IPC-CC-830B.pdf - 第15页

If and when a conformal coating manufacturer recom- mends a primer for use with a conformal coating (as a sys- tem), the primer shall be used in conjunction with the con- formal coating material during qualiﬁcation testi…

in the individual test method, shall be made at temperature

of 15 to 35°C [59 to 95°F], air pressure of 650 to 800 mil-

limeters mercury [0.86 to 1.05 bar], and a maximum rela-

tive humidity of 75%. Whenever the test conditions must

be closely controlled in order to obtain reproducible results

for referee purposes, temperature, relative humidity and

atmospheric pressure conditions of 25 ± 3°C [77 ± 5.4°F],

40 to 60% RH, and 650 to 800 millimeters mercury [0.86

to 1.05 bar], shall be speciﬁed.

4.5.2 Permissible Temperature Variation in Environ-

mental Chambers

When chambers are used, specimens

under test shall be located only within the working area

deﬁned as follows:

a. Reference temperature variation within working area:

The controls for the chambers shall be capable of main-

taining the temperature of any single reference point

within the working area within ± 2°C [± 3.6°F].

b. Spatial temperature variation within working area:

Chambers shall be so constructed that, at any given

time, the temperature of any point within the working

area shall not deviate more than 3°C [5.4°F] from the

reference point, except for the immediate vicinity of

specimens generating heat.

4.5.3 Reference Conditions Reference conditions as a

base for calculations shall be 25°C [77°F] for temperature,

760 millimeters mercury [1.01 bar] of air pressure, and a

relative humidity of 50%.

4.6 Inspection Routine Inspections shall be performed

in accordance with testing requirements deﬁned in 3.2

thereof. Test specimens shall be prepared in accordance

with 4.7 and subjected to the procedure of test methods

listed in Table 3-1.

4.7 Inspection Sampling

4.7.1 Test Vehicles

Test vehicle to be used shall be in

accordance to speciﬁc test method as outline in Table 4-1.

A IPC-B-25A Standard Test Board is illustrated in Figure

4-1. Test pattern to be used shall be as speciﬁed in test

method.

Test assemblies for temperature and humidity aging test

shall be made with the base material in accordance with

IPC-4101/21, IPC-4101/24, IPC-4101/25 or IPC-4101/26,

with tin plated or solder coated 17 µm copper ‘‘Y’’ shape

conductor, as illustrated in Figure 4-2. Test assemblies

shall contain two resistors, one with marking ink and one

with color code bars.

Glass plates to be used shall be standard laboratory glass

plates of 50 mm x 50 mm [1.97 in x 1.97 in] minimum

size.

Test strips for ﬂammability testing shall be 13 mm [0.512

in] wide by 130 mm [5.118] long in accordance with UL

94 speciﬁcation.

Tin panels shall be prepared in accordance with FED-STD-

141, Method 2012.

4.7.2 Sample Size The minimum number of test speci-

mens shall be as outlined in Table 4-1, or it shall be of

sufficient quantity to achieve statistical conﬁdence required

by agreement between customer and supplier.

4.7.3 Preparation Prior to Coating The prepared test

vehicles shall be cleaned, handled and stored so that, at the

time of priming and/or coating, they meet the cleanliness

requirements of IPC-6012 (see 6.3 and 6.4).

Table 4-1 Test Vehicles and Sample Sizes

Paragraph Test to Run Test Method Test Vehicle

Number of

Specimen

3.5.2 Appearance Visual

Glass Plate*

4 coated,

1 uncoated

3.5.3 Fluorescence Visual under UV

4.7.4 Thickness ASTM-D-1005

3.5.4 Fungus Resistance IPC-TM-650

2.6.1.1

Glass Plate 4 coated

3.5.5 Flexibility IPC-TM-650

2.4.5.1

Tin Panel 4 coated

3.5.6 Flammability UL 94 HB UL 94 Test Strip 20 coated

3.6.1 Dielectric Withstanding Voltage IPC-TM-650

2.5.7.1

IPC-B-25A Test

Board

5 coated

3.7.1 Moisture and Insulation Resistance IPC-TM-650

2.6.3.4

IPC-B-25A Test

Board

4 coated,

1 uncoated

3.7.2 Thermal Shock IPC-TM-650

2.6.7.1

IPC-B-25A Test

Board

5 coated

3.7.3 Temperature and Humidity Aging

(Hydrolytic Stability)

IPC-TM-650

2.6.11.1

‘‘Y’’ shape test

assembly

5 coated

(1 as control)

* Same specimens are used for these inspections.

