IPC-TM-650 EN 2022 试验方法.pdf - 第569页

6.1 The dielectric breakdown of the material may be adversely affected if the drilling process used to produce the holes is inadequate. Use of a sharp high speed drill is recom- mended to prevent burning the material or …

5.2

Test Condition

The

test shall be performed at ambient

temperature (23°C ± 5°C). Relative humidity is not significant

as the tests are performed under oil.

5.3

Equipment Set Up

5.3.1

Adjust

the transformer on the high voltage tester

(manually for most models) to the position which will allow for

the necessary voltage to be achieved with adequate current

capacity for breakdown.

5.3.2

Set

the machine for testing using a 500 volt per sec-

ond rate of rise.

5.4

Test

5.4.1

Remove

a preconditioned specimen from the ambient

temperature water and wipe dry with a lint free paper towel.

5.4.2 Insert

the first specimen into the fixture (inserting the

tapered pins from opposite sides) and immerse in the oil bath.

5.4.3

Attach

leads (if not permanently wired) so that one

high voltage lead is connected to one tapered pin electrode

and the ground lead is connected to the other tapered pin

electrode.

5.4.4

Operate

the tester such that the voltage is applied with

a 500 volts per second rate of rise and observe the specimen

until an electrical breakdown occurs.

5.4.5

Record

the voltage at which breakdown occurs, using

the meter memory device if available.

Note:

the breakdown

appears to be in the oil and no specimen damage is obvious

it is recommended that the same sample be retested. If the

specimen still will not breakdown due to breakdown of the oil,

the oil should be filtered or replaced.

5.4.6

Determine

the starting voltage and steps for the

remaining specimens from the same sample from Table 1.

5.4.7

Change

the high voltage tester to manual (or pro-

grammed stepped) operation, remove a specimen from the

water bath, wipe dry, and insert the second specimen.

5.4.8

Set

the voltage to the 50% value (plus or minus the

value of one step) and apply the voltage for 60 seconds.

5.4.9 If

no breakdown occurs increase the voltage in steps

per Table 1 until the material breaks down or the breakdown

capacity of the machine or oil is reached. Record the break-

down voltage to the nearest kilovolt or record ‘‘N. B.’’ if there

is no breakdown of the material.

Note:

the minimum value

required by the material specification is not exceeded, but

material breakdown does not occur, it is necessary to replace

or filter the oil.

5.4.10

Repeat

steps 5.4.7-5.4.9 for the remaining speci-

mens from the sample.

5.5

Calculation

5.5.1

Average

the values for the three specimens tested

using the stepped technique and round to the nearest kilovolt.

Even if some specimens do not break down, the maximum

individual voltages will be used to calculate an average.

Note:

the accuracy of the meter on the machine is not within 5%

for all values in the range, apply a correction obtained from the

last machine calibration to each reading to determine the

actual value for the dielectric breakdown.

5.6

Report

5.6.1

Report

the average value of the dielectric breakdown

(if all specimens actually breakdown), e.g., 85KV average.

5.6.2

Report

the average with a plus after the value if one or

two specimens do not break down, e.g., 82 + KV average

2NB.

5.6.3

Report

the minimum value at which the oil broke

down, if no actual specimen breakdowns are obtained, e.g.,

75 + KV N.B.

5.6.4

Report

any anomalies in the test or any variations from

prescribed procedures or tolerances.

6.0 Notes

able 1 Voltage increments for Step by Step Test

Breakdown

Voltage (KV) Increment KV

less than 12.5 0.5

over 12.5 to 25 1.0

over 25 to 50 2.5

over 50 to 100 5

over 100 10

IPC-TM-650

Number

2.5.6

Subject

Dielectric

Breakdown of Rigid Printed Wiring Material

Date

5/86

Revision

age2of3

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ

6.1

The

dielectric breakdown of the material may be

adversely affected if the drilling process used to produce the

holes is inadequate. Use of a sharp high speed drill is recom-

mended to prevent burning the material or producing rough

holes.

