Standardization (EW, Sept. 1975)



Component Parts Eng. Dept., Norden Div.. United Aircraft Corp.

Try to imagine the problems there would be without standardization--with 4 million active and 1% million inactive items now federally catalogued--including roughly 225,000 resistors!

STANDARDIZATION is a never-ending quest, in an era of sophisticated dynamic technologies, to properly document and catalogue hardware. The standard of living we enjoy today and the means by which our children will reap the benefits of our continuing research and development can be credited to standardization. Rapid advances in technology and our ever-changing needs have spurred the development of guidelines and standards.

The food we eat, the clothes we wear, the roof over our heads, and virtually every product we use are subject to standards-voluntary or imposed. Voluntary standards have played a significant role in our industrial development and are preferred by many industries rather than government regulation. Standardization has also long been an important element of military logistics and designs, research, development, and engineering. It even helped establish and provide the basis for the mass production and distribution of goods to the civilian population. The military services have had standardization procedures in effect for many years for establishing requirements to be met by contractors.

Experience during two World Wars and the critical international situation that has existed since World War II have demonstrated the importance of standardization.

In order to reduce redundant effort and control documentation of specifications and standards, the Department of Defense set up the Defense Standardization Program. Its purpose was to establish current policies and responsibilities governing the DOD Standardization Program (DSP). The directive applies to all DOD departments and agencies and covers items and related engineering practices, processes, services, and documentation which supports design, development, procurement, production, inspection, supply, maintenance, and disposal functions.

In late 1966 and during 1967, NASA established a branch, called "Prince Apec," at Huntsville, Alabama. Its purpose was to provide a central agency for the collection and exchange of test data from numerous Government sub-contractors. To obtain information or assistance was a simple matter of calling an operator at NASA in Huntsville and indicating the type of data needed. The only requirement for participation in the program was current involvement as a prime or subcontractor on some Government program.

Copies of test data compiled at contractor facilities, in the course of evaluation of components or assemblies, were to be submitted to this information bank so that other manufacturers could benefit too. This was valuable in that it made previously unavailable data accessible. Although a useful service, it was limited primarily to collection of data of interest to NASA and its subcontractors.

A similar program, but far broader in scope, was set up by the military services in March, 1965 and designated IDEP (Interservice Data Exchange Program). This tri-service program was designed to provide automatic interchange of parts/ components test data among Government contractors and agencies, thereby reducing duplicate expenditures for parts testing and improving system reliability. In March, 1968, IDEP was expanded into a storage and retrieval system for all types of data and reports, including environmental test reports and procedures, reliability specifications, failure analysis data, and general technical information as well as reports on research and development. The name was changed to Interagency Data Exchange Program and included the Military Services (Army, Navy, Air Force), the National Aeronautics and Space Administration (NASA), and the Canadian Military Electronics Standards Agency (CAMESA). With the involvement of NASA in the expanded IDEP program, "Prince Apec" was abandoned.

The need for a free exchange of information and conformity to similar standards has long been recognized and many national organizations (EIA, IEEE, ASA, and IHF, among others) have made valuable contributions toward these goals.

There are obvious benefits from standardization such as a reduction in the types, kinds, and sizes of parts that must be stocked. For example, consider a contract such as the F-111 aircraft whose prime contractor is General Dynamics. The subcontractors building constituent assemblies are located throughout the country. If there were no standardization on the use of components, methods of test and evaluation, as well as application, then it would be almost impossible to integrate various subassemblies into a plane.

To cite one example of the immensity of the task, according to a report by the Committee on Government Operations, there are approximately 4 million active and 1 1/2 million inactive items now federally catalogued. There are roughly 225,000 different resistors alone.

The Air Force analyzed the comparative costs of buying parts to MIL-Specs versus the contractor's own drawings after an initial report indicated that the F-111 would have approximately 220,000 nonstandard parts. Investigation disclosed that certain electronic components were being purchased by a number of subcontractors, each of whom had established his own specifications. One might require that the part be burned-in (tested by operating) for 50 hours, a second for 75, a third for 120. Even though the component was the same, it was being processed differently and would therefore be assigned a different stock number. A voluntary effort was made to have the prime contractor meet with his subcontractors and arrive at common specifications on these items, which would then be used to update the military specification if necessary. A similar voluntary program was used on the C-5. It was discovered that five different diodes in the aircraft's various systems had an average cost of $13.60 if supplied from company drawings but $4.53 if bought from MIL-Specs. With 7779 such diodes being used in the plane, savings of $70, 011 per aircraft could be effected.

On any military contract it is usually specified that military standard components (referred to as MIL-STD components) must be used throughout. Any deviation or use of a nonstandard device must be amply justified and reported accordingly. MIL-STD components must meet applicable MIL-Specs and be periodically rechecked to those specifications. Most MIL-STD parts or specifications have an associated QPL list (Qualified Products List). Components from a QPL-listed manufacturer, for a particular MIL-approved part, insures that the component selected can meet applicable MIL-Specs.

If it becomes necessary, either because of a packaging (size) problem or a particular functional design requirement, to use a nonstandard (non-MIL) device, then drawings must be generated describing component requirements. These drawings, as a general rule, must be equal to existing MIL specifications insofar as the requirements for initial qualification testing and lot-acceptance criteria are concerned. Primary deviations from the MIL part are in physical or functional characteristics. A nonstandard part might be used if additional screening or testing over and above the MIL-STD is required to assure even higher reliability. Here, again, a special drawing must be generated.

There are two basic types of drawings used for the purchase of nonstandard parts: Specification Control and Source Control drawings. The primary difference between the two is that the Source Control drawing is used to describe a special device for procurement and complete control is to be exercised over its configuration. Thus any changes that might affect form, fit, or function, sometimes also referred to as process or geometry changes, are prevented or controlled. Also, in the Source Control drawing the approved vendors are the only firms from which the component may be purchased. The Specification Control drawing is a mechanism for describing commercial or catalogue-available components, following essentially the same format as the Source Control drawing but without limitations on configuration or vendors.

Most recent Government contracts make provision for the formation of a Parts Control Board with a requirement that each major subcontractor be a participant. This usually entails meetings once a month in the early stages of the program but less frequently as initial problems are resolved. The primary purposes of such a board are to control component usage, effect commonality wherever possible, and function as a forum where problems, however minor, can be discussed and resolved.

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Power-Supply Improvement


(adapted from: Electronics World magazine; Jul. 1975)


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