What are the types of sections

In any production and construction industry, certain images are used to make parts and structures. They represent the appearance of the object from different points of view and assume at times the use of taking a cut or section.

This approach in engineering graphics is performed in accordance with certain standards. They clearly specify the types of cross-sections, allowing to bring this technology to uniform standards. This allows engineers, working properly to understand such images. From this directly depends the quality of the entire production process and the final result of the work of the organization. Therefore, special requirements are put forward for the creation of images.

The standard for performing images

Implementation of schematic images, their sections, different types of sections, cones, beams, drawing them on the drawings regulate different standards. The main one is the Unified System of Design Documentation (ESKD) "Images - views, sections, sections".

This GOST was introduced on January 1, 1968. He stipulates that the image is viewed as a projection of the object on a plane at a certain angle. GOST "Images - views, sections, sections" says that such drawings should be a minimum number. But thanks to them, a specialist should receive full information about the facility.

Therefore, all the images, according to their content, GOST divides into views, sections and sections. This document also establishes types of notations, inscriptions and signs.

GOST 2.305-08 specifies that all images should be applied to the drawing using orthogonal (rectangular) projection technology. Ideally, the object is in the middle between the observer and the project plane.

But in view of the fact that some nodes and elements require consideration from a different angle, this condition is violated. Therefore, the types of sections, whose drawings are used in production conditions, are called images. For their implementation, the standards regulate a number of simplifications and reductions.

Concept of view, section and section

Cross-sections, cross-sections, views are the three main categories in the construction of engineering graphics. They are different in content. Therefore, deserve a detailed consideration.

A view is a drawing of the surface of a part that is turned towards the observer. To simplify the work of an engineer, it is allowed in this figure to indicate invisible surfaces in dotted lines.

The main view is the image of the part from the front. But there are other varieties of it. The part is also displayed on the left, top, right, rear, or bottom.

The incision is a drawing of a detail, which the plane (one or several) has mentally dissected. The section will show what is in the plane of the section and beyond it.

But the cross-section also refers to such an examination of the element, under which a plane has been dissected in a certain way. But shown in the figure only what was in this cutting plane. What is behind it can not be seen in the drawing.

These definitions are necessarily taken into account by a specialist who performs technological tasks using engineering graphics.

Remote and superimposed cross-sections

The ESKD standard types, cuts, sections are revealed using a certain classification. According to this approach, it is possible to better understand the assertions of the standards for the performance of graphic images of details.

Sections can be made or imposed. Both these subspecies are not included in the composition of the incision.

Preferred in the engineering schedule to use the outlined cross-sections. They are usually placed in the gap between the constituent elements of the same species.

Such a contour (as well as the image that is part of the cut) is applied in thick lines to the drawing. If the cross section is superimposed, its boundaries are denoted by solid, but thin boundaries.

To denote the axis of symmetry of such images, dotted lines are used. They are applied thinly and are not denoted by any letters or arrows.

But to indicate the trace of a secant plane, it is necessary to use a thick open line. It is indicated by arrows that make it clear the direction of the view.

The very plane of dissection is denoted by Russian capital letters. The inscription of the type of the section of wires, assemblies or parts is made according to the type "A-A".

In this case, the final and initial strokes must not intersect the contour. Alphabetic letters are assigned in alphabetical order without repetitions or omissions. The font should be 2 times larger than the number indicating the size.

The letters are arranged in parallel with the main inscription. And it does not depend on how the secant plane is located.

The position of the cutting plane

Depending on the position of the cutting plane, there are several types of images that govern GOST. Types, sections, sections, according to generally accepted rules, are defined in space with respect to the horizontal plane.

Accordingly, the dissecting plane can pass through the object horizontally, vertically or inclined.

In the first case, the cross-sectional view is viewed transversely, parallel to the horizontal plane. In many drawings this type of engineering graphics is called a plan. Such sections can also be called differently in each production process.

Vertical cross sections assume that the cut is perpendicular to the base. And the inclined varieties form a certain angle between the horizontal and secant planes. It is different from direct.

Vertical sections are frontal (parallel to the frontal projection line) or profile (parallel to the profile projection line).

If the cut is directed along the height or length of the object, this is the longitudinal section. But there is also another orientation of the drawing. There are types of cross sections that have a perpendicular orientation in the space of the cutting plane, relative to the length or height of the object.

In the drawing, the position of the section is indicated by arrows and is indicated by an open line.

Number of cutting planes

For simple details, it is sufficient to use only one section plane. This is enough to understand how a technician should make this detail. But for complex blanks this is not enough. For example, there are such types of cross-sections of beams that need to be mentally cut in a more complex way.

For this, the standards regulate the use of several cutting planes. They can be broken or stepped. Orientation of planes in this matter plays an important role.

The angle at which they relate to each other determines the name. If the planes, joining, form a right angle, this is a stepped cut. When this ratio is characterized by another slope, the section is broken.

