IPC-CC-830B.pdf - 第12页

the conformal coating product. A change in chemistry as detected by FTIR may or may not constitute a product change. See 4.4 for the deﬁnition of product change. 3.5 Physical Requirements 3.5.1 Viscosity V iscosity of un…

3-1 are satisﬁed. Tests shall be performed in accordance

with the test methods speciﬁed using test specimens pre-

pared in compliance with 4.7 at a frequency deﬁned in

4.3.3. Pertinent results shall be compared with the results

of the original qualiﬁcation testing. An inspection report

shall be completed in accordance with 4.9 and relevant test

data retained as substantiation for the quality conformance.

An example of quality conformance inspection report is

shown in Appendix C.

Conformal coating quality conformance inspection is gen-

erally performed by the coating manufacturer, but may

with appropriate agreement be used as an incoming mate-

rial inspection procedure by the customers.

3.2.4 Additional Testing Additional testing on different

test vehicles, at different test frequency or conditions, or

for properties outside the scope of this standard may be

agreed upon between the manufacturers and the customers.

It shall not be used as a substitute for any testing require-

ment speciﬁed herein.

3.3 Materials Requirements

3.3.1 Materials

The conformal coating materials shall

be free of deleterious substances.

3.3.2 Shelf Life The conformal coating shall meet all

requirements of this standard within the shelf life and stor-

age conditions speciﬁed by the conformal coating manufac-

turer. Shelf life of coating with two or more components

shall be that of the component with the shortest shelf life.

The tests shall consist of Insulation Resistance (IR) and

Dielectric Withstanding Voltage (DWV).

3.3.3 Cure The conformal coating shall exhibit all

desired properties when applied and cured using the proce-

dures speciﬁed by the conformal coating manufacturer.

When coating materials are tested as speciﬁed, the coating

material shall be cured to full hardness in the time and

temperature recommended by the supplier.

3.4 Chemical Requirements

3.4.1 Fourier Transform Infrared Spectroscopy Test

(FTIR)

Fourier Transform Infrared Spectroscopy (FTIR)

test shall be performed in accordance with IPC-TM-650,

Test Method 2.3.42, or equivalent, as part of data gathering

for the conformal coating during qualiﬁcation inspection.

When used in qualiﬁcation retention inspection, FTIR

spectra shall be compared to those obtained during qualiﬁ-

cation inspection. Absorption peaks completely missing or

additional peaks signify change in chemistry present within

Table 3-1 Requirements for Qualiﬁcation, Qualiﬁcation Retention

and Quality Conformance of Conformal Coating Products

Paragraph Requirement Test Method

Column A Column B Column C

Qualiﬁcation

Retention of

Qualiﬁcation

Quality

Conformance

3.3.1 Materials Visual X X X

3.3.2 Shelf Life — X

3.3.3 Cure — X X X

3.4.1 Fourier Transform Infrared

Spectroscopy Test (FTIR)

IPC-TM-650

2.3.42

3.5.1 Viscosity ASTM D-1084 X X

3.5.2 Appearance Visual X X X

3.5.3 Fluorescence Visual under

UV light

XXX

3.5.4 Fungus Resistance IPC-TM-650

2.6.1.1

3.5.5 Flexibility IPC-TM-650

2.4.5.1

3.5.6 Flammability UL 94 HB X X

3.6.1 Dielectric Withstanding Voltage IPC-TM-650

2.5.7.1

3.7.1 Moisture and Insulation

Resistance

IPC-TM-650

2.6.3.4

X* X*

3.7.2 Thermal Shock IPC-TM-650

2.6.7.1

3.7.3 Temperature and Humidity

Aging (Hydrolytic Stability)

IPC-TM-650

2.6.11.1

Required for Class

B Products Only

X Denotes inspection and test required for all classes.

* Denotes requirement is different for Class A and Class B. See 3.7.1 for Class A and B requirements.

August 2002 IPC-CC-830B

Provided by IHS under license with IPC

Not for Resale

No reproduction or networking permitted without license from IHS

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the conformal coating product. A change in chemistry as

detected by FTIR may or may not constitute a product

change. See 4.4 for the deﬁnition of product change.

3.5 Physical Requirements

3.5.1 Viscosity

Viscosity of uncured conformal coating

materials, except type xy, shall be measured per ASTM

D-1084 and the test conditions shall be deﬁned by the

coating manufacturer. Viscosity shall be measured as part

of data gathering for the conformal coating during qualiﬁ-

cation inspection. This viscosity data shall be used by the

manufacturer to pre-determine an acceptable viscosity

range for quality conformance inspection.

