Assembly drawing. Reading assembly drawings

Any electronic device, household appliance, even furniture in our houses are made on the basis of specially drawn up drawings. In which the individual elements are first traced, and then the assembly of these parts, methods of fastening and positioning them relative to one another are shown. People who work on the assembly of products must be able to read the drawings, because they serve as a guide to how to assemble the designer's plans, as well as what material and what method to make the necessary parts.

Basic concepts

The term "assembly drawing" means an engineering document that shows a composite unit with the necessary dimensions and technical requirements necessary for its manufacture, as well as quality control. Such a drawing is done when developing the product documentation. It should give a complete picture of the location of the assembly in the finished product relative to other parts. Assembly drawing is carried out according to the requirements of GOST 2.102-68 "Types and completeness of design documents".

Detail - a product manufactured according to the requirements of the ESKD from one material and without the use of assembly operations.

Drawing details - the document of the designer, where there is a picture of the part, all the necessary dimensions to make it, and in the technical requirements, it is prescribed, if necessary, to cover it.

What should the drawing contain?

Any assembly drawing of the part must contain the following:

- how the assembly part is located in the finished product with respect to other elements;

- how the parts are fastened together;

- overall dimensions - they will show the length, height and width of the product;

- installation dimensions - demonstrate the basic dimensions of all the elements that are needed for the installation of the product;

- connecting dimensions - show the dimensions of the connection points with other parts or assembly units;

- reference dimensions - are indicated on the drawing from the reference books (for standard sizes of threads, nuts, bolts, screws, etc.);

- the maximum permissible deviations during manufacture, which will be used to control the quality of the product;

- methods of attaching parts to each other, indicating all the connections and ways to implement them;

- the positions of each part in the assembly, made in the specification;

- scale in which the drawing is executed;

- product mass.

Basic Rules for Executing Assembly Drawings

Execution of the assembly drawing is made in accordance with the requirements of GOST 2.109-73. If you want to identify rotating or moving parts of the product, you can show them either in the extreme or in the intermediate position. It is necessary to specify the required dimensions. If the reading of the assembly drawing becomes difficult, then some parts can be shown separately, having made the necessary signatures indicating the positions.

When making sections or cuts on the same part, you must maintain the same slope of the lines and the distance between them when hatching.

If the cut is made at the place of joining of two different parts, then the hatching at the place of the cut of each of them is applied in different directions or with different distances between the inclined lines.

If necessary, the figure indicates the roughness, permissible deviations from the norm for any specific details or holes. There are also a number of standard parts for which you can not produce individual drawings, but if there is a lack of necessary information, they are placed on the field of the assembly drawing.

If the docking of individual parts must be ensured by fitting or matching, appropriate signatures shall be made.

Specifying part positions

All components of the assembly unit are numbered according to GOST 2.109-73.

Each component, as well as the materials used, standard products must have their own sequence number, which is assigned to them when drawing up a specification for this assembly drawing.

All positions in the drawing are indicated by lead lines, which are drawn from each individual part or material. The end of the line, which is in the image of the part itself, thickens with a dot. The line itself and the leader-strip are represented by a continuous thin line. In the basic view, all visible parts are indicated. Positions of invisible details are indicated on additional views or sections.

Positions of positions are made parallel with respect to the main inscription in the frame of the drawing. Also, positions must be taken out beyond the contour of parts, they can be grouped.

If the same part is present on the assembly drawing several times, then its position is put only once, and in parentheses next to the figure it is indicated how many times it is repeated in the drawing.

Item numbers are indicated in a font that is 2 sizes larger than the specifications and frame.

Crossing of lines at positioning of positions is not supposed, and they should not have the same direction, as well as lines of hatching.

Simplifications and symbols in the drawings

When carrying out the assembly drawing, you can use the permissible designations and simplifications.

In the drawings it is possible not to show chamfers, grooves, fillets, small protuberances, grooves, etc., as well as some gaps, if they are small in size.

If in the drawing you want to depict those parts of the product that are covered with a lid or flap, then the latter are allowed not to be shown. Also add an inscription about the detail of which position is not shown.

If the same component (wheel, support) is applied several times in the product, it is allowed to display its image only once.

Places of soldering, gluing or welding can be shown as uniform surfaces. At the same time, the boundaries between the sections of different parts remain.

Also, according to GOST 2.315-68, the details of fastenings are shown in a simplified way.

Specification

This design document, which prescribes the full composition of the assembly product in accordance with GOST 2.108-68. This document is executed on A4 format separately for each assembly. All components of the assembly unit are successively written in it. Based on the general case, the specification is made up of consecutive sections of the following sections: documentation, assembly parts, parts, standard products, other products, materials, kits.

It is not necessarily the presence of all sections in each specification. If one of them is not filled, it is simply not prescribed. The title of the section is written by skipping two lines from the last record of the previous one, in the middle of the graph a name underlined by a thin straight line.

Products are written in alphabetical order. The numbering of positions goes from the first section through the entire document. Also in the corresponding column is indicated the GOST or the designation of a separate part and their number in this assembly.

Sequence of execution of assembly drawings

The assembly drawing is performed either already from the finished product, or first sketch the details in programs such as SolidWorks, Kompas 3D, and only then do they create the drawings themselves.

Before you start the drawing, you need:

- study the details, the principle of the product and its purpose;

- to reveal in what order the assembly of the finished product will be made;

- draw up a plan with a designation of all components;

- make sketches for all the parts included in the assembly (except for the standard ones only), check that all parts have all the dimensions necessary for the manufacture, and also specify surface treatments , roughness ;

- select the most information images for the location on the drawing field, make a minimum number of additional views and cuts;

- based on the size of the selected image, the number of views and cuts, select the most appropriate format size;

- fill the frame of the drawing;

- Draw the outline of all images, check the work done;

- apply all sizes, numbering of positions, sign all types, cuts;

- write the technical requirements for the manufacture of parts for this drawing;

- fill in the specification.

Below are the simplest examples of assembly drawings.

How to correctly read assembly drawings

Reading assembly drawings involves, first of all, a preliminary study of information about how the product is arranged and how it works.

When reading the drawings you need:

- understand the principle of operation and what this product is intended for, based on the inscriptions in the frame of the document;

- to determine the constituent parts of the product according to the specification;

- to understand what each separate detail, its features of location and work in relation to other elements is needed for;

- determine in what order the disassembly and assembly of the product will be performed (reading the main label in the frame, the contents of the drawing and its features, correlating the information in the specification and on the drawing field);

- to study the description of the finished product or its analog;

- to find out the way in which individual parts are attached to each other.

Detailing of general drawings

Detailing an assembly drawing is a painstaking and hard work. Having only a general assembly of a part, it is necessary to make drawings of all parts on the basis of this drawing and specification, and to choose the most convenient angle for their implementation and applying all the necessary sizes and designations.

What size will be a particular part, learn, based on the scale of the general drawing and the size of this part on it. The dimensions of the standard parts are taken from the standard reference book, and not from the drawing data.

The detailing of the assembly drawing usually consists of three stages:

- Reading an assembly drawing having a general view;

- definition of the forms of individual parts;

- drawing of each part.