Drawing lines graphic work 1 vertically. Practical and graphic work on drawing

METHODOLOGICAL INSTRUCTIONS

on fulfillment of control tasks

by discipline

OP.01 “Engineering graphics”

for specialty 02.23.03

Maintenance and repair of motor vehicles

for distance learning

(basic training)

Considered at the meeting of the Central Committee

Technical and economic direction

Protocol No.__ dated “___” ______2015.

Chairman of the Central Committee

O.V.Kobeleva

Methodical manual on “Engineering graphics” for the specialty

02.23.03 Maintenance and repair of motor vehicles for distance learning

Developer organization:

State educational institution of secondary vocational education Kemerovo Vocational Technical College.

Kazannikova Valentina Grigorievna, teacher of the highest qualification category of the State Educational Institution of Secondary Professional Education of the Kemerovo Vocational Technical College.

Reviewers:

Shartynova Evgeniya Sergeevna, teacher of engineering graphics of the highest qualification category at Kemerovo Vocational Technical College

Mashkina Valentina Vladimirovna, teacher of engineering graphics of the highest qualification category at the Kemerovo Municipal Construction College named after V.I. Zauzelkov

INTRODUCTION

The academic discipline “Engineering Graphics” is a general professional discipline that forms the basic knowledge necessary for mastering special disciplines: the ability to read and execute drawings of parts, assembly drawings, and circuit drawings.

Guidelines for completing control tasks are compiled in accordance with the work program of the discipline OP.01 “Engineering Graphics” in the specialty 02.23.03 Maintenance and repair of motor vehicles for correspondence courses, which provides for the student to independently study the theoretical foundations and perform a number of control tasks in order to develop drawing skills. Carrying out graphic work helps to master the technique of drawing, develop spatial thinking, without which active creative work of students is impossible when completing coursework, theses and further work in their specialty.

As a result of mastering the discipline, the student should be able to:

Prepare design, technological and other technical documentation in accordance with the current regulatory framework;

Create images, cuts and sections on drawings;

Perform assembly drawing detailing;

Solve graphic problems.

As a result of mastering the discipline, the student should know:

Basic rules for constructing drawings and diagrams;

Methods of graphical representation of spatial images;

Possibilities of computer graphics application packages in professional activities;

Basic provisions of design, technological and other regulatory documentation;

Basics of construction graphics.

Methodological instructions include the content of the educational material of the discipline for independent study of theoretical material, indicating references to educational literature and the topics of tests, methodological instructions and tasks for graphic works, which the student performs under the guidance of a teacher during the lessons of the practical cycle and independently when preparing the test.

Each practical task of the manual includes methodological instructions, where methodological assistance is provided in completing the task, and samples of drawing design are provided for each work. All assignment options are made in the same style; the selection of assignments covers the material from the main sections of the program, which allows for an objective assessment of the knowledge acquired by students while studying the discipline “Engineering Graphics”. A description of the procedure for completing a task facilitates and speeds up the process of completing it.

Under the heading “Please note,” the guidelines tell you exactly what changes have occurred in the standard and what is important when performing the drawing.

The appendix includes the reference materials necessary for performing graphic work.

The final grade is obtained based on the results of checking each graphic work, the evaluation criteria of which are the following indicators:

Selecting the scale and location of the drawing format;

Layout of the drawing;

– the correctness of the task;

Dimensioning;

– drawing lines;

Filling out the title block.

GENERAL GUIDELINES

As practice shows, the greatest effect of studying engineering graphics can be achieved when students complete individual graphic tasks, which are presented in these guidelines by task options. The option is selected by number in the list of the class magazine. All problems are solved after independent study of the corresponding section in the textbook. A link to educational literature is given in section 2 of this manual, which indicates the topics being studied, their content and pages on textbooks available in the technical school library; below is an additional list of references.

Graphic tasks are performed on standard sheets of drawing paper, in pencil. Each sheet is framed and certified by the main inscription of Form 1 according to GOST 2.104-2006 (see Appendix 11). A sample of its filling is shown in Fig. 1. In an additional column measuring 14x70, which is located in the upper corner along the long side of the format, indicate the drawing code in an inverted position.

The code indicates the address of the drawing manufacturer and writes it in font No. 7:

KPTT – Kemerovo Vocational Technical College; name of the discipline: IG - engineering graphics; option number: 05 - fifth option; number of graphic work: 10 - graphic work No. 10.

For example: KPTT IG 05.10.00

For some sheets, instead of the last zeros, the part position number, circuit code, etc. are indicated.

In the main inscription in the “name” column the name of the graphic work is written. The scale of the image is indicated in the title block.

To set dimensions in drawings, use font No. 3.5.

Accepted designations:

Points on projections are designated by the same lowercase letters of the Russian alphabet with strokes indicating the projection plane (a, a", a");

Angles - in lowercase letters of the Greek alphabet, indicating degrees (α, β).

All text inscriptions on the drawings are made in drawing font in accordance with GOST 2.304-81; for ease of use of this manual, Appendix No. 2 shows the design of letters and dimensions for font numbers 3.5; 5; 7 and 10. Upon completion of all graphic tasks, the sheets are bound into an album, the first sheet of which is the title page (its number is not indicated on the sheet). The album is submitted to the teacher for review.

GRAPHIC WORKS

GRAPHIC WORK No. 1

Workbook

Introduction to the Subject of Drawing

The history of the emergence of graphic methods of images and drawings

Drawings in Rus' were made by “draftsmen”, a mention of which can be found in the “Pushkar Order” of Ivan IV.

Other images - drawings, were a bird's eye view of the structure.

At the end of the 12th century. In Russia, large-scale images are introduced and dimensions are indicated. In the 18th century, Russian draftsmen and Tsar Peter I himself made drawings using the method of rectangular projections (the founder of the method is the French mathematician and engineer Gaspard Monge). By order of Peter I, the teaching of drawing was introduced in all technical educational institutions.

The entire history of the development of the drawing is inextricably linked with technical progress. Currently, the drawing has become the main document of business communication in science, technology, production, design, and construction.

It is impossible to create and check a machine drawing without knowing the basics of the graphic language. Which you will meet while studying the subject "Drawing"

Types of graphic images

Exercise: label the names of the images.

The concept of GOST standards. Formats. Frame. Drawing lines.

Exercise 1

Graphic work No. 1

"Formats. Frame. Drawing lines"

Examples of work performed

Test tasks for graphic work No. 1

Option #1.

1. What designation according to GOST has a format of size 210x297:

a) A1; b) A2; c) A4?

2. What is the thickness of the dash-dot line if in the drawing the solid main thick line is 0.8 mm:

a) 1mm: b) 0.8 mm: c) 0.3 mm?

______________________________________________________________

Option #2.

Select and underline the correct answers to the questions.

1. Where in the drawing is the main inscription located:

a) in the lower left corner; b) in the lower right corner; c) in the upper right corner?

2. How much should the axial and center lines extend beyond the contour of the image:

a) 3...5 mm; b) 5…10 mm4 c) 10…15 mm?

Option #3.

Select and underline the correct answers to the questions.

1. What arrangement of A4 format is allowed by GOST:

A) vertical; b) horizontal; c) vertical and horizontal?

2. . What is the thickness of a solid thin line if in the drawing the solid main thick line is 1 mm:

a) 0.3 mm: b) 0.8 mm: c) 0.5 mm?

Option number 4.

Select and underline the correct answers to the questions.

1. At what distance from the edges of the sheet is the drawing frame drawn:

a) left, top, right and bottom – 5 mm each; b) left, top and bottom – 10 mm, right – 25 mm; c) left – 20 mm, top, right and bottom – 5 mm each?

