IPC-TM-650 EN 2022 试验方法.pdf - 第709页

6.0 Notes Contact IPC for a list of test 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…

4.1

Tank

Testing

shall be done in an ultrasonic tank, pref-

erably 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 eas-

ily than most new cleaning agents and is, therefore, consid-

ered a ‘‘worst case’’ ultrasonic testing fluid. Care must be

taken to maintain water level during testing. Water tempera-

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

It is recommended that testing equipment operate near 40Khz

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

chart below. Power is measured as the output from the gen-

erator to the transducers. Note in the chart that the amount of

power necessary is scaled for various tank sizes.

ank Size

liters (gallons)

Power Density

watts/liter (watts/gallon)

Magnetostrictive Piezoelectric

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

38 (10) 53-68 (200-220) 26.5-29 (100-110)

95 and greater

(25 and greater)

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

If frequencies other than 40 KHz range or power densities or fre-

quencies 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.

4.2 Basket

Loose

components will be placed randomly in

a basket or in a beaker (pyrex or stainless steel) for testing. If

a basket is used, it should be made of stainless steel and

preferably have a solid bottom for optimal ultrasonic transmis-

sion. Tight mesh should always be avoided. If a beaker is

chosen, plastic is not acceptable as it will dampen ultrasonic

transmission.

5.1

Procedure

Note:

Standard ESD handling methods should be used in

handling and assembly so as not to have ESD damage misin-

terpreted as damage by ultrasonic exposure.

5.1.1

Perform

functional electrical tests on components to

be subjected to ultrasonic energy. All components should go

though standard prescreening tests to eliminate infant mortal-

ity. Note any anomalies and ignore any malfunctions in further

testing.

5.1.2 Fill

the test tank with de-ionized 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. Place

components randomly in basket or in a beaker. Baskets

should be suspended off the bottom of the tank or contain

stand off legs to keep it from setting directly on the bottom of

the tank. If a beaker is to be used, it should be filled with

deionized water and degassed as described in the above

paragraph. The beaker should be suspended in the water-

filled tank and not placed on the tank bottom.

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 also be considered caused by the ultrason-

ics.

5.2.2

Any

defect which is not assignable to a previously

documented defect will also be considered caused by ultra-

sonics.

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

Energy Task Group through the IPC for compilation in the

attached list.

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 for cer-

tain components. All information received will be

entered into a database for all IPC members to access.

The data will prove more useful as the volume of data

increases.

IPC-TM-650

Number

2.6.9.2

Subject

Test

to Determine Sensitivity of Electronic Components to

Ultrasonic Energy

Date

1/95

Revision

age2of4

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6.0

Notes

Contact

IPC for a list of test 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 - Quartz

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

2.6.9.2

Subject

Test

to Determine Sensitivity of Electronic Components to

Ultrasonic Energy

Date

1/95

Revision

age3of4

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Ultrasonic

Test Data Record

Name

of tester

Date

Company

Address

Phone Fax

Make

and model of equipment

ank size (liters)

Dimensions

(cm x cm x cm)

Generator

output power (watts)

Frequency

(KHz)

No.

of boards tested per trial

Substrate

Exposure

time (minutes)

Other

stress testing (pre- or post-)

Describe

Component

tested No. tested Passed Failed Comments

Type Mfgr Part #

Mail

to: IPC Fax to: 847-509-9798

2215 Sanders Road

Northbrook, IL 60062-6135

Attn: Ultrasonic Cleaning Task Group

IPC-TM-650

Number

2.6.9.2

Subject

Test

to Determine Sensitivity of Electronic Components to

Ultrasonic Energy

Date

1/95

Revision

age4of4

电子技术应用　　　　　　　ｗｗｗ．ＣｈｉｎａＡＥＴ．ｃｏｍ