The electronics manufacturing world runs on acronyms, tribal knowledge, and nuanced supply chain language. This glossary isn't just a list - it's a translator for anyone building, sourcing, or managing complex assemblies. It reflects how real work gets done on the production floor and in the planning room.
Whether you're a buyer, engineer, or program manager, or OEM startup founder, understanding common PCB assembly terms can help you:
This glossary combines commonly searched electronics terms, SMT-specific language, and high-value keyword phrases like SMT process, PCB manufacturing terms, and how to read a BOM to ensure both clarity and search engine visibility.
PCB (Printed Circuit Board): The rigid or flexible platform that connects and supports all components.
Substrate: The insulating base of a PCB, often made from fiberglass (FR4) or polyimide.
Copper Trace: The conductive path on a PCB that carrier electrical signals.
Pad: The exposed area of metal where a component is soldered.
Via: A plated hole that allows signals to pass between PCB layers.
Solder Mask: A protective green (or other colored) coating that prevents solder bridging.
Silkscreen: The white (or colored) later printed with part numbers and outlines.
Component Polarity: Refers to the direction-dependent nature of components like diodes, LEDs, and electrolytic capacitors.
Fiducial Marks: Reference points on a PCB that allow automated assembly machines to align accurately.
SMT (Surface Mount Technology): A method where components are placed directly onto the surface of the PCB.
THT (Through-Hole Technology): Components are inserted into holes and soldered on the opposite side.
Mixed Assembly: Combines SMT and THT components.
Pick and Place Machine: Automated equipment that places components with speed and precision.
Stencil: A laser-cut sheet used to apply solder paste onto pads.
Reflow Soldering: Melts solder paste in a controlled oven to form permanent joints.
Wave Soldering: Commonly used for THT; boards pass over molten solder.
Desoldering: The process of removing solder to replace or reposition components.
Jumper: A wire or bridge used to connect or bypass certain pads or signals.
AOI (Automated Optical Inspection): Uses cameras to scan boards for missing, skewed, or incorrectly placed components.
X-Ray Inspection: Used for hidden joints like BGAs (Ball Grid Arrays).
ICT (In-Circuit Test): Probes components electrically while they're still on the board.
Functional Test: Simulates real-world operation to ensure the board works as intended.
Test Fixture: Hardware used during ICT or functional testing.
ESD (Electrostatic Discharge): Important for handling protocols.
BOM (Bill of Materials): A detailed list of components required for an assembly.
AML (Approved Manufacturers List): A list of approved part manufacturers tied to each BOM line item.
Alternate: A customer-approved substitute part.
Attrition: Expected loss of parts during assembly—accounted for in planning.
Authorized Distributor: A supplier with contractual rights from the manufacturer.
Broker/Non-Authorized Distributor: A supplier outside the manufacturer’s official channel—requires customer signoff.
MOQ (Minimum Order Quantity): The smallest quantity a supplier will sell.
MOV (Minimum Order Value): The smallest dollar amount a supplier will transact.
NCNR (Non-Cancelable/Non-Returnable): Once purchased, material cannot be returned or canceled.
Obsolete Inventory: Material no longer used or supported.
Aged Inventory: Stock held past its planning window—often subject to write-offs.
Allocation: When demand exceeds supply, certain components become "allocated" and have long or uncertain lead times.
Actualize: To release a planned work order to the floor for execution.
Planned Work Order: An internal forecast of what will be built—used for procurement and labor planning.
Can Build: The quantity that is fully ready for assembly based on current material status.
MRP (Material Requirements Planning): Software-driven planning for purchasing and scheduling.
NPI (New Product Introduction): A cross-functional process for validating first-time builds. At SMT, our NPI reviews ensure design intent meets manufacturing reality—before any material hits the floor.
MRR (Manufacturing Readiness Review): A formal review six weeks before a scheduled build.
DFX (Design for Excellence): Umbrella term for DFM, DFT, etc.
PPV (Purchase Price Variance): The difference between expected and actual material cost.
COO (Country of Origin): Country of origin
WIP (Work in Process): Assemblies that have been started but not completed.
NCM (Non-Conforming Material): Stock that failed inspection.
CSP (Customer Supplied Parts): Zero-cost inventory provided by the customer.
Consigned Inventory: Customer-owned inventory managed by SMT.
Obsolete, Inactive, Excess: Inventory classifications for demand planning.
Every term in this glossary reflects the reality of building electronics at scale—where clarity, timing, and execution are everything. Understanding this language is the first step toward higher reliability, faster launches, and better ROI.