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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If and when a conformal coating manufacturer recom-

mends a primer for use with a conformal coating (as a sys-

tem), the primer shall be used in conjunction with the con-

formal coating material during qualiﬁcation testing.

4.7.4 Coating The conformal coating shall be applied to

the test vehicles over the patterns and/or assemblies and

cured for the time and temperature recommended by the

manufacturer. Thickness shall be measured in accordance

with ASTM-D-1005 or by micrometer or indicator accurate

to 12.5 ± 2.5 µm [0.5 ± 0.1 mil]. For Type XY, the thick-

ness may be measured optically. A glass plate may be used

for referee in conformal coating thickness measurement.

For the purpose of qualiﬁcation, qualiﬁcation retention and

quality conformance inspection, the cured conformal coat-

ing on the test vehicle shall have a thickness as speciﬁed

in Table 4-2. For actual thickness requirements of applied

and cured conformal coating on a printed wiring assembly

product, refer to J-STD-001 or IPC-2221.

4.8 Failures One or more failures shall be cause for

repeating the failed test after the failure mode has been

determined and corrected. If the corrective action results in

a product change per 4.4, qualiﬁcation of the changed

product shall be veriﬁed.

4.9 Inspection Reporting

4.9.1 Qualification Reporting

Because samples, equip-

ment, procedures and conditions may vary between loca-

tions or test systems, complete and precise reporting of

sample preparation, test details and verifying data is

required. Results of inspection shall be summarized in a

qualiﬁcation inspection report, with classiﬁcation attained

clearly indicated. An example of the format is shown in

Appendix A.

4.9.2 Qualification Retention Reporting Complete and

precise reporting of sample preparation, test details and

verifying data is required for qualiﬁcation retention inspec-

tion. Results shall be compared with the original qualiﬁca-

tion inspection results and reported accordingly. Results of

inspection shall be summarized in a qualiﬁcation retention

inspection report. An example of the format is shown in

Appendix B.

4.9.3 Quality Conformance Reporting Results from the

quality conformance inspection shall be compared with the

original qualiﬁcation inspection results and previous qual-

ity conformance inspection results. Results of inspection

shall be summarized in a quality conformance inspection

report. An example of the format is shown in Appendix C.

5 PREPARATION FOR DELIVERY

5.1 Containers

Containers for packaging shall be in

accordance with good commercial practices. Containers

IPC-830b-4-1

Figure 4-1 IPC-B-25A

IPC-830b-4-2

Figure 4-2 Test Coupon with ‘‘Y’’ Shape Pattern

75 mm

[2.95 in]

4.7 mm

[0.185 in]

38 mm

[1.50 in]

19 mm

[0.748 in]

6.30 mm [0.2480 in]

2.3 ± 0.13 mm DIA

[0.0906 ± 0.00513 in DIA]

Hole 0.75 ± 0.08 mm DIA

[0.0295 ± 0.0031 in DIA]

0.75 mm [0.0295 in MIN]

0.75 mm ± 0.08 mm [0.0295 in ± 0.0031 in MIN]

0.75 mm [0.0295 in MIN]

3.2 mm

[0.126 in]

25 ± 1.5 mm

[0.984 ± 0.0591 in MIN]

3.8 ± 0.13 mm DIA

[0.150 ± 0.00512 in DIA]

HOLE 1.3 ± 0.08 mm DIA

[0.051 ± 0.0031 in DIA]

Table 4-2 Thickness Requirements on Test Vehicle

Type of Coating Thickness

AR 25-75 µm [0.98-2.95 mil]

UR 25-75 µm [0.98-2.95 mil]

ER 25-75 µm [0.98-2.95 mil]

SR 50-200 µm [1.97-7.87 mil]

XY 12.5-50 µm [0.49-1.97 mil]

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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shall be of a corrosion resistant material that will not react,

deteriorate or affect the quality of the conformal coating

product being packaged. When a conformal coating prod-

uct consist of more than one component, each component

shall be individually furnished in sufficient quantities nec-

essary to react with the other and total amount to be that

speciﬁed in the purchase order.

