposits before reflow soldering. GreatPCB supports single- and double-sided SMT assembly, including BGA and other fine-pitch packages.
For BGA devices, the review also considers the land pattern, nearby components, thermal requirements and inspection access. Hidden joints need an inspection approach suited to the package; a visible surface check alone cannot assess them.
See our SMT capabilities and BGA assembly services for more detail.
Through-Hole and Mixed Assembly
Through-hole assembly is used for components with leads inserted through the PCB, such as many connectors, transformers and larger power components. Mixed assembly combines these parts with surface-mount devices on the same board.
Soldering methods depend on component access, thermal limits and the surrounding layout. Identify parts with special mounting, lead-forming or temperature requirements in the assembly drawing so they can be included in the process review.
Flex, Rigid-Flex and Product Assembly
Flexible and rigid-flex boards require attention to support, handling and component placement near flexible sections. Provide the assembled shape, stiffener details and any bend restrictions alongside the fabrication data.
For products that extend beyond the PCB, GreatPCB also offers cable and enclosure integration through box-build assembly. Mechanical drawings and connection instructions help define where board assembly ends and product assembly begins.
| Assembly requirement | Service scope | Information to review |
|---|---|---|
| Surface-mount components | Single- or double-sided SMT, including BGA packages | BOM, placement data, package details and thermal restrictions |
| Through-hole components | Leaded component insertion and soldering; mixed SMT/THT builds | Assembly drawing, mounting details and soldering access |
| Flexible boards | Flex and rigid-flex assembly | Board support, stiffeners, assembled geometry and handling limits |
| Product integration | Programming, cables, enclosure assembly and specified testing | Firmware, wiring and mechanical drawings, test instructions |
Turnkey and Consigned Assembly
Choose the material arrangement around the parts you already have and the purchasing work you want GreatPCB to handle. The project review establishes who supplies the bare boards and each BOM item before procurement or assembly begins.
Full Turnkey
With full turnkey assembly, GreatPCB coordinates PCB fabrication, component sourcing and assembly within the agreed scope. You provide the released design files, purchasing requirements and approvals. This gives you one project contact for the board and its assembly materials.
Partial Turnkey
Partial turnkey combines selected customer-supplied parts with components sourced by GreatPCB. It can suit projects where you already hold critical devices or need to retain purchasing control over particular items.
Mark the supply responsibility for each BOM line. A part listed twice, or left without an owner, can create unnecessary purchasing and scheduling problems.
Consigned Assembly
For a customer-supplied kit, review board and component acceptance before shipping. Provide a packing list that matches the BOM, component quantities and packaging details. Include the handling history of opened moisture-sensitive parts where applicable.
| Arrangement | Bare boards | Components | Customer preparation |
|---|---|---|---|
| Full turnkey | GreatPCB supplies within the agreed fabrication scope | GreatPCB sources agreed BOM items | Release files and approve purchasing requirements |
| Partial turnkey | Supply responsibility agreed for the project | Split between GreatPCB and customer | Identify who supplies each item and confirm arrival dates |
| Consigned | Customer supply, subject to acceptance review | Customer supply, subject to kit review | Provide a complete packing list, suitable packaging and agreed spare quantities |
Our component sourcing service covers BOM review and purchasing coordination. Specify manufacturer part numbers, do-not-populate positions and any approved alternatives. Similar packaging or a matching nominal value alone does not establish that a substitute is suitable for your circuit.
From Prototype to Production
Each build stage answers a different question. A prototype checks the design; a pilot build checks how it will be manufactured; repeat production follows the approved materials and process.
Prototype assembly
Establish the correct revision, resolve assembly questions and define the checks needed for design evaluation. Agree whether a first article needs customer approval before the remaining boards are assembled.
Pilot and low-volume assembly
Use the build to identify recurring assembly or test issues, confirm work instructions and prepare fixtures where needed. Record the changes before increasing quantities. Our low-volume PCB assembly service supports this transition.
Repeat production
Build against the approved BOM, fabrication files, assembly instructions and test requirements. When a revision changes, identify its effective build and review the effect on purchased parts and work already in progress.
For quick-turn PCB assembly, share the required delivery date early. Feasibility depends on usable material availability, file approval, production scheduling and the testing scope; placement time is only one part of the schedule.
PCB Assembly Process
The following sequence shows the main stages. Double-sided boards and mixed assemblies may require additional passes, while programming, cleaning and coating are included according to the project plan.
