IPC-TM-650 EN 2022 试验方法.pdf - 第137页

4.8 Flame Gauging Device A thin steel scale template for gauging flame height 4.9 Burner Base A block support for use as a burner base with a 20° incline for proper positioning of the burner flame under the sample 5 Proc…

Scope

This

test method is intended to evaluate the rela-

tive flame resistance characteristics of a permanent solder

mask coating on specified printed wiring laminates. It is

intended for use on laminate 0.5 mm thick and greater. It

should indicate to what degree, if any, that the coating may

diminish the flammability of the laminate. The performance

level of a material by these methods should not be assumed

to correlate with its performance in end-use applications.

Applicable Documents

IPC-TM-650 Test Method Manual

2.3.6

Etching, Ammonium Persulfate Method

2.3.7 Etching, Ferric Chloride Method

2.3.7.1 Cupric Chloride Etching Method

Test Specimen

3.1

Test

specimens shall be prepared using vendor recom-

mendations or manufacturers’ production process and fabri-

cated parallel to either the warp or the fill direction as conve-

nient.

3.2 Test

specimens shall be 130 mm±5mminlength and

13 mm ± 0.5 mm in width by the thickness being tested.

Metal cladding shall be removed by etching, using IPC-TM-

650, Test Method 2.3.6, 2.3.7, or 2.3.7.1.

3.3

The

solder mask coating shall be applied evenly at both

the minimum and maximum anticipated coating thickness

over both the minimum and maximum laminate thickness

desired.

3.4

All

of these specimen sets, as well as one specimen set

of uncoated laminate, for each laminate thickness, should

come from the same laminate lots. In addition, if other solder

masks are to be compared, all should be applied to the same

lots, or results can vary widely. Pretesting of laminate lots is

recommended.

3.5

Edges

may be smoothed after fabrication, providing that

any radius imparted to the corners does not exceed 12.5 mm.

3.6 Five

specimens shall be prepared for each condition

required (two conditions—see specimen conditioning).

Reserve duplicates of five specimens are also required in the

event a retest is necessary. Total specimens per set are there-

fore equal to 20. Total sets required, including uncoated sub-

strate, would be six.

Note:

Additional

coatings tests would not have to include the

uncoated sets if the laminate lots are the same and submitted

simultaneously.

Apparatus

4.1 Test Chamber

laboratory hood, totally enclosed,

with a heat resistant glass window for observing the test, shall

be used. The exhaust fan shall be turned off during the test,

but may be turned on periodically to clear out the fumes and

carbonized airborne particles between tests.

4.2

Clamping Devices

clamping device, adjustable for

vertical positioning of the test specimen, shall be provided

within the test chamber so the specimen will hang with its

length in a vertical position approximately coincident with the

central vertical axis of the test chamber.

4.3

Laboratory Burner

Bunsen or Tirrell Burner shall be

used having a tube length of 100 mm and an inside diameter

of 9.4 mm ± 1.5 mm. The burner shall not be equipped with

end attachments.

4.4

Gas Supply

The

gas supply shall be regulated and

metered for uniform flow. The standard gas shall be technical

grade methane. Natural gas having a nominal heat content of

1000 BTU per cubic foot may be substituted. Other fuel

gases, such as butane, propane, and acetylene may be used;

however, technical grade methane will be used for referee

testing.

4.5

Timing Device

stop watch or other suitable timing

device with a precision of 0.5 seconds minimum

4.6

Desiccator

desiccator containing dried silica gel or

calcium chloride

4.7

Circulating Oven

conditioning oven of circulating

draft type capable of maintaining 70°C ± 1°C

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062-6135

IPC-TM-650

TEST

METHODS MANUAL

Number

2.3.10.1

Subject

Flammability

of Soldermask on Printed Wiring

Laminate

Date

8/98

Revision

Originating Task Group

N/A

Material

in this Test Methods Manual was voluntarily established by Technical Committees of the IPC. This material is advisory only

and its use or adaptation is entirely voluntary. IPC disclaims all liability of any kind as to the use, application, or adaptation of this

material. Users are also wholly responsible for protecting themselves against all claims or liabilities for patent infringement.

Equipment referenced is for the convenience of the user and does not imply endorsement by the IPC.

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4.8

Flame Gauging Device

thin steel scale template for

gauging flame height

4.9

Burner Base

block support for use as a burner base

with a 20° incline for proper positioning of the burner flame

under the sample

Procedure

5.1 Specimen Conditioning

5.1.1

Specimen

sets should first be brought to room tem-

perature (23°C ± 2°C) for 24 hours prior to being thermal

shocked within the specifications of both the laminate and

solder mask being tested.

5.1.2

Specimen

sets shall then be divided into two groups

of 10 each. The first group shall be conditioned prior to test-

ing by exposure to standard laboratory conditions of 23°C

± 2°C and RH of 50% ± 5% for a minimum of 48 hours.