2. What type of line are the axial and center lines made in the drawings:

a) a solid thin line; b) dash-dotted line; c) dashed line?

Option #5.

Select and underline the correct answers to the questions.

1. What are the dimensions of the A4 format according to GOST:

a) 297x210 mm; b) 297x420 mm; c) 594x841 mm?

2. Depending on which line the thickness of the drawing lines is selected:

a) dash-dotted line; b) a solid thin line; c) a solid main thick line?

Fonts (GOST 2304-81)

Font types:

Font sizes:

Practical tasks:

Calculations of drawing font parameters

Test tasks

Option #1.

Select and underline the correct answers to the questions.

What value is taken as the font size:

a) the height of a lowercase letter; b) height of capital letter; c) the height of the spaces between the lines?

Option #2.

Select and underline the correct answers to the questions.

What is the height of the capital letter of rift No. 5:

a) 10 mm; b) 7 mm; c) 5 mm; d) 3.5 mm?

Option #3.

Select and underline the correct answers to the questions.

What is the height of lowercase letters that have protruding elements? c, d, b, r, f:

a) the height of the capital letter; b) the height of a lowercase letter; c) greater than the height of the capital letter?

Option number 4.

Select and underline the correct answers to the questions.

Are uppercase and lowercase letters different in writing? A, E, T, G, I:

a) differ; b) do not differ; c) do they differ in the spelling of individual elements?

Option #5.

Select and underline the correct answers to the questions.

What does the height of the numbers of a drawing font correspond to:

a) the height of a lowercase letter; b) the height of the capital letter; c) half the height of a capital letter?

Graphic work No. 2

"Drawing of a flat part"

Cards - tasks

1 option

Option 2

Option 3

Option 4

Geometric constructions

Dividing a circle into 5 and 10 parts

Dividing a circle into 4 and 8 parts

Dividing a circle into 3, 6 and 12 parts

Dividing a segment into 9 parts

Fixing the material

Practical work:

Based on these types, build a third one. Scale 1:1

Option #1

Option No. 2

Option #3

Option No. 4

Fixing the material

Write your answers in your workbook:

Option #1

Option No. 2

Practical work No. 3

"Modeling from a drawing."

Directions for use

To make a cardboard model, first cut out its blank. Determine the dimensions of the workpiece from the image of the part (Fig. 58). Mark (outline) the cutouts. Cut them along the outlined contour. Remove the cut out parts and bend the model according to the drawing. To prevent the cardboard from straightening after bending, draw lines on the outside of the bend with some sharp object.

The wire for modeling must be soft and of arbitrary length (10 – 20 mm).

Fixing the material

Option No. 1 Option No. 2

Fixing the material

In your workbook, draw a drawing of the part in 3 views. Apply dimensions.

Option No. 3 Option No. 4

Fixing the material

Working with cards

Fixing the material

Using colored pencils, complete the task on the card.

Amount (increase)

Clipping

Reinforcement task

Oval -

Algorithm for constructing an oval

1. Construct an isometric projection of a square - rhombus ABCD

2. Let us denote the points of intersection of the circle and the square 1 2 3 4

3. From the top of the rhombus (D) draw a straight line to point 4 (3). We obtain segment D4, which will be equal to the radius of the arc R.

4. Let's draw an arc that will connect points 3 and 4.

5. At the intersection of segment B2 and AC, we obtain point O1.

When the segment D4 and AC intersect, we obtain point O2.

6. From the resulting centers O1 and O2 we will draw arcs R1 that will connect points 2 and 3, 4 and 1.

Fixing the material

Complete a technical drawing of the part, two views of which are shown in Fig. 62

Graphic work No. 9

Part sketch and technical drawing

1. What is called sketch?

Fixing the material

Exercise tasks

Practical work No. 7

"Reading Blueprints"

Graphic dictation

“Drawing and technical drawing of a part based on a verbal description”

Option #1

Frame is a combination of two parallelepipeds, of which the smaller one is placed with a larger base in the center of the upper base of the other parallelepiped. A through stepped hole runs vertically through the centers of the parallelepipeds.

The total height of the part is 30 mm.

The height of the lower parallelepiped is 10 mm, length 70 mm, width 50 mm.

The second parallelepiped has a length of 50 mm and a width of 40 mm.

The diameter of the bottom step of the hole is 35 mm, height 10 mm; diameter of the second stage is 20 mm.

Note:

Option No. 2

Support is a rectangular parallelepiped, to the left (smallest) face of which is attached a half-cylinder, which has a common lower base with the parallelepiped. In the center of the upper (largest) face of the parallelepiped, along its long side, there is a prismatic groove. At the base of the part there is a through hole of a prismatic shape. Its axis coincides in the top view with the axis of the groove.

The height of the parallelepiped is 30 mm, length 65 mm, width 40 mm.

Half-cylinder height 15 mm, base R 20 mm.

The width of the prismatic groove is 20 mm, the depth is 15 mm.

Hole width 10 mm, length 60 mm. The hole is located at a distance of 15 mm from the right edge of the support.

Note: When drawing dimensions, consider the part as a whole.

Option No. 3

Frame is a combination of a square prism and a truncated cone, which stands with its large base in the center of the upper base of the prism. A through stepped hole runs along the axis of the cone.

The total height of the part is 65 mm.

The height of the prism is 15 mm, the size of the sides of the base is 70x70 mm.

The height of the cone is 50 mm, the lower base is Ǿ 50 mm, the upper base is Ǿ 30 mm.

The diameter of the lower part of the hole is 25 mm, height 40 mm.

The diameter of the upper part of the hole is 15 mm.

Note: When drawing dimensions, consider the part as a whole.

Option No. 4

Sleeve is a combination of two cylinders with a stepped through hole that runs along the axis of the part.

The total height of the part is 60 mm.

The height of the lower cylinder is 15 mm, the base is Ǿ 70 mm.

The base of the second cylinder is Ǿ 45 mm.

Bottom hole Ǿ 50 mm, height 8 mm.

The upper part of the hole is Ǿ 30 mm.

Note: When drawing dimensions, consider the part as a whole.

Option No. 5

Base is a parallelepiped. In the center of the upper (largest) face of the parallelepiped, along its long side, there is a prismatic groove. There are two through cylindrical holes in the groove. The centers of the holes are spaced from the ends of the part at a distance of 25 mm.

The height of the parallelepiped is 30 mm, length 100 mm, width 50 mm.

Groove depth 15 mm, width 30 mm.

Hole diameters are 20 mm.

Note: When drawing dimensions, consider the part as a whole.

Option No. 6

Frame It is a cube, along the vertical axis of which there is a through hole: semi-conical at the top, and then turning into a stepped cylindrical one.

Cube edge 60 mm.

The depth of the semi-conical hole is 35 mm, the upper base is 40 mm, the bottom is 20 mm.

The height of the bottom step of the hole is 20 mm, the base is 50 mm. The diameter of the middle part of the hole is 20 mm.

Note: When drawing dimensions, consider the part as a whole.

Option No. 7

Support is a combination of a parallelepiped and a truncated cone. The cone with its large base is placed in the center of the upper base of the parallelepiped. In the center of the smaller side faces of the parallelepiped there are two prismatic cutouts. A through hole of cylindrical shape Ǿ 15 mm is drilled along the axis of the cone.

The total height of the part is 60 mm.

The height of the parallelepiped is 15 mm, length 90 mm, width 55 mm.

The diameters of the cone bases are 40 mm (lower) and 30 mm (upper).

The length of the prismatic cutout is 20 mm, width 10 mm.

Note: When drawing dimensions, consider the part as a whole.

Option No. 8

Frame is a hollow rectangular parallelepiped. In the center of the upper and lower base of the body there are two conical tides. A through hole of cylindrical shape Ǿ 10 mm passes through the centers of the tides.