5.2 Packaging Preservation, packing and marking shall

be in accordance with MIL-STD-1188.

5.3 Marking The following markings are required:

a. Manufacturer’s part number

b. Manufacturer’s lot or batch number

c. Name of manufacturer

d. Date of manufacture

e. Expiration date

f. Precautionary handling

6 NOTES

6.1 Order Data

It is recommended that the following

information be speciﬁed in procurement documents:

a. Title, number and date of this standard; type (see 1.3.1)

and class (see 1.3.2) of material contained in the pack-

age

b. Solvent compatibility information

c. Special packing instructions if required

d. Size of containers

e. Quantity of material required

f. Other special instructions

6.2 Formulation Change It is important that the proper-

ties of conformal coating material remain consistent

throughout the life of the product. Small changes in the

composition of the material may have dramatic effects

upon certain properties (such as ﬂammability, adhesions,

etc.) and hence behaviors of the product during the appli-

cation process and in end use environment. Compatibility

of conformal coating with associated materials can often be

a sensitive issue. Therefore, it is important that formulation

consistency be maintained and users be informed when any

change has been made.

6.3 Conditioning It is recommended that the test boards

be baked at 121°C [249.8°F] for minimum one hour, but no

more than four hours, prior to coating. It is also suggested

that the environment in which the conformal coating is

applied should be clean. Monitoring of relative humidity,

temperature and particle counts ensures a better-coated

assembly.

6.4 Cleanliness It is of paramount importance that the

test vehicle be thoroughly cleaned prior to conformal coat-

ing application. A ‘‘dirty’’ test vehicle will decrease values

for dielectric withstanding voltage, insulation resistance,

and will adversely impact adhesion. An unclean test

vehicle cannot yield an accurate evaluation of the confor-

mal coating material.

6.5 Adhesion The level of adhesion between conformal

coatings and substrates varies greatly. Among the factors

which inﬂuence adhesion are soldering procedures, primer

and/or coating application, curing process, chemistry of

conformal coating, solder mask, ﬂux and cleaning agent (if

any).

Some applications require high-level adhesion; others

desire easy removal of conformal coating from the coate-

dassembly. The key to the determination of adhesion

requirement is an agreement between manufacturer/

assembler or assembler/user of conformal coating, sup-

ported by adequate understanding of subsequent manufac-

turing processes and end use environments.

The adhesion test used shall be agreed upon the

manufacturer/assembler or assembler/user of conformal

coating. A standard paint type tape test may be used for

some coated printed wiring assemblies. Alternate methods,

such as temperature and/or humidity cycling etc., may be

employed. The applicability of test result shall be deter-

mined by the user.

6.6 Solvent Compatibility The compatibility of a confor-

mal coating product with solvents may be evaluated to

avoid potential degradation of conformal coating and

coated printed wiring assemblies in subsequent manufac-

turing processes or end use environments.

Described below is a recommended procedure for the

evaluation of solvent compatibility of a conformal coating

product.

a. Immerse a coated specimen in the solvent at 25 ± 5°C

[77 ± 9°F] for two minutes.

b. Remove the coated specimen from solvent, air dried for

10 minutes at ambient laboratory conditions.

c. Oven bake the coated specimen for 30 minutes at 65 ±

3°C [147 ± 5.4°F].

d. Cool to room temperature.

e. Examine coated specimen for evidence of surface tack,

blistering, dilation and color change.

6.7 Identification of Solvent Sensitive Conformal Coat-

ings

It is recommended that solvent sensitive conformal

coating be identiﬁed on the coated printed wiring assem-

blies by using labels, bar codes, color-coding, etc. This will

provide useful cautionary information for subsequent

manufacturing processes and/or end use applications,

which might otherwise incur solvent incompatibility.

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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