Introduction: A turnkey PCBA order runs from engineering review and BOM sourcing through bare board fabrication, SMT assembly, and final test, with one supplier owning the result.
When procurement teams split a build across a board shop, a component distributor, and an SMT house, every handoff creates risk: files get rechecked, schedules have no single owner, and one shortage can stall a launch. Turnkey pcb assembly services close those gaps by placing fabrication, sourcing, stencil, assembly, and test under one roof. The order flow moves from engineering review to final test, and each stage shows where responsibility sits, what the manufacturer needs from you, and how to judge whether a supplier can carry the full build.
Every turnkey order starts with files, and the quality of the first review shapes the rest of the project. Before quoting, a PCB assembly manufacturer needs Gerber data, a BOM with manufacturer part numbers, and the quantity and test scope you expect. Engineering then checks layer count and stackup, minimum trace width and spacing, drill sizes, and whether the selected surface finish fits the assembly process. These checks follow IPC-A-600, IPC-6012, and IPC-2221 practice, giving both sides a shared reference for a conforming board and its process window. If the first build is a pcb prototype service, the same file review still applies; prototype status changes the schedule and quantity, not the need for complete data. The BOM gets stress-tested at this stage. Engineering looks for obsolete parts, missing MPNs, ambiguous package footprints, and components whose land patterns do not match the datasheet. A line item marked "or equivalent" often causes delay because the substitute may have a different pin pitch or thermal profile. Catching these issues before fabrication avoids a second round of tooling and a lost week. The same review confirms whether the board can hit your impedance target, whether the stackup supports your routing density, and whether the assembly line needs test points the current layout does not yet provide. A fast, complete answer keeps the project on schedule; a slow reply quietly pushes the launch.
Bare boards coming off the fabrication line are not finished products. Between final electrical test on the panel and the first component placed, several decisions determine whether the assembly run is smooth or full of rework. Most of them are settled before the machine starts.
Stencil design looks simple from the outside, but it controls how much paste lands on each pad. A laser-cut stencil with the right aperture ratio deposits consistent paste volumes, and that consistency keeps solder joints uniform across thousands of placements. IEC 61188-1-2 describes how component attachment and solder joint geometry behave in surface mount designs, so aperture size, stencil thickness, and pad dimensions need to be matched rather than estimated. When the stencil is wrong, defects appear quickly: bridging on fine-pitch parts, insufficient solder on thermal pads, or tombstoning on small passives. Settling paste type and stencil design before printing starts, especially for the lead-free processes most electronics now require, takes one variable out of the run.
Kitting is where a turnkey order earns its name. Instead of shipping partial reels to a separate assembler, the manufacturer pulls the full BOM, consolidates line items, and releases a complete kit to the SMT line. Getting that right depends on market conditions: component lead times move with supply and demand, and a part quoted at two weeks in January may run eight weeks in June. A supplier that tracks incoming material and flags shortages early gives you time to approve a substitute or adjust the build plan instead of discovering the gap on the line. Compliance rides along with sourcing as well. The EU RoHS directive restricts what can go onto the board, and documents such as RoHS, REACH, UL, or IATF16949 are provided by project need rather than issued automatically with every order. Maxipcb runs this stage through an ERP tracking system and a supplier base that includes Isola, Panasonic, Rogers, and Sheng Yi, so material status stays visible from purchase order to kit release. For the buyer, custom pcb assembly depends on those sourcing choices as much as on the SMT program.
Once boards are populated, the question shifts from "can you build it" to "how do I know it is right." Inspection starts with AOI, which catches missing parts, reversed polarity, and solder defects across the panel. X-Ray covers joints AOI cannot see — BGA, QFN, and anything with a hidden pad underneath. For boards with a functional requirement, ICT checks electrical continuity and resistance against the netlist, while FCT runs the board through conditions close to its real application. When a project calls for it, inspection can run to IPC Class III criteria, and the acceptance level is best agreed before the run rather than debated afterward. Delivery tracking is the other half of trust. A manufacturer running an ERP system can show where an order sits at any point: material received, boards in fabrication, kit released, assembly in progress, test complete. That visibility answers the question your own management will ask first: when does the order ship? A published on-time delivery rate above 95% tells you something about how the shop schedules work, but your internal milestones should still be tied to the date quoted for your specific build. Good pcb solutions connect those test results back to the build record, so the documentation you receive matches the boards you receive. Maxipcb produces this flow across a 23,000 m² factory with a 280-person team, and AOI, X-Ray, ICT, and FCT can be selected per project rather than assumed.
A turnkey PCBA order is really a question about ownership. When one manufacturer handles engineering review, bare board fabrication, component sourcing, laser stencil, SMT assembly, and testing, handoff risk drops and the schedule has a single owner. The tradeoff is that the quote depends on complete files — Gerber, BOM, quantity, and test scope — because assembly price and lead time both move with those inputs. Before committing, send the full package for review, ask which parts are in stock versus ordered, and confirm the test plan, documentation, and inspection class your project needs. That conversation takes far less time than fixing a build that was quoted from partial information.
A: Gerber files, a BOM with manufacturer part numbers and quantities, and a clear test scope cover the basics. The manufacturer also needs target quantity, surface finish, inspection class, and whether you need full or partial assembly. With those files, engineering can review stackup, footprint matching, and part availability, then return a real price and lead time instead of a rough estimate.
A: Yes, when fabrication and assembly run under the same roof. Maxipcb covers bare board fabrication, component sourcing, laser stencil, SMT assembly, and AOI/X-Ray/ICT/FCT testing options as one turnkey flow, so you get one schedule and one point of responsibility. Component lead time still follows market supply, so confirm stock and delivery against your specific BOM before the build starts.
A: Start with a clean BOM: one row per part, full manufacturer part number, package, and quantity per board. Note any approved alternates and mark parts that need traceable sourcing. For testing, state whether you need AOI and X-Ray only, or in-circuit and functional test as well, and describe what the board should do when powered. Those details let the manufacturer quote assembly scope accurately the first time.
WORKMANSHIP STANDARD FOR SURFACE MOUNT TECHNOLOGY
RoHS Directive - Environment - European Commission