The total height of the part is 59 mm.

The height of the parallelepiped is 45 mm, length 90 mm, width 40 mm. The thickness of the walls of the parallelepiped is 10 mm.

The height of the cones is 7 mm, the base is Ǿ 30 mm and Ǿ 20 mm.

Note: When drawing dimensions, consider the part as a whole.

Option No. 9

Support is a combination of two cylinders with one common axis. A through hole runs along the axis: at the top it is prismatic in shape with a square base, and then cylindrical in shape.

The total height of the part is 50 mm.

The height of the lower cylinder is 10 mm, the base is Ǿ 70 mm. The diameter of the base of the second cylinder is 30 mm.

The height of the cylindrical hole is 25 mm, the base is Ǿ 24 mm.

The base side of the prismatic hole is 10 mm.

Note: When drawing dimensions, consider the part as a whole.

Test

Graphic work No. 11

“Drawing and visual representation of the part”

Using the axonometric projection, construct a drawing of the part in the required number of views on a scale of 1:1. Add dimensions.

Graphic work No. 10

“Sketch of a part with design elements”

Draw a drawing of a part from which parts have been removed according to the markings applied. The projection direction for constructing the main view is indicated by an arrow.

Graphic work No. 8

“Drawing of a part with transformation of its shape”

General concept of shape transformation. Relationship between drawing and markings

Graphic work

Making a drawing of an object in three views with transforming its shape (by removing part of the object)

Complete the technical drawing of the part, making, instead of the protrusions marked with arrows, notches of the same shape and size in the same place.

Logical thinking task

Topic “Design of drawings”

Crossword "Projection"

1.The point from which the projecting rays emanate during central projection.

2. What is obtained as a result of modeling.

3. Cube face.

4. The image obtained during projection.

5. In this axonometric projection, the axes are located at an angle of 120° to each other.

6. In Greek, this word means “double dimension.”

7. Side view of a person or object.

8. Curve, isometric projection of a circle.

9. The image on the profile projection plane is a view...

Rebus on the topic “View”

Rebus

Crossword "Axonometry"

Vertically:

1. Translated from French as “front view”.

2. The concept in drawing of what the projection of a point or object is obtained on.

3. The boundary between the halves of a symmetrical part in the drawing.

4. Geometric body.

5. Drawing tool.

6. Translated from Latin, “throw, throw forward.”

7. Geometric body.

8. The science of graphic images.

9. Unit of measurement.

10. Translated from Greek as “double dimension”.

11. Translated from French as “side view”.

12. In the drawing, “she” can be thick, thin, wavy, etc.

Technical Dictionary of Drawing

Workbook

Practical and graphic work on drawing

The notebook was developed by Anna Aleksandrovna Nesterova, teacher of the highest category of drawing and fine art, teacher of the Municipal Budget Educational Institution “Secondary School No. 1 of Lensk”

Introduction to the Subject of Drawing
Materials, accessories, drawing tools.

Task “Line Types”

Purpose performing graphic work is the acquisition of skills in working with drawing tools, as well as securing drawing lines, is the acquisition of skills in working with drawing tools, as well as securing drawing lines
To complete graphic work 2, the student needs to know the topic “Rules for drawing the contours of technical details” /1/§1..4, /2/ §3…§9, /3 / work 2.

2 .1 Execution of drawing lines

To correctly complete graphic work tasks, you must familiarize yourself with GOST 2.303-68 and 2.304-68 ESKD.

Trace the lines of the drawing according to GOST 2.304-81.

1. Solid thick main line It is used to depict the visible contour of an object, the contour of an extended section and part of a section and has a thickness of S = 0.5...1.4 mm.

2. Solid thin line used to depict dimension and extension lines, hatch lines of sections, contour lines of an overlaid section, leader lines, lines for depicting boundary details (“furnishings”).

3. Solid wavy line used to depict break lines, view and section demarcation lines.

4. Dashed line used to depict an invisible outline. Stroke length

5. Dot-dash thin line used to depict axial and center lines, section lines, which are axes of symmetry for superimposed or offset sections. The length of the strokes must be the same and is selected from approximately 5 to 30 mm depending on the size of the image. Distance between strokes -3...5 mm.

6. Dot-dash thick line used to depict elements located in front of the cutting plane (“Superimposed projection”), lines indicating surfaces to be heat treated or coated.

7. Open line used to indicate a section line. The length of the strokes is taken in the range of 8...20 mm depending on the size of the image.

8. Solid thin line with kinks used for long break lines.

9. Dashed line with two dots used to depict parts of products in extreme or intermediate positions; fold lines on developments; for the scan image combined with the view.

Considering the degree of complexity of the drawings and the size of their formats, when drawing lines you should take the dimensions given in Table 1.1.

The table also provides recommendations for selecting pencils used when tracing a drawing.Strokegives the drawing clarity, contrast and makes the drawing easier to read. To obtain clear and black lines, the pencil must be applied with sufficient pressure. It is recommended to draw straight lines with two counter movements from one ruler setting; circle - making two turns of the compass. Since circles are difficult to draw with strong pressure, a lead slightly softer than a pencil lead (no more than one notch) should be inserted into the compass.All lines of the outlined drawing, regardless of their structure, must have the same brightness.

Assignment (sheet 1) It is carried out on an A4 sheet, according to its own version, and is dedicated to drawing lines in accordance with GOST 2.303-68 (see Table 1.1).

Instructions for completing the task

It is more convenient to begin completing the task by drawing a thin vertical line through the middle of the inner frame of the drawing, on which marks are made in accordance with the dimensions given in the task. Thin auxiliary lines are drawn through the designated points (Fig. 1.2), making it easier to complete the graphic part of the task. On the vertical axes intended for circles, points are marked through which the circles are drawn using the lines specified in the task. Figure 1.2

It is proposed to take the thickness of the main solid line within the range of 0.8...1 mm, and the thicknesses of all other lines are set in accordance with the data in Table. 2.1. When making dashed and dash-dotted lines, you need to maintain their thickness, the length of individual strokes and the distance between them. An example of task 1 on sheet 1 is shown in Fig. 1.2;1..3.

2.1. The concept of ESKD standards. If each engineer or draftsman executed and designed drawings in his own way, without following the same rules, then such drawings would not be understandable to others. To avoid this, the USSR adopted and operates state standards of the Unified System of Design Documentation (ESKD).

ESKD standards are regulatory documents that establish uniform rules for the implementation and execution of design documents in all industries. Design documents include drawings of parts, assembly drawings, diagrams, some text documents, etc.

Standards are established not only for design documents, but also for certain types of products manufactured by our enterprises. State standards (GOST) are mandatory for all enterprises and individuals.

Each standard is assigned its own number along with the year of its registration.

The standards are revised from time to time. Changes in standards are associated with the development of industry and the improvement of engineering graphics.

For the first time in our country, standards for drawings were introduced in 1928 under the title “Drawings for all types of mechanical engineering.” Later they were replaced with new ones.

2.2. Formats. The main inscription of the drawing. Drawings and other design documents for industry and construction are performed on sheets of certain sizes.

For economical use of paper, ease of storage and use of drawings, the standard establishes certain sheet formats, which are outlined with a thin line. At school you will use a format whose sides measure 297X210 mm. It is designated A4.

Each drawing must have a frame that limits its field (Fig. 18). The frame lines are solid thick basic ones. They are carried out from above, to the right and below at a distance of 5 mm from the outer frame, made by a continuous thin line along which the sheets are cut. On the left side - at a distance of 20 mm from it. This strip is left for filing drawings.

