CIT Requirements for Soldered Electrical and Electronic Assemblies 3

Question 1

Under IPC J-STD-001, which class of product has the MOST stringent soldering requirements?

Accepted Answer

Class 3 (High Reliability Electronics)

Answer

Class 3 (High Reliability Electronics) has the most stringent requirements, covering equipment where continued performance is critical and downtime cannot be tolerated.

Question 2

What is the maximum allowable solder ball diameter per IPC J-STD-001 for Class 2 assemblies?

Accepted Answer

0.25 mm (0.010 in)

Answer

For Class 2 assemblies, solder balls must not exceed 0.13 mm (0.005 in) in diameter to be acceptable per IPC J-STD-001.

Question 3

In IPC J-STD-001, 'dewetting' is defined as a condition where:

Accepted Answer

Solder initially wets the surface but then recedes, leaving an irregular mounded appearance

Answer

Dewetting occurs when molten solder coats a surface and then pulls back, leaving irregular mounds of solder with base metal exposed between them.

Question 4

What is the primary purpose of activated flux in the soldering process?

Accepted Answer

To remove oxides from metal surfaces to allow proper wetting

Answer

Activated flux chemically removes oxide layers from metal surfaces, enabling the molten solder to wet and bond properly to the base metal.

Question 5

Per IPC J-STD-001, a solder bridge between two conductors that are supposed to be electrically isolated is classified as:

Accepted Answer

A defect for all product classes

Answer

A solder bridge between isolated conductors is a defect for all product classes (1, 2, and 3) because it creates an unintended electrical short circuit.

(CIT) Certified IPC Trainer Practice Test

(CIT) Certified IPC Trainer Practice Test

CIT Requirements for Soldered Electrical and Electronic Assemblies 3