Drawing programs of our time. Designations on drawings in mechanical engineering and metalworking Creation of drawings. Working with drawings

Creating drawings is one of the final stages of product design. The engineer passes the drawings on to other people who will be working on the drawings. It is very important to create a competent drawing in accordance with all the rules for creating design documentation, to avoid mistakes when constructing the necessary views and sections, and to display the features of the product as accurately as possible.

Creation of drawings. Working with drawings

IN modern world Industrial enterprises strive to speed up the design process of each product, which entails a reduction in the work time of each engineer. People have to do more work in a shorter time. Today's computer-aided design systems can significantly reduce the workload on a person, make his work easier, and create information in in electronic format, convenient for storage and printing.

Compass 3D allows you to create drawings both manually and build views automatically using previously created 3D models. Creating a drawing based on a finished 3D model significantly saves time and allows you to quickly and accurately create projection views, sections, and scale the image. The advantage of drawing from a finished model is that the image automatically changes after the model is changed. The manual mode is not characterized by high productivity, accuracy and ease of drawing and is more suitable for designing simple parts. The advantage is that there is no need for a 3D model. The method of obtaining the drawing is chosen directly by the engineer.

Regardless of the drawing method, the user is faced with a lot of questions that will be discussed in detail in our lessons on creating and working with drawings.

Almost everything that man has created - the keys to the house that we carry in our pockets, the cars in which we travel out of town, the boilers that provide heat, the street lamps that illuminate the park, the forged staircase of the house in which we live, products made from metal profiles - All this was developed according to drawings.

The fruits of the labor of design engineers are easy to see with the naked eye: everything that was not created by design engineers, or by Uncle Igor in the workshop, was created by designers in drawings and three-dimensional models. For an engineer, a drawing is not only a means of communication with colleagues, it is an idealized, but at the same time, clearly consistent with practice, picture of the expression of his thoughts. That is why engineers prefer to draw products, carry out calculations or draw up operating documentation. While people of art can create their works without regard for anyone or anything, an engineer is forced to act within the framework of the real world, regulations, GOST, and even with restrictions in time, money and in accordance with the desires of the people who control the project from the outside. Engineers are forced to look for solutions to problems that initially do not even know how to approach them. Unlike the artist, graphic space serves the engineer not for the artistic display of the surrounding world in order to evoke aesthetic pleasure, but for detailing and concretizing the engineering idea into an expanded chain, scientific justification and mathematical calculation, so that later working drawings can be completed - a document for the worker to implement it plans: to create a competitive product.

In this article, I will try to talk about the basics of reading symbols on a drawing. Careful reading of the drawings will help you not only examine the details on it, allowing you to accurately imagine the future shape of the product in finished form, but also find out the mass of the product, the number of identical parts, the name, present each stage of processing and production of the product in all cycles, and also analyze how this part or product will be used in the final product or assembly, on what principle it will work, under what conditions it will be used, and what purpose it will serve. But in ordinary life, these skills are simply necessary: ​​many sooner or later want to build something basic with their own hands. How can we do without drawings?

How can we do without drawings?

Drawings and symbols on them convey the ideas of the developers in the same way as text - thoughts in works, only according to the regulations and more precisely. Drawings of metal products cannot be read differently; all people who take part in the manufacture of products according to drawings, repair of equipment, and its operation must know how to read and understand them in the same way.

A drawing of a product is a graphic representation of it, made to a certain scale, indicating the dimensions and conventionally expressed technical conditions, compliance with which must be ensured during the manufacture of the product. Drawings are carried out according to the uniform rules established in GOST standards of the Unified System of Design Documentation (ESKD).

A part is a product made from a material that is homogeneous by name and brand, without the use of assembly operations. For example: shaft, bushing, cast housing, rubber cuff (non-reinforced). Parts also include products that have been coated (protective or decorative), or manufactured using local welding, soldering, and gluing. For example: a body made by metal casting, coated with a primer; galvanized steel nut; a box made by welding from one sheet of metal, etc. According to their purpose, the parts are: fastening: nut, washer, bolt, screw, screw, nail, rivet: transmission parts: shaft, key, pulley, belt, sprocket, gear, etc. Parts are divided into simple parts: nut, key and complex parts: crankshaft, gear housing, machine bed.

