IPC-TM-650 EN 2022 试验方法.pdf - 第655页

1 Scope This test method is to determine the degradation of insulating materials by examination of the visual and electri- cal insulation resistance properties of printed board speci- mens after exposure to high humidity…

1.0

Scope

This

test method is designed for use in deter-

mining the amount of water absorbed by plastic laminates

when immersed in distilled water for 24 hours.

2.0

Applicable Documents

IPC-TM-650

Method

2.3.6, Etching Ammonium Persulfate

Method

IPC-TM-650 Method

2.3.7, Etching, Ferric Chloride Method

IPC-TM-650

Method

2.3.7.1, Etching Cupric Chloride

3.0

Test Specimens

3.1 Dimensions

The

test specimens used in this test shall

be 2.0 inches long by 2.0 inches wide by the thickness of the

material (unless otherwise specified). Tolerance on length and

width shall be ±.03.

3.2

Edge Finish

The

edges of the specimens shall be milled

or sanded smooth with 400 grit sandpaper.

3.3

Number of Specimens

Three

specimens shall be used

for this test.

3.4

Removal of Metal Cladding

The

metal cladding shall

be removed by etching per IPC-TM-650, Methods 2.3.6,

2.3.7 or 2.3.7.1, or other suitable method which does not

affect the surface of the laminate.

4.0

Apparatus

4.1

Circulating

air oven capable of maintaining a uniform

temperature of 105° to 110°C (221° to 230°F).

4.2

Desiccator

stabilization chamber (drying cabinet)

capable of maintaining less than 20% R.H. at 21 ±2°C.

4.3

Analytical Balance

5.0 Procedure

5.1 Cleaning

The

specimens shall be cleaned by at least

three repeated wipings with a clean damp cloth.

5.2

Conditioning

The

specimens shall be conditioned by

drying in an oven for 1 hour at 105° to 110° (221° to 230°F),

cooled to room temperature in a desiccator, and weighed

immediately upon removal from the desiccator.

5.3

Weighing

The

weight of each conditioned specimen

shall be determined to the nearest 0.1 milligram and recorded.

5.4

Immersion

The

conditioned specimens shall be placed

in a container of distilled water maintained at 23°±1.1°C (73.5

±2°F) and shall rest on edge entirely immersed. At the end of

24 hours minus 0 plus 30 minutes, the specimens shall be

removed from the water one at a time, all surface water

removed with a dry cloth, and weighed immediately. A weigh-

ing bottle shall be used for materials where water absorption

during weighing has been demonstrated to significantly affect

results.

5.5

Calculations

Calculate

and record the percent

increase in weight for each specimen to the nearest 0.01 per-

cent as follows:

Increase in weight, percent =

wet weight—conditioned weight

conditioned

weight

X 100

5.6

Report

the average for the three specimens.

Report individual specimen results when requested.

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062-6135

IPC-TM-650

TEST

METHODS MANUAL

Number

2.6.2.1

Subject

Water

Absorption, Metal Clad Plastic Laminates

Date

5/86

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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Scope

This

test method is to determine the degradation

of insulating materials by examination of the visual and electri-

cal insulation resistance properties of printed board speci-

mens after exposure to high humidity and heat conditions.

This method allows testing with (Method A) or without

(Method B) Conformal Coating. When not specified, Method A

is the default method.

Applicable Documents

IPC-CC-830

Qualification

and Performance, Insulating Com-

pounds for Printed Circuits Assemblies

Test Specimens

3.1

Test

specimens shall be comprised of a minimum of two

conductor lines per conductive layer, sufficient to allow resis-

tance testing between adjacent conductor patterns both

between layers and on the same layer. See 6.1 for examples

of test specimen patterns recommended for this test method.

Apparatus or Material

4.1

clean test chamber capable of programming and

recording an environment of temperature ranging between

25 °C ± 2 °C [77 °F ± 4 °F) and 65 °C ± 2 °C [149 °F ± 4 °F],

and 85% to 93% relative humidity.

4.2

power supply capable of producing a standing bias

potential of 100 volts DC with a tolerance of ± 10%.

4.3

resistance meter capable of reading high resistance at

the voltage described in the procurement documentation.

4.4

Solder or Flux-Cored Solder

Flux

shall be removable

in a manner which will not adversely affect the test specimen.

4.5

Soft

Bristle Brush.

4.6

Deionized

or distilled water (2 megohm-cm, minimum

resistivity recommended).

4.7

Isopropyl

alcohol.

4.8

Drying

oven(s) capable of maintaining 50 °C ± 5 °C

[122 °F ± 9 °F] and 125 °C ± 5 °C [257 °F ± 9 °F].

4.9

Insulating

compound (conformal coating) which con-

forms to IPC-CC-830.

4.10 Equipment

necessary to apply and cure conformal

coating.

Procedure

5.1 Specimen Preparation

5.1.1

Mark

specimen with positive, permanent, and non-

contaminating identification.

5.1.2

Visually

inspect the test specimens for any obvious

defects, as described in the applicable performance specifica-

tion. If any test specimen is noncompliant, the test specimen

should be replaced and the replacement noted.

5.1.3

Solder

single stranded (to decrease the opportunity for

flux contamination from the wire) insulated wire which is not

affected by the test environment to each of the connection

points of the test specimens. These wires will be used to con-

nect the test patterns of the test specimens to the power

supply and for insulation resistance testing.