Rice. 18. Design of A4 sheet

On the drawings, the main inscription is placed in the lower right corner (see Fig. 18). Its shape, size and content are established by the standard. On educational school drawings you will make the main inscription in the form of a rectangle with sides 22X145 mm (Fig. 19, a). A sample of the completed title block is shown in Figure 19, b.

Rice. 19. The main inscription of the educational drawing

Production drawings made on A4 sheets are placed only vertically, and the main inscription on them is only along the short side. On drawings of other formats, the title block can be placed along both the long and short sides.

As an exception, on educational drawings in A4 format, the main inscription is allowed to be placed both along the long and short sides of the sheet.

Before starting the drawing, the sheet is applied to the drawing board. To do this, attach it with one button, for example, in the upper left corner. Then a crossbar is placed on the board and the upper edge of the sheet is placed parallel to its edge, as shown in Figure 20. Pressing the sheet of paper to the board, attach it with buttons, first in the lower right corner, and then in the remaining corners.

Rice. 20. Preparing the sheet for work

The frame and columns of the main inscription are made with a solid thick line.

What are the dimensions of an A4 sheet? At what distance from the outer frame should the drawing frame lines be drawn? Where is the title block placed on the drawing? Name its dimensions. Look at Figure 19 and list what information it contains.

2.3. Lines. When making drawings, lines of various thicknesses and styles are used. Each of them has its own purpose.

Rice. 21. Drawing lines

Figure 21 shows an image of a part called a roller. As you can see, the part drawing contains different lines. In order for the image to be clear to everyone, the state standard establishes the outline of lines and indicates their main purpose for all industrial and construction drawings. In technical and maintenance lessons you have already used various lines. Let's remember them.

In conclusion, the thickness of lines of the same type should be the same for all images in a given drawing.

Information about the drawing lines is given on the first flyleaf.

1. What is the purpose of a solid thick main line?
2. Which line is called a dashed line? Where is it used? How thick is this line?
3. Where is the dash-dotted thin line used in the drawing? What is its thickness?
4. In what cases is a solid thin line used in a drawing? How thick should it be?
5. Which line shows the fold line on a development?

In Figure 23 you see an image of the part. Various lines are marked on it with numbers 1,2, etc. Make a table based on this example in your workbook and fill it out.

Rice. 23. Exercise task

Graphic work No. 1

Prepare a sheet of A4 drawing paper. Draw the frame and columns of the main inscription according to the dimensions indicated in Figure 19. Draw various lines, as shown in Figure 24. You can choose another arrangement of groups of lines on the sheet.

Rice. 24. Assignment for graphic work No. 1

The main inscription can be placed both along the short and along the long side of the sheet.

2.4. Drawing fonts. Sizes of letters and numbers of a drawing font. All inscriptions on the drawings must be made in drawing font (Fig. 25). The style of letters and numbers of a drawing font is established by the standard. The standard determines the height and width of letters and numbers, the thickness of stroke lines, the distance between letters, words and lines.

Rice. 25. Inscriptions on drawings

An example of constructing one of the letters in the auxiliary grid is shown in Figure 26.

Rice. 26. Example of letter construction

The font can be either slanted (about 75°) or without slanting.

The standard sets the following font sizes: 1.8 (not recommended, but allowed); 2.5; 3.5; 5; 7; 10; 14; 20; 28; 40. The size (h) of a font is taken to be the value determined by the height of capital letters in millimeters. The height of the letter is measured perpendicular to the base of the line. The lower elements of the letters D, Ts, Shch and the upper element of the letter Y are made due to the spaces between the lines.

The thickness (d) of the font line is determined depending on the height of the font. It is equal to 0.1h;. The width (g) of the letter is chosen to be 0.6h or 6d. The width of the letters A, D, Ж, М, ​​Ф, X, Ц, Ш, Ш, Ъ, ы, У is greater than this value by 1 or 2d (including the lower and upper elements), and the width of the letters Г, 3, С is less by d.

The height of lowercase letters is approximately the same as the height of the next smaller font size. So, the height of lowercase letters of size 10 is 7, size 7 is 5, etc. The upper and lower elements of lowercase letters are made due to the distances between the lines and extend beyond the line in 3d. Most lowercase letters are 5d wide. The width of the letters a, m, c, ъ is 6d, the letters zh, t, f, w, shch, s, yu are 7d, and the letters z, s are 4d.

The distance between letters and numbers in words is taken to be 0.2h or 2d, between words and numbers -0.6h or 6d. The distance between the lower lines of the lines is taken equal to 1.7h or 17d.

The standard also establishes another type of font - type A, narrower than the one just discussed.

The height of letters and numbers in pencil drawings must be at least 3.5 mm.

The layout of the Latin alphabet according to GOST is shown in Figure 27.

Rice. 27. Latin font

How to write in drawing font. It is necessary to draw up drawings with inscriptions carefully. Poorly written inscriptions or carelessly applied digits of different numbers may be misunderstood when reading the drawing.

To learn how to write beautifully in a drawing font, first draw a grid for each letter (Fig. 28). After mastering the skills of writing letters and numbers, you can only draw the top and bottom lines of the line.

Rice. 28. Examples of making inscriptions in drawing font

The outlines of the letters are outlined with thin lines. After making sure that the letters are written correctly, trace them with a soft pencil.

For the letters G, D, I, Ya, L, M, P, T, X, C, Ш, Ш, you can only draw two auxiliary lines at a distance equal to their height A.

For the letters B, V, E, N. R, U, CH, Ъ, И, ь. Between the two horizontal lines, another one should be added in the middle, but which is filled with their middle elements. And for the letters 3, O, F, Yu, four lines are drawn, where the middle lines indicate the boundaries of the roundings.

To quickly write inscriptions in a drawing font, various stencils are sometimes used. You will fill out the main inscription in 3.5 font, the title of the drawing in 7 or 5 font.

1. What is the font size?
2. What is the width of capital letters?
3. What is the height of size 14 lowercase letters? What is their width?

1. Complete several inscriptions in your workbook according to the teacher’s instructions. For example, you can write your last name, first name, and home address.
2. Fill in the main inscription on sheet of graphic work No. 1 with the following text: drew (last name), checked (teacher's last name), school, class, drawing No. 1, title of the work “Lines”.

2.5. How to apply dimensions. To determine the size of the depicted product or any part of it, dimensions are applied to the drawing. Dimensions are divided into linear and angular. Linear dimensions characterize the length, width, thickness, height, diameter or radius of the measured part of the product. Angular size characterizes the size of the angle.

Linear dimensions in the drawings are indicated in millimeters, but the unit of measurement is not indicated. Angular dimensions are indicated in degrees, minutes and seconds with the designation of the unit of measurement.

The total number of dimensions in the drawing should be the smallest, but sufficient for the manufacture and control of the product.

The rules for applying dimensions are established by the standard. You already know some of them. Let's remind them.

1. Dimensions in the drawings are indicated by dimensional numbers and dimensional lines. To do this, first draw extension lines perpendicular to the segment, the size of which is indicated (Fig. 29, a). Then, at a distance of at least 10 mm from the contour of the part, draw a dimension line parallel to it. The dimension line is limited on both sides by arrows. What the arrow should be is shown in Figure 29, b. Extension lines extend beyond the ends of the arrows of the dimension line by 1...5 mm. Extension and dimension lines are drawn as a solid thin line. Above the dimension line, closer to its middle, the dimension number is applied.

Rice. 29. Applying linear dimensions

2. If there are several dimension lines parallel to each other in the drawing, then a smaller dimension is applied closer to the image. So, in Figure 29, first dimension 5 is applied, and then 26, so that the extension and dimension lines in the drawing do not intersect. The distance between parallel dimension lines must be at least 7 mm.