Detail. The body is made by metal casting.

The standard establishes six main views that are obtained when projecting an object placed inside a cube, the six faces of which are taken as projection planes

Six main views that are obtained when projecting an object placed inside a cube.

Name of drawing views

A development is a flat figure obtained by combining the surface of a geometric body with one plane (without overlapping faces or other surface elements on top of each other). Above the image of the scan there is a special circle sign with an arrow down to the right.

Reamers are used for the manufacture of machine casings, machine enclosures, ventilation devices, pipelines, where it is necessary to cut out reamers from sheet material and bend them according to the drawing.

The drawing standard can be ANSI, ISO, DIN, JIS, BSI, GOST (ESKD) or GB. More often in practice, I draw up drawings according to the ESKD, that is, the ESKD is applied on a voluntary basis, unless otherwise provided by an agreement, contract, individual laws, court decision, etc. The main purpose of the ESKD standards is to establish uniform optimal rules, requirements and compliance standards , registration and circulation of design documentation. ESKD standards apply to mechanical engineering and instrument making products.

The working drawing of the part contains:

• Images indicating the scale, if it differs from that indicated in the title block of the drawing (views, sections, sections) (GOST 2.305-68). The number of images should be minimal, but sufficient to fully determine the geometric shape of the part. Letter designation of bases, which include tolerances for the shape and location of the surfaces of the part. The use of the letters И, О, ​​Ъ, И, ь is not allowed. The additional view can be rotated relative to the specified viewing direction, while maintaining the position adopted for of this subject in the main image. In this case, a special circle sign with a down arrow on the left “⟲” is added to the letter inscription, replacing the word ““rotated”” indicating the degree of rotation if it is not divided by an integer by 90 degrees. The walls of the product cut by a secant plane must (hatched ▧ ▨) be applied with an inclination to the left or right, but in the same direction on all sections related to the same part in accordance with the material of the part. Rules for applying shading and graphic designation materials, depending on their type, are determined by GOST 2.306–68. If the part is complex, then for clarity I add an axonometry of the part (3D image).

Axonometry of the part (3D image) in the drawing for clarity of the manufacture of wheel grooves.

Images (types, sections, sections) (GOST 2.305-68)

• Dimensions linear 30, ⃞30, ◠70 or radial (Ø12 - hole / shaft diameter, circle with a crossed line at an angle) with alphanumeric tolerances (a combination of letters main deviation and numbers for example: Ø12H12 for hole) (GOST 2.307-68), as well as numerical values ​​(for example: 15+-0.1). Dimensional numbers of linear and radial dimensions, defining their shape and dimensions, determining the relative position of elements are indicated in millimeters without indicating a unit of measurement, angular dimensions are indicated in degrees (examples: 12°; 30°15 " ; 1°0 " 19"" ) . If there are a large number of holes in a part, I advise you to look at GOST 2.318-81 Rules for simplified drawing of hole sizes. General tolerances for linear and angular dimensions according to GOST 30893.1: “H14, h14, +- IT14/2" are indicated in the technical requirements for the drawing. Can also be applied letter designation“General tolerances GOST 30893.1-m.”, where the letter corresponds to the accuracy class. The type of thread (thrust) can also be additionally indicated in the dimensions. S28x10, metric M30, pipe cylindrical G1⅜″, trapezoidal Tr30x6 and etc) , min And max size, number of grooves, chamfers, holes on the part are the same or the presence of a sphere “Sphere Ø 18”. Simple flat parts are depicted in a single projection. In these cases, its thickness is indicated by the letter S and the inscription on the drawing is made according to the type " S5" and is located on the shelf of the leader line. The length of the object is indicated by the letter L.

• Images and designations of threads are applied in accordance with (GOST 2.311-68)

Conventional image of the thread in the drawings.

