Unlock High Difficulty PCBs

PCBMASTER Decodes PCBA Processing Terminology Unlocking the Knowledge Treasure of Electronics Manufacturing


Author: Jack Wang


In the field of electronics manufacturing, PCBA processing is a critical stage involving numerous technical terms. A deep understanding of these terms not only enhances communication among professionals and ensures precise control over production processes but also lays a solid foundation for related work. Below is a systematic guide to the common terminology in PCBA processing.

 

 

 

1. PCBA (Printed Circuit Board Assembly)

The complete process of assembling a printed circuit board. It begins with SMT (Surface Mount Technology) to place miniature components onto the PCB, followed by DIP (Dual In-line Package) insertion for pin-through-hole components. Subsequent steps include functional testing to verify circuit performance and final assembly to create a fully operational circuit board module. These interconnected steps directly determine the final product’s quality and reliability.

 



2. PCB (Printed Circuit Board)

The core structural component of electronic devices. Classified by layer count:

Single-layer: Circuits on one side, ideal for simple designs.

Double-layer: Circuits on both sides for more complex connections.

Multilayer: Multiple conductive layers for high-performance applications.
Common materials include FR-4, resin, glass fiber, and aluminum substrates, each with distinct advantages in electrical performance, mechanical strength, and thermal management.

 



3. Gerber Files

A set of standardized documents detailing PCB design data, including copper layers, solder mask, silkscreen, and drilling/routing information. Submitting Gerber files to manufacturers ensures accurate quoting and production planning.

 



4. BOM (Bill of Materials)

A comprehensive list of all components required for PCBA production. It specifies part numbers, quantities, and critical parameters, serving as the foundation for cost estimation, procurement, and process control.

 



5. SMT (Surface Mount Technology)

A core PCBA process involving:

Solder Paste Printing: Transferring solder paste through a stencil onto PCB pads.

Component Placement: High-precision machines position miniature components.

Reflow Soldering: Heating to melt solder paste, forming reliable electrical connections.




6. Solder Paste Printing

A process where solder paste is spread over a stencil and transferred to PCB pads. Consistency in paste thickness (typically 80–150 μm) directly impacts soldering quality.

 



7. SPI (Solder Paste Inspection)

A quality control system that measures solder paste volume, height, and distribution using 3D scanning. Detects defects like insufficient paste or bridging, ensuring optimal printing results.

 



8. Reflow Soldering

PCB boards pass through a reflow oven with controlled temperature zones (preheat, soak, reflow, cooling). Proper temperature profiling prevents defects like cold joints or component damage.




9. AOI (Automated Optical Inspection)

Uses cameras and AI algorithms to detect soldering defects such as missing components, misalignment, shorts, or opens. Improves defect detection rates by over 95% compared to manual checks.




10. Rework

Repairing defective boards identified by AOI or manual inspection. Techniques include solder touch-up, component replacement, or localized reflow.




11. DIP (Dual In-line Package)

A through-hole technology for components with leads. Steps include insertion, wave soldering, lead trimming, touch-up, and cleaning. Ideal for high-power or mechanically stressed components.




12. Wave Soldering

PCBs pass over a molten solder wave to solder DIP components. Key stages:

Flux Spraying: Removes oxides.

Preheating: Prevents thermal shock.

Soldering: Forms connections.

Cooling: Solidifies solder joints.




13. Lead Trimming

Cutting excess component leads post-soldering to prevent short circuits and ensure a clean appearance.




14. Touch-Up Soldering

Manual repair of incomplete solder joints using soldering irons or hot air tools to meet IPC-A-610 standards.




15. Board Cleaning

Removes flux residues, ionic contaminants, or debris using solvents or ultrasonic cleaners. Critical for high-reliability applications (e.g., medical or aerospace).




16. Conformal Coating

A protective layer (acrylic, silicone, or urethane) applied to PCBA to resist moisture, dust, vibration, and corrosion. Enhances lifespan in harsh environments.



 

17. Pad

A metalized area on a PCB where components are soldered. Pads ensure electrical connectivity and mechanical stability.




18. Component Packaging

DIP: Through-hole components with high mechanical strength.

SMD (Surface Mount Device): Compact components for high-density designs.




19. Pin Pitch

The distance between adjacent component leads. Smaller pitches (e.g., 0.4 mm for QFNs) demand higher placement accuracy.




20. QFP (Quad Flat Package)

A surface-mount IC with leads on all four sides. Common in high-pin-count applications.




21. BGA (Ball Grid Array)

A high-density package with solder balls arranged in a grid. Offers superior thermal and electrical performance for CPUs, GPUs, and FPGAs.




22. QA (Quality Assurance)

Ensures compliance with standards through material inspections, process audits, and final product testing.




23: Common Soldering Defects

Cold Joint: Dull, grainy solder due to insufficient heat.

Tombstoning: Component lifts due to uneven solder paste.

Solder Balls/Spatter: Excess solder causing short risks.

Missing/Misplaced Components: Caused by BOM or placement errors.




24. ICT (In-Circuit Test)

Tests electrical continuity, component values, and solder integrity via bed-of-nails probes. Identifies 95%+ defects in minutes.




25. FCT (Functional Test)

Simulates real-world operation to validate PCBA performance under load, voltage, and signal conditions.




26. Burn-In Testing

Stresses PCBAs at elevated temperatures/humidity for 48–72 hours to weed out early-life failures.




27. Vibration Testing

Assesses resilience to mechanical shocks and vibrations per MIL-STD-810 standards.

 

 



Unlock More Expertise at www.pcbmaster.com
For further insights into PCBA processing, material selection, or DFM guidelines, contact PCBMASTER’s engineering team. Elevate your electronics manufacturing knowledge today!

 

 

 

Note: Terms and processes align with IPC-A-610, J-STD-001, and ISO 9001 standards.

 Author: Jack Wang

Finished reading
Contact Us
How to order