The first set shall be referred to as ‘‘as received’’ specimen.

5.1.3

The

second group shall be conditioned for a duration

of 168 hours (seven days) at 70°C ± 1°C and then cooled in

a desiccator over anhydrous calcium chloride for at least four

hours at room temperature (23°C ± 2°C) prior to testing.

This second set shall be referred to as ‘‘conditioned’’ speci-

men.

5.1.4

From

each of these groups, one half (five specimens)

will be burned for the evaluation, with the remaining five speci-

mens being held in reserve for retest if needed.

Note:

See

5.6 to determine if and when the reserve sets will

be needed.

5.2

Adjustment of Test Flame

The

burner is ignited and

adjusted to produce a blue flame 19 mm high. The correct

flame is obtained by adjusting the gas supply and the air ports

of the burner until a blue flame with a yellow tipped outer cone

19 mm high is produced. The air supply is increased slightly

by opening the air ports until only the yellow tip just disap-

pears and it forms completely blue inner and outer flame

cones. The flame is remeasured to assure correct height. The

procedure is repeated as necessary until all conditions are

met. The burner tube is vertical during the adjustment and

measuring (see Figure 1).

5.3

Specimen Mounting

Each

specimen is mounted in the

test fixture with its longitudinal axis vertical. The clamp used

shall cover no more than the upper 6.5 mm of the specimen.

The vertical position of the test fixture/specimen assembly is

adjusted so that the lower end of the specimen is 9.5 mm

above the top of the burner tube (see Figure 2).

5.4

Flame Test

The

test flame is placed centrally under

the lower end of the specimen. Timing begins immediately for

10 ± 0.5 seconds. The burner is withdrawn at least 152 mm

away from the specimen. If active combustion ceases prior to

the specimen being completely consumed, the test flame is to

be immediately placed under the specimen again for an addi-

tional 10 ± 0.5 seconds, then withdrawn as before.

5.5

Data to be Observed and Recorded

The

following

test data is to be recorded:

a. Duration of specimen burning to the nearest second after

the first test flame application for each specimen

b. Duration of specimen burning to the nearest second after

the second test flame application for each specimen

c. Duration of specimen burning plus glowing to the nearest

second after the second test flame application for each

specimen, only if required by the specification

d. If any specimen burns up to the holding clamp on any igni-

tion

e. If any specimen drips flaming particles, and if they ignite

the dry absorbent surgical cotton located 305 mm below

the test specimen

IPC-23101-1

Figure

1 Burner Flame

19 mm

9.5 mm

IPC-TM-650

Number

2.3.10.1

Subject

Flammability

of Soldermask on Printed Wiring Laminate

Date

8/98

Revision

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Calculation of the total specimen burning time or the aver-

age specimen burning time as applicable based on 10 igni-

tions per set of five specimens (see Figure 3)

g. Calculation of the glowing time for each specimen if

required by the specification

5.6

Evaluation and Reporting

The

material shall be con-

sidered to be out of compliance with the specification if:

a. More than one specimen per set burns up to the holding

clamp on any ignition

b. More than one specimen per set burns for a period of time

longer than allowed by the specification for a single speci-

men

c. The total specimen burning time as applicable exceeds the

maximum allowed by the specification and is beyond the

tolerance specified in 5.6.2

d. More than one specimen glows for a period of time greater

than allowed by the specification (when applicable)

e. More than one specimen drips flaming particles, which

ignite the dry absorbent surgical cotton

5.6.2

Reporting

Each

test condition is reported separately.

The parameters outlined in 5.6 are to be reported only as

applicable.

5.6.3

Retests

only one specimen per set (five) fails to

comply with the requirements, the reserve set of specimen

shall be tested. In the case of total and/or average specimen

burning time, the reserve set shall be tested only if these cal-

culated values exceed the specification maximum by five sec-

onds or less. All specimens, their total, and their average from

the reserve set shall comply with the requirements.

6 Notes

6.1

The

inside of the burner barrel should be cleaned fre-

quently. Specimen combustion by-products can collect

around and inside the barrel tip. These deposits can be

flushed out during burner ignition and flame adjustment,

resulting in a false yellow flame tip. Proper flame adjustments

then become very difficult if allowed to remain.

6.2

When

the flame is correct and the specimen’s end is at

the proper height above the burner (9.5 mm), the inner blue

cone of the flame will just meet the end of the specimen. The

hottest area of the flame will then ignite the specimen.

6.3

Accurate

centering of the flame under the specimen is

essential for consistent test results.

IPC-23101-2

Figure

2 Specimen Mounted in the Test Fixture

Specimen

9.5 mm

19 mm

304 mm

y absorbant

surgical cotton

Mounting

Block

Burner

IPC-TM-650

Number

2.3.10.1

Subject

Flammability

of Soldermask on Printed Wiring Laminate

Date

8/98

Revision

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