• Tolerances of the shape and location of the surfaces of the part using graphic symbols (GOST 2.308-68). General tolerances of the shape and location of surfaces not specified individually are regulated by GOST 30893.2, indicated in the technical requirements for the drawing, for example: “General tolerances GOST 30893.2-K.”, where the letter corresponds to the accuracy class. If a location or shape tolerance is not specified as dependent, then it is considered independent. For independent tolerances, the symbol "S" may be used, although it is not required. Independent tolerances are used for critical connections when their value is determined by the functional purpose of the part. Dependent tolerances must be indicated by the dependent base symbol “M” or specified in text in the technical requirements. Dependent tolerances are established for parts mating simultaneously along two or more surfaces, for which interchangeability is reduced to ensuring assembly along all mating surfaces (connecting flanges using bolts). After the tolerance value, the symbol “L” can be indicated, and on the part this symbol indicates the area relative to which the deviation is determined. The basic standards of interchangeability and tolerances for the location of the axes of holes for fasteners are regulated by GOST 14140-81.

Tolerances of the shape and location of the surfaces of the part in the frame, tolerance value in mm

• Roughness (GOST 2.309-68) is measured in micrometers (μm), parameter Ra is preferred. Indicate the permissible values ​​of microroughness for individual surfaces and the common value for all other surfaces (upper right corner of the drawing), ensuring the functionality of the part in connection with others. Depending on the operating conditions of the surface, a roughness parameter is assigned when designing machine parts, and there is also a relationship between the maximum size deviation and roughness.

Surface roughness designation

A series of numerical values ​​for surface roughness

• Designation of coatings, thermal and other types of treatment (GOST 2.310-68).

Heat treatment designation

• Instructions on marking and branding (GOST 2.314-68). The graphic indication contains a link to the technical requirements of the drawing, for example point 3.

Instructions for marking and branding

• Text inscriptions (GOST 2.316-68). If additional data, clarification or instructions are required for a drawing that cannot be graphic display and display using symbols, they are placed in the text part of the drawing. They are divided into a text part, consisting of technical requirements and technical characteristics; inscriptions indicating images, as well as those relating to individual elements of the product; tables with sizes and other parameters, symbols etc.

Drawing of a gear wheel. Table on the drawing with dimensions and other parameters for control and manufacturing.

The drawing must provide all the necessary information for the manufacture of a part or product. This means that it is necessary to specify not only the geometric shapes and dimensions of the product, but also the requirements for heat treatment, manufacturing accuracy, coating, adjustment, and testing methods. This information is indicated in the Technical Requirements (TR). The heading “Technical requirements” is written only if the drawing contains a table “ Specifications" In all other cases, the heading “Technical Requirements” is not written.

✍ Example of technical requirements for a part drawing:

1. General tolerances according to GOST 30893.1: H14, h14, +-IT14/2.

2. * Dimensions are provided by the tool.

3. **Dimensions for reference.

4. On the surface I, a center hole of no more than A5 GOST 14034-74 is allowed.

5. In sections K, transitional hardness of high-frequency particles and an overestimation of the diameter by 0.015 mm are allowed.

6. Unspecified tolerances for the location of surfaces in accordance with GOST 25059-81.

7. *** Dimensions up to HDTV.

If the material of the part can be replaced, then this is also indicated in the technical specifications.

Substitute material 30KhGSA GOST 4543-71.

If heat treatment of a part or coating is required, then the hardness is indicated in the technical requirements.

Heat: 1078-1274 MPa (110-130 kgf/mm).

Coating: Chem. Oks. prm.

The main inscription indicates: the name of the part (assembly unit), its designation, the material of the part, the mass in kilograms ㎏, changes made to the drawing, by whom and when the drawing was made, the company, etc.

An example of a part drawing. Lid

The developer’s task is not only to come up with a part, but also to fully imagine the full cycle of its production in production.

Part manufacturing operations.

The operation of processing a part on a CNC machine.

Part manufacturing operations.

Assembly unit is a product consisting of two or more component parts connected to each other at the manufacturer by assembly operations (stitching, screwing, welding, soldering, riveting, flaring, gluing, joining with metal brackets, etc.).

For example: machine tool, conveyor, casting ladle, gear motor, welded body, etc.

Assembly unit. A reservoir is a container for liquids and gases.

Assembly drawing is a document containing an image of an assembly unit and the data necessary for its assembly and control.

Reference dimensions of an assembly drawing are dimensions that are not subject to execution according to this drawing and are indicated for greater convenience in using the drawing. Reference dimensions in the drawing are marked with a “*” sign, and in the technical requirements they write: “*Dimensions for reference.”