3.5.2 Appearance Appearance of conformal coating on

the test vehicle speciﬁed herein shall be observed visually

with the aid of a 3-diopter (approximately 1.75x) minimum

magniﬁcation. Referee inspections shall be accomplished

at 10x magniﬁcation.

The uncured conformal coating materials shall be free of

deleterious substances, bubbles, pinholes, whitish spots,

blistering, wrinkling, cracking, and peeling. The cured con-

formal coating shall be smooth, homogenous, transparent

or translucent, and tack-free when observed at ambient

conditions. In addition, the conformal coating on the test

vehicles shall have no bubbles, pinholes, blisters, cracking,

crazing, peeling, wrinkles, mealing, or evidence of rever-

sion, or cause a corrosion.

3.5.3 Fluorescence Conformal coating materials, except

type XY, shall be ﬂuorescent by ultra-violet illumination

(black light).

3.5.4 Fungus Resistance The resistance of the confor-

mal coating material to support or be attacked by biologi-

cal growth shall be determined in accordance with IPC-

TM-650, Test Method 2.6.1.1.

The cured conformal coating shall not contribute to or be

attacked by biological growth.

3.5.5 Flexibility Tin panels prepared in accordance with

FED-STD-141, Method 2012 shall be used as test vehicles

for ﬂexibility testing. When the coated panels are tested in

accordance with IPC-TM-650, Test Method 2.4.5.1, there

shall be no evidence of cracking or crazing on the cured

conformal coating.

3.5.6 Flammability Flammability testing of the cured

conformal coating shall be performed in accordance with

the detailed requirements of UL 94 HB (Horizontal Burn-

ing Test) test methods.

The cured conformal coating shall meet UL 94 HB (Hori-

zontal Burning Test) requirements:

a. Not have a burning rate exceeding 40 mm [1.57 in] per

minute over a 75 mm [2.95 in] span for specimens hav-

ing a thickness of 3.0 to 13 mm [0.118 to 0.512 in], or

b. Not have a burning rate exceeding 75 mm [2.95 in] per

minute over a 75 mm [2.95 in] span for specimens hav-

ing a thickness less than 3.0 mm [0.118 in], or

c. Cease to burn before the 100 mm [3.937 in] reference

mark.

3.6 Electrical Requirements

3.6.1 Dielectric Withstanding Voltage (DWV)

Dielectric

withstanding voltage of the cured conformal coating shall

be measured in accordance with IPC-TM-650, Test Method

2.5.7.1.

There shall be no disruptive discharge evidenced by ﬂash-

over (surface discharge), sparkover (air discharge) or

breakdown (puncture discharge). The leakage rate shall not

exceed 10 microamperes.

3.7 Environmental Requirements

3.7.1 Moisture and Insulation Resistance

The confor-

mal coating materials shall be tested in accordance with

IPC-TM-650, Test Method 2.6.3.4. After the completion of

temperature and humidity testing cycles, the panels shall

be maintained at the reference conditions at a temperature

of 25 ± 5°C [77 ± 9°F] and a relative humidity of 50 ± 5%,

for a period of 24 hours.

The minimum insulation resistance shall be 100 MΩ for

Class A and 500 MΩ for Class B products during humid-

ity, after humidity and one to two hours at reference con-

ditions, and after 24 hours at reference conditions.

Appearance shall be assessed and dielectric withstanding

voltage shall be tested and meet the requirements as speci-

ﬁed in 3.5.2 and 3.6.1 respectively; after 24 hours at the

reference conditions.

3.7.2 Thermal Shock Conformal coating products shall

be tested in accordance with IPC-TM-650, Test Method

2.6.7.1, with test conditions of -65°C [-85°F] to 125°C

[257°F], 100 cycles.

After the temperature cycles are completed, the coated test

vehicles shall be maintained at the reference conditions at

a temperature of 25 ± 5°C [77 ± 9°F] and a relative humid-

ity of 50 ± 5% for a period of 24 hours; after which appear-

ance shall be assessed and dielectric withstanding voltage

shall be tested and meet the requirements as speciﬁed in

3.5.2 and 3.6.1 respectively.

3.7.3 Temperature and Humidity Aging (Hydrolytic Sta-

bility)

Class B conformal coating products shall be tested

in accordance with IPC-TM-650, Test Method 2.6.11.1.