1. File Review and Material Preparation
Review the PCB data, BOM, placement file and assembly drawing together. Resolve mismatched reference designators, unclear polarity and component substitutions before releasing the build. Material preparation also checks the supplied quantities, packaging and applicable handling requirements.
2. Solder Paste Printing and SMT Placement
A stencil deposits solder paste on the required pads. Solder paste inspection (SPI), where specified, checks the deposits before components obscure them. Placement equipment then positions the surface-mount parts using the approved program and component data.
3. Reflow Soldering
The populated board passes through a controlled heating and cooling cycle to form the SMT solder joints. Profile development accounts for the solder paste, component limits and the board’s thermal response. An oven setting alone does not establish the temperatures experienced across an assembly.
4. Through-Hole Assembly
Leaded components are inserted and soldered using a suitable method. Wave soldering forms joints as the underside of the board contacts a wave of molten solder; it is a different process from reflow soldering. Board layout, nearby SMT components and heat-sensitive parts affect the method and any protection required.
5. Inspection and Project-Specific Testing
Inspect the assembly at the agreed stages and carry out the specified electrical or functional checks. Optical inspection, X-ray and electrical testing address different questions, as shown below. Where programming is included, use the approved firmware version and programming settings.
6. Coating and Final Preparation
If conformal coating is required, define the material, coverage and keep-out areas before processing. Surface preparation must suit the assembly and coating system. Connectors, contacts and other excluded areas need protection according to the drawing. Complete the agreed final checks and packaging before shipment.
Inspection and Testing
GreatPCB’s published assembly processes include SPI, AOI and X-ray, alongside electrical and functional testing options. The inspection and test plan should identify what needs checking, the acceptance criteria and any records required with delivery.
Process and Solder Joint Inspection
SPI assesses solder-paste deposits. Automated optical inspection (AOI) examines visible component and solder-joint features covered by its program. X-ray can assess suitable hidden solder structures, including joints beneath BGA packages.
These methods complement one another. X-ray interpretation depends on the package, viewing geometry and inspection conditions; an image does not establish that firmware, interfaces or every electrical function work correctly.
Electrical and Functional Testing
Electrical testing checks the connections or parameters included in the test program. Functional testing operates the assembly under defined conditions and compares the response with specified pass/fail limits.
| Method | Main purpose | Requirements and limits |
|---|---|---|
| SPI | Assess solder-paste position and deposit geometry | Uses the printing requirements; does not verify the final reflowed joint |
| AOI | Identify covered, visible placement and soldering anomalies | Depends on visibility and programming; cannot directly inspect all hidden joints |
| X-ray | Examine suitable hidden solder structures | Needs defined inspection locations and criteria; does not replace functional testing |
| ICT or flying probe | Check accessible electrical connections or component parameters | Requires suitable test access and test data; method and coverage need review |
| Functional testing | Verify specified board behavior | Requires operating conditions, firmware where applicable, expected results and pass/fail limits |
For functional testing, provide the required power sources, loads, interface connections and test sequence. Identify any fixtures or software you will supply. Environmental or life testing requires a separate specification; passing an assembly test does not establish untested long-term reliability.
You can also view our PCB assembly factory for further manufacturing information.
Files for PCB Assembly
Start with the Gerber files, BOM and quantity for an initial review. Before production, the documents need to describe the same approved revision and include the instructions required for the work you are ordering.
| File or requirement | What to include |
|---|---|
| PCB fabrication data | Gerber and drill files, fabrication drawing, stackup, material, copper and finish requirements when board fabrication is included |
| Bill of materials | Manufacturer and part number, reference designators, quantity per board, DNP positions and substitution restrictions |
| Placement file / CPL | Reference designator, X/Y position, rotation, board side and coordinate convention |
| Assembly drawing | Component orientation, polarity, special mounting, mechanical constraints and instructions not clear from placement data |
| Build information | Quantity, revision, requested date, material supply responsibilities and first-article approval requirements |
| Programming files, if required | Device part number, approved firmware version, file format, programming settings and verification instructions |
| Test requirements | Test procedure, operating conditions, equipment or fixture needs, pass/fail limits and required records |
| Additional operations | Coating areas and exclusions, cable drawings, enclosure details, labels and packaging instructions as applicable |
For IC programming, identify any configuration, security or locking settings that affect programming and verification. These instructions need review before the build, especially where a setting cannot be reversed.
Discuss Your PCB Assembly Project
Send your files and tell us which materials you will supply. GreatPCB can review the assembly requirements, identify outstanding questions and discuss a production plan with you.