IPC-TM-650 EN 2022 试验方法-- - 第768页

t1 210 ± 15 – Target pre heat time t2 270 ± 10 – Target peak r eflow time t3 330 ± 15 – Target cool-d own start ti me t3 - t 1 120 ± 30 – Target time above T1 T1 – 230 Maximum preheat temperature T2 – 260 ± 5 Ta rget ref…

4.2 Convection Reflow Oven or Simulator

4.2.1

The system used to simulate the thermodynamic

effects of assembly

be convection reflow.

4.2.1.1

The system have adequate environmental

controls to maintain the tolerance range and limits in accor-

dance with the reflow profile depicted in either Figure 5-1,

Figure 5-2 or Figure 5-3.

4.2.1.2

The system should accommodate verifiable calibra-

tion compliance and reflow profile generation. See note 6.1 for

additional considerations.

4.2.1.3

The test specimen be handled and stored in a

controlled environment to minimize moisture ingression. See

IPC-1601 for details on the proper handling and storage of

test specimens.

4.2.2

Deviations to the equipment requirements and

acceptability of the alternative methods

be AABUS.

4.3 Microscope

4.3.1

The magnification used for defect recognition must be

in agreement with the inspection requirements/capabilities

defined in the applicable performance specification (e.g., IPC-

6012, IPC-6013, IPC-6018, etc.) and IPC-A-600.

4.4 Resistance Measurements of IPC-2221 Appendix A,

D Coupons

4.4.1

When specified by performance specification or pro-

curement documentation, resistance measurements of the

IPC-2221B Appendix A, D coupons

be required.

4.4.2

The resistance measurement have enough pre-

cision to clearly determine the resistance percent change as

required by the user for the resistance level of each sample’s

nets.

4.4.3

The total system uncertainty from resistance, tem-

perature and time/cycle variations

be less than 10% of

the failure criteria required by the user. For example, if the

required failure criteria is 5% then the total system uncertainty

be no greater than 0.50%.

4.4.4

The resistance data consist of at least 1 reading

per sample net every second during the entire reflow cycle.

5 Procedure

5.1 Conditioning

5.1.1 The test specimen be conditioned by drying in an

oven to remove moisture for a minimum of six (6) hours at 105 to

125 °C [221 to 257 °F].

5.1.2

Test specimens that are thicker or more complex may

require longer baking times to achieve acceptable moisture

levels. Record the bake times and temperature if different than

those stated in 5.1.1. See IPC-1601 for additional guidance

on baking to achieve acceptable moisture levels. See note

6.2.

5.1.3

Deviations to the conditioning requirements in 5.1.1

such as when used for acceptance criteria and/or any

changes to the time and temperature

be AABUS. See

6.3.

5.2 Reflow Profile

5.2.1

Reflow the test specimen in accordance with Table

5-1 (default), Table 5-2 (low temperature profile) or Table 5-3.

5.2.2

The reflow profile be in accordance with either

Figure 5-1, Figure 5-2 or Figure 5-3. Figure 5-1 represents the

default reflow profile. Figure 5-2 represents the low tempera-

ture profile. Figure 5-3 represents a 245 °C reflow profile. The

times to t1, t2 and t3 may vary based on the mass of the

sample test specimen. To avoid over stressing of samples,

times should be shortened for low mass samples. Times

should be extended for high mass samples, such that the

zone (air) temperature

be more than 25 °C above

the target surface temperature at any point in the cycle.

The attachment of thermocouples to the sample test speci-

men

be such that the reflow profile is calibrated to the

surface temperature of the test specimen.

5.2.3

The test specimen be subjected to a minimum

of six (6) reflow cycles.

5.2.4

The cool down rate be in accordance with Table

5-1, Table 5-2 or Table 5-3, based on the reflow profile

selected in 5.2.1. The cool down is complete when the test

specimen reaches 45 °C. The test specimen

achieve a

thermal equilibrium of 45 °C or less prior to starting the next

reflow cycle. If the time it takes to achieve thermal equilibrium

cannot be determined, then a five (5) minute dwell between

reflow cycles

be required.

5.2.5

Deviations to the reflow profile or number of cycles

be AABUS.

Number

2.6.27

Subject

Thermal Stress, Convection Reflow Assembly Simulation

Date

2/2020

Revision

IPC-TM-650

shall

not

shall

Page

t1 210 ± 15 – Target preheat time

t2 270 ± 10 – Target peak reflow time

t3 330 ± 15 – Target cool-down start time

t3 - t1 120 ± 30 – Target time above T1

T1 – 230 Maximum preheat temperature

T2 – 260 ± 5 Target reflow temperature

A 0 30

Upper specification limit values

B 100 230

C 195 230

D 255 265

E 285 265

F 345 230

G 550 30

H 30 30

Lower specification limit values

I 157 93

J 225 230

K 260 255

L 280 255

M 315 230

N 383 30

A-B & I-J 2.0 Maximum preheat rate

H-I 0.5 Minimum preheat rate

F-G -1.0 Minimum cool-down rate

M-N -3.0 Maximum cool-down rate

Number

2.6.27

Subject

Thermal Stress, Convection Reflow Assembly Simulation

Date

2/2020

Revision

IPC-TM-650

―

Table

5-1

260

Nominal

Reflow

Profile

Specifications

(Default)*

Value

Time

(Seconds)

Temperature

(

℃)

Description

Point

Time

(Seconds)

Temperature

(

℃)

Description

Segment

Slope

(

℃

second)

Description

Page

IPC-2627-5-1

Number

2.6.27

Subject

Thermal Stress, Convection Reflow Assembly Simulation

Date

2/2020

Revision

IPC-TM-650

260

Reflow

Profile

Specifications

Figure

5-1

260

Nominal

Reflow

Profile

Chart

(Default)*

JnlB-l

Page