Reference dimensions on the assembly drawing include:

➤ dimensions transferred from the drawings of parts and used as installation and connecting dimensions;

➤ overall dimensions transferred from the drawings of parts or being the sum of the dimensions of several parts.

Assembly drawing must contain:

➤ image of an assembly unit;

➤ required executive and connecting dimensions;

➤ center of mass, center of gravity if necessary;

➤ instructions for assembly operations (stitching, screwing, welding, soldering, riveting, flaring, gluing, joining with metal staples, etc.). GOST 2.313-82 “Conventional images and designations of permanent joints”, GOST 2.312-72 “Conventional images and designations of seams of welded joints”;

Designation of the seam on the drawing according to GOST; if the seam is not regulated, then the dimensions of the weld are indicated.

Weld seam designation marks.

Most often in my work I had to use the following regulations for seams.

1. GOST 11534-75“Manual arc welding. Welded joints at acute and obtuse angles. Main types, structural elements and dimensions.”
2. GOST 14771-76 “Arc welding in shielding gas. Welded connections. Basic types, structural elements and dimensions."
3. GOST 16037-80“Welded connections for steel pipelines. Basic types, structural elements and dimensions."

If the seam is not regulated, then in a separate view you can see its dimensions; such cases happened to me when designing elements of nuclear power plants. If there are many different weld seams, they are entered into a table on the assembly drawing. Standard welds can be marked on the drawing; the GOST technical document for the seam can be specified in the technical requirements, for example:

1. Welded joint of class II according to STB 1016-96.
2. Welds according to GOST 14771-76. Welding wire Sv-08GS or Sv-08G2S GOST 2246-70. It is allowed to make welds in accordance with GOST 5264-80. Electrodes E-42 GOST 9467-75.

Symbols and symbols of various permanent connections.

Instructions for assembly operations on the drawing.

➤ position numbers - by the position number on the assembly drawing you can find in the specification the name, designation of this part, as well as quantity;

Item numbers on the assembly drawing

➤ technical requirements - grouped by homogeneity (for example, by product quality, testing conditions and methods, transportation and storage rules, special operating conditions, etc.);

➤ technical characteristics of the product (if necessary).

Technical characteristics of the product on the assembly drawing.

01. Requirements for product assembly. Dimensions and their maximum deviations.

02. Requirements for the quality of surfaces, coatings applied to them, instructions regarding finishing;

03 Location various elements structures, gaps between them;

04. Adjustment and configuration of products, as well as the requirements for it;

05. Other requirements for the quality characteristics of products (silence, self-braking, vibration resistance, etc.);

06. Test methods and conditions;

07. Instructions for branding and marking;

08. Storage and transportation rules;

09. Special conditions of use;

✍ Example of technical requirements for an assembly drawing:

1. *Dimensions for reference.

2. General tolerances according to GOST 30893.1: H14, h14, +- IT14/2.

3. Welding wire 1.2Sv-08G2S GOST 2246-70.

4. Non-standard welds No. 9 are performed semi-automatically in a carbon dioxide environment.

5. Coating Primer GF-021-VI-U3 GOST 25129-82.

6. Label on the tag 87.07.01.06.05.00.00.

An example of an assembly drawing. Loading section.

Marking on products is needed by both consumers and institutions that will transport, sell and store products. The use of labeling provides an opportunity to protect yourself from counterfeits and significantly simplifies the process of tracking the transportation of goods from manufacturer to consumer. Not to mention the simplification of control and accounting for the sale of labeled products. The designation and (or) name of the unit is marked.

According to GOST 2.104 “ESKD. Main inscriptions”, paragraph 6 - Procedure for filling out the main inscription and additional columns:

The product name must comply with accepted terminology and be as short as possible. The name of the product is written in the nominative singular case. In a name consisting of several words, a noun is placed in the first place, for example: “Loading section.” You can select the appropriate part name from the listbelow.

Each product must be assigned a designation in accordance with GOST 2.101-68. The designation of a product and its design document must not be used to designate another product and design document. Products and design documents retain the designation assigned to them regardless of in which products and design documents they are used.

The types and completeness of design documents are regulated by GOST 2.102-2013 one system design documentation.

