Automation requires stable processes and clearly defined data
SMT assembly from prototype to series production
– with early project planning, reproducible process control, and integrated quality assurance.
Anyone developing an electronic assembly cannot avoid surface mount technology (SMT). And for a good reason: SMT assembly is the most cost-effective method for manufacturing printed circuit board assemblies (PCBAs).
In SMT, components are mounted directly onto the pads of the printed circuit board (PCB). Supplied on reels in feeders, the components are picked up by high-speed placement machines and precisely positioned on the board. The assembly then passes through reflow soldering. The key is not only speed but, above all, reproducibility: from prototype to series production, each assembly is manufactured using the same defined process parameters.
For context: modern placement machines can typically achieve placement accuracies of ±30 µm (3 sigma) and process components as small as 01005 packages; this corresponds to passive components with a footprint of 0.4 × 0.2 mm. Fine-pitch components with pitches below 0.4 mm and very small passive components place particular demands on solder paste deposition and reflow profiles. These must be defined and documented on a project-specific basis.
Surface mount devices as the preferred approach—and where the decision starts
Electronics manufacturing services at the highest level: Manual quality inspection and assembly of PIR sensor modules in our ESD-protected electronics manufacturing facility.
In practice, it is not a question of “SMT or THT?” but rather “Can this assembly be implemented entirely or predominantly with SMT?”
The objective is always to implement as much as possible using surface mount technology because of its cost efficiency, suitability for automation, and stable process control.
Through-hole technology (THT) or through-hole reflow (THR) are used only when surface mount device (SMD) versions are unavailable, when power requirements or component form factors necessitate them, or when mechanical stresses demand a different type of connection.
Through-hole reflow components have shortened leads, are inserted into prepared paste-filled holes, and are soldered during the reflow process. They combine the advantages of both technologies and provide an option for implementing through-hole assembly within the SMT process in mixed-technology assemblies.
For THR to work, the hole diameter must exceed the lead diameter by at least 0.2–0.25 mm. This is the minimum value defined in IPC-2221 to ensure that sufficient solder paste can flow into the hole and form a reliable connection. Where component geometry permits, THR eliminates a separate THT soldering process and can thus greatly simplify manufacturing logistics.
What makes EPnP stand out
Many problems in SMD manufacturing do not originate on the production line but rather during product development or as a result of inadequate control and documentation of component or revision changes.
EPnP therefore starts earlier in the process: during the structured project definition phase before the production line.
Drawing on our experience in electronics development, we successfully combine both disciplines. We develop products with a focus on manufacturability and cost efficiency. Before production begins, we review all data in detail based on our practical experience.
Project review and data validation before production
Before assembly, we systematically review feasibility, production data, and specifications.
Design for manufacturing (DFM) ensures that assembly requirements, process windows, and test concepts are aligned to balance effort, cost, and quality.
Process chain with a clear logic
Applying solder paste, placing components, performing reflow soldering, and conducting optical inspection are all well-established steps.
The key is to match them to the specific layout and component mix. Only then can the process window remain stable and the results reproducible.
Quality assurance as an integral part of the process
At EPnP, testing is not a downstream step but rather an integral part of manufacturing logistics. Especially in regulated sectors such as medical devices, aerospace, and vehicle manufacturing, test concepts are defined according to the application, approvals are documented, and traceability is ensured.
Supply chain and lifecycle considerations built in
Surface mount technology assembly is highly dependent on component availability. EPnP evaluates alternatives, second sources, and PCN strategies at an early stage so that supply bottlenecks are minimized and lifecycle changes remain manageable.
Mixed assembly as part of the overall concept
Many assemblies combine SMT and THT. For SMT, this means that PCB layout, process sequence, double-sided assembly, and soldering strategy must be coordinated to ensure that clearances, protection concepts, and the test strategy are aligned.
From prototype to series production
Surface mount technology assembly can accommodate a wide range of production volumes.
The transition from prototype to series production depends not on production volume but rather on data quality, a manufacturable layout, and a robust test concept designed to prevent unnecessary iterations.
FAQ
EPnP covers the entire EMS process chain: SMD/SMT assembly, THT, wave and selective soldering, mixed-technology assembly, reflow soldering, conformal coating or potting as required, and functional and end-of-line testing, including custom test setups. This enables assemblies to be produced from prototype to series production with clearly defined process control.
EPnP provides design for manufacturing (DFM) recommendations on PCB layout, footprints, and component selection as well as design for test (DFT) guidance on test points, boundary scan, and test concepts. The goal is an assembly that can be manufactured reliably, reproducibly, and cost-effectively.
For an accurate quotation, EPnP ideally requires: a bill of materials (BOM) with part numbers, manufacturer information, and specifications, design and manufacturing data such as Gerber, ODB++, or IPC-2581 files, placement data, schematics, and information on the test strategy, production volumes, and forecast. The more complete the data, the more accurately manufacturability, effort, and costs can be assessed.
Direct data upload via our inquiry portal:
faster quotations, automated data verification, transparent communication, and secure data exchange (GDPR-compliant, encrypted, and hosted on servers in Germany).