IPC-TM-650 EN 2022 试验方法.pdf - 第666页

5.5.4 Apply a reverse polarization potential of 500 ± 50 volts dc with the resistance meter for one minute. Next, take the measurements at 500 volts dc ± 50 volts dc between each pair of terminals, 1 to 2, 2 to 3, 3 to 4…

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

Page2of3

5.5.4 Apply a reverse polarization potential of 500 ± 50 volts

dc with the resistance meter for one minute. Next, take the

measurements 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.

5.5.5 Note any reason(s) for deleting values, i.e., scratches,

condensation, bridged conductors, etc.

5.6 Evaluation

5.6.1

The values to be reported shall only be the readings

taken in 5.5 through 5.5.5, which are the ‘‘After Recovery’’

values. See Figure 2 for a typical IR plot.

5.6.2 After completion of all electrical testing, the test speci-

mens shall be examined for measling, blisters, delamination,

or other forms of degradation, following 24 hour stabilization

at laboratory ambient temperatures.

6 Notes

6.1

Documented alternative cleaning procedures may be

implemented if there is a concern that scrubbing will adversely

affect test results.

6.2 A failure due to measling, blistering, delamination, or any

other form of degradation, may be due to several factors, and

not necessarily due to inferior coatings.

IPC-2632-2

Figure 2 Typical IR and MIR plot

READING

LOG OF I. R.

1 2

IR Initial = 3.57E+014 ohms

M & IR = 6.47+ 010 ohms

2 hr Recov = 4.20E+013 ohms

24 hr Recov = 4.49+013 ohms

IPC-TM-650

Number

2.6.3.2

Subject

Surface Insulation and Moisture Resistance, Copper Clad

Flexible Dielectric Material

Date

8/14/15

Revision

Page3of3

Scope

This

test method is to characterize fluxes by

determining the degradation of electrical insulation resistance

of rigid printed wiring board specimens after exposure to the

specified flux. This test is carried out at high humidity and heat

conditions.

Applicable Documents

IPC-B-24

Surface

Insulation Resistance Test Board

IPC-A-600

Acceptability

of Printed Boards

IPC

J-STD-004

Requirements

for Soldering Fluxes

IPC-9201

Surface

Insulation Resistance Handbook

Test Specimen

minimum of 10 ml of liquid flux, a rep-

resentative container of solder paste, cored wire, paste flux, or

extracted solder preform flux. The reflow/extraction process

should be carried out in accordance with IPC J-STD-004.

3.1

Comb Patterns

Use

the IPC-B-24 test pattern (see

Figure 1), which consists of four comb patterns per coupon.

Each individual comb has 0.4 mm lines and 0.5 mm spacing.

The metallization shall be unpreserved bare copper.

3.2

Laminat

The

laminate material for this test shall be

FR-4 epoxy-glass.

Apparatus

4.1

clean test chamber capable of programming and

recording an environment of 25 +10/-2 °C [77 + 18/-3 °F] to

at least 85 ± 2 °C [185 ± 3.6 °F] and 20% ± 5% to 85% ± 2%

relative humidity. A salt solution and desiccator may be used

to maintain humidity if a tight temperature control is main-

tained on the chamber.

4.2

power supply capable of producing a standing bias

potential of 45-50 volts DC with a tolerance of ± 10%.

4.3

resistance meter capable of reading high resistance

(10

ohms)

with a test voltage of 100 volts, or an ammeter

capable of reading 10

-10

amps

in combination with 100 volts

DC power supply.

4.4

Three

2000 ml beakers.

4.5

Exhaust

ventilation hood.

4.6

Metal

tongs.

4.7 Soft

bristle brush.

4.8

Deionized

or distilled water (2 megohm-cm minimum

resistivity recommended).

4.9

Drying

oven capable of maintaining at least 50 °C

[122 °F].

Procedure

5.1 Test Conditions

All

fluxes will be tested at 85 ± 2 °C,

[185 ± 3.6 °F], 85 ± 2% relative humidity for 168 hours.

5.2

Specimen Preparation

There

shall be three test cou-

pons for each liquid flux to be tested in the cleaned state

(Table 1, Sample Group A). When testing liquid fluxes which

are intended to remain in the uncleaned state, six test cou-

pons are required. Three uncleaned test coupons shall be

soldered pattern side down (Table 1, Sample Group B) and

three shall be soldered pattern side up (Table 1, Sample

Group C).

Solder paste coupons shall be reflowed pattern side up and

either cleaned (Table 1, Sample Group D) or not cleaned

(Table 1, Sample Group E).

IPC-2633-1

Figure

1 Test Pattern from IPC-B-24

2215

Sanders Road

Northbrook, IL 60062-6135

IPC-TM-650

TEST

METHODS MANUAL

Number

2.6.3.3

Subject

Surface

Insulation Resistance, Fluxes

Date

06/04

Revision

Originating Task Group

Flux Specifications Task Group, (5-24a)

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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