Standards in the design and construction of electronic devices

According to GOST 1.0—68, standardization is the establishment and application of rules for the purpose of streamlining activities in a particular area. Standardization is based on the combined achievements of science, technology, and best practices.

Standard - a regulatory and technical document that establishes a set of rules, regulations, requirements and approved by the competent authority. The standard can be developed both for products and for norms, rules, requirements for them of organizational, methodical and general technical nature.

The main objectives of standardization: the acceleration of technical progress, increasing the efficiency of social production, productivity of engineering labor, etc. The main objectives of standardization:

• development of requirements for the quality of finished products based on the comprehensive standardization of their characteristics, as well as the materials and component parts required for their manufacture with high quality and efficient operation;
• establishment of requirements and methods in the field of design and production of radio electronic facilities in order to ensure their optimum quality and exclude irrational diversity of types and sizes;
• the introduction of uniform documentation systems, including unified ones used in automated control systems;
• the establishment of common terms and notation. Standards according to GOST 1.0–68 are divided into categories: State standards of the USSR — GOST index; industry standards — the OST index; Republican Standards - PCT Index; standards of enterprises — the STF index.

The system of standards ESKD has the greatest application in the design of radio electronic devices.

The technological designer has to deal with hundreds and thousands of different GOSTs, industry standards and enterprise standards. Therefore, reference books on the GOST nomenclature, which should be able to use, and the use of AIPS are of great importance.

Standardization is based on unification and typification. Unified parts and assembly units can be used in many products.

Typification is a way to eliminate the excessive diversity of products by reasonably reducing them to a limited number of selected types (sizes), in which the dimensions and parameters change with a certain step. At the same time, parametric series are created, they are standardized within the enterprise, industry, state. In the latter case, the greatest economic and organizational effect is achieved. Standardized parametric series are the most appropriate form of typification.

This raises the fundamental question of the “step” of the parametric series. If you take a step with a small change in the parameter or size, then the designer has a large selection and he can choose the size in more detail and conveniently, adapting the living room detail (element, assembly unit) to the design. This results in a gain in the parameters of the design being created, but there is a loss due to a decrease in the production volume of the guest parts (elements, assembly units) and because of the complexity of the supply organization, as the nomenclature increases. If you increase the step, then often the use of the living part (element, assembly unit) will lead to a noticeable deterioration of the design parameters.

For example, discrete non-wire resistors according to GOST are produced in a parametric range with a step in power of 0.125; 0.25; 0.5; one; 2.5 watts. For obvious reasons, the resistors in this series differ in cost and size. Suppose you want to use a 1.25 watt resistor. If there were resistors 1 in this row; 1.1; 1.2; 1.3 W, then it was possible to use a resistor with smaller dimensions and weight, and if there are many of them in the RES, then get a win on costs, sizes and mass. But then the number of sizes would increase several times with the corresponding consequences.

Similar contradictions arise in much more complicated cases, for example, in the power of the generator lamps, in the size of the antennas, in the number of sizes of supporting structures. The selection of standardized series is challenging and requires research.

When researching strive to optimize the parametric series of economic criteria. If we determine the cost of the entire production of products of a series, we get:

(4.1)

where k _p - the number of sizes in the series; N _j - release for each standard size; With _{p.d.pj - the} cost of design and preparation of production for each standard size; With _{izpr.j -} costs for the manufacture and use in each size; j - size number from 1 to K

- total output.

In the simplest case

; and (4.2)

where s _{izg. max} - the cost of manufacturing and applying the maximum size.

We believe that the cost of manufacturing and use increases with increasing j , since when j = K _p we mean the production of products with the highest cost, power, voltage, mass, etc. If the number of options in the series is small, then the step is significant and one has to apply and produce products with a higher cost and mass than is achievable with a large Xp. From (2.19) and (2.20) we get:

(4.3)

or per copy:

(4.4)

or

(4.5)

where With _rppn - the cost of design and preparation of production, reduced to one product.

Using the obtained expression, it is possible to optimize. The optimization curves are shown in Fig. 4.1 (for C _rpdn = 0.1 and C _{izg.pr. Max} = 1, a = 1).

It follows from the curves that, for the example under consideration, K _p = 4 is optimal . Obviously, if we keep in mind the automated production, the relative value of C _rpdn will be greater. If a remains unchanged, the smaller number of options is optimal. By increasing ^ it is profitable to automate production, since it is permissible to increase With _rpppn and it is possible to increase the number of options in the parametric series.

In some cases, the required number of types is so great that standardization leads to an inefficiently large number of options, and specialization of production is inexpedient. This problem has arisen with respect to a number of products, for example, some transformers and other coiled products.

The theory and experience have shown that in this case, standardization should also be at the heart of design and production, but it should be that parts of structures are being standardized, the manufacture of which requires the use of special technological processes, such as ferrite toroidal cores, steel cores, IC bodies and substrates. others

Fig. 4.1 Optimizing the number of sizes

In some conditions, at specialized enterprises, typical technological processes for the manufacture of elements in Fig.4.1 are explored and tested. Optimize the number of designs and equipment. These typical processes can be considered as peculiar "standards". At the same time, an enterprise in need of manufacturing relevant products uses standard technological processes and equipment.

As can be seen from the above, the standardization in the RES can take different forms, depending on the features of their structures and technology, as well as on the elements and details that are part of them. It is desirable to strive to ensure that as many products as possible in the distribution zone are designed and manufactured at specialized enterprises and meet the requirements of GOSTs and OSTs.