CIS Conformal Coating & Encapsulation 2

Question 1

What conformal coating defect is described as small circular depressions or craters that expose the underlying substrate?

Accepted Answer

Fisheye (cratering)

Answer

Delamination

Answer

Orange peel

Answer

Blooming

Question 2

An 'orange peel' texture on a cured conformal coating surface is generally considered:

Accepted Answer

Acceptable in most cases per IPC-A-610

Answer

A defect requiring immediate rework

Answer

A target condition for all classes

Answer

Only acceptable for Class 1 assemblies

Question 3

Which condition would constitute a defect in conformal coating per IPC-A-610 for Class 2 and Class 3 assemblies?

Accepted Answer

Exposed conductors or solder connections that are required to be coated

Answer

Slight color variation across the coating

Answer

Thin coating over the tops of component bodies

Answer

A matte finish instead of a glossy surface

Question 4

When inspecting conformal coating under ultraviolet (UV) light, what does a dark or non-fluorescing area indicate?

Accepted Answer

Missing or insufficient coating coverage

Answer

Proper coating thickness has been achieved

Answer

The coating has cured correctly in that area

Answer

The coating contains no UV tracer, which is normal

Question 5

During conformal coating application, which types of features MUST typically be masked to prevent coating?

Accepted Answer

Edge connectors, test points, and adjustable components

Answer

SMT chip resistors and capacitors

Answer

Through-hole component leads

Answer

Component reference designators

Question 6

Applying conformal coating over an assembly with ionic contamination will most likely result in:

Accepted Answer

Delamination, loss of adhesion, or accelerated corrosion under the coating

Answer

Improved adhesion due to increased surface energy

Answer

Reduced coating thickness from chemical reaction

Answer

Enhanced long-term environmental protection

Question 7

Which conformal coating application method provides the most precise deposition and reduces masking requirements by applying coating only to specified areas?

Accepted Answer

Selective robotic coating system

Answer

Dip coating

Answer

Brush coating

Answer

Aerosol spray coating