IPC-TM-650 EN 2022 试验方法.pdf - 第420页

1.0 Scope This method describes a technique for evaluat- ing a material to resist tracking when subjected to a low cur- rent arc just above the surface of the material. It can be used on materials of various thickness by…

IPC-TM-650

Number Subject Date

Revision

Page 7 of 7

2.4.54 Test Method for Thermal Transmission Properties of 09/2022

Metal Based Printed Boards (MBPB)

N/A

6 Notes

6.1

The following information should be given in the measurement report associated with the measurement. Show all measured

values and the mean value for all parameters:

6.2 General information:

6.2.1 Measurement institution

6.2.2 Testing apparatus (identification)

6.2.3 Date

6.2.4 Contact person

6.3 Specimen identification:

6.3.1 Name of the manufacturer

6.3.2 Batch or lot number

6.3.3 Grade designation

6.3.4 Nominal thickness

6.3.5 Any other information pertinent to the identification of the material

6.4 Results and thermal properties

6.4.1 Number of layers used in the test

6.4.2 Average temperature of the specimen (@ max pressure)

6.4.3 Temperature difference over the specimen (@ max pressure)

6.4.4 Pressure used during testing

6.4.5 Apparent thermal conductivity (@ max pressure)

6.4.6 Thermal resistance (@ max pressure)

6.4.7 Uncertainty of the thermal measurement (@ max pressure)

6.4.8 Layer thicknesses of top, base and dielectric layer

6.4.9 Microscopic images of the layer thicknesses

6.4.10 Used material to reduce contact resistances between meter bars and specimen

6.4.11 Assumptions of the thermal conductivity of the top and base plate to determine the thermal properties of the dielectric

layer

6.4.12 Determined thermal conductivity of the dielectric layer (@ max pressure)

6.5 The following information show how to use the values from this method for CFD simulation.

Build up a three-layer system in your simulation tool according to Figure 5. Use for upper and lower metal layer the mean value

of the thickness from microsection and the thermal conductivity of each metal layer. Use the mean value of apparent thermal

conductivity (Table 1 Equation 16) and thickness of the dielectric material.

1.0

Scope

This

method describes a technique for evaluat-

ing a material to resist tracking when subjected to a low cur-

rent arc just above the surface of the material. It can be used

on materials of various thickness by stacking materials. This

procedure is based on techniques described in ASTM D495.

2.0

Applicable Documents

ASTM D495

Standard

Test Method for High Voltage, Low-

Current, Dry Arc Resistance of Solid Electrical

Insulation

Manufacturer’s Instruction Manual

3.0

Test Specimens

3.1 Number

Three

specimens shall be used unless other-

wise specified.

3.2

Form

Each

specimen shall be 3.0 in. x 2.0 in. Material

under 0.06 in. in thickness shall be built up to provide a speci-

men at least 0.06 in. but not exceeding 0.125 in. For very thin

laminates a 1/16 in. laminate of the same type may be used

under the actual specimen subjected to the arc, permitting a

reduction of the material required without significantly affecting

the results.

3.3

Location

Specimens

may be cut from any location in a

sheet (except from the outer 1 in. of full size sheets).

3.4

Foil Clad Materials

All

foil clad materials shall have the

foil removed by etching and shall be thoroughly cleaned prior

to conditioning or testing.

4.0

Apparatus/Materials

4.1

Arc

tester (Beckman ART-1

equivalent, see ASTM

D495).

4.2

Tungsten

electrodes (Beckman

equivalent, see

ASTM D495).

4.3

Constant

temperature water bath capable of 50°C ±

2°C, filled with distilled water.

4.4

Beaker

or pan filled with ambient temperature distilled

water.

4.5

Racks

for supporting specimens in the water bath with

all surfaces exposed.

4.6

Shear,

saw or paper cutter for cutting specimen.

4.7

Alcohol

or other solvent for cleaning electrode.

4.8

Crocus

cloth.

4.9

Gage

blocks for checking electrode spacing 0.248 in.

and 0.252 in.

