IPC-TM-650 EN 2022 试验方法.pdf - 第794页

IPC-3-8-4 Figure 4 T olerances for T erminal-Peak Sawtooth Shock Pulse IPC-3-8-5 Figure 5 T olerance Limits for Measuring System Frequency Response IPC-TM-650 Number 3.8 Subject Mechanical Shock, Connectors Date 7/75 Rev…

5.2.2 The test sample shall be connected to the discontinu-

ity monitor and a minimum current of 100 milliamperes shall

be established in the series circuit comprising all contacts of

the test sample.

5.2.3 The test sample shall be subjected to three (3) shocks

in each direction along each of three (3) orthogonal axes (18

shocks total). During and after the application of each shock,

the contacts shall be monitored for discontinuities in excess of

1 microsecond.

NOTE:

The oscillogram should include a time about 3D long

with the pulse approximately in the center. The integration to

determine the velocity change should extend from 0.4D

before the pulse to 0.1D beyond the pulse. The peak accel-

eration,

magnitude of the sawtooth pulse is P and its duration is D.

Any measured acceleration pulse which can be contained

between the broken line boundaries is nominal terminal-peak

sawtooth pulse of nominal peak value, P, and nominal dura-

tion, D. The velocity-change associated with the measured

acceleration pulse is V.

6.0 Notes

6.1

Acceptance criteria shall be established in terms of one,

or any combination, of the following:

A. Loss of continuity during or after any imposed shock.

B. Mechanical damage,

IPC-3-8-3

Figure 3 Tolerances for Half Sine Shock Pulse

IPC-TM-650

Number

3.8

Subject

Mechanical Shock, Connectors

Date

7/75

Revision

Page4of5

IPC-3-8-4

Figure 4 Tolerances for Terminal-Peak Sawtooth Shock Pulse

IPC-3-8-5

Figure 5 Tolerance Limits for Measuring System Frequency Response

IPC-TM-650

Number

3.8

Subject

Mechanical Shock, Connectors

Date

7/75

Revision

Page5of5

1.0 Scope

1.1

To determine the effects of a controlled salt laden atmo-

sphere on connector components, finishes and mechanisms.

This test is intended to explore the corrosion resisting proper-

ties of various materials and finishes and not to simulate cli-

matic conditions of a seacoast or shipboard environment.

2.0 Reference Documents

2.1

Information in this section is intended to parallel the test

method described in EIA-RS-364/TP-26.

3.0 Test Specimen

3.1

A connector (plug and receptacle) complete with appli-

cable guide, keying, and engaging hardware or a card-edge

receptacle and mating printed circuit board (if required by the

individual connector specification). The connector or recep-

tacle shall be mated unless otherwise specified in the indi-

vidual connector specification.

3.2 Neither the plug nor receptacle shall be mounted or ter-

minated during this test, unless such mounting (or termination)

is necessary (1) to insure the mechanical integrity of the com-

ponent, (2) to measure the specified electrical characteristic(s),

(3) was a requirement of previously imposed environmental or

functional tests.

3.3 Printed circuit boards and electrical connections to the

test specimen, except those connections considered under

test, may be coated with a suitable wax to inhibit corrosion.

The coating shall not be applied to any termination or portion

of the connector under test.

3.4 The plug, receptacle, or mated connector shall be sus-

pended or supported within the test chamber in a normal (or

typical) mounting attitude using non-corrosive material (e.g.,

plastic rods, hooks, waxed string, etc.). The test specimens

shall be positioned so that they do not shield each other from

the freely settling fog, and so that corrosion products and

condensate from one specimen do not fall upon another.

4.0 Apparatus

4.1

A chamber capable of maintaining a dry bulb tempera-

ture of +35°C (+1.1, -1.7°C) within the exposure zone. Satis-

factory methods for controlling the temperature are: (1) hous-

ing the chamber in a properly controlled constant-

temperature room; (2) insulating the chamber and pre-heating

the air to the proper temperature prior to atomization; (3) jack-

eting the chamber and controlling the temperature of the

water or air within the jacket.

NOTE:

The use of immersion heaters within the exposure

zone to maintain temperature is prohibited.

The chamber and all accessories exposed to the salt fog

atmosphere shall be constructed of non-reactive material

(e.g., glass, hard rubber, plastic, or wood other than ply-

wood). The exposure zone shall be vented to prevent a pres-

sure build-up affecting test conditions.

4.2 A compressed air supply free from all impurities such as

oil and dirt. Means shall be provided to humidify and warm the

compressed air as required to meet the operating conditions.

The air pressure shall be suitable to produce a finely divided

dense fog with the atomizer(s) used. To insure against clog-

ging of the atomizer(s) by salt deposition, the air should have

a relative humidity at the point of release from the nozzle

greater than 85 percent for the 20 percent solution and

greater than 95 percent for the 5 percent solution. A satisfac-

tory method of humidification is to pass the air in very fine

bubbles through a tower containing heated water. The tem-

perature of the water should be 35°C or higher, as necessi-

tated by increasing volume of air flow or increasing heat loss

through the chamber walls; it should not exceed a value

above which an excess of moisture is introduced into the

chamber or a value which makes it impossible to maintain the

operating temperature.

4.3 Atomizer(s) capable of an approximate atomization rate

of 3 quarts of salt solution per 10 cubic feet of exposure zone

volume per 24-hour period of test. The atomization and dis-

persion shall be such that a suitable receptacle at any point in

the exposure zone will collect 0.5 to 3.0 milliliters of solution

per hour for each 80 square centimeters of horizontal collect-

ing area (10 centimeters diameter) based on a minimum col-

lection period of 16 hours. The specific gravity of collected

solution shall meet the specified requirements of paragraph

4.4.

2215 Sanders Road

Northbrook, IL 60062-6135

IPC-TM-650

TEST METHODS MANUAL

Number

3.9

Subject

Salt Spray, Connectors

Date

7/75

Revision

Originating Task Group

N/A

Material in this Test Methods Manual was voluntarily established by Technical Committees of the 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 the IPC.

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