How to learn to read drawings of metal structures? Reading an assembly drawing. Reading Order - Technical Drawing Reading Part Drawings

There is another option to learn to understand drawings. If you know engineers, then it will be much easier to understand all the tricks, provided that the student can visually imagine the object; this is impossible without a developed imagination.

How to read a drawing yourself?

The ability to read blueprints and print drawings is one of the main requirements of many technical professions. Estimator, welder, installers, masons, architects - that’s far from full list professions that require an understanding of the basics of drafting.

Each profession has its own specifics, as well as the rules for developing diagrams and drawings. For construction, you need house designs, for the production of parts - a part diagram, so in order to correctly draw up or read a drawing you need to know all the basic rules for drawing up drawings in this area. Next, we will consider in more detail several basic rules for drawing up drawings.

Rules for reading drawings

No matter in what area you plan to create a drawing, during the work you must adhere to certain rules:

You need to be able to visualize an object, then you will be able to imagine its exact characteristics. It is impossible to create a drawing of a part without correctly imagining its appearance.
It is necessary to constantly analyze the drawing, so you can imagine the contours of the part, its appearance. You can mentally break down a part into its component parts, presenting them in understandable terms. geometric shapes and try to recreate on paper what you saw.
Studying the table of contents of the drawing will provide a lot of information about the main parameters of the product (object) and its scope. Having seen the inscriptions about the scale and the name of the part, it becomes much easier to imagine the finished product.
Each drawing has certain symbols, what they are for and what they mean must be understood in order to understand the drawing itself in more detail.

It is impossible to read a drawing without a detailed analysis of it; each detail has its own purpose, shape, and parameters. Weight, size, scale, configuration - all these parameters are indicated on the drawings at a certain scale. Knowing the required standards and dimensions of the part, it will not be difficult to recreate its appearance.

If the knowledge of the standards is rather weak, then when reading the drawings it is necessary to have the appropriate literature with a detailed description of all the standards applicable in this area. If necessary, it will be easier to find a specific part and familiarize yourself with its characteristics. Similar reference books in various areas Today there is a lot of information that can be found online on websites of relevant topics.

Summarizing the above recommendations, it is worth emphasizing the need to know the basics and methods of drawing drawings, understanding the basic designations and rules for the manufacture of parts and construction of objects. Without these basic skills, understand what a part should be and what it looks like in finished form it will be hard.

Any production, any construction metal structures unrealistic without preliminary development technical documentation – wiring diagrams, drawings of metal structures. Almost everything that man has created - the clothes we wear, the cars we drive, Street lights, which illuminate the roads, the houses in which we live, buildings made of metal structures - all this was developed according to diagrams and drawings.

Schemes and drawings convey the ideas of designers in the same way as text conveys the thoughts of writers. Drawings of metal structures cannot be read differently; all people who take part in the manufacture of products according to the drawings, repair of equipment, and its operation must know how to read and understand them in the same way. It is necessary to develop and draw up KMD drawings taking into account the rules for drawing up drawings according to GOST, taking into account building codes and rules (SNiP), according to the requirements of the System project documentation for construction" - SPDS, according to the requirements " Unified system design documentation" - ESKD, as well as with symbols.

Therefore, these drawings are designed by the design bureau of the design bureau. The project documentation must contain a graphic part of the working designs and an explanatory text note. The text note consists of calculation results that justify decisions made, technical and regulatory documents, which are used during the preparation of project documentation, references to GOSTs, as well as descriptions of adopted technical solutions and their explanations. The graphic part displays accepted technical solutions and is done in the form of detailed plans, installation drawings, large installation, assembly diagrams of metal structures, executive diagrams and drawings. Thus, for each construction project, working documentation is developed, which consists of specifications of products and equipment, working drawings of components and documents in text form.

How to learn to read blueprints

1. You need to start reading a drawing by studying the basic methods, rules, types of drawing objects of various sizes and shapes on a plane onto paper, as well as standards and symbols, which should be on any drawing when you draw it up. You should learn the processing technology of the relevant products.