IPC-CC-830B August 2002

Provided by IHS under license with IPC

Not for Resale

No reproduction or networking permitted without license from IHS

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The control specimen shall be maintained at the reference

conditions at 25 ± 5°C [77 ± 9°F] and 50 ± 5% relative

humidity. The aged conformal coating shall be tack free to

touch.

There shall be no evidence of softening, chalking, blister-

ing, surface tack, cracking, loss of adhesion or reversion to

the liquid state. The clarity of the conformal coating must

remain suitable for the viewing of identiﬁcation markings

and color codes used to identify components over which

the conformal coating is applied.

4 QUALITY ASSURANCE PROVISION

4.1 Responsibility for Inspection

Unless otherwise

speciﬁed, the conformal coating manufacturer is respon-

sible for all testing required in this standard. Test facilities

utilized must be agreed upon by all parties concerned and

may be those of the conformal coating manufacturer,

printed board assembler, user, or other mutually acceptable

test laboratory or combination thereof. The user reserves

the right to conﬁrm that any of the speciﬁed inspection

procedures and test results conform to the prescribed para-

graphs.

4.2 Categories of Inspection

4.2.1 Qualification Inspection

Qualiﬁcation inspection

allows a conformal coating manufacturer to assess the

properties of a conformal coating product on standardized

test vehicles using standardized test procedures. Variation

to the qualiﬁed formulation may or may not imply a

change of product, and may or may not be inspected for

qualiﬁcation as a new product accordingly. See 4.4 for

deﬁnition of Product Change.

4.2.2 Qualification Retention Inspection The qualiﬁca-

tion of a conformal coating product can be retained with

the satisfaction of qualiﬁcation retention inspection.

4.2.3 Quality Conformance Inspection Quality con-

formance inspection shall be performed in order to express

consistency of material properties and process control.

Batches of conformal coating material shall be inspected

for compliance to the original requirements fulﬁlled during

qualiﬁcation testing at a frequency adequate to assure con-

tinuing performance. Quality conformance inspection shall

be integrated into statistical process control programs or

other quality assurance programs (e.g., ISO 9000).

4.3 Frequency of Inspection

4.3.1 Qualification Inspection

Conformal coating quali-

ﬁcation inspection shall be performed once on each confor-

mal coating product.

4.3.2 Qualification Retention Inspection Conformal

coating qualiﬁcation retention inspection shall be per-

formed once every two years on each conformal coating

product in order to prove consistent compliance to the

original qualiﬁcation.

4.3.3 Quality Conformance Inspection Quality con-

formance inspection shall be performed for every batch of

conformal coating product. A batch shall consist of all con-

formal coating materials produced by one continuous run.

Batch identiﬁcation is required (see 5.3).

4.4 Product Change The following variations in the for-

mulation of a conformal coating material originally quali-

ﬁed by a supplier constitute a product change and shall

require a new name or product designation. The extent of

the name change is up to the supplier, but the change in the

name or designation must be prominently displayed and/or

obvious to the customer or end-user. Additional qualiﬁca-

tion of the changed conformal coating formulation shall be

required. Qualiﬁcation results of the original formula are

not to be assumed for the new formula:

• Changes exceeding ± 2% in the formula weight of any

nonvolatile ingredient from the ingredient’s original for-

mula weight.

• Addition or elimination of any nonvolatile ingredient.

• Changes in type or dye of pigment.

• Addition, deletion or change in composition of ‘‘inert’’

materials in the formulation.

The following do not constitute a change in formulation

and do not require additional qualiﬁcation of the change,

but do require notiﬁcation of the customer:

• Changes of less than ± 2% in the formula weight of any

nonvolatile ingredient from the ingredient’s original for-

mula weight.

• Addition, elimination or changes in any volatile ingredi-

ent (solvent) with less than 1% dried weight of residue in

the dried conformal coating (using recommended drying

procedures).

• Changes in the ratio of solids to volatile for viscosity

adjustment.

4.5 Test Equipment and Inspection Facilities Test and

measuring equipment and inspection facilities shall be of

sufficient accuracy, quality and quantity to permit the per-

formance of required inspection and shall be established

and maintained by or be accessible to all concerned parties.

The establishment and maintenance of a calibration system

to control the accuracy of the measuring and test equip-

ment shall be in accordance with ANSI/NCSL Z540-1 or

ISO 10012-1.

4.5.1 Standard Laboratory Conditions Test measure-

ments and conditions, unless otherwise speciﬁed herein, or

August 2002 IPC-CC-830B

Provided by IHS under license with IPC

Not for Resale

No reproduction or networking permitted without license from IHS

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