IPC-TM-650 EN 2022 试验方法.pdf - 第704页

Note: It is important that the IPC receives as much data as possible, whether it be to support previously submitted data, add new data, or provide conflicting data on cer- tain components. All information received will b…

should

be of the same general size and construction as pro-

duction boards. A minimum of five boards shall be run.

4.0

Apparatus

4.1 Tank

Testing

shall be done in an ultrasonic tank, preferably in the

equipment to be used in production. Water is to be used as

the ultrasonic transmission testing fluid, regardless of the

cleaning agent to be used in the production process. Water

will degas, transmit ultrasonics, and cavitate more easily than

most new cleaning agents and is, therefore, considered a

‘‘worst case’’ ultrasonic testing fluid. Care must be taken to

maintain water level during testing. Water temperatures

should be maintained at 60°C ±5°C (140°F ±10°F).

It is recommended that testing equipment operate near 40

KHz or higher and have a power output in the range listed in

the chart below. Power is measured as the output

from

the

generator to the transducers. Note in the chart that the

amount of power necessary is scaled for various tank sizes.

If power densities or frequencies differing from the

ranges listed above are to be used in production, they

should be used in testing as well, and noted on the

Ultrasonic Test Data Record.

5.0

Procedure and Evaluation

Note:

Standard ESD handling methods should be used in

handling and assembly so as not to have ESD damage

misinterpreted as damage by ultrasonic exposure.

5.1

Procedure

5.1.1

Solder

components into (onto) a test circuit board.

Perform functional electrical tests on components to be sub-

jected to ultrasonic energy. It is suggested that all compo-

nents go through standard prescreening tests to eliminate

infant mortality. Note any anomalies and ignore any malfunc-

tions in further testing.

5.1.2

Visually

inspect the solder joints of SMD leads at

10-15x for conformance with J-STD-001. Document any

observed defects with notes or photos.

5.1.3 Fill the test tank with deionized water. Turn on ultra-

sonics and allow a minimum of 15 minutes for the water to

degas. Evidence of cavitation should be obtained by placing a

piece of aluminum foil in the water for one minute and inspect-

ing for an erosion pattern (evidence of cavitational activity). If

the surface of the foil is not disrupted, continue to degas until

the foil confirms ultrasonic activity.

Test components in the equipment described above. Boards

should be placed in the tank in the same quantity and orien-

tation as will be the case in production, taking into consider-

ation the size of the test tank in relation to the production unit.

Boards should be positioned perpendicular to the radiating

surface (tank surface where transducers are mounted) and

should not be allowed to rest on the radiating surface (Figure

1).

Subject specimens to ultrasonics for a time period 10 times

longer than the expected exposure anticipated under normal

cleaning conditions or thirty minutes, whichever is longer.

5.1.3

(Optional)

Conduct any environmental stressing test(s)

as specified by the reliability requirement of the product line in

concern.

5.2

Evaluation Method

5.2.1

Repeat

the functional electrical test in 5.1.1. Any fail-

ures should be analyzed for cause of failure. Any failure,

excluding those noted in 5.1.1 or attributable to a docu-

mented defect, will be considered caused by the ultrasonics.

5.2.2

Repeat

the visual inspections as described in 5.1.2.

Any defect which is not assignable to a previously docu-

mented defect will also be considered caused by ultrasonics.

5.2.3

Any

component exhibiting no failures or 100% reliabil-

ity after ultrasonic testing will be considered safely resistant to

ultrasonics under the conditions tested. Any component with

less than 100% reliability will be suspect unless subsequent

testing can demonstrate that it is 100% reliable. Unless clas-

sified or proprietary, please report test results to the Ultrasonic

Cleaning Task Group of the IPC for compilation in the

attached list.

ank Size liters

(gallons)

Power Density

watts/liter(watts/gallon)

Magnetostrictive Piezoelectric

(5) 66-76 (250-290) 33-38 (125-145)

38 (10) 53-58 (200-220) 26.5-29 (100-110)

95 and greater (25

and greater)

21-32 (80-120) 10.5-16 (40-60)

IPC-TM-650

Number

2.6.9.1

Subject

Test

to Determine Sensitivity of Electronic Assemblies to

Ultrasonic Energy

Date

1/95

Revision

age2of5

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Note:

It is important that the IPC receives as much data as

possible, whether it be to support previously submitted

data, add new data, or provide conflicting data on cer-

tain components. All information received will be

entered into a database for all IPC members to access.

The database will prove more useful as the volume of

data increases.

6.0

Notes

Contact

IPC for a list of tested components.

6.1

References

6.1.1

William

Vuono and Ayche McClung, ‘‘An Update on

an Assessment of Ultrasonic Cleaning Techniques for Military

Printed Wiring Boards,’’ presented at IPC Fall Meeting, 1990.

6.1.2

B.P.

Richards, P. Burton and P.K. Footner, ‘‘Does

Ultrasonic Cleaning of PCBs Cause Component Problems: An

Appraisal,’’ IPC Technical Review, June 1990.

6.1.3

B.P.

Richards, P. Burton and P.K. Footner, ‘‘The

Effects of Ultrasonic Cleaning on Device Degradation,‘‘ Circuit

World. Vol 16, No. 3.

6.1.4

B.P.

Richards, P. Burton and P.K. Footner, ‘‘The

Effects of Ultrasonic Cleaning on Device Degradation—An

Update,‘‘ Circuit World. Vol 17, No. 4.

6.1.5

B.P.

Richards, P. Burton and P.K. Footner, ‘‘The

Effects of Ultrasonic Cleaning on Device Degradation—Quality

Crystal Devices,’’ Circuit World. Vol. 18, No. 4.

6.1.6

B.P.

Richards, P.K. Footner, and P. Burton, ‘‘A Study

of the Effect of Ultrasonic Cleaning on Component Quality—

Hybrid Devices,’’ Circuit World. Vol 19, No.1.

6.1.7 Fritz

Ehorn, ‘‘Final Report on the Structural Dynamic

Analysis of Selected PWB Components Under the 400 Khz

Ultrasonic Cleaning Environment,’’ MEL Ref. MS7507, March

6, 1991.

6.1.8

William

Puskas and Gary Ferrell, ‘‘Process Control

Ultrasonic Cleaning,’’ presented at Nepcon West, 1988.

6.1.9

Kenneth

S. Suslick, ‘‘The Chemical Effects of Ultra-

sound,’’ Scientific American, February, 1989

6.1.10

Ismail

Kashkoush, Ahmed Busnaina, Frederick Kern,

Jr. and Robert Kunesh, ‘‘Particle Removal Using Ultrasonic

Cleaning,’’

Institute of Environmental Sciences, 1990

Proceedings.

IPC-TM-650

Number

2.6.9.1

Subject

Test

to Determine Sensitivity of Electronic Assemblies to

Ultrasonic Energy

Date

1/95

Revision

age3of5

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ

Figure

IPC-TM-650

Number

2.6.9.1

Subject

Test

to Determine Sensitivity of Electronic Assemblies to

Ultrasonic Energy

Date

1/95

Revision

age4of5

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