Requirements for manufacturability and metrological support

In accordance with the ESTPP standards, the requirements for manufacturability of the design, as well as (if necessary) the main controlled parameters, initial requirements for methods and means of measurement, staff qualifications, etc., are given. The quantitative characteristic of the manufacturability is called an indicator of the manufacturability of the design. The indicator taken as the initial one in the evaluation of manufacturability is called the base product PTC.

A private PTK product characterizes one of its constituents, and a complex one — several private or complex properties that comprise it.

The function of pre-production, including a set of interrelated measures for managing manufacturability and improving the conditions for performing work during production, operation and repair of products, is called ensuring the manufacturability of the product design. Development of the product design for manufacturability is part of the work to ensure manufacturability, aimed at achieving a given level of manufacturability and is performed at all stages of product development.

The main factor determining the requirements for manufacturability is the type of product, the volume of production and type of production. The type of product determines the main structural and technological signs that determine the basic requirements for the manufacturability of the structure, and the production volume and type of production determine the degree of technological equipment, mechanization and automation; technological processes.

Evaluation of the technological design of the product can be of high quality; and quantitative. Qualitative assessment characterizes the manufacturability of the design generally based on the experience of the designer and is necessary at all design stages, when choosing the best constructive solution, it is necessary to determine the degree of difference between the manufacturability of the compared variant

To quantify the manufacturability of the design under development; relevant indicators are intended. The selection of indicators is technologically made taking into account the requirements of GOST 14.201–73. GOST 14.202—73

According to the nomenclature of basic indicators of technological design, all the blocks in the standard OST 4 G0.091.021 are divided into 4 classes: radio engineering; electronic; electromechanical, mechanical; connecting, switching, distribution. Within each class of products, no more than 7 indicators are selected that have the greatest influence on the manufacturability of the structure.

The standards for integrated indicators of the manufacturability of some products are given in OST 4 GO.091.219 and are set for the stages of development of working documentation.

Evaluation of the technological design of the product may require a lot of labor and time (the number of indicators of manufacturability more than 80). A quantitative assessment of the manufacturability of the structure is rational only depending on the characteristics that significantly affect the quality of the structure under consideration. Therefore, the composition of private indicators for different designs and production conditions is different and the selected composition of indicators must be justified. The generalization of the private indicators of the technological design is an important methodological principle for a comprehensive assessment of the quality of the RES design. The indicators of manufacturability in their composition can characterize the manufacturing technology or design features of the product. Such indicators as the coefficient of unification and standardization, complexity of assembly, repeatability of ERE, applicability of integrated circuits and semiconductor devices, etc. directly depend on the design. Some indicators depend both on the design and on technology. For example, the rational form of the part and the choice of material are the designer’s prerogative, and the orientation of the cutting and the method of stamping are the tasks of the technologist. It should be emphasized that the configuration and material of parts significantly affect the manufacturability of the design.

The design of the assembly unit must meet the requirements of manufacturing, operation and repair in the most productive and economical ways under the specified production conditions, which is achieved by splitting the assembly unit into a rational number of components, taking into account aggregation, unification and standardization. The design of an assembly unit should allow assembly with constant basing of component parts and provide for the possibility of using structural bases as technological ones. The design of the assembly unit should provide convenient access to places of control, adjustment and adjustment. The joints of the components must be accessible for the mechanization of assembly work, and the design of the joints should not require additional machining. The accuracy of the component parts and the assembly method must be justified by the type of production, output and calculation of dimensional chains, carried out by a probabilistic method, except for short (with the number of links less than five), with high accuracy of the closing link, when the method of maximum-minimum is justified. The following assembly procedure is recommended for the diminishing productivity of assembly work: with complete interchangeability; with incomplete interchangeability; with group interchangeability; with adjustable compensators; with fit.

The design of the assembly unit should provide for devices, such as centering, fixing, and others, to ensure the accuracy of the location of the components.

The design of the part must ensure the use of standard and unified elements (landings, threads, splines, radii of interface surfaces, etc.). The heterogeneity of the shapes of the surfaces being machined in one piece causes an increase in the required operations, transitions and equipment for processing. The required accuracy of the parameters should be ensured by proper dimensioning and a rational choice of design bases. The dimensions and surfaces of the parts must be economically and structurally substantiated, respectively, accuracy and roughness. It should be remembered that an increase in accuracy and a decrease in roughness (improvement in quality) always lead to significant costs, but they do not always improve quality. The design of the part must ensure the possibility of using standard and standard technological processes in its manufacture.

The properties of the selected material must comply with the requirements of manufacturing technology, storage and transportation. The choice of a rational type of workpiece and its configuration allows for the use in the design of parts with untreated surfaces or minimal allowances for processing.

Manufacturability is considered as a set of product design properties that characterize one of its quality indicators. Therefore, in order to improve manufacturability, it is unacceptable to reduce other technical characteristics that determine compliance with the requirements for the functioning of the product (performance indicators, ergonomic, aesthetic, etc.).