Study the contents of the main inscription on the drawings. Using it, you will find out the scale of the drawing, the material that is used to make them, as well as the name of the parts.
Identify the images used to represent the details of the drawings.
Analyze the drawing images. Represented shapes of a product or part. If you can’t see the part right away, you can mentally divide it into a couple of parts and try to imagine their geometric shape.
Study the dimensions of the part - its represented values.

Familiarization with the drawing will help you imagine the details depicted on it: by what principles they are located, how they interact, etc. Careful reading of the drawings will help not only to examine the details on it, allowing you to accurately imagine the future shape of the product in finished form, but also to find out the mass of the product, the number of identical parts, the name, and also calculate the scale, taking into account all the standards and requirements.

3. After this, read in detail all the dimensions shown in the drawing in order to find out the permissible deviation from the established dimensions.

4. In the end, you need to establish the type of surface cleanliness of each element, so that in the future, based on the information obtained from reading the drawing, you can represent each stage of processing and production of the product in all cycles, as well as analyze how this part or product will be used in the final product or node, on what principle it will work, under what conditions it will be operated, and what purpose it will serve.

Video lessons

If you have a situation where you need to quickly learn how to read drawings correctly, then you will have to spend some time on this. You will read a lot of literature, often unnecessary, search the Internet for various textbooks, and so on.

If you want to learn this quickly, then you need an experienced engineer who will directly show you how to work with them. For some, it will be enough to familiarize yourself with GOSTs, the self-instruction manual “Drawing for Dummies” and the electronic version of drawing up drawings. But having a good spatial imagination is the most important thing for a correct understanding of the drawing, otherwise no amount of experience and knowledge will give the desired result.

Knowing how to read drawings is necessary for the following professions: concrete worker, bricklayer, estimator, mechanic, sometimes welder, installer, etc. To read them correctly, you need to work with them directly. If you have not received an appropriate education in civil or industrial engineering, then you need to know the simplifications, conventions, rules and standards specific to the area that interests you (building a house or manufacturing a part). Teach This will provide you with the general rules:

If you have imagined a model of an object or product, you can accurately find out its exact dimensions in the drawing.
Analyze the drawing drawing. It is the representation of the shape of a part or product that helps to understand the essence of the data that was entered into it. But if you can’t recreate the entire part in your imagination, try dividing it into parts and imagining their geometric shape.
Check out the title inscription on the drawing. It is this step that will allow you to find out what the part is made of, scale and name.
Image designations that served as a prototype for the part shown in the drawing.

Study the drawing, this will allow you to find out the mass of the product, its size and scale, the number of parts that are needed to create it, you will also see the parts depicted there, and this will allow you to more accurately imagine the configuration of the product in finished form, if you take into account all the standards and necessary requirements .

So that you have free access to information on technological requirements and standardization for your industry (manufacture of structures, parts, construction of pipelines, houses), you must have for personal use a textbook or drawing reference book that contains this information. You can also print out information from the Internet so you have it on hand.

To summarize: reading the drawing must begin with familiarization with all the methods and rules for applying products of various sizes and shapes on paper. Remember the standards and conventions that are needed when drawing up a drawing correctly.

Video lessons

The material presented above makes it possible to read simple drawings. Reading a drawing consists of understanding the three-dimensional shape of a part from flat images and determining its dimensions, surface roughness and other data shown in the drawing.

1. Read the title block of the drawing. From it you can find out the name of the part, the name and brand of the material from which it is made, the scale of the images, the designation of the drawing and other information.
2. Determine what types of parts are given in the drawing, which of them is the main one.
3. Consider the types in mutual connection and try to determine the shape of the part with all the details.

This task is aided by image analysis. Having presented from the drawing which geometric bodies The part is put together and the received data is mentally combined into a single whole.

4. Determine the dimensions of the part and its elements from the drawing. In this case, you need to pay attention to the signs Æ, □, R, standing before the dimensional numbers. As indicated, the sign 0 means that this element of the part has the shape of a body of revolution, the sign □ defines the elements square section and so on.
5. Determine what the surface roughness of the part should be. If there are no roughness signs on the image of the surface in question, then you should look for an indication of roughness in the upper right corner of the drawing.