3. To indicate the diameter, a special sign is applied in front of the size number - a circle crossed out by a line (Fig. 30). If the dimensional number does not fit inside the circle, it is taken outside the circle, as shown in Figure 30, c and d. The same is done when applying the size of a straight segment (see Figure 29, c).

Rice. 30. Sizing circles

4. To indicate the radius, write the capital Latin letter R in front of the dimension number (Fig. 31, a). The dimension line to indicate the radius is drawn, as a rule, from the center of the arc and ends with an arrow on one side, abutting the point of the arc of the circle.

Rice. 31. Applying dimensions of arcs and angles

5. When indicating the size of an angle, the dimension line is drawn in the form of a circular arc with the center at the vertex of the angle (Fig. 31, b).

6. Before the dimensional number indicating the side of the square element, a “square” sign is applied (Fig. 32). In this case, the height of the sign is equal to the height of the numbers.

Rice. 32. Applying the size of the square

7. If the dimension line is located vertically or obliquely, then the dimension numbers are placed as shown in Figure 29, c; thirty; 31.

8. If a part has several identical elements, then it is recommended to indicate on the drawing the size of only one of them with an indication of the quantity. For example, an entry on the drawing “3 holes. 0 10" means that the part has three identical holes with a diameter of 10 mm.

9. When depicting flat parts in one projection, the thickness of the part is indicated as shown in Figure 29, c. Please note that the dimensional number indicating the thickness of the part is preceded by the Latin small letter 5.

10. It is allowed to indicate the length of the part in a similar way (Fig. 33), but in this case a Latin letter is written before the dimension number l.

Rice. 33. Applying the part length dimension

1. In what units are linear dimensions expressed in mechanical engineering drawings?
2. How thick should extension and dimension lines be?
3. What distance is left between the outline of the image and the dimension lines? between size lines?
4. How are dimensional numbers applied on inclined dimensional lines?
5. What signs and letters are placed before the dimensional number when indicating the values ​​of diameters and radii?

Rice. 34. Exercise task

1. Draw into your workbook, maintaining the proportions, the image of the part given in Figure 34, enlarging it by 2 times. Apply the required dimensions, indicate the thickness of the part (it is 4 mm).
2. Draw circles in your workbook with diameters of 40, 30, 20 and 10 mm. Add their dimensions. Draw circular arcs with radii of 40, 30, 20 and 10 mm and mark the dimensions.

2.6. Scale. In practice, it is necessary to create images of very large parts, for example parts of an airplane, ship, car, and very small ones - parts of a clock mechanism, some instruments, etc. Images of large parts may not fit on sheets of standard format. Small details that are barely visible to the naked eye cannot be drawn in full size using existing drawing tools. Therefore, when drawing large parts, their image is reduced, and small ones are increased in comparison with the actual dimensions.

Scale is the ratio of the linear dimensions of the image of an object to the actual ones. The scale of images and their designation on drawings sets the standard.

Reduction scale - 1:2; 1:2.5; 1:4; 1:5; 1:10, etc.
Natural size - 1:1.
Magnification scale - 2:1; 2.5:1; 4:1; 5:1; 10:1, etc.

The most desirable scale is 1:1. In this case, when creating an image, there is no need to recalculate the dimensions.

The scales are written as follows: M1:1; M1:2; M5:1, etc. If the scale is indicated on the drawing in a specially designated column of the main inscription, then the letter M is not written before the scale designation.

It should be remembered that, no matter what scale the image is made, the dimensions on the drawing are actual, i.e. those that the part should have in kind (Fig. 35).

The angular dimensions do not change when the image is reduced or enlarged.

1. What is the scale used for?
2. What is scale?
3. What are the magnification scales established by the standard? What scale of reduction do you know?
4. What do the entries mean: M1:5; M1:1; M10:1?

Rice. 35. Drawing of the gasket, made in various scales

Graphic work No. 2
Flat part drawing

Make drawings of the “Gasket” parts using the existing halves of the images, separated by an axis of symmetry (Fig. 36). Add dimensions, indicate the thickness of the part (5 mm).

Complete the work on an A4 sheet. Image scale 2:1.

Directions for use. Figure 36 shows only half of the image of the part. You need to imagine what the complete part will look like, keeping in mind symmetry, and sketch it on a separate sheet. Then you should proceed to the drawing.

A frame is drawn on an A4 sheet and space is allocated for the main inscription (22X145 mm). The center of the working field of the drawing is determined and the image is constructed from it.

First, draw the axes of symmetry and build a rectangle with thin lines that corresponds to the general shape of the part. After this, images of the rectangular elements of the part are marked.

Rice. 36. Tasks for graphic work No. 2

Having determined the position of the centers of the circle and semicircle, draw them. The dimensions of the elements and overall, i.e., the largest in length and height, dimensions of the part are indicated, and its thickness is indicated.

Outline the drawing with the lines established by the standard: first - circles, then - horizontal and vertical straight lines. Fill out the title block and check the drawing.