Example. Designation on the drawing of the part.

assigned according to the codifier of the developer's organization.

assigned to the product and design document according to the ESKD classifier. To assign code to a designer, you only need to answer five questions. The code structure must include class, subclass, group, subgroup and product type:

When classifying parts, the decisive feature is “geometric shape”, as the most stable and objective when describing a part.

assigned according to classification characteristics from 001 to 999.

should consist of a product designation and a document code established by ESKD standards (for example, “SB”, “VO”, “MC”, etc.).

Brand is a sign indicating compliance of a part or assembled unit (assembly unit) with the technical requirements for critical parts. The mark is placed on the unit after it has been checked either by the assembler or by a technical control worker.

Specification– a document defining the composition of an assembly unit.

Example of specification design. Loading section

The specification for assembly drawings typically includes the following sections:

1. Documentation;
2. Complexes;
3. Assembly units;
4. Details;
5. Standard products;
6. Other products;
7. Materials;
8. Kits.

The name of each section is indicated in the “Name” column, underlined with a thin line and highlighted with empty lines.

In the “Documentation” section, design documents for the assembly unit are entered. This section includes “Assembly drawing” and other types of design documents in accordance with GOST 2.102 - 68.

The sections “Assembly units” and “Parts” include those components of the assembly unit that are directly included in it. In each of these sections, the components are written by their name.

The “Standard Products” section records products used in accordance with state, industry or republican standards. Within each category of standards, records are made in homogeneous groups, within each group - in alphabetical order of product names, within each name - in ascending order of standard designations, and within each standard designation - in ascending order of the main parameters or dimensions of the product.

The “Other Products” section includes a set of products not included in other sections; these can be purchased products included in the assembly unit.

The “Kits” section records a set of products that have a general operational purpose of an auxiliary nature, for example, a set of spare parts, a set of tools and accessories, a set of measuring equipment, etc.

The “Materials” section includes all materials directly included in the assembly unit. Materials are recorded by type and in the sequence specified in GOST 2.108 - 68. Within each type, materials are recorded in alphabetical order of the names of materials, and within each name - in ascending order of size and other parameters.

In the “Quantity” column indicate the number of components per one specified product, and in the “Materials” section - the total quantity of materials per one specified product indicating the units of measurement - (for example, 0.2 kg). Units of measurement may be written in the “Note” column.

Engineering graphics has become my favorite subject, for which I thank the teachers of the college and university, they taught me their subject very well. In many explanatory dictionaries and reference books, the word “engineer” is defined as a specialist with a higher technical education. However, education gives him the right to call himself an engineer when he is actually involved in engineering activities, creatively applies his knowledge acquired at the university, and also after graduation, when he becomes a creator of new technology, a designer, a tester, and finally, a skillful organizer of production . An engineer must be able to do something that cannot be expressed in one word “knows”; he must also have a special type of thinking, different from both ordinary and scientific.

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Design Engineer Tools

An engineer in any industry uses his head as his main tool - unless, of course, he is a real engineer.

In addition, there are many (countless) devices that provide the possibility and convenience of performing this type of activity.

In the course of his intellectual work, a design engineer uses both tangible and intangible tools. Quite conventionally, they can be divided into the main stages of the design process:

• information processing and making design and technological decisions. The creative part of the process where intangible resources are involved. Of the real ones, of course, this is an engineering calculator.
• design of technical solutions, the main tool for this is drawing.

A rapid breakthrough and change in the existing foundations and rules in design (new GOSTs appeared, adjusted for the production of documentation, drawings using a computer, engineer’s tools underwent changes) and the work of design engineers and developers was brought about by the appearance of computers. About the capabilities of a computer, which, due to its versatility, is a successful alternative to many design tools. Correctly selected CAD software saves a lot work time, increases labor efficiency and speeds up the “release” of the drawing.

Automated designer workstation (AWS)

A modern automated designer workstation (AWS) includes a computer and graphics devices for performing various images, both input and output - from a printer (plotter), to a professional interactive pen display and flipchart.

Computer graphics is the process of creating, processing, transmitting, storing and practical application graphic images using a computer. By creating a spatial model on a computer screen (monitor), it can be rotated and modified at will, which provides good conditions for the creative process when designing.

