The dimensions on the working drawings are put down so that it is convenient to use them in the process of manufacturing parts and during their control after manufacturing.

In addition to what is stated in 1.7 "Basic Dimensioning Information", here are some guidelines for dimensioning drawings.

When a part has several groups of holes that are close in size, the images of each group of holes must be marked with special signs. As such signs, blackened sectors of circles are used, using their different number and location for each of the groups of holes (Fig. 6.27).

Rice. 6.27.

It is allowed to indicate the dimensions and number of holes of each group not on the image of the part, but on the plate.

For parts with symmetrically located elements of the same configuration and size, their dimensions in the drawing are applied once without indicating their number, grouping, as a rule, all dimensions in one place. The exception is the same holes, the number of which is always indicated, and their size is applied only once (Fig. 6.28).

Rice. 6.28.

The detail shown in fig. 6.27, has a number of holes with the same distance between them. In such cases, instead of a chain of dimensions repeating the same size several times, it is applied once (see size 23). Then extension lines are drawn between the centers of the extreme holes of the chain and the size is applied in the form of a product, where the first factor is the number of gaps between the centers of adjacent holes, and the second is the size of this gap (see size 7 × 23 = 161 in Fig. 6.27). This method of dimensioning is recommended for drawings of parts with the same distance between the same elements: holes, cutouts, protrusions, etc.

The position of the centers of holes or other identical elements, unevenly located around the circle, is determined by the angular dimensions (Fig. 6.28, but). With uniform distribution of identical elements around the circle angular dimensions do not apply, but are limited to indicating the number of these elements (Figure 6.28, b).

Dimensions referring to one structural element parts (hole, protrusion, groove, etc.) should be applied in one place, grouping them on the image in which this element is most clearly depicted (Fig. 6.29).

Rice. 6.29.

The position of the inclined surface can be specified in the drawing with an angle size and two (Fig. 6.30, but) or three linear dimensions (Fig. 6.30, b). If the inclined surface does not intersect with the other, as in the first two cases, but is mated with a curved surface (see Fig. 6.17), the straight sections of the contour are extended with a thin line until they intersect and extension lines are drawn from the points of intersection to apply dimensions.

Rice. 6.30.

but - first case; b - second case

GOST 2.307–68 also established the rules for depicting and applying the dimensions of holes in views in the absence of cuts (sections) (Fig. 6.31). These rules reduce the number of cuts that reveal the shape of these holes. This is done due to the fact that in views where the holes are shown in circles, after specifying the diameter of the hole, they apply: the size of the hole depth (Fig. 6.31, b), the size of the chamfer height and angle (Figure 6.31, c), the size of the chamfer diameter and angle (Figure 6.31, d), the size of the diameter and depth of the counterbore (Figure 6.31E). If, after specifying the diameter of the hole, there are no additional instructions, then the hole is considered to be through (Fig. 6.31, a).

Rice. 6.31.

When sizing, the methods of measuring parts and features are taken into account technological process their manufacture.

For example, it is convenient to measure the depth of an open keyway on the outer cylindrical surface from the end, therefore, the dimension given in Fig. 6.32, but.

Rice. 6.32.

but - open; b- closed

The same size of the closed groove is easier to check if the size shown in fig. 6.32, b. It is convenient to control the depth of the keyway on the inner cylindrical surface by the size indicated in Fig. 6.33.

Rice. 6.33.

Dimensions must be affixed so that during the manufacture of the part you do not have to figure out anything by counting. Therefore, the size indicated on the section along the width of the flat (Fig. 6.34) should be considered unsuccessful. The dimension defining the flat is shown correctly on the right-hand side of fig. 6.34.

Rice. 6.34.

In fig. 6.35 shows examples of dimensioning by chain, coordinate and combined methods. With the chain method, the dimensions are located on a chain of dimension lines, as shown in Fig. 6.35, but. When setting the overall (overall) size, the circuit is considered closed. A closed dimensional chain is allowed if one of its dimensions is reference, for example, overall (Figure 6.35, but) or included in the chain (Fig.6.35, b).

Reference dimensions 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 an asterisk, which is applied to the right of the dimension number. The technical requirements repeat this sign and write down: Size for reference(fig.6.35, a, b).