TO SAOU SPO "Pedagogical College of Tambov" METHODOLOGICAL INSTRUCTIONS for performing practical work in the discipline "Engineering Graphics" for students of the specialty "280707 Protection in emergency situations, rescue technician" (Works No. 1-6) TAMBOV, 2013 Author: TARASOV V.E., teacher of special disciplines of the State Autonomous Educational Institution of Secondary Professional Education "Pedagogical College of Tambov" Reviewer: Lappa T.I. Engineering graphics" for students of the specialty "280707 Protection in emergency situations, rescue technician" (Works No. 1-6) Guidelines for performing graphic work in the course "Engineering graphics" are intended for students of the specialty 280707 "Protection in emergency situations." The manual contains the necessary theoretical and reference material for performing graphic works No. 1-6. Recommended by the scientific and methodological council of the college as a teaching aid. INTRODUCTION The program of the course "Engineering Graphics" for students in the specialty of secondary vocational education 280707 Protection in emergency situations, rescue technician determines the amount of knowledge required to carry out mechanical engineering drawings and diagrams. Students perform most of the work independently, so when studying an engineering graphics course they are recommended to familiarize themselves with the requirements of ESKD standards for the execution of drawings. All graphic work by students must be completed in accordance with their version according to the serial number in the educational journal. The purpose of this publication is to familiarize students with fonts, lines, methods for constructing connections, depicting objects, arrangement of views, making cuts, sections and axonometric projections, drawing dimensions and maximum deviations, graphic designation of materials in graphic works and drawing electrical circuits. REQUIREMENTS OF ESKD STANDARDS FOR THE PERFORMANCE OF GRAPHIC TASKS The Unified System of Design Documentation (ESKD) is the most important system of permanent technical and organizational requirements that ensure the interchange of design documentation without its re-registration between industries and individual enterprises. It allows for increased unification in the design development of industrial product projects; simplification of document forms and reduction of their nomenclature, as well as graphic images: mechanized and automated creation of documentation and, most importantly, the readiness of industry to organize the production of any product at any enterprise in the shortest possible time. The ESKD presents a set of state standards that establish interrelated unified rules and regulations on the procedure for the development and circulation of design documentation used by various organizations and enterprises. These uniform rules also apply to educational documentation, which may include graphic tasks performed by students, therefore all images must be made clearly, accurately and in accordance with the requirements of the Unified Design Design Document. Assignments are completed on sheets of drawing paper in A3 and A4 format (GOST 2.301-68). After drawing the frame on the sheet in the lower right corner, mark the dimensions of the main inscription of the task, which is the same for all formats. The form of the main inscription is adopted in accordance with the requirements of GOST 2.104-68. Images must be made on the scale specified in the assignment, but in compliance with GOST 2.302-68. When filling out the main and other inscriptions, it is necessary to comply with the requirements of GOST 2.304-81. When applying dimensions, it is recommended to use GOST 2.307-68. When tracing an image, the thickness of the main lines should be 0.8 - 1.0 mm, and the thickness of the remaining lines should be in accordance with GOST 2.303-68. LIST OF REFERENCES 1. Bogolyubov S.K.Engineering graphics. - M.: Mechanical Engineering, 2004. -352s 2. GOST 2. 303-68. Lines. 3. GOST 2. 304-81. Drawing fonts. 4. GOST 2. 305-68. Images - views, sections, sections. 5. GOST 2. 301-68. Formats // ESKD. General rules for making drawings. GOST 22.301-68 - GOST 2.321-84. M., 1988. 239 p. 6. GOST 2. 302-68. Scale. 7. GOST 2. 307-68. Drawing dimensions and maximum deviations. 8. Levitsky V.S. Mechanical engineering drawing/ V.S. Levitsky. M., 1998. 383 p. 9. Mechanical engineering drawing / G.P. Vyatkin, A.N. Andreeva, A.K. Boltukhin et al. M., 1985. 368 p. 10. Popova G.N. Mechanical engineering drawing / G.N. Popova, S.Yu. Alekseev. St. Petersburg, 1999. 453 p. 11. S.K. Bogolyubov Individual assignments for the drawing course: Practical. A manual for technical school students. - M.: Higher. school, 1989 - 368 pp.: ill. 12. Fedorenko V.A. Handbook of mechanical engineering drawing/ V.A. Fedorenko, A.I. Shoshin. L., 1986. 416 p. PRACTICAL WORK No. 1 DRAWING THE FORMAT AND BASIC LETTER FOR GRAPHIC AND TEXT DOCUMENTS Purpose of the work: to study graphic formats, types of main inscriptions on drawings All drawings must be made on sheets of paper of a standard format. The formats of paper sheets are determined by the dimensions of the outer frame of the drawing (Fig. 3). It is drawn with a continuous thin line. The drawing frame line is drawn as a solid thick main line at a distance of 5 mm from the outer frame. A 20 mm wide margin is left on the left for filing. The designation and dimensions of the sides of the formats are established by GOST 2.304-68. Data on the main formats are given in table. 1. Table 1 Format designation Dimensions of the sides of the format, mmА0841х1189А1594х841А2420х594А3297х420А4210х297 RULES AND ORDER OF WORK The work is carried out in pencil on a sheet of A3 (297x420) or A4 (210x297) format in accordance with given example. The drawing is drawn up with an internal frame (in the form of a solid main line), a margin of 20 mm is left from the borders of the format on the left side, and 5 mm on all other sides. In the lower right corner of the drawing, draw the main inscription (stamp) in accordance with GOST 2.104-68* in accordance with Figure 1. It is recommended to fill in the following columns of the main inscription in the conditions of the educational process (the standard column designation is retained): Column 1 - name of the part or assembly unit (name topics on which the assignment was completed); Column 2 - designation of the document according to the system adopted at the college (name of the group, year, number on the list, number of the work performed - ZChS.31.2011.05.02.); Column 3 - designation of the part material (fill in only on part drawings); Column 4 - do not fill out; Column 5 - weight of the product (do not fill in); column 6 - image scale (in accordance with GOST 2.302-68* and GOST 2.109-73); column 7 - serial number of the sheet (on documents consisting of one sheet, the column is not filled in); column 8 - the total number of sheets of the document (the column is filled out only on the first sheet of the document); column 9 - name of the educational institution and group number; column 10 - the nature of the work performed by the person signing the document, for example: Developed by: (student) Checked by: (teacher) column 11 - clear spelling of the names of the persons signing the document; column 12 - signatures of persons whose surnames are indicated in column 11; Column 13 - date of signing of the document (indicate the month and year). Fig. 1 The text in the drawing field and in the main inscription is made in 3.5, 5 or 7 mm font, and the dimensional numbers are in 3.5 or 5 mm. An example of filling out the main inscription is given in Figure 2. The work is performed in thin lines, then the final outline of the drawing is made with lines in accordance with their purpose. The outline begins with dash-dotted and solid thin lines, then the main solid lines are outlined: first curved sections, then straight ones. TASK: on a sheet of A4 drawing paper, draw the lines of the drawing frame and the main inscription. PRACTICAL WORK No. 2 IMPLEMENTING A DRAWING FONT Purpose of the work: To study the pits of drawing fonts, to gain skills in writing in a drawing font. GOST 2.304-81 establishes drawing fonts applied to drawings and other technical documents of all industries and construction. The font size determines the height h of capital letters in mm. The line thickness of the font d depends on the type and height of the font. GOST sets the following font sizes: (1.8); 2.5; 3.5; 5; 7; 10; 14; 20 (Tables 1, 2). The use of 1.8 font is not recommended and is allowed only for type B. The following font types are installed: Type A with a slope of 75° - d = (1/14)h; Type A without tilt - d = (1/14)h; Type B with an inclination of 75° - d = (1/10)h; Type B without tilt - d = (1/10)h. Font parameters are given in tables 1 and 2. Table 1 - Font parameters, mm Font parameters Designations3,55,07,010,014,0ABABABABABHeight of capital lettersh3,53,55,05,07,07,010101414Height of lowercase lettersc2,52,53,53,55, 05,07,07,01010Spacing between lettersa0,50,70,71,01,01,41,42,022,8Minimum line spacingb5,56,08,08,511,012,016,017,02224Minimum spacing between wordse1,52,12,13,03,04,24 ,26,06,08,4Thickness of font linesd0,250,350,350,50,50,70,71,01,01,4 Table 2 - Width of letters and numbers of type B font, mm Letters and numbersRelative size3,55,07,010,014,0Capital lettersB, V, I, J, K, L, N, O, P, R, T, U, C, H, L, E, Z 6d23469A, D, M, X, S, Yu7d2.53.55711Zh, F, Sh, Ш, ъ8d345.5812Э, Г, З, С5d1.82.53.557 Lowercase lettersA, b, c, d, d, f, h, i, j, k, l, n, o, p, r, y, x, h . 