IPC-TM-650 EN 2022 试验方法.pdf - 第135页

flushed out during burner ignition and flame adjustment resulting in a false yellow flame tip. Proper flame adjustment becomes very difficult. 6.3 When the flame is correct and the specimens end is at the proper height a…

[257 ± 3.6°F],

then cooled in a desiccator for 4 hours mini-

mum prior to testing.

5.2.3

Reserve

sets of specimens may also be conditioned

concurrently for failure verification purposes.

5.3

Preparation for Testing

5.3.1 Adjustment of Test Flame

The

burner is ignited and

adjusted to produce a blue flame 19 mm [0.75 in] 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 [0.75 in] high is produced. The air supply

is increased slightly by opening the air ports only until the yel-

low tip just disappears and completely blue inner and outer

flame cones are formed. The flame is remeasured for correct

height. The procedure is repeated as necessary until all con-

ditions are met. The burner tube is vertical during adjustment

and testing. (See 6.2, 6.3, and 6.4.)

5.3.2

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 6.4 mm [0.25 in] 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 [0.375 in] above the top of the burner

tube.

5.4

Measurement

5.4.1

The

test flame is placed centrally under the lower end

of the specimen for 10 ± 0.5 seconds. The burner is with-

drawn 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 for an additional

10 ± 0.5 seconds, then withdrawn as before.

5.4.2

Evaluation and Report

Steps

5.5.1, 5.5.2, and

5.5.3 shall be performed for each test condition.

5.5

Recording Data

The

following data is to be observed

and recorded.

5.5.1

Duration

of specimen burning to the nearest second

after the first test flame application for each specimen.

5.5.2

Duration

of specimen burning to the nearest second

after the second test flame application for each specimen.

5.5.3

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.

5.5.4 If any specimen burns up to the holding clamp on any

ignition.

5.6

Calculation

5.6.1

Calculate

the total specimen burning time and the

average burning time based on ten ignitions per set of five

specimens.

5.6.2

Calculation

of the glowing time for each specimen, if

required by the specification.

5.7

Report

The

material shall be reported as out of compli-

ance for one or more of the following test results, unless oth-

erwise specified.

5.7.1

than one specimen per set burns up to the hold-

ing clamp on any ignition.

5.7.2

than one specimen per set burns for a period of

time longer than allowed by the specification for a single

specimen.

5.7.3

The

total specimen burning time or the average speci-

men burning time as applicable exceeds the maximum

allowed by the specification and is beyond the tolerance

specified in 5.5.4.

5.7.4

than one specimen glows for a period of time

greater than allowed by the specification (when applicable).

5.8

Retest

only one specimen per set fails to comply with

the requirements, the reserve set of specimens shall be

tested. In the case of total or average specimen burning time,

the reserve set shall be tested only if these calculated values

exceed the specification maximum by five seconds or less. All

specimens from the reserve set shall comply with the require-

ments.

6.0 Notes

6.1

Most

laminates covered by this test method do not drip

molten

or flaming material, and therefore provisions for this evalu-

ation have not been described. If necessary, refer to UL-STD-94.

6.2 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

IPC-TM-650

Number

2.3.10

Subject

Flammability

of Laminate

Date

12/94

Revision

age2of3

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flushed

out

during

burner ignition and flame adjustment resulting

in a false yellow flame tip. Proper flame adjustment becomes very

difficult.

6.3

When

the flame is correct and the specimens end is at

the proper height above the burner 9.5 mm [0.375 in], the

inner blue come of the flame will just meet the end of the

specimen. The specimen will then be ignited by the hottest

area of the flame.

6.4

Accurate

centering of the flame under the specimen is

essential for consistent testing.

6.5

Desiccator Conditions

The

Test Methods Task Group

determined that a great majority of test laboratories are unable

to consistently hold the Relative Humidity in a desiccator to

less than 20%. Based on data from participating company lab

management, the lowest practically feasible RH for use with

the affected IPC Test Methods is 30% maximum.

IPC-TM-650

Number

2.3.10

Subject

Flammability

of Laminate

Date

12/94

Revision

age3of3

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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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