IPC-TM-650 EN 2022 试验方法.pdf - 第696页

1 Scope This test method is to determine the physical endurance of applied polymer solder mask to sudden changes of high and low temperature excursions to cause physical fatigue. 2 Applicable Documents IPC-CC-830 Qualifi…

7 Notes

7.1

The design of the thermal cycling system must be flex-

ible enough to allow for an extremely high rate of temperature

change and for the rate of temperature change to be deter-

mined. Some issues to consider are as follows:

• Thermal mass compensation capability (energy vs. time)

• Environmental control capability (heating and cooling)

• Reproducibility of parameters

• Transfer speed (if applicable)

• Heating ramp rate

• Cool down rate

• Programming capability

• Profile memory

7.2 Suggested Drawing Note As this method addresses

assembly issues with printed boards, it is recommended that

the user of the printed board establish a drawing note in the

procurement documentation to provide the printed board fab-

ricators with guidance relative to the intended reflow process

of the printed board. An example of such a drawing note is

provided as follows:

XX. IPC D COUPON TESTING

A. COUPONS SHALL INCLUDE COMPONENT (A), VIA (B)

AND ALL PROPAGATED B STRUCTURES IAW IPC-

2221B APPENDIX A. 2 OF EACH COUPON DESIGN

SHALL BE TESTED PER MANUFACTURING PANEL.

B. THE IPC D COUPONS SHALL BE SUBJECTED TO 6

REFLOW SIMULATIONS IAW IPC-TM-650, METHOD

2.6.27 USING THE [230 °C, OR 245 °C, OR 260 °C]

PROFILE. ACCEPTANCE CRITERIA SHALL BE<5%

CHANGE IN RESISTANCE.

C. AFTER REFLOW SIMULATION TESTING, THE IPC D

COUPONS SHALL BE SUBJECTED TO 100 THERMAL

SHOCKS IAW IPC-TM-650, METHOD 2.6.7.2 FROM

-55C TO [MINIMUM OF (LAMINATE T

–10°C), OR

(REFLOW PEAK TEMPERATURE – 25 °C), OR

210 °C]. ACCEPTANCE CRITERIA SHALL BE<5%

CHANGE IN RESISTANCE.

Note: Parameters in bold should be tailored to each

application.

IPC-TM-650

Number

2.6.7.2

Subject

Thermal Shock, Thermal Cycle and Continuity

Date

3/2020

Revision

Page5of5

Scope

This

test method is to determine the physical

endurance of applied polymer solder mask to sudden

changes of high and low temperature excursions to cause

physical fatigue.

Applicable Documents

IPC-CC-830

Qualification

and Performance of Electrical

Insulating Compounds for Printed Board Assemblies

IPC-SM-840

Qualification

and Performance of Permanent

Coating (Solder Mask) for Printed Boards

Test Specimens

3.1 Qualification Testing

Six

IPC-B-25A test boards (see

Figure 1) coated with solder mask and cured in accordance

with solder mask supplier’s recommendations.

3.2

Conformance Testing

Six

IPC-B-25A boards (see Fig-

ure 1) containing the C pattern (‘‘Y’’ pattern) with 0.635 mm

lines/0.635 mm spacing [25.00 mil lines/25.00 mil spacing] or

minimum spacing on the production board, whichever is

smaller, coated with solder mask according to the coating

supplier’s recommendations.

Apparatus

4.1 Chamber

Automatically

controlled dual temperature

environmental test equipment or two separate chambers

capable of maintaining -65° ± 5°C [-85° ± 9°F] and +125° ±

5°C [+257° ± 9°F].

Procedure

5.1 Specimen Preparation

order to test the compatibil-

ity of solder mask with conformal coating, conformal coat

three of the above test specimens with a coating in accor-

dance with IPC-CC-830 and cure in accordance with the

coating supplier’s recommendations

5.2

Test

5.2.1

Place

the test specimens into the test chamber, so that

they do not touch one another, and set the parameters as fol-

lows:

a. Temperature Extremes: as specified in IPC-SM-840 ± 5°C

[± 9°F].

b. Dwell Time at Temperature Extremes: 15 minutes

c. Transfer Time: Less than two minutes

d. Number of Cycles: 100

5.2.2

Activate

the test chamber and begin testing.

5.2.3

One

thermal cycle consists of the following:

a. Expose the specimens to the high temperature for 15 min-

utes.

b. Transfer the specimens to the low temperature in less than

two minutes.

c. Expose the specimens to the low temperature for 15 min-

utes.

d. Transfer the specimens to the high temperature in less

than two minutes.

IPC-2673-1

Figure

1 IPC-B-25A Test Board

2215

Sanders Road

Northbrook, IL 60062-6135

IPC-TM-650

TEST

METHODS MANUAL

Number

2.6.7.3

(Supersedes

2.6.7.1 for Solder Mask Test)

Subject

Thermal Shock - Solder Mask

Date

07/00

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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5.2.4

Repeat

the above cycle to 100 cycles without interrup-

tion.

5.2.5

Remove the specimens and allow them to reach labo-

ratory conditions as specified in IPC-SM-840.

5.2.6

Evaluation

Examine the specimens, on both sides,

for all visual requirements of IPC-SM-840 using 10X magnifi-

cations (Referee of 30X magnifications).

Note: The presence of cracks in solder mask is not a suffi-

cient reason for rejection unless the conformal coating has

also cracked. Report findings and support results with the

photographs, if appropriate.

IPC-TM-650

Number

2.6.7.3

Subject

Thermal

Shock - Solder Mask

Date

07/00

Revision

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