MIL-PRF-83421 Capacitors, Fixed, Metallized, Plastic Film Dielectric, \(Dc, Ac, Or Dc And Ac\), Hermetically Sealed In Metal Cases Or Ceramic Cases, Established Reliability, General Specification ForThis specification covers the general requirements for established reliability \(ER\), metallized plastic film dielectric, fixed capacitors, hermetically sealed in metal or ceramic cases. Capacitors covered by this specification have failure rate levels \(FRL\) established in accordance with MIL-STD-690. The reliability for each level is identified by a symbol in accordance with table I. These FRLs are established at a 90 percent confidence level and maintained at a 10 percent producer\'s risk and, unless otherwise specified \(see 3.1\), are based on life tests performed at maximum rated voltage at maximum rated temperature. Unless otherwise specified \(see 3.1\), an acceleration factor of 5:1 has been used to relate life-test data obtained at 140 percent of rated voltage at maximum rated temperature, to rated voltage at maximum rated temperature \(see 6.1\). A part per million \(PPM\) quality system is used for documenting and reporting the average outgoing quality of capacitors supplied to this specification. Statistical process control \(SPC\) techniques are required in the manufacturing process to minimize variation in production of capacitors supplied to the requirements of this specification.

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MIL-PRF-83421E

4.6.1.2.4 PPM calculations. The manufacturer shall establish a PPM system in accordance with 3.3.2 for

assessing and calculating average outgoing quality of capacitors. A PPM rate combining capacitance, DF, IR

(+25�C), and ESR shall be assessed for lots that have passed the group A inspection. The manufacturer's PPM

system shall also address rectification procedures for lots failing PPM assessment. Data from the rectification

process shall not be used to calculate PPM.

4.6.2 Periodic group B inspection. Periodic group B inspection shall consist of the tests specified in table V, in the

order shown, and shall be performed on sample units selected from inspection lots that have passed group A

inspection. Except where the results of these inspections show noncompliance with the applicable requirements (see

4.6.2.3), delivery of products that have passed group A shall not be delayed pending the results of periodic

inspection.

4.6.2.1 Sampling plan.

4.6.2.1.1 Subgroup 1. Every 2 months, 12 sample units from production shall be inspected as shown in table V.

4.6.2.1.2 Subgroup 2. A minimum of 10 sample units shall be selected from each group A inspection lot as

defined in 4.6.1.1.1. The actual number of sample units required to maintain the required FRL may be more.

If qualification has been granted at the "R" or "S" FRL for MIL-PRF-83421/2 styles (CRH11, CRH12, and CRH13),

and production is not sufficient to maintain the FRL, qualification may be maintained by similarity with MIL-PRF-

83421/1 styles. However, a minimum number of hours shall be generated from MIL-PRF-83421/2 styles to maintain

"P" FRL. This may require more than the minimum number of 10 sample units. Similarity may only be used for FRL

maintenance and not for initial qualification.

4.6.2.1.3 Subgroup 3. Sample units of the same style shall be inspected (see 3.1). Testing need only be done in

January and July (30 V dc units); February and August (50 V dc units); March and September (100 V dc units); April

and October (200 V dc units); May and November (400 V dc units); and June and December (300 V dc and 600 V dc

units).

4.6.2.1.4 Subgroup 4. Every 6 months, 2 sample units of each case diameter produced shall be inspected as

shown in table V. The maximum and minimum case sizes manufactured shall be represented in the sample in at

least the approximate ratio of production.

4.6.2.1.5 Subgroup 5. Every 6 months, 18 sample units from production shall be divided and inspected as shown

in table V. The maximum and minimum case sizes manufactured shall be represented in the sample in at least the

approximate ratio of production.

4.6.2.2 Disposition of sample units. Subgroup 2 through subgroup 5 inspections are considered destructive.

Sample units that have been subjected to these inspections shall not be delivered on the contract.

4.6.2.3 Noncompliance. If a sample unit fails to pass group B inspection, the manufacturer shall notify the

qualifying activity and cognizant activity of such failure and take corrective action on the materials or processes, or

both, as warranted, and on all units of product which can be corrected and which were manufactured under

essentially the same conditions, with essentially the same materials, processes, and so forth, and which are

considered subject to the same failure.

4.7 Methods of inspection and test.

4.7.1 Visual and mechanical inspection. All capacitors shall be examined using 5X to 7X magnification to verify

that the materials, design, construction, physical dimensions, marking, and workmanship are in accordance with the

applicable requirements (see 3.1, 3.4, 3.5, 3.31, and 3.33).