IPC-TM-650 EN 2022 试验方法.pdf - 第664页

1 Scope This test method defines the procedures for deter- mining the surface insulation resistance of a copper foil clad flexible dielectric material in the presence of moisture. This test method may be used for testing…

5.8.3 Class T Evaluation

5.8.3.1

Three separate sets of measurements are to be

recorded for the uncoated specimen, the ‘as received’ speci-

men, and the specimen after solder exposure. Each set of

readings shall be averaged and shall be greater than the mini-

mum listed in the relevant specification. No individual insula-

tion resistance (IR) value may be less than 0.1 x IR

min

, where

min

is the minimum in the set of IR values measured. Two

measurements may be excluded from calculating the average

if there is an assignable cause of low insulation resistance that

can be attributable to the laminate itself or to the process

used to produce the board. Such assignable causes include

but are not limited to:

a. Contamination of the insulating surface of the board such

as lint, solder splines, or water droplets from the condition-

ing chamber.

b. Incompletely etched patterns that decrease the insulating

space between conductors by more than the amount

allowed in the appropriate design requirements drawing.

c. Scratched, cracked or obviously damaged insulation

between conductors.

5.8.3.2 The average insulation resistance (IRavg) is calcu-

lated from:

avg

=10

[

log IR

]

Where:

N = Number of test points (12 nominal)

= Individual insulation resistance measurements.

5.8.3.3 After completion of all electrical testing and following

the nominal 24-hour stabilization at laboratory ambient tem-

peratures (see 5.8.1.6), the test specimens shall be examined

for mealing, blisters, delamination or other forms of degrada-

tion.

6 Notes

6.1

Initial wire placement must be maintained to ensure

reproducible results.

6.2 Specimens may be stabilized at ambient conditions

specified, inside the chamber.

IPC-TM-650

Number

2.6.3.1

Subject

Solder Mask - Moisture and Insulation Resistance

Date

03/07

Revision

Page5of5

1 Scope This test method defines the procedures for deter-

mining the surface insulation resistance of a copper foil clad

flexible dielectric material in the presence of moisture. This

test method may be used for testing both metal clad dielec-

tric as produced per IPC-4204 and bondply dielectric that

must be evaluated for surface insulation resistance in a lami-

nated format as metal clad dielectric.

The moisture resistance test is performed for the purpose of

evaluating, in an accelerated manner, the resistance of mate-

rials to the deleterious effects of high humidity and heat con-

ditions. The test method is designed to simultaneously assess

leakage current caused by ionized water films and electro-

chemical degradation (corrosion and dendritic growth) of the

test vehicle.

2 Applicable Documents

2.1 IPC

IPC-A-600

Acceptability Guidelines

3 Test Specimen The test specimen shall consist of an

etched conductor pattern in accordance with Figure 1. Test a

minimum of three test specimens per clad side. For double

clad material, a separate sample unit shall be prepared for

each side.

3.1 The test points for comb patterns are 1 to 2, 2 to 3, 3 to

4, and 4 to 5. Test points 1-3-5 are connected to the positive

(+) terminal, and test points 2-4 are connected to the negative

(-) terminals of the resistance meter.

4 Apparatus

4.1 Test Chamber

A test chamber capable of producing

and recording an environment of 65 °C±2°C[149 °F ±

3.6 °F] and 85% - 93% relative humidity and which will allow

the insulation resistance to be measured while the specimens

are under the specified conditions. This chamber is to be used

for static insulation resistance testing, involving a single tem-

perature and relative humidity to stress the test specimen over

the specified test time.

4.2 Power Supply A power supply capable of producing a

bias potential of 100 volts dc with a tolerance of ± 10%.

4.3 Resistance Meter A resistance meter capable of read-

ing 10

ohms or greater, with a measurement error not to

exceed 10%, with a test voltage of 500 volts dc.

4.4 Other Equipment or Materials

4.4.1

Soft bristle brush.

4.4.2 Deionized or distilled water (2 megohm cm minimum

resistivity recommended).

4.4.3 Isopropyl alcohol.

4.4.4 Single-stranded* PTFE or other fluorocarbon insulated

wire. (Shielded wire recommended.) [*single-stranded mini-

mizes flux wicking]

4.4.5 Soldering iron (25 - 40 watts).

4.4.6 Drying oven capable of maintaining at least 60 °C.

IPC-2632-1

Figure 1 Insulation resistance test pattern

The lines are all 0.64mm [0.025"] wide.

