Electronic Assembly & Manufacturing Processes Flashcards
7 cards from real CIS practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Electronic Assembly & Manufacturing Processes flashcards as text
What is the primary difference between Class 1 and Class 2 electronic assemblies per IPC-A-610?
Answer: Class 1 is general electronics with limited life expectancy; Class 2 requires extended reliable service
Class 1 covers general electronics where cosmetic imperfections are acceptable, while Class 2 requires extended service life and reliable performance in typical environments.
What causes 'cold solder joints' during hand soldering?
Answer: Insufficient heat or movement during solidification
Cold solder joints result from inadequate heat transfer or disturbing the joint before it fully solidifies, producing a grainy, dull appearance and weak bond.
In SMT stencil printing, what is the 'area ratio' rule used to determine?
Answer: Whether an aperture will release solder paste cleanly from the stencil
The area ratio (aperture opening area divided by aperture wall area) predicts paste release; a ratio above 0.66 generally ensures clean release.
What is the function of the 'dross skimmer' in a wave solder machine?
Answer: Remove oxidized solder from the surface of the solder bath
The dross skimmer removes the layer of oxidized solder (dross) that forms on the molten solder bath surface to maintain solder quality.
Which IPC document provides design requirements for printed boards (PCB fabrication)?
Answer: IPC-2221
IPC-2221 is the Generic Standard on Printed Board Design, defining requirements for PCB design including materials, electrical, thermal, and mechanical criteria.
What is 'pad cratering' in PCB assemblies?
Answer: Fracture within the PCB laminate beneath a surface pad
Pad cratering is a fracture in the PCB laminate directly below the copper pad, often caused by mechanical stress during assembly or testing.
What does 'wetting' mean in the context of soldering?
Answer: The formation of a smooth, continuous, adherent solder fillet on the base metal
Wetting is the ability of molten solder to flow and bond metallurgically to a base metal surface, forming a smooth adherent fillet when properly achieved.