Quality Control & Inspection Procedures 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 Quality Control & Inspection Procedures flashcards as text
An inspector observes a solder bridge between two adjacent SMD pads on a Class 2 assembly. Which of the following best describes the disposition?
Answer: Defect — requires rework or rejection
Solder bridges between conductors that should not be electrically connected are unconditional defects under IPC-A-610 for all product classes.
What is the purpose of a control chart in a PCB assembly quality system?
Answer: To track process variation over time and detect out-of-control conditions
Control charts (SPC tools) monitor process metrics over time, enabling detection of trends or special-cause variation before defects are produced.
Per IPC-A-610, which condition is allowed for a Class 1 product but not for Class 3 regarding chip component solder joints?
Answer: End-cap solder coverage extending only onto the bottom face
For Class 1, solder restricted to only the bottom (land) face of a chip component termination may be acceptable, whereas Class 3 requires solder on the end cap for maximum mechanical strength.
When performing solderability testing per J-STD-003, what does the wetting balance test measure?
Answer: The force exerted on a component lead as it is immersed in molten solder
The wetting balance (Meniscograph) test measures the time-force curve as a lead is immersed in solder, quantifying the speed and degree of solder wetting.
A CIS inspector observes a through-hole lead that extends 0.5 mm beyond the secondary side of the board on a Class 3 assembly. Per IPC-A-610, this is:
Answer: A defect — lead protrusion is below the minimum
IPC-A-610 Class 3 requires a minimum lead protrusion of 0.5 mm (some versions specify slightly higher), so 0.5 mm is at the borderline — verify against the current revision, but insufficient protrusion is a defect.
What does the term 'Cpk' represent in a PCB assembly quality control context?
Answer: A process capability index accounting for both spread and centering relative to spec limits
Cpk measures process capability by comparing the process spread to the specification limits while also accounting for how centered the process is between those limits.
Which of the following is an example of a destructive inspection technique used in PCB quality assurance?
Answer: Cross-sectioning a solder joint for metallographic analysis
Cross-sectioning (microsectioning) requires cutting and polishing a sample, permanently destroying the board, but reveals internal joint quality, barrel fill, and intermetallic layers.