CIS Conformal Coating & Encapsulation 3

Question 1

What is the fundamental difference between conformal coating and encapsulation?

Accepted Answer

Conformal coating is a thin protective film that follows assembly contours; encapsulation fully embeds components in a resin mass

Answer

Conformal coating uses UV curing; encapsulation uses thermal curing

Answer

Conformal coating applies only to connectors; encapsulation applies to active components only

Answer

There is no meaningful difference; the terms are used interchangeably

Question 2

Which IPC standard specifically addresses the qualification and performance requirements for conformal coating materials?

Accepted Answer

IPC-CC-830

Answer

IPC-A-610

Answer

J-STD-001

Answer

IPC-7711/7721

Question 3

Which conformal coating type is designated 'XR' in IPC-CC-830 and is applied through a chemical vapor deposition (CVD) process?

Accepted Answer

Paraxylylene (Parylene)

Answer

Acrylic Resin

Answer

Xylene-based Resin

Answer

Cross-linked Rubber

Question 4

Bubbles or voids in a conformal coating are classified as defects under which condition?

Accepted Answer

When they expose conductors, create pinholes, or appear as lifting bridges across conductors

Answer

Any bubble or void is always acceptable

Answer

Only when the assembly is Class 3

Answer

Only when more than 10 bubbles are present per square inch

Question 5

In the context of conformal coating materials, what is 'pot life'?

Accepted Answer

The working time a mixed or catalyzed coating material remains usable before beginning to cure

Answer

The total time the cured coating remains effective in service

Answer

The shelf life of the unopened coating container

Answer

The total time required for a coating to fully cure at room temperature

Question 6

Per IPC-A-610, what governs whether conformal coating is required and which areas must be coated on a given assembly?

Accepted Answer

The engineering documentation and applicable drawings for that assembly

Answer

The coating applicator's discretion based on visual inspection

Answer

The IPC class of the assembly alone (Class 1, 2, or 3)

Answer

The type of conformal coating material selected

Question 7

Which conformal coating designation in IPC standards corresponds to Urethane Resin?

Accepted Answer

UR

Answer

AR

Answer

SR

Answer

XR