523446d23469 TASK. Using size 10 type B font, write the letters of the alphabet shown (lowercase and uppercase), numbers from 0 to 10 and any two words. A sample of the task is shown in Figure 1. INSTRUCTIONS FOR COMPLETING THE TASK First you need to prepare a sheet of paper in standard A4 format with a frame at a distance of 5 mm from the edges at the top, right and bottom and 20 mm on the left. The sequence of completing the task of writing a standard type B font, size 10, is as follows: - draw all the auxiliary horizontal straight lines that define the boundaries of the lines of the font; - set aside a distance between lines equal to 15 mm; - set aside the font height h, i.e. 10 mm; - lay down segments equal to the width of the letters plus the distance between the letters; - draw inclined lines for the grid at an angle of 75° using two triangles: with an angle of 45° and with angles of 30° and 60°. Example of completing the task PRACTICAL WORK No. 3 DRAWING LINES Purpose of the work: to gain skills in drawing lines and using drawing tools All drawings are made with lines of various purposes, styles and thicknesses (Table 3). The thickness of the lines depends on the size, complexity and purpose of the drawing. According to GOST 2.303-68, to depict products in drawings, lines of various types are used depending on their purpose, which helps to identify the shape of the depicted product. Table 1 - Types of lines Inscription Line thickness in relation to the thickness of the main line Name Applications A solid thick main line is made with a thickness indicated by the letter s, ranging from 0.5 to 1.4 mm, depending on the complexity and size of the image in a given drawing, as well as on the format drawing. A solid thick line is used to depict the visible contour of an object, the contour of an extended section and part of a section. s/3-s/2 A solid thin line is used to depict dimension and extension lines, hatching sections, a contour line of an overlaid section, a leader line, a line for depicting boundary details (“furnishings”). s/3-s/2 A solid wavy line is used to depict break lines, the line demarcating the view and section s/3-s/2 The dashed line is used to depict an invisible contour. The length of the strokes must be the same. The length should be chosen, depending on the size of the image, from approximately 2 to 8 mm, the distance between strokes is 1...2 mm.s/3-s/2The dash-dotted thin line is used to depict axial and center lines, section lines, which are axes of symmetry for superimposed or offset sections. The length of the strokes must be the same and is selected depending on the size of the image, approximately from 5 to 30 mm. The distance between the strokes is recommended to be 2...3 mm.s/2-2s/3The dash-dotted thickened line is used to depict elements located in front of the secant plane (“superimposed projection”), lines indicating surfaces to be heat treated or coated.s/3 -s/2An open line is used to indicate a section line. The length of the strokes is taken to be 8...20 mm depending on the size of the image. s/3-s/2 A solid thin line with kinks is used for long break lines. s/3-s/2 A dash-dotted line with two dots is used to depict details in the extreme or intermediate positions; fold lines on developments The quality of the drawing largely depends on the quality and adjustment of the tools, as well as on their care. Drawing tools and accessories must be kept in full working order. After work, tools should be wiped and stored in a dry place. This prevents warping of wooden instruments and corrosion of metal ones. Before work, you should wash your hands and wipe the squares and crossbar with a soft rubber band. Pencils. The accuracy and precision of the drawing largely depends on the correct sharpening of the pencil. You can sharpen graphite using sandpaper. The student must have three brands of pencil: M-B, TM-HB and T-H. When making drawings with thin lines, it is recommended to use a pencil of grade T. You should trace the lines of the drawing with a pencil TM or M. A lead of grade M should be inserted into the compass. A circular compass is used for drawing circles. A needle is inserted into one leg of the compass and secured with a screw, and a pencil insert into the other. To measure dimensions and plot them on the drawing, use an insert with a needle. Calipers are used to draw circles of small diameter (from 0.5 to 10 mm). For ease of use, the rotating leg moves freely along the axis of the caliper. When drawing circles of large radii, an extension is inserted into the leg of the compass into which a pencil insert is secured. Lines are drawn in a certain direction: Horizontal lines are drawn from left to right, vertical lines are drawn from bottom to top, circles and curves are drawn clockwise. The center of the circle must necessarily be at the intersection of the strokes of the axial and center lines. Hatching in the drawings is performed in the form of parallel lines at an angle of 45° to the center line or to the contour line taken as the main one. The inclination of the hatch lines can be either left or right. Two touching figures are hatched in different directions. If a third figure is adjacent to two touching figures, then you can diversify the hatching by increasing or decreasing the distance between the hatching lines. Non-metallic materials, including fibrous monolithic and slab (pressed) cross-sections are lined with a checkered pattern. TASK: Draw the given lines and images (in accordance with the task option, Figure 1, 2), observing their indicated location. The thickness of the lines should be carried out in accordance with GOST 2.303 - 68, do not apply dimensions. Complete the task on a sheet of A4 drawing paper. INSTRUCTIONS FOR COMPLETING THE TASK It is more convenient to begin the task by drawing a thin vertical line through the middle of the inner frame of the drawing, on which marks are made in accordance with the dimensions given in the task. Thin auxiliary horizontal lines are drawn through the designated points to facilitate the graphic part of the task. On the vertical axes intended for circles, points are marked through which the circles are drawn using the lines specified in the task. In training drawings, a solid main thick line is usually made with a thickness of s = 0.8...1 mm. Figure 1 - even numbers of options Figure 2 - odd numbers of options PRACTICAL WORK No. 4 EXECUTION OF A DRAWING OF A DETAIL WITH MATINGS Purpose of work: to study the implementation of mating curves, to draw a part with mates 1. Dividing circles into equal parts Dividing a circle into 4 and 8 equal parts 1) Two mutual perpendiculars to the diameter of the circle divide it into 4 equal parts (points 1, 3, 5, 7). 2) Next, divide the right angle into 2 equal parts (points 2, 4, 6, 8) (Figure 1 a). Dividing a circle into 3, 6, 12 equal parts 1) To find points dividing a circle of radius R into 3 equal parts, it is enough to draw an arc of radius R from any point on the circle, for example point A(1) (points 2,3) (Figure 1 b). 2) We describe arcs R from points 1 and 4 (Figure 1 c). 3) We describe arcs 4 times from points 1, 4, 7, 10 (Figure 1 d). abc where Figure 1 - Dividing circles into equal parts a - into 8 parts; b - into 3 parts; c - into 6 parts; g - into 12 parts; d - into 5 parts; e - into 7 parts. Dividing a circle into 5, 7, equal parts 1) From point A with radius R, draw an arc that intersects the circle at point n. From point n, a perpendicular is lowered to the horizontal center line, obtaining point C. From point C with radius R1 = C1, an arc is drawn that intersects the horizontal center line at point m. From point 1 with radius R2=1m, draw an arc intersecting the circle at point 2. Arc 12=1/5 of the circumference. Points 3,4,5 are found by plotting segments equal to m1 with a compass (Figure 1e). 2) From point A we draw an auxiliary arc of radius R, which intersects the circle at point n. From it we lower a perpendicular to the horizontal center line. From point 1 with radius R=nc, 7 notches are made around the circle and 7 required points are obtained (Figure 1 e). 2. Construction of conjugations Conjugation is a smooth transition of one line to another. For accurate and correct execution of drawings, it is necessary to be able to construct conjugations that are based on two provisions: 1. To conjugate a straight line and an arc, it is necessary that the center of the circle to which the arc belongs lies on the perpendicular to the straight line, restored from the conjugation point (Figure 2 a ). 2. To conjugate two arcs, it is necessary that the centers of the circles to which the arcs belong lie on a straight line passing through the conjugation point (Figure 2 b). Figure 2 - Provisions on conjugations a - for a straight line and an arc; b - for two arcs. Conjugation of two sides of an angle with a circular arc and a given radius Conjugation of two sides of an angle (acute or obtuse) with an arc of a given radius is performed as follows: Parallel to the sides of the angle at a distance equal to the radius of the arc R, draw two auxiliary straight lines (Figure 3 a, b). The intersection point of these lines (point O) will be the center of an arc of radius R, i.e. mating center. From the center O, they describe an arc that smoothly turns into straight lines - the sides of the angle. The arc ends at the connecting points n and n1, which are the bases of the perpendiculars drawn from the center O to the sides of the angle. When constructing a mating of the sides of a right angle, it is easier to find the center of the mating arc using a compass (Figure 3 c). From the vertex of angle A, draw an arc of radius R equal to the conjugation radius. Conjugation points n and n1 are obtained on the sides of the angle. From these points, as from centers, arcs of radius R are drawn until they intersect each other at point O, which is the center of conjugation. From the center O, describe the conjugation arc. Figure 3 - Conjugate angles a - acute; b - stupid; in - direct. Conjugation of a straight line with a circular arc Conjugation of a straight line with a circular arc can be performed using an arc with an internal tangency (Figure 4 b) and an arc with an external tangency (Figure 4 a). To construct a conjugation, draw a circle of radius R and a straight line AB using an external touch. A straight line ab is drawn parallel to a given