In complex sections, the lines of intersection between the planes are traced together. On the final and initial of them the arrows are pointed in the direction of the observer's sight. They are located 2-3 mm from the stroke. Near the arrows, the letters are placed at the intersection points from the position of the outer corner. The cut itself in this case is always marked as "A-A".

Local section

Section can be performed only in one specific location of the object. Such a limited consideration of the procurement device is called local. It can be applied anywhere in the drawing, indicating the associated area of the image with the arrow. It is convenient for the image of long, but permanent in shape sections of objects.

Such an image may be limited by the smallest line of the clipping. The types of wire cross-sections due to their long length can be performed using this approach.

Such a cut is highlighted against the background of the image by a solid wavy line. These lines do not coincide with other boundaries of the drawing.

The local section is indicated on the image by type "A". The associated type also indicates the corresponding letter designation.

Additional section

Images (views, sections, sections) can be performed on planes that are not parallel to the main sections of the projections. They are called additional. Such an approach in engineering graphics is used when it is impossible to show any part of the subject on the main types without distorting the shapes or sizes.

This section is signed by type "A". The object corresponding to the additional sectional view is associated with it by an arrow and is signed by a similar letter. The pointer also gives an understanding of the direction of the observer's view.

If the additional slice is located directly on the projection of the corresponding image, the inscription and the arrow are not required to be applied to the drawing.

Additional sections can be rotated. But the main position of the object is preserved. To the inscription of type "A" is added another sign of rotation.

Applying this approach avoids hatching the drawing. It makes understanding difficult and worsens the clarity of the image. Because these techniques allow you to improve the quality of graphics.

Symmetry

The types of cross-sections are allowed to be placed in the gap, which is formed between parts of the same image. This can be done by continuing the trace of the plane of the cut. But such an approach is only permissible with a symmetrical figure, which is obtained by cutting. The section is carried to any part of the drawing field. It is also possible to perform a turn.

For symmetrical sections in the drawing, the trace of the plane is not represented in any way. Also there is no inscription on such a cut.

The asymmetric sections are performed in a break or superimposed on the drawing. The trail of the plane for such graphics is depicted, but the letters do not sign. Also there is no inscription.

The resulting section is surrounded by a thick, continuous contour. If it is applied, the line for its designation is thin, continuous.

If the object has several identical sections, their outline is denoted by one letter. In this case, only one slice is drawn.

Simplification

Images (views, sections, sections) for their ease of understanding can be simplified. Standards and norms regulate this process.

For symmetrical figures it is allowed to draw only one half of the cut or most of it with the line of the breakage applied. When an object has several identical elements, only one of them is drawn. The remaining identical parts are drawn schematically.

The projections of the intersection lines can be represented in a simplified manner. But only if their detailed image is not required.

Performing a drawing of simple figures, for example, if you need to consider the types of sections of a cone, use a certain approach to the graph. This makes it easier to understand the drawings. When one surface changes with a particular pattern, it can be interrupted.

If one surface smoothly passes into another, their boundary is not indicated or is designated conditionally.

Non-hollow symmetric parts and products in the drawing are shown uncut in the longitudinal section. And if the size of the part of the product in the drawing is less than 2 mm, it is represented with a deviation from the main scale.

To denote flat surfaces, diagonals can be drawn by solid lines.

It should also be borne in mind that the permanent connections of electrical or radio devices are simplified by the corresponding type of product standards. These are the basic simplifications, which are regulated by the Unified System of Design Documentation. They are often used to build drawings in large industries, where you want to depict complex parts, nodes or mechanisms.

Some special cases of simplifications

If in the drawing cuts, sections, views are displayed for regularly changing surfaces, they can be torn. This is done in a certain way. There are three variants of the restriction.

The first type involves using a solid, thin broken line. It can extend beyond the border of the image by 2-4 mm. Also, the contour of the parts can be joined by a continuous wavy line or hatching.

To simplify the drawing, it is allowed to make a cut between the cutting plane and the observer by a dashed line. Also, complex slices are used to improve the understanding of graphics.

When displaying the holes of some parts (the hubs of the gears, keyways, pulleys), only their contours are given. If a groove located on the circular flange is not in the cutting plane, it is shown in a section.

In the case of the presence of an ornament on the detail, a continuous grid, it is allowed to depict only a small part of it or simplify the elements of the drawing.

Such methods allow to achieve the purity of the drawing, to facilitate its understanding. After all, the use of engineering graphics to create all kinds of objects implies the use of a single symbolic language. Every specialist must know it, whose work is related to this type of images. The quality of the final result depends on this.

Having studied the types of sections, you can understand the basic principles of their implementation and understanding. Using the recommendations of the standards, you can achieve good cleanliness of the drawing. This facilitates the process of its interpretation. Understanding the difference between a view, a section and a cut, knowing their classifications and the technology of correct drawing design, a specialist can create the correct image. It can be easily understood by a technician who performs a workpiece or a finished product and will be able to create knots and parts that meet all the requirements. The quality of the whole production depends on this process.