SMT Assembly Sourcing & Quality from China

4 resources tagged with "Smt"

SMT (surface-mount technology) is the core of PCB assembly in China — solder paste printing, pick-and-place, reflow, and inspection — and each stage has a defect mode you should know before auditing a line. IPC-A-610 defines the acceptance criteria, with Class 2 the default for consumer and commercial electronics and Class 3 reserved for high-reliability work; the difference shows up in things like allowed BGA void percentage and solder fillet requirements. The mistake buyers make is not specifying the IPC class in the PO, then disputing solder-joint quality against a standard the factory never agreed to build to.

SMT is the automated process that places and solders surface-mount components onto a PCB. When sourcing it from China, we specify the IPC-A-610 class up front, verify stencil and DFM rules, and inspect the reflow and AOI stages, since most field failures trace back to a paste or placement defect that proper inspection catches.

Guides (1)

PCB Assembly in China: Buyer's Guide

How to source PCB assembly from China — choosing factories, reading Gerbers, understanding IPC standards, and running quality inspection.

Wiki (3)

DFM for PCB: Design for Manufacturability Reference

PCB DFM rules for China manufacturing: trace spacing, via sizing, component clearances, stencil aperture ratios, fiducials, and test point layout.

IPC-A-610: Acceptability of Electronic Assemblies Reference

IPC-A-610H for electronics from China: Class 1/2/3 quality levels, BGA void limits, common SMT defect categories, and how to specify class in POs.

SMT PCB Assembly: Technical Reference for Buyers

SMT assembly for China-sourced PCBAs: solder paste printing, pick-and-place, reflow, and inspection stages — essential before auditing a Chinese factory.

FAQ

What IPC-A-610 class should I specify for SMT assembly?

Class 2 is the standard for most consumer and commercial electronics. Class 3 (high-reliability, e.g. medical, aerospace) has stricter limits on voids and solder fillets and costs more. State the class in the PO — otherwise you have no agreed acceptance criteria.

What are the main stages of SMT assembly to inspect?

Solder paste printing, pick-and-place, reflow soldering, and inspection (AOI and often X-ray for BGAs). Most defects originate at paste printing and placement, so those plus AOI/X-ray coverage are what to check during a factory audit.

What's the most common SMT defect from low-cost factories?

Solder issues — bridging, insufficient solder, tombstoning, and BGA voids beyond IPC limits — usually from poor paste printing or an uncontrolled reflow profile. Specifying IPC-A-610 Class 2 and requiring AOI/X-ray data catches most of them.

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