MIL-STD-202H.pdf - 第221页

MI L - S TD - 202 - 217 CO NT E N T S PARAGRAPH PAG E FOREW ORD … ………………………………………………………. ii 1. SCOPE 1 1.1 Purpose …… ………………… …………………. …… .. …………. 1 2. APPLICABLE D O C U M EN T S 1 2.1 Non - Govern m e nt pu bl i c at i…

MIL-STD-202-217

FOREWORD

1. This standard is approved for use by all Departments and Agencies of the Department of Defense.

2. This entire standard has been revised. This revision has resulted in many changes to the format, but the most

significant one is the splitting the document into test methods. See MIL-STD-202 for the change summary.

3. Comments, suggestions, or questions on this document should be emailed to std202@dla.mil or addressed to:

Commander, Defense Logistics Agency, DLA Land and Maritime, ATTN: VAT, P.O. Box 3990, Columbus, OH

43218–3990. Since contact information can change, you may want to verify the currency of this address

information using the ASSIST Online database at https://assist.dla.mil.

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MIL-STD-202-217

CONTENTS

PARAGRAPH PAGE

FOREWORD…………………………………………………………. ii

1. SCOPE 1

1.1 Purpose………………………………………….……..…………. 1

2. APPLICABLE DOCUMENTS 1

2.1 Non-Government publications……………………………….… 1

3. DEFINTIONS 1

4. GENERAL REQUIREMENTS 1

4.1 Apparatus……………….…….…………………….….........……. 1

4.2. Procedure…………….………………………..….….………….. 2

4.2.1 Calibration..……………....…………………..……..……………. 2

4.2.2 Test setup…….……………………………………….………….. 2

4.2.3 Test procedure…….…………………………..……..……….…. 2

4.2.3.1 Degausing………………………….…………..……..……….…. 2

4.2.3.2 Lead protection……………….…………..……..…………….…. 2

4.2.3.3 Testing………….…………..……..…………………………..…. 3

4.2.3.4 Marking…….……………….……..…………………………..…. 3

4.2.3.5 Failed units………………….……..…………………………..…. 3

5. DETAILED REQUIREMENTS 3

5.1 Summary…………………………………………..…..…………. 3

6. NOTES 7

6.1 Supersession data………………………………………………. 7

FIGURES PAGE

1. Typical test circuit…………………………………………………………... 4

2. Representative oscilloscope traces..……………………………………... 5

3. Shock test fixture…………………………………………….……………... 6

iii

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MIL-STD-202-217

METHOD 217

PARTICLE IMPACT NOISE DETECTION (PIND)

1. SCOPE

1.1 Purpose. The purpose of this test is to detect the presence of free moving particulate contaminants within

sealed cavity devices. This test method is specifically directed toward relays and other devices where internal

mechanism noise makes rejection exclusively by threshold level impractical. This test method also may be used prior

to final sealing in the manufacturing sequence as a means of eliminating loose particles from the interior of the

device.

2. APPLICABLE DOCUMENTS

2.1 Non-Government publications. The following documents form a part of this document to the extent specified

herein. Unless otherwise specified, the issues of these documents are those cited in the solicitation or contract.

NATIONAL CONFERENCE OF STANDARDS LABORATORIES (NCSL)

NCSL Z540.3 - Requirements for the Calibration of Measuring and Test Equipment

(Copies of this document are available online at www.ncsli.org)

3. DEFINTIONS

This section not applicable to this standard.

4. GENERAL REQUIREMENTS

4.1. Apparatus. The basic PIND system is comprised of the following components: (Substitutions of individual

units or complete system may be made providing the test requirements of paragraph 3 are met.)

a. Vibration power source consisting of electrical driver audio oscillator and low frequency audio amplifier.

b. Ultrasonic sound detection system consisting of a crystal transducer with frequency response of 36 kHz - 44

kHz and associated translator preamplifier capable of converting transducer output to 20 Hz - 5 kHz.

c. Small vibration shaker or two shakers coupled together.

d. Oscilloscope, single beam, with 100 kHz minimum bandwidth capable of external synchronization.

e. Audio speaker or headset.

f. Test fixture to adapt transducer to shaker head and isolate it from external noise sources.

g. Holding fixture designed to hold flat surface of unit under test firmly against the sensing surface of the

transducer.

h. Shock test fixture (see figure 3).

i. Calibration unit per 4.2.1c.

j. Random vibration generator.

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