IPC-TM-650 EN 2022 试验方法.pdf - 第658页

6.1.2 Comb Patterns Various ‘‘comb patterns’’ can be properly tested following the procedures in this document. The test points for comb patterns such as in Figure 3 are 1 to 2, 2 to 3, 3 to 4, and 4 to 5. Test points 1-…

IPC-263-01

Figure

1 Moisture and Insulation Resistance Test Graph

IPC-263-2

Figure

2 Insulation Resistance Coupon E (See Table 7-3), mm [in]

IPC-TM-650

Number

2.6.3

Subject

Moisture

and Insulation Resistance, Printed Boards

Date

05/04

Revision

age3of4

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6.1.2

Comb Patterns

Various

‘‘comb patterns’’ can be

properly tested following the procedures in this document.

The test points for comb patterns such as in Figure 3 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.

6.1.3

Production Board Testing

Occasionally,

production

boards must be tested in lieu of test patterns. When this is

required, one must use good judgment and select adjacent

conductors for wiring terminal lands for testing, because con-

ductor spacing and placement can affect test results.

6.2 Documented alternative cleaning procedures may be

implemented. As an example, if there is a concern that scrub-

bing will adversely affect test results, e.g., when the test

specimens have very fine spacing and/or are plated with soft

metals (tin/lead, gold, etc.).

6.3 If

printed boards are to be stored before coating, place

the boards in a dry noncontaminating environment.

6.4

Performance

specifications should specify the method

of test specimen preparation, test condition class, and any

deviations to this test method.

6.5

The

test chamber should be constructed out of materi-

als that will not corrode or add ionic contamination to the test

environment.

IPC-263-3

Figure

3 Typical ‘‘Comb Pattern’’ (from IPC-B-25A)

IPC-TM-650

Number

2.6.3

Subject

Moisture

and Insulation Resistance, Printed Boards

Date

05/04

Revision

age4of4

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1 Scope This test method is used to determine the mois-

ture and insulation resistances of applied polymer solder mask

under two separate prescribed conditions of temperature and

humidity. One condition is described as Class T and the other

Class H. Raw material qualification testing is performed on

designated comb patterns. Production quality conformance

testing is performed on a standard ‘‘Y’’ pattern.

2 Applicable Documents

IPC-A-25A-G-KIT

Multipurpose One-Sided Test Pattern -

Gerber Format

IPC-SM-840 Qualification and Performance of Permanent

Solder Mask

J-STD-004 Requirements for Soldering Fluxes

IPC-A-600 Acceptability for Printed Boards

3 Test Specimens The IPC-A-25A-G-KIT artwork package

provides the Gerber files necessary for the fabrication of the

standard IPC-B-25A test board used with this test method.

3.1 Qualification Testing

3.1.1 Class H

Three IPC-B-25A boards using the D comb

patterns with 0.32 mm [0.0126 in] lines/spaces (see Figure 1).

Of which, two are to be coated and one uncoated with solder

mask according to the solder mask supplier’s recommenda-

tions.

3.1.2 Class T Three IPC-B-25A boards using the E and F

comb patterns with 0.41 mm [0.016 in] lines and 0.51 mm

[0.020 in] spaces (see Figure 1). Of which, two are to be

coated and one uncoated with solder mask according to the

solder mask supplier’s recommendations.

3.2 Conformance Testing IPC-B-25A board C (‘‘Y’’

shape) pattern with 0.64 mm lines/0.64 mm spacing [0.025 in

lines/0.025 in spacing] or pattern with minimum spacing on

the production board (see Figure 1), whichever has the small-

est line spacing, coated with solder mask according to the

solder mask suppliers recommendations.

4 Apparatus

4.1 Chamber

A clean chamber capable of programming

and recording an environment of 25±2°C[77±3.6°F]toat

least 65±2°C[149 ± 3.6 °F] and 90-98% relative humidity.

NOTE: This test requires a clean chamber and clean water

for repeatable test results. The following recommendations

are made:

• Incoming water purity should be between 0.5 and 0.1

micro-siemens/cm.

• Fresh deionized water should be used for each test, rather

than using a recirculating water sump.

• Chamber workspaces should be cleaned at least every six

months.

1. www.ipc.org/onlinestore

IPC-2631-1

Figure 1 IPC-B-25A Test Board

3000 Lakeside Drive, Suite 309S

Bannockburn, IL 60015-1249

IPC-TM-650

TEST METHODS MANUAL

Number

2.6.3.1

Subject

Solder Mask - Moisture and Insulation Resistance

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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