As an example, let's read the drawing of the tip (Fig. 1.35).

First, we will present the questions to the drawing, and then the answers to them. (The questions are arranged in the order corresponding to in the correct order reading the drawing.)

Questions about the drawing(Fig. 1.35)

1. What is the name of the part?
2. At what scale is the drawing made?
3. What material is the part made from?
4. What types does the drawing contain?
5. What geometric bodies make up the shape of the part?
6. Describe the general shape of the part.
7. What are the overall dimensions and dimensions? individual parts details?
8. What is the surface roughness of the part?

Answers to questions about the drawing(Fig. 1.35)

1. The part is called "Tip". We learn this from the main inscription.
2. Scale 1:2, i.e. the linear dimensions in the drawing are 2 times smaller than the linear dimensions of the object itself.
3. The part is made of steel grade 45 according to GOST 1050–88.
4. The drawing contains two views: the main (front) and the left view, which is located to the right of the main view and on the same level with it.
5. Let's look at the leftmost element first. In the main view it has a trapezoidal outline; in the left view it is depicted as two circles. Such images may have a truncated cone.

Rice. 1.35.

In the main view, the second element appears as a rectangle and a circle in the left view, which, together with the Æ sign, indicates its cylindrical shape.

The shape of the third element is also established by comparing its two images. This element has the shape of a hexagonal prism, with conical chamfers removed from both ends. Curved lines drawn in the main view and a large circle in the view on the left were obtained on the part when removing conical chamfers on a hexagonal prism.

When determining the shape of the next element, we are guided only by its image in the main view and the Æ sign, since this element is not visible in the view on the left. The rectangular outline, centerline and diameter sign indicate the cylindrical shape of this element.

The last element on the right, which has a trapezoidal outline and a size of 1 × 45°, is a truncated cone (chamfer), since the trapezoidal outline and size in the form of a conventional notation are characteristic of this element.

Based on the dashed lines in the main view and the smaller circle in the left view, it can be judged that there is a through cylindrical hole inside the part.

6. Combining all the information received, we establish the general shape of the object (Fig. 1.36). It is a combination of a truncated cone, a cylinder, a hexagonal prism, a cylinder and a truncated cone, located on common axis. A cylindrical through hole runs along the axis of the part.

Rice. 13.6.

7. dimensions details, i.e. defining the limiting external or inner dimensions, are as follows: length – 170 mm, largest size hexagonal element (height) - 72.1 mm, part width - 65 mm, hole diameter - 20 mm (see Fig. 1.35).

The large diameter of the first element on the left is 48 mm, the apex angle is 30°, and its length is 20 mm. The diameter of the next cylindrical element is the same as the larger diameter of the cone and is equal to 48 mm, and its length is determined as the difference between 55 and 20, i.e., equal to 35 mm.

Two dimensions of the part element, which has the shape of a hexagonal prism, are marked in the left view: between parallel edges - 65 mm (turnkey size), between two of the ribs - 72.1 mm (diameter of the circumscribed circle). The length of this element is not specified; it is determined after the dimensions of 170.55 and 46 mm are met. The dimensions of the chamfers on the prism are: the diameter of the larger base is 72.1 mm, the diameter of the smaller base of the truncated cone is 64 mm, the angle at the apex of the cone is 120°.

The diameter of the right cylinder is 50 mm, and its length is 45 mm (46 – 1 = 45 mm). The larger diameter of the truncated cone is equal to the diameter of the cylinder, i.e. 50 mm, its height is 1 mm, and the angle of inclination of the generatrices to the plane of the base is 45°.

8. Surface roughness of a truncated cone located at the left end of the part, Ra 6.3, roughness of a nearby cylinder with a diameter of 48 mm Ra 3.2. The surface of a cylinder with a diameter of 50 mm, located at the other end of the part, should also have a roughness Ra 3.2. All other surfaces must be rough Ra 10.

