CIS CIS Acceptability Criteria & Defect Recognition 3

Question 1

What does 'non-wetting' mean in solder joint evaluation?

Accepted Answer

A condition where molten solder fails to adhere to a base metal surface

Answer

Non-wetting is the failure of molten solder to bond to the base metal surface, typically caused by contamination, oxidation, or inadequate flux.

Question 2

For IPC-A-610 Class 3, what is the acceptability status of a pinhole or blowhole in a solder joint?

Accepted Answer

Defect

Answer

Pinholes and blowholes in solder joints are defects for Class 3 assemblies because they indicate voiding and potential joint weakness.

Question 3

According to IPC-A-610, what is the minimum acceptable side overhang for a rectangular SMT chip component on a Class 2 assembly?

Accepted Answer

Up to 25% of the land width

Answer

For Class 2, side overhang is acceptable up to 25% of the applicable land width or component end cap width, whichever is less.

Question 4

What is a 'measling' defect on a printed circuit board?

Accepted Answer

White spots or crosses below the surface of the base laminate caused by separation of glass fibers from the resin

Answer

Measling appears as white spots or crosses beneath the laminate surface, caused by the separation of glass fibers from the resin binder, typically from thermal or mechanical stress.

Question 5

IPC-A-610 defines 'minimum electrical clearance' violations as:

Accepted Answer

Defects for all classes

Answer

Any violation of minimum electrical clearance between conductors is a defect for all IPC classes because it creates a risk of arcing, shorts, or dielectric breakdown.

(CIS) Certified IPC Specialist Practice Test

(CIS) Certified IPC Specialist Practice Test

CIS CIS Acceptability Criteria & Defect Recognition 3