To the reference size included in a closed circuit, limit deviations are not affixed. The most common are open circuits. In such cases, one dimension, for which the lowest accuracy is permissible, is excluded from the dimensional chain or the overall dimension is not affixed.

Dimensioning according to the coordinate method is carried out from a pre-selected base. For example, in Fig. 6.35, in this base is the right end of the roller.

Most often, the combined method of dimensioning is used, which is a combination of chain and coordinate methods (Figure 6.35, G).

Rice. 6.35.

a, b - chain; in- coordinate; G- combined

On the working drawings of machined parts, in which sharp edges or edges must be rounded off, indicate the size of the rounding radius (usually in technical requirements), for example: Radii of roundings 4 mm or Radii not specified are 8 mm.

The dimensions that determine the position of the keyways are also affixed taking into account the technological process. In the image of the groove for the segment key (Fig.6.36, but) the size is taken to the center of the disk cutter, with which the keyway will be milled, and the position of the keyway for the parallel key is set in size to its edge (Fig.6.36, b), since this groove is cut with a finger cutter.

Rice. 6.36.

but - for a segmented key; 6 – for prismatic

Some elements of parts depend on the shape cutting tool... For example, the bottom of the deaf cylindrical bore turns out to be conical because conical shape has a cutting end of a drill. The size of the depth of such holes, with rare exceptions, is affixed to the cylindrical part (Figure 6.37).

Rice. 6.37.

In the drawings of parts with cavities, the internal dimensions related to the length (or height) of the part are applied separately from the external ones. For example, in the drawing of the housing, the group of dimensions that defines the outer surfaces is located above the image, and inner surfaces details are determined by another group of sizes located below the image (Fig. 6.38).

Rice. 6.38.

When only part of the surfaces of the part is subject to machining, and the rest must be "black", ie. such as they turned out during casting, forging, stamping, etc., the dimensions are affixed according to a special rule, also established by GOST 2.307-2011. A group of dimensions related to machined surfaces (ie, formed with the removal of a layer of material) must be associated with a group of dimensions of "black" surfaces (ie, formed without removal of a layer of material) by no more than one dimension in each coordinate direction.

The housing has only two surfaces to be machined. The size that connects the groups of outer and internal dimensions, marked on the housing drawing with the letter A.

If the dimensions of the body cavity were put down from the plane of the left end face of the part, during its processing it would be necessary to maintain limit deviations several sizes at once, which is almost impossible.

A hole is an open or through hole in some solid object.

The hole drawing is carried out on the basis of GOST 2.109-73 - a unified system for design documentation (ESKD).

You can download this simple drawing for free for any purpose. For example, for placement on a nameplate or sticker.

How to draw a drawing:

You can draw a drawing both on a sheet of paper and using specialized programs. No special engineering knowledge is required to complete simple sketch drawings.

A sketch drawing is a drawing made "by hand", observing the approximate proportions of the depicted object and containing sufficient data for the manufacture of the product.

A design drawing with all technological data for manufacturing can only be performed by a qualified engineer.

For designation in the drawing, you must perform the following operations:

1. Draw an image;
2. Add dimensions (see example);
3. Specify to manufacture (for more details on the technical requirements, read the article below).

It is most convenient to draw on a computer. Subsequently, the drawing can be printed on paper on a printer or plotter. There are many specialized programs for drawing on a computer. Both paid and free.

Drawing example:

This image depicts how simple and fast a drawing is performed using computer programs.

List of programs for drawing on a computer:

1. KOMPAS-3D;
2. AutoCAD;
3. NanoCAD;
4. FreeCAD;
5. QCAD.

Having studied the principles of drawing in one of the programs, it is not difficult to switch to work in another program. Drawing methods in any program do not fundamentally differ from each other. We can say that they are identical and differ from each other only in convenience and in the presence of additional functions.

Technical requirements:

For the drawing, it is necessary to affix dimensions sufficient for manufacturing, maximum deviations and roughness.

The technical requirements for the drawing should indicate:

1) The method of manufacturing and control, if they are the only ones that guarantee the required quality of the product;
2) Indicate a specific technological method that guarantees the provision of individual technical requirements for the product.