One of the most important advantages of making a drawing on a computer is the ease of correction: it is easy to “erase” extra lines, while the corrections made are invisible; You can freely move images around the field, “reflect” and duplicate them. Another advantage is obtaining color drawings, in which, for example, thin lines are made in one color, solid thick ones in another, etc. Color drawings are easy to read.

It is convenient to store in computer memory and transmit to almost anywhere in the world (whereas transmitting paper drawings requires considerable time). Electronic drawings are easy to reproduce (replicate).

Measuring tool

Devices such as the slide rule or drawing utensils (which are still used in intermediate stages) are becoming a thing of the past and are practically no longer used today.

Let us note only some of the actual and material tools of the designer’s labor, in particular measuring instruments.

Today, Soviet-style measuring instruments can only be found in design bureaus that, for some reason, have not embarked on the path of modernization or are carrying out non-urgent research and development projects; operational and urgent orders are practically impossible to complete on Whatman paper. Here are just some of the older types of measuring equipment.

Geometric dimension meters: tape measure (folding meter, ruler, etc.), electronic rangefinder, height gauge (used for marking), caliper (although digital has successfully replaced it), calipers, depth gauge, bore gauge (determining the width of cavities), micrometer, end gauges length measures for calibration and control.

Angle meters: square, protractor.

Electronic equipment: thickness gauge, metal detector, 3D scanner

Geodetic equipment: theodolite, level, tacheometer, curvimeter.

In addition: thread gauges, sets of probes and templates, a torque wrench, a Kashkarov or Fizdel hammer.

Let's take a closer look at some of them.

Ready room

A set of drawing tools placed in a case is called a ready-to-use set. The preparation kit includes a drawing compass for drawing circles and arcs, a marking compass, which is used for transferring and setting aside dimensions, and a drawing board for tracing the drawing.

Ready room

The preparation kit may include an extension for the drawing compass, a pencil case for storing spare needles and graphite rods for the drawing compass, a center and other tools.

Drawing compass

The CC consists of a long stem with a needle and a short one for a pencil insert. The insert in the leg is secured with a clamp (screw with a round nut).

A medium-hard graphite rod is clamped into the pencil insert. It is sharpened into a cone or a flat cut.

You used a ruler to measure distances and draw straight lines along it. In drawing, a ruler is also used in connection with a transverse bar-head. Such a ruler is called a ruler.

Set of rulers for drawing

When working, the head of the crossbar is pressed by hand against the left edge of the drawing board. Using a ruler, draw horizontal lines.

Drawing paper

For drawing, use thick white unlined paper (Whatman paper) with a state sign. Checkered paper is also used for sketches.

Checkered paper and whatman paper on a roll

Pencils

Pencils are needed for drawing and tracing drawings. They are hard (T), soft (M) and medium hard (TM and ST). Hard pencils: T, 2T, ZT, etc.; soft: M, 2M, ZM, etc.

The larger the number on the edge of the pencil next to the letter, the harder or softer the pencil.

Koh-i-noor pencil set

Pen display

One of the modern gadgets that has appeared to help the engineer is the pen display. Its necessity can hardly be overestimated; the device is very useful for a novice engineer or student; it is very convenient to make sketches and drafts of future developments. Functionality Let's look at the example below of interactive pen displays. The screen size (and, accordingly, the working area of ​​the tablet) of this device is on average 20 inches diagonally and the resolution is 1600x1200 pixels. The screen is protected by a special plastic coating, which protects the LCD panel from mechanical damage - unlike conventional monitors.

The texture of the surface of the protective coating prevents the pen tip from sliding too freely, allowing you to simulate tactile sensations similar to those that arise in the process of drawing with a regular pencil on paper.

Pen display

As a rule, graphics tablets are designed to be used in a horizontal position, while the monitor screen in most cases is installed almost vertically. The interactive display is installed on the desktop on a special stand, the design of which allows you to smoothly change the angle of inclination of the screen relative to the supporting surface.

The design of the stand resembles a sketchbook: the tilt of the screen is adjusted by changing the angle between two supports connected at the top point by a hinge. The rear support is equipped with rollers that provide smooth movement on almost any surface. The locking mechanism fixes the supports in a position corresponding to the selected screen tilt angle.