4.10

Lint

free paper towels.

4.11

Variac

autotransformer

type W1OMT or equivalent.

5.0

Procedure

5.1 Preconditioning

Unless

otherwise specified the speci-

mens shall be conditioned for 48 hours (± 2 hours -0 hours) in

distilled water maintained at 50°C ± 2°C. Following this step

the specimens shall be immersed in ambient temperature dis-

tilled water for 30 minutes minimum, 4 hours maximum, to

allow them to reach temperature equilibrium without loss of

moisture.

5.2

Test Conditions

The

test shall be run at ambient tem-

perature 23°C ± 5°C and ambient humidity.

5.3

Equipment set up

5.3.1

The

electrode assembly shall be cleaned thoroughly

using alcohol or other suitable solvent and, if required, with

crocus cloth. The electrode gap shall be adjusted if necessary

to provide a gap of 0.250 in. ± 0.002 in. when the electrodes

ART-1 or ART-2 manufactured by Beckman Instruments Cedar Grove Essex County New Jersey, U.S.A.

2. Electrodes manufactured by Beckman Instruments

3. Variac available from General Radio

The

Institute for Interconnecting and Packaging Electronic Circuits

2215 Sanders Road • Northbrook, IL 60062

IPC-TM-650

TEST

METHODS MANUAL

Number

2.5.1

Subject

Arc

Resistance of Printed Wiring Material

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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rest

on the test specimen.

5.3.2

The

arc tester should be set up for operation in the

automatic mode.

5.3.3

Set

the Variac to the voltage which produces 12,500

volts based on the last calibration of the Instrument (generally

105V to 115V).

5.3.4

Reset

the timer on the tester to ‘‘0’’ seconds if

required.

5.4

Test Procedure

5.4.1

Remove

a preconditioned specimen from the ambient

temperature distilled water and wipe dry with a lint free paper

towel.

5,4.2

Place

a specimen (individual or built up) in the elec-

trode fixture.

5.4.3

Operate

the tester in accordance with the manufactur-

er’s instructions such that an arc is generated and automati-

cally switched as indicated below.

ime (sec) On/Off Time Amperage

0-60 0.25 sec/1.75 sec 10 milliamps

60-120 0.25 sec/0.75 sec 10 milliamps

120-180 0.25 sec/0.25 sec 10 milliamps

180 continuous 10 milliamps

5.4.4

Observe

the arc carefully and, at the point which the

arc disappears and tracking occurs, stop the timer and record

the time for the specimen to the nearest second.

5.4.5

Remove

the specimen, remove and clean the elec-

trodes thoroughly using a solvent and if necessary the crocus

cloth.

5.4.6

Replace

the electrode and check the electrode gap.

5.4.7

Reset

the timer and proceed as in 5.4.1 through 5.4.6.

5.5

Calculation

5.5.1

Average

the values of the specimens tested from the

same sample and round to the nearest second.

5.6

Report

5.6.1

Report

the average value of the arc resistance in sec-

onds.

5.6.2 Report

the ambient temperature and relative humidity

at the time of the test.

5.6.3

Report

how the specimen was prepared, e.g. indi-

vidual, # of plies built up, or with a spacer.

5.6.4

Report

the preconditioning procedure.

5.6.5

Report

any anomalies in the test or variations from

procedures or tolerances specified.

6.0 Note

6.1

The

results of arc tests may be significantly affected by

contamination of the electrodes. Any irregularity of the arc in

the early portion of the test may be an indication of contami-

nation. If this occurs, the test should be stopped, the elec-

trodes cleaned and a fresh specimen should be tested (or the

test may be run in a different area of the same specimen).

6.2

While

values for reinforced material may vary with the

grain direction of reinforcement, the effect is generally insignifi-

cant with glass reinforced product. At least one specimen in

both machine and transverse direction is recommended to

verify this.

IPC-TM-650

Number

2.5.1

Subject

Arc

Resistance of Printed Wiring Material

Date

5/86

Revision

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