A bit of theory:

A drawing is a projection image of a product or its element, one of the types of design documents containing data for the production and operation of the product.

A drawing is not a drawing. The drawing is carried out in size and on the scale of a real product (structure) or part of a product. Therefore, to carry out drawing works, the work of an engineer with sufficient experience in the production of drawing works is required (however, for a beautiful display of a product for booklets, it is quite possible that the service of an artist who has an artistic look at the product or part of it is required).

A drawing is a constructive image with the necessary and sufficient information about the dimensions, manufacturing method and operation. You can download the drawing presented on this page free of charge.

A drawing is an artistic image on a plane, created by means of graphics (brush, pencil or specialized program).

A drawing can be either an independent document or a part of a product (structure) and technical requirements related to surfaces processed together. Instructions for joint processing are placed on all drawings involved in joint processing of products.

For more details on drawings, technical requirements for design and indication of manufacturing methods, see GOST 2.109-73. See the list of standards for the development of design documentation.

Drawings ordering information:

In our design organization, you can any product (both parts and assemblies), which will include a drawing of the hole, as an element of the design documentation of the product as a whole. Our design engineers will develop documentation in the shortest possible time in strict accordance with your technical specifications.

The thread on the rods is depicted along the outer diameter with solid main lines, and along the inner diameter with solid thin lines.

You studied the basic elements of metric threads (outer and inner diameters, thread pitch, thread length and angle) in the fifth grade. The figure shows some of these elements, but they do not make such inscriptions in the drawings.

The thread in the holes is depicted with solid main lines along the inner diameter of the thread and solid thin lines along the outer.

The thread symbol is shown in the figure. It is necessary to read like this: metric thread (M) with an outer diameter of 20 mm, third class of accuracy, right-hand, with a large pitch - “Thread M20 cl. 3 ".

The figure shows the designation of the thread "М25Х1,5 cl. 3 left "should be read like this: metric thread, outside diameter threads 25 mm, pitch 1.5 mm, fine, third class of accuracy, left-hand.

Questions

1. What lines represent the thread on the rod?
2. What lines show the thread in the hole?
3. How is the thread indicated in the drawings?
4. Read the records "М10Х1 cl. 3 "and" М14Х1,5 cl. 3 left ".

Working drawing

Each product - a machine or mechanism - consists of separate, interconnected parts.

Parts are usually made by casting, forging, stamping. In most cases, such parts are machined on metal-cutting machines - turning, drilling, milling and others.

Drawings of parts, provided with all instructions for manufacturing and control, are called working drawings.

The working drawings indicate the shape and dimensions of the part, the material from which it must be made. The drawings indicate the cleanliness of surface treatment, the requirements for manufacturing accuracy - tolerances. Manufacturing methods and technical requirements to the finished part is indicated by an inscription on the drawing.

Surface finish. Traces of processing and irregularities always remain on the treated surfaces. These irregularities, or, as they say, surface roughness, depend on the tool with which it is processed.

For example, a surface treated with a bruiser will be rougher (uneven) than after processing with a personal file. The nature of the roughness also depends on the properties of the material of the product, on the cutting speed and the amount of feed when machining on metal-cutting machines.

To assess the quality of processing, 14 classes of surface cleanliness have been established. Classes are indicated in the drawings by one equilateral triangle (∆), next to which the class number is affixed (for example, ∆ 5).

Methods for obtaining surfaces of different purity and their designations in the drawings. The cleanliness of the processing of one part is not always the same; therefore, the drawing indicates where and what processing is required.

The sign at the top of the drawing indicates that there are no requirements for cleanliness of processing for rough surfaces. ∆ sign 3 on the right upper corner the drawing, taken in brackets, is placed if the same requirements are imposed on the surface treatment of the part. This is a surface with traces of processing with brute files, roughing cutters, and an abrasive wheel.

Signs ∆ 4 - ∆ 6 - semi-finished surface, with subtle traces of processing with a finishing cutter, personal file, grinding wheel, fine sandpaper.

Signs ∆ 7 - ∆ 9 - clean surface, no visible traces of processing. Such processing is achieved by grinding, filing with a velvet file, scraping.