5.1.4

Clean

test lead terminals with isopropyl alcohol and

scrub with a soft bristle brush for a minimum of 30 seconds.

During the remainder of the test specimen preparation, handle

test specimens by the edges only (see 6.2).

5.1.5

Spray

rinse thoroughly with fresh isopropyl alcohol.

Hold test specimen at an approximate 30° angle and spray

from top to bottom.

5.1.6

Rinse

cleaned area thoroughly with fresh deionized or

distilled water. Hold test specimen at an approximate 30°

angle and spray from top to bottom.

5.1.7

Dry

test specimens in a drying oven for a minimum of

three hours at an oven temperature of between 50 °C ± 5 °C

[122 °F ± 9 °F) (see 6.3).

2215

Sanders Road

Northbrook, IL 60062-6135

IPC-TM-650

TEST

METHODS MANUAL

Number

2.6.3

Subject

Moisture

and Insulation Resistance, Printed Boards

Date

05/04

Revision

Originating Task Group

Rigid Printed Board Performance Task Group

(D-33a)

Material

in this Test Methods Manual was voluntarily established by Technical Committees of 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 IPC.

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ASSOCIA

TION CONNECTING

ELECTRONICS INDUSTRIES

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5.1.8

Specimen

preparation for METHOD B is now com-

pleted, continue the procedure with 5.2.

5.1.9

METHOD A - Application of Conformal Coating.

Continuation of Sample Preparation

Apply

coating to the

appropriate area of the test specimen, in a manner concurrent

with user’s production techniques or as specified by the coat-

ing supplier.

5.1.10

After

the application of coating, the test specimens

are to be cured, as specified by the coating supplier.

5.1.11

After

curing, stabilize to ambient temperature.

5.2

Test

5.2.1

Take

the initial insulation resistance measurements at

laboratory ambient temperature. Apply the voltage specified in

the procurement documentation on the test specimen’s test

points as specified in 5.2.2 with the resistance meter, and

take the reading after measurement stabilization.

5.2.2

Test

points on the test specimens shall be connected

in a manner that will allow adjacent conductor patterns, both

between conductor layers and on the same conductor layer,

to alternate between the positive (+) and negative (–) terminals

of the power supply or resistance meter.

5.2.3

Place

test specimens in chamber in a vertical position

and under a condensation drip shield. Connect the DC volt-

age source to the test specimen test points as indicated in

5.2.2. Apply a 100 ± 10 volts DC polarization voltage to all test

specimens.

5.2.4

Expose

test specimens to one of the following speci-

fied test conditions: (See 6.4.)

(a) Class1–35°C±5°C[95°F±9°F], 85% to 93% rela-

tive humidity, for four days (static).

(b) Class2–50°C±5°C[122 °F ± 9 °F], 85% to 93% rela-

tive humidity, for seven days (static).

+5/-2 °C [77 °F +9/-4 °F] to 65 °C ± 2 °C [ 149 °F ± 4 °F],

85% to 93% relative humidity, 160 hours total.

5.2.4.1

Temperature cycling

The

following constitutes

one complete cycle (for the Class 3 Test Condition).

(a) Start test at 25 °C +5/-2 °C [77 °F +9/-4 °F], and raise

temperature at 65 °C ± 2 °C [149 °F ± 4 °F], over a time

span of 150 minutes ± 5 minutes.

(b) Maintain temperature at 65 °C ± 2 °C [149 °F ± 4 °F] over

a time span of 180 minutes ± 5 minutes.

25 °C +5/-2 °C [77 °F +9/-4 °F] over a time span of 150

minutes ± 5 minutes.

There shall be no delay between cycles. Polarizing voltage

shall be maintained throughout the 20 cycle period. The

humidity may drop a minimum of 80% relative humidity when

going from high to low temperature. See Figure 1 for a graphi-

cal illustration of temperature cycling.

5.3

Measurement

5.3.1

Disconnect

100 volts DC polarized voltage source

before taking any insulation resistance measurement. Insula-

tion resistance shall be read as specified in 5.2.1. Voltage

polarity for measurement should be identical to that of the

polarizing voltage.

5.3.2

Final

resistance measurements shall be made after

removal of specimen from the chamber, and after one hour

and before two hours stabilization at laboratory ambient tem-

peratures.

Any reasons for deleting values, e.g., scratches, condensa-

tion, bridged conductors, etc., must be noted.

5.4

Evaluation

5.4.1

Each

test specimen shall be evaluated for insulation

resistance quality for its class, following and/or during the ini-

tial, wet and/or dry conditions, as applicable.

5.4.2

After

completion of all electrical testing, the test speci-

mens shall be examined for evidence of mealing, blistering,

delamination, or other forms of degradation, following 24 hour

stabilization at laboratory ambient temperatures.

6 Notes

6.1

Test Pattern Examples

6.1.1 ‘‘Y’’ Patterns

There

are a variety of ‘‘Y’’ test patterns

(also referred to as ‘‘E’’ test coupons) in various specifications

within the industry. See Figure 2 for an illustration of ‘‘Y’’ pat-

tern test coupons.

IPC-TM-650

Number

2.6.3

Subject

Moisture

and Insulation Resistance, Printed Boards

Date

05/04

Revision

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