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

Solder that has exceeded its wetting angle limit

Answer

A joint where too much solder has been applied

Answer

Solder that has been reflowed more than once

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

Acceptable if only one per joint

Answer

Process indicator

Answer

Acceptable if the hole diameter is less than 0.5 mm

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

The component must not overhang at all

Answer

Up to 25% of the component width or 0.5 mm, whichever is less

Answer

Up to 50% of the land width

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

Delamination between copper layers and the substrate

Answer

Surface contamination causing solder non-wetting

Answer

Micro-cracks in the solder mask coating

Question 5

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

Accepted Answer

Defects for all classes

Answer

Process indicators requiring documentation only

Answer

Defects for Class 2 and Class 3 only

Answer

Acceptable if no functional failure is detected

Question 6

What is the correct interpretation of a 'target condition' in IPC-A-610?

Accepted Answer

The ideal, preferred condition showing a high degree of workmanship

Answer

The minimum acceptable condition for product acceptance

Answer

The marginal condition that triggers a process review

Answer

The condition requiring mandatory rework