We judge the roughness of other surfaces by the sign in front of the brackets in the upper right corner of the drawing.

The basic requirements for the drawing are as follows:

1. The drawing of the part must contain a minimum number of views, cuts and sections, made using only such conventional images as are established by the standards, but sufficient to understand its shape.
2. The surface roughness must be indicated on the drawing and all necessary dimensions must be applied geometrically completely and technologically correctly.
3. The drawing must contain the necessary technical requirements reflecting the features of the part: material and indicators of its properties, coating, maximum deviations sizes, geometric shape and arrangement of surfaces.

Among the requirements for a part drawing, special mention should be made of the requirement for manufacturability, i.e., the connection of the drawing with the manufacturing technology of the part. The requirement for manufacturability applies both to the design of the part itself and to its depiction in the drawing.

Technologically correct dimensionalization in the drawing is of great importance for the manufacture of parts. In this case, it is necessary to take into account: what elements of parts should be taken as dimensional bases so that they are consistent with the technological and measurement bases; what dimensions to indicate in order to take into account all types of intermediate control during the manufacturing process of the part; what dimensions in the drawing of a part must be coordinated with the corresponding dimensions of adjacent mating parts that interact with this one.

In the production practice of a mechanic (when replacing individual parts that have become unusable during equipment repairs), there is often a need to use sketches.

Sketches are temporary drawings made without the use of a drawing tool and without exact adherence to scale.

When drawing up sketches, the rules established by the standards for drawings should be applied; It is necessary that the sketches are easy and quick to read, do not contain anything superfluous, and meet production requirements.

Reading the drawing begins with familiarization with the main inscription and then proceeds in the following order:

establish the relationship between all images, and also find out which of the simplified and conventional images of part elements are used;

determine the shape of the part, mentally dividing it into its constituent geometric elements;

understand which elements of the part the dimensions refer to, what size they represent (diameter, length, width, etc.), find the dimensions of the base, decipher the size symbols, as well as the designations of surface roughness;

get to know everyone in detail technical requirements and other instructions that determine the features and sequence of work according to the drawing.

Among the graphic documentation that a mechanic uses in the process of work, assembly drawings occupy a large place. They are used for assembly, i.e. connecting parts into assembly units, and then assembly units and parts into finished finished products.

To read and draw up assembly drawings, you need to know and be able to apply the rules, conventions and simplifications established for them by the standards. The main ones are the following:

1. Images, views, sections and sections are placed on assembly drawings, as well as on drawings of parts, in projection connection.
2. Hatching of adjacent sections of parts on assembly drawings is performed at an angle of 45° in opposite directions or with a shift of the strokes, or with a change in the distance between them.
3. Bolts, screws, rivets, keys, rods, solid shafts, balls, spindles, handles, nuts, washers are shown uncut in longitudinal sections.
4. Invisible contour lines on assembly drawings are used only to depict simple (invisible) elements, when making cuts does not make the drawing easier to read, but increases its complexity.
5. When depicting a threaded rod (bolt, stud, threaded end of a part) screwed into a hole, the external thread (on the rod) is depicted in full, and internal thread(in the hole) is shown only if it is not covered by the thread of the rod.
6. The engagement of gears, racks and worms, as well as some other parts, such as springs, are depicted in assembly drawings conditionally (simplified).
7. In some cases, complex assembly drawings are supplemented with kinematic diagrams to explain the principle of the mechanism and the interaction of its parts.

When studying the operation of various machines, mechanisms, when setting up or repairing them, during installation electrical equipment It is often necessary to understand the fundamental connection between the elements of a mounted device without specifying it design features. For this purpose are intended various schemes: kinematic, hydraulic, electrical and others.

Kinematic diagrams display the connection and interaction between the moving elements of the device.

Hydraulic diagrams show a fluid control system.

Electrical diagrams explain the principle of operation and the relationship between the elements of an electrical device.

In the diagrams, parts are depicted in a simplified manner, using the symbols established by the standards. The front flyleaf shows a kinematic diagram of a vertical drilling machine with a visual explanation of the symbols of assembly units and parts.