6.2 This test requires voltages which are life threatening. The

High Voltage Tester must be installed and operated in accor-

dance with the manufacturer’s instructions. If the test cham-

ber is not totally enclosed, with a safety interlock, extreme

care must be exercised in performance of the test.

IPC-TM-650

Number

2.5.6

Subject

Dielectric

Breakdown of Rigid Printed Wiring Material

Date

5/86

Revision

age3of3

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ

1 Scope The dielectric strength test (also called high-

potential [Hi-Pot], over potential, or voltage breakdown) con-

sists of the application of a test voltage for a specific time

between mutually insulated portions of a printed board or

between insulated portions and ground. This is used to prove

that the printed board can operate safely at its rated voltage

and withstand momentary overpotentials due to switching,

surges, and other similar phenomena.

2 Applicable Documents

ASTM D 149

Standard Test Method for Dielectric Break-

down Voltage and Dielectric Strength of Solid Electrical Insu-

lation Materials at Commercial Power Frequencies

3 Test Specimen Three 102 mm x 102 mm [4.016 in x

4.016 in] squares of glass epoxy laminate materials having

1 ounce (0.0343 mm [0.00135 in] nominal) copper foil lami-

nates on one side, and having the test specimen polymer film

applied to the copper surface (see specimen preparation).

4 Apparatus

4.1

Any high voltage potential test equipment capable of

providing voltage increases of 500 VDC per second, up to at

least 10,000 VDC (see Section 6).

4.2 A standard Type 1 electrode per ASTM D 149, with a 51

mm [2.0 in] diameter, 25 mm [1.0 in] thick, with edges

rounded to 6.4 mm [0.25 in.] radius to cover the test surface.

5 Procedure

5.1 Preparation of Test Specimen

5.1.1

Cut the laminate specimen to 102 mm x 102 mm

[4.016 in x 4.016 in] and sand the edges lightly.

5.1.2 If double clad material is used, etch off all copper foil

on one side.

5.1.3 Clean the copper foil surface thoroughly, per the poly-

mer manufacturer’s recommendations, prior to applying poly-

mer coating.

5.1.4 Apply a film of the polymer test material on an area of

76.2 mm x 76.2 mm [3.0 in x 3.0 in] at the center of the cop-

per clad surface. A pinhole free film is essential.

5.1.5 Cure the polymer coating per manufacturer’s recom-

mendations.

5.2 Test

5.2.1

Clip the ground terminal of the tester over the thick-

ness of the copper foil and substrate, being careful not to let

the clip extend inward to the polymer coating (see Figure 1).

5.2.2 Place the positive electrode on top of test panel at the

center. Make certain the electrode and clip are electrically iso-

lated by the test polymer film.

5.2.3 Set up the potential voltage tester. Increase the volt-

age 500 VDC per second, until specimen exceeds require-

ment or breakdown occurs.

5.2.4 Measure the coating thickness of each of the test

specimens to the nearest 0.0025 mm [0.0001 in] in at least

four locations. Compute the average coating thickness and

standard deviation.

5.3 Evaluation Determine the dielectric strength, E

, using:

where t is the thickness of the specimen, to the nearest

0.0025 mm [0.0001 in], measured in 5.2.4 and V

the breakdown voltage measured in 5.2.3. Record results as

‘‘V/mm’’ or ‘‘V/in.’’

6 Notes

6.1

Suggested source for tester: Hipotronics Model HD-140

from Hipotronics, Inc. Brewster, NY 10509, or equivalent.

6.2 Safety must be exercised because of the potential dan-

ger of electrical shock.

IPC-2561-1

Figure 1

3000 Lakeside Drive, Suite 309S

Bannockburn, IL 60015-1249

IPC-TM-650

TEST METHODS MANUAL

Number

2.5.6.1

Subject

Solder Mask - Dielectric Strength

Date

03/07

Revision

Originating Task Group

Solder Mask Performance Task Group (5-33b)

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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