straight line at a distance equal to the radius r (radius of the conjugate arc). From the center O, draw an arc of a circle with a radius equal to the sum of the radii R and r until it intersects the straight line ab at point O1. Point O1 is the center of the mating arc. The conjugation point c is found at the intersection of straight line OO1 with a circular arc of radius R. Conjugation point C1 is the base of the perpendicular dropped from the center O1 to this straight line AB. Using similar constructions, points O2, C2, C3 can be found. In Figure 6 b, an arc of radius R is paired with a straight arc AB of radius r with an internal tangency. The center of the conjugation arc O1 is located at the intersection of an auxiliary line drawn parallel to this line at a distance r with the arc of an auxiliary circle described from the center O with a radius equal to the difference R-r. The conjugation point is the base of the perpendicular dropped from point O1 to this straight line. The mating point c is found at the intersection of straight line OO1 with the mating arc. ab Figure 4 - Conjugation of an arc with a straight line a - with external contact; b - with internal touch. Conjugation of an arc with an arc The conjugation of two circular arcs can be internal, external or mixed. With internal conjugation, the centers O and O1 of the mating arcs are located inside the mating arc of radius R (Figure 5 a). When externally conjugating mating arcs of radii R1 and R2 are located outside the mating arc of radius R (Figure 5 b). With a mixed conjugation, the center O1 of one of the mating arcs lies inside the mating arc of radius R, and the center O of the other mating arc lies outside it (Figure 5 c). abc Figure 5 - Arc mates a - internal; b - external; in - mixed. When drawing the contours of complex parts, it is important to be able to recognize certain types of interfaces in smooth transitions and be able to draw them. To acquire skills in constructing interfaces, perform exercises on drawing the contours of complex parts. To do this, it is necessary to determine the order in which the interfaces are constructed and only then begin to implement them. TASK: Draw images of the contours of the parts indicated in the drawing of the task, apply dimensions. Complete the task on a sheet of A4 drawing paper. Instructions for completing the task When performing each task, a certain sequence of geometric constructions must be observed: - axial, center lines, main descriptive lines; - arcs, roundings; - stroke, shading, extension lines; - dimensions. Variants of the task PRACTICAL WORK No. 5 PERFORMANCE OF VIEWS ACCORDING TO AN AXONOMETRIC IMAGE OF A PART Purpose of the work: to gain skills in constructing projections of a part model. TASK: construct three types of parts based on this visual image in an axonometric projection in accordance with the task option. The task is performed on sheets of drawing paper in A3 or A2 format (GOST 2.301-68). After drawing the frame on the sheet in the lower right corner, mark the dimensions of the main inscription of the task, which is the same for all formats. The form of the main inscription is adopted in accordance with the requirements of GOST 2.104-68. If necessary, images should be drawn to scale, GOST 2.302-68. When filling out the main and other inscriptions, it is necessary to comply with the requirements of GOST 2.304-81. When applying dimensions, it is recommended to use GOST 2.307-68. When tracing an image, the thickness of the main lines should be 0.8 - 1.0 mm, and the thickness of the remaining lines should be in accordance with GOST 2.303-68 (ST SEV 1178-78). Objects in technical drawings are depicted using the method of rectangular projection onto six faces of a hollow cube. In this case, it is assumed that the depicted object is located between the observer and the corresponding face of the cube (see Fig. 1). The faces of the cube are taken as the main projection planes. There are six main projection planes: two frontal -1 and 6 (front view or main view, rear view), two horizontal -2 and 5 (top view and bottom view), two profile -3 and 4 (left view and right view) . The main projection planes are combined into one plane along with the images obtained on them. The image on the frontal plane of projections is taken as the main one in the drawing. The object is positioned relative to the frontal plane of projections so that the image on it - the main image - gives the most complete idea of ​​the shape and size of the object. Objects should be depicted in a functional position or in a position convenient for their manufacture. Items consisting of several parts should be depicted in a functional position. The question of which of the main views should be used in the product drawing must be resolved so that with the smallest number of views in combination with other images (local and additional views, sections and sections, extensions), the drawing fully reflects the design of the product. Procedure for completing the task: 1) study GOST 2.305-68, 2.307-68; 2) carefully familiarize yourself with the design of the figure based on its visual representation and identify the main geometric bodies of which it consists; 3) select the appropriate area on a sheet of paper for each type of part; 4) finely draw all the lines of the visible and invisible contour with a pencil, mentally dividing the part into basic geometric bodies; 5) apply all necessary extension and dimension lines; 6) put dimensional numbers on the drawing; 7) fill out the main inscriptions and check the correctness of all constructions; 8) trace the drawing with a pencil. Variants of the task PRACTICAL WORK No. 6 PERFORMANCE OF A TECHNICAL DRAWING OF A SIMPLE DETAIL A technical drawing is a visual image that has the basic properties of axonometric projections or a perspective drawing, made without the use of drawing tools, on an eye scale, in compliance with proportions and possible shading of the shape. A technical drawing can be performed using the central projection method, and thereby obtain a perspective image of the object, or the parallel projection method (axonometric projections), constructing a visual image without perspective distortions. Technical drawing can be performed without revealing the volume by shading, with shading of the volume, as well as conveying the color and material of the depicted object. In technical drawings, it is allowed to reveal the volume of objects using the techniques of shading (parallel strokes), scribbling (strokes applied in the form of a grid) and dot shading. The most commonly used technique for identifying the volume of objects is shaking. It is generally accepted that light rays fall on an object from the top left. Illuminated surfaces are not shaded, while shaded surfaces are covered with shading (dots). When shading shaded areas, strokes (dots) are applied with the smallest distance between them, which allows you to obtain denser shading (dot shading) and thereby show shadows on objects. Table 1 shows examples of identifying the shape of geometric bodies and parts using shattering techniques. Rice. 1. Technical drawings with volume revealed by shading (a), scribbling (b) and dot shading (e) Table1. Shading of the form using shading techniques Technical drawings are not metrically defined images if they are not marked with dimensions. An example of constructing a technical drawing in a rectangular isometric projection (isometry) with a distortion coefficient along all axes equal to 1. When the true dimensions of the part are plotted along the axes, the drawing turns out to be 1.22 times larger than the real part. Methods for constructing an isometric projection of a part: 1. The method of constructing an isometric projection of a part from a form-generating face is used for parts whose shape has a flat face, called a form-generating face; The width (thickness) of the part is the same throughout; there are no grooves, holes or other elements on the side surfaces. The sequence of constructing an isometric projection is as follows: * constructing the axes of the isometric projection; * construction of an isometric projection of the formative face; * construction of projections of other faces by depicting the edges of the model; outline of the isometric projection (Fig. 1). Rice. 1. Construction of an isometric projection of a part, starting from the form-forming face 2. The method of constructing an isometric projection based on the sequential removal of volumes is used in cases where the displayed form is obtained as a result of removing any volumes from the original form (Fig. 2). 3. The method of constructing an isometric projection based on sequential increment (adding) of volumes is used to create an isometric image of a part, the shape of which is obtained from several volumes connected in a certain way to each other (Fig. 3). 4. Combined method of constructing an isometric projection. An isometric projection of a part, the shape of which is obtained as a result of a combination of various shaping methods, is performed using a combined construction method (Fig. 4). An axonometric projection of a part can be performed with an image (Fig. 5, a) and without an image (Fig. 5, b) of invisible parts of the form. Rice. 2. Construction of an isometric projection of a part based on sequential removal of volumes Fig. 3. Construction of an isometric projection of a part based on sequential increments of volumes Fig. 4. Using a combined method for constructing an isometric projection of a part Fig. 5. Options for depicting isometric projections of a part: a - with the image of invisible parts; b - without images of invisible parts TASK: in accordance with the task option and the dimensions of the part, construct a technical drawing on A4 format of checkered paper in a rectangular isometric projection. Task options Option 1-2-3 Option 4-5-6 Option 7-8-9 Option 10-11-12 Option 13-14-15 Option 16-17-18 Option 19-20-21 Option 22-23-24 -25 1