The spacing between lines is 1.27mm [0.050"]

▼

50.8mm

[2"]

▼

50.8mm

[2"]

LAND AREAS

6.0mm

5.2mm

3.2mm

3000 Lakeside Drive, Suite 105N

Bannockburn, IL 60015-1249

IPC-TM-650

TEST METHODS MANUAL

Number

2.6.3.2

Subject

Surface Insulation and Moisture Resistance,

Copper Clad Flexible Dielectric Material

Date

8/14/15

Revision

Originating Task Group

D-15

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.

Page1of3

5 Procedure

5.1 Test Conditions

5.1.1

The test conditions shall besetat65°C±2°C[149

°F ± 3.6 °F]; 85% – 93% RH for a minimum of 96 hours.

5.2 Specimen Preparation

5.2.1

Permanently identify each test specimen.

5.2.2 Visually inspect the test specimens for any obvious

defects, as described in IPC-A-600. If there is any doubt

about the overall quality of a test specimen, it should be

discarded.

5.2.3 Solder single-stranded PTFE or other fluorocarbon

insulated wire to each land of the test specimen. As flux resi-

due is of great concern with this test, soldering should initially

be attempted without use of any flux. If flux is required by

qualitative observation, use rosin (RO), low activity flux. The

solder and/or rosin must not spread beyond the land areas.

These wires will be used to connect each land for polarization

and for insulation resistance testing. The test pattern shall

not exhibit any spatter of the flux or solder. It is recommended

to cover or otherwise protect the test patterns during the sol-

dering operation.

5.2.4 Spray rinse thoroughly with deionized water. Hold test

specimen at an approximate 30° angle and spray from top to

bottom.

5.2.5 Immerse the test specimen in deionized water and

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

During the remainder of the specimen preparation, handle test

specimens by the edges only.

5.2.6 Immerse the test specimen in clean, virgin isopropyl

alcohol and agitate for a minimum of 30 seconds. Scrub with

a soft bristle brush to remove flux residue. Rinse specimen

thoroughly with clean isopropyl alcohol.

5.2.7 Dry the cleaned test specimens in a drying oven for a

minimum of three hours at 49 °C - 60 °C [120 °F - 140 °F].

5.3 Initial Insulation Resistance Measurement at Stan-

dard Laboratory Conditions (Ambient)

5.3.1

Condition test specimens a minimum of 24 hours at

standard laboratory conditions of 23 °C±5°C[73°F±9°F]

and50%±10%relative humidity. This is Test Condition A.

5.3.2 Take an initial insulation resistance measurement

between each pair of terminals, 1 to 2, 2 to 3, 3 to 4, and 4

to 5 at standard laboratory conditions. Before taking the mea-

surement, apply a polarizing potential of 500 volts dc ± 50

volts dc, with the resistance meter for one minute, then take

the measurement at 500 volts dc ± 50 volts dc.

5.4 Insulation Resistance Measurement at Elevated

Temperature and Humidity

5.4.1

Place the test specimens from Test Condition A in the

test chamber, in a vertical position parallel to airflow, and

under a condensation drip shield. Apply a 100 volt dc

polarization potential to each pair of terminals of the test

specimens.

5.4.2 Expose the material test specimens to the conditions

of65°C±2°C[149 °F ± 3.6 °F] and 85% -93% relative

humidity for a minimum of 96 hours.

5.4.3 Disconnect the 100 volt dc polarization potential.

5.4.4 Apply a reverse polarization potential of 500 ± 50 volts

dc with the resistance meter for one minute, then take the

measurement at 500 volts dc ± 50 volts dc between each pair

of terminals, 1 to 2, 2 to 3, 3 to 4, and 4 to 5, of the test

specimen.

5.4.5 Measure and record the insulation resistance at the

end of the nominal 96 hour conditioning period. These tests

are to be conducted without opening the test chamber.

5.5 Insulation Resistance Measurement after Recovery

from Elevated Temperature and Humidity

5.5.1

Remove the test specimens from the test chamber

after disconnecting the bias voltage (100 volts dc).

5.5.2 Stabilize the test specimens, at the following condi-

tions: 23 °C±5°C[73.4 °F ± 9 °F] and 50% ± 10% relative

humidity, for 24 hours [+ 0.5 hours/-0hours].

5.5.3 Take the insulation resistance measurements and

record such at laboratory ambient temperature at 23 °C ±

5 °C [73.4 °F ± 9 °F] after the above stabilization conditioning.

IPC-TM-650

Number

2.6.3.2

Subject

Surface Insulation and Moisture Resistance, Copper Clad

Flexible Dielectric Material

Date

8/14/15

Revision

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