The ∆ 10 mark is a very clean surface, achieved by fine grinding, lapping on donuts, filing with a velvet file with oil and chalk.

Signs ∆ 11 - ∆ 14 - surface cleanliness classes, achieved by special treatments.

Manufacturing methods and technical requirements for the finished part in the drawings are indicated by an inscription (for example, blunt sharp edges, harden, burnish, drill a hole along with another part and other requirements for the product).

Questions

1. What are the icons for surface finish?
2. After what kind of processing can a surface finish of ∆ 6 be obtained?

The task

Read the drawing in the figure and answer in writing the questions on the proposed form.

"Locksmithing", I. G. Spiridonov,
G.P.Bufetov, V.G. Kopelevich

A part is a part of a machine made from one piece of material (e.g. bolt, nut, gear, lead screw lathe). A knot is a connection of two or more parts. The product is assembled according to assembly drawings. A drawing of such a product, which includes several units, is called an assembly, it consists of drawings of each part or unit and depicts an assembly unit (a drawing of a single ...

The dimensions of the countersinks are affixed as shown in Fig. 63, 64.

If the holes in the part are located on the axes of its symmetry, then the angular dimensions should not be affixed. Other holes should be coordinated with an angular dimension. In this case, for holes located along a circle at equal distances, the diameter of the center circle is set and an inscription about the number of holes is set (Fig. 65, 66).

In drawings cast parts requiring mechanical processing, indicate the dimensions so that only one dimension is placed between the untreated surface - the casting base and the processed - the main dimensional base (Fig. 67). In fig. Figures 67 and 68 are drawing dimensional examples of a cast part and a similar machined part for comparison.

The dimensions of the holes in the drawings are allowed to be applied in a simplified manner (according to GOST 2.318-81) (Table 2.4) in the following cases:

▪ the diameter of the holes in the image is 2 mm or less;

▪ there is no image of the holes in the section (section) along the axis;

▪ hole punching general rules complicates the reading of the drawing.

Table 7

Simplified dimensioning on Various types holes.

Hole type

d1 x l1 –l4 x

d1 x l1

d1 x l1 –l4 x

d1 / d2 x l3

Continuation of table. 7

Hole type

Example of simplified hole sizing

d1 / d2 x φ

Z x p x l2 - l1

Z x p x l2 - l1 - l4 x

The dimensions of the holes should be indicated on the shelf of the leader line drawn from the axis of the hole (Fig. 69).

2.3.2. Image, designation and dimensioning of some elements of parts

The following elements are most common: chamfers, fillets, grooves (grooves), grooves, etc.

Chamfers - conical or flat narrow cuts (blunting) of sharp edges of parts - are used to facilitate the assembly process, to protect hands from cuts with sharp edges (technical requirements

safety), giving products more nice looking(requirements of technical aesthetics) and in other cases.

The dimensions of the chamfers and the rules for their indication in the drawings are standardized. According to GOST 2.307-68 *, the dimensions of the chamfers at an angle of 45o are applied as shown in Fig. 70.

Rice. 70 The dimensions of the chamfers at other angles (usually 15, 30 and 60 °) are indicated by

general rules: put down linear and angular dimensions (Fig. 71, a) or two linear dimensions (Fig. 71, b).

The size of the chamfer height c is selected according to GOST 10948-64 (Table 8). Table 8

Normal chamfer sizes (GOST 10948-64)

Note. For stationary landings, chamfers should be taken: at the end of the shaft 30 °, in the bore of the sleeve 45 °.

Fillets - rounding of external and inner corners on machine parts - they are widely used to facilitate the manufacture of parts by casting, stamping, forging, to increase the strength properties of shafts, axles and other parts at the transition from one diameter to another. In fig. 74, the letter A marks the place of stress concentration that can cause a crack or fracture of the part. The fillet eliminates this hazard.

Rice. 74 The dimensions of the fillets are taken from the same series of numbers as for the value with

The radii of the fillets, the dimensions of which on a drawing scale of 1 mm or less, are not shown and their dimensions are applied, as shown in Fig. 74.

To obtain a full profile thread along the entire length of the rod or hole, a groove is made at the end of the thread for the tool to exit. There are two types of grooves. In the drawing, the details of the groove are depicted in a simplified manner, and the drawing is supplemented with an extension element on an enlarged scale (Fig. 49, 51). The shape and size of the grooves, the dimensions of the run and undercut are set by GOST 10549-80, depending on the thread pitch p.

In fig. 75 shows an example of a groove for external metric thread, and in Fig. 76 - for internal metric threads.

Rice. 76 The dimensions of the groove are selected from the tables of GOST 10549-80 (see Appendix 5), their

Below are the dimensions of the grooves for external metric threads:

Edges grinding wheel are always slightly rounded, therefore, in the place of the part where an indent from the edges is undesirable, a groove is made for the exit of the grinding wheel.

Such a groove in the drawing of the part is depicted in a simplified manner, and the drawing is supplemented with a remote element (Fig. 77, 78).

The dimensions of the grooves, depending on the diameter of the surface, are established by GOST 8820-69 (Appendix 4).

The dimensions of the grooves for the exit of the grinding wheel can be calculated by

2.3.3. Roughness of part surfaces

Depending on the manufacturing method of the part (Fig. 79), its surfaces can have different roughness (Tables 9, 10).

Rice. 79 Surface roughness Is a set of microroughnesses

of the processed surface, considered at the section of the standardized length (L). This length is called the base, it is selected depending on the nature of the measured surface. The greater the height of microroughness, the greater the base length is taken.

To determine the surface roughness, GOST 2789-73 provides six parameters.

Altitude: Ra - arithmetic mean deviation of the profile; Rz - the height of the profile irregularities at ten points; Rmax is the highest profile height.

Stepper: S - average step of local profile protrusions; Sm is the average step of irregularities; Ttp - relative reference length, where p - value of the profile section level.

Most common in technical documentation are the parameters Ra (arithmetic mean deviation of the profile) and Rz (the height of the profile irregularities at ten points).

Knowing the shape of the surface profile, determined by the profilograph at its base length L, it is possible to construct a roughness diagram (Fig. 80),

This has been discussed a lot here. I will repeat in a general sense why it is necessary to show the transition lines conditionally: 1. To make the drawing readable. 2. From the transition lines, shown conditionally, you can set dimensions, which are often no longer in any view and section. Here's an example. There is a difference? 1. As can now be displayed in all the listed CAD systems. And here's how to display. The transition lines are shown conditionally and the dimensions are shown, which in other display modes of the transition lines simply cannot be set. Why was this required by the normative controller? Yes, just so that the drawings have a familiar look after many years of work in 2D and are easy to read, especially by the customer who approves them.



This is true :) this is nonsense :) in TF you can do this and so =) there will be no tangible difference in speed, you can even then take any copy to repaint, change holes, delete holes, whatever ... and the array will still remain an array - it will be possible to change the number of copies, direction, etc., to cut the video or believe so? :) This is true, but what is the task? Translate as SW splines by points to splines by poles or what, if you think about this also some change in the original geometry - there are no comments on this? :) As I understand it, TF only 1 to 1 and translates, the rest can already be configured in the TF template before export in DWG - see the figure under the spoiler, or scale it in the form of AC, which, in principle, does not contradict the main methods of working with AutoCAD, and since, in view of the prevalence of AC in the early stages of the peak of the popularity of CAD implementation, the age generation is even more familiar with this: And if still get to the bottom of the export / import capabilities of different CAD systems: 1) how can I export only selected lines from a 2D SW drawing to DWG? (from 3D documents, more or less SW is adapted, only it will still have to small window clean the excess manually). Remove everything that is not needed in advance, and then export-> somehow not modern, not youthful :) 2) And vice versa, as selected lines in AutoCAD, quickly import into SW (for example, for a sketch, or just as a set of lines for drawing)? (for TF: selected a set of necessary lines in AC -ctrl + c and then in TF just ctrl + v - everything)

What detail are we talking about, or maybe this detail should not be mirrored, but simply tied differently and it will be just right. A mirror part is the same configuration just created by the machine, you can make the configuration of the part yourself and in some cases it may turn out to be more elegant, it is also easier to edit later.