What are the requirements for cylindrical surfaces? Technical requirements for the part. Brass is an alloy
Topic: “Graphic representation of cylindrical parts.”
The purpose of the lesson: - teach students to read and perform a sketch, technical drawing, drawing, show the rules for constructing drawings. Practical skill in making a product. Development of skills in working with marking and cutting tools.
Visual range - samples of various cylindrical products,visual aids for depicting products and their manufacture.
Safety instructions and visual aids.
Material: - pine block.
Tool: - square, ruler, triangle, notebook, pen, pencil, eraser, caliper, plane, rasp, sandpaper.
During the classes.
Organizational part – Checking readiness for the lesson.
Reporting the topic of the lesson and its purpose
During technology lessons you will make products that, along with flat rectangular parts also contain cylindrical parts. For example, the handles of mallets, shovels, rakes, etc. have this shape.
Today we will look at drawings of cylindrical products.
We will mark the workpieces ourselves and learn how to process them.
Repetition of covered material
- What shapes of parts do you know? ( prismatic, cylindrical, conical)
- What dimensions are indicated on the drawing for prismatic parts?
- What drawings are called assembly drawings?
- What is shown on the assembly drawing?
- What does the specification contain?
- What dimensions are indicated on the assembly drawing?
- How should you read an assembly drawing?
Presentation of new material
In the design documentation, cylindrical parts are depicted as shown in Figure 10.
Rice. 10. Technical drawing and drawing of a simple cylindrical part.
When making drawings of simple parts that have a cylindrical shape, you can limit yourself to one main view. The Ø diameter sign and the center line in the image indicate the cylindrical shape of the part. Other views are shown only if there are elements on the parts whose shape is difficult to show in one view (Fig. 11).
Cylindrical parts (made of wood and metal) often have such structural elements as chamfers, fillets, grooves, shoulders, etc. (Fig. 12), The dimensions of the chamfer in the drawing are indicated by the type entryZH45°, where3-chamfer height (in mm),45°- corner,under which it is completed.
MANUFACTURING CYLINDRICAL PARTS WITH HAND TOOLS
The cylindrical part (see Fig. 10) can be made by hand. First you need to prepare a workpiece - a square block. If you cannot find a ready-made block of the required size, you can saw off the workpiece from the board. The dimensions of the workpiece must include allowance for processing. The side of the square A should be approximately 2 mm larger than the diameter of the part being manufactured, and the length of the bar L - approximately 20 mm longer than its length (Fig. 15). At both ends of the workpiece, centers are found (as the point of intersection of the diagonals) and circles are drawn corresponding to the diameter of the part.
Then, on each surface of the workpiece, two marking lines are drawn along the edges using a thicknesser. The thickness gauge is set to a size of 2⁄7 A (Fig. 16). An octagon is marked at the ends of the workpiece (Fig. 17). The workpiece is fixed on the workbench between the wedges. The edges are planed with a plane to the marking lines and an octagon is obtained. Its edges are cut off without marking until a hexahedron is obtained (Fig. 18). For final rounding, the workpiece is cleaned with a rasp, removing the remaining ribs. It is advisable to carry out this operation in a device (Fig. 19).
The part obtained in this way is cleaned with sandpaper (Fig. 20).
The required length of the part is obtained by sawing with a hacksaw in a device (Fig. 21).
The compliance of the diameter of the cylindrical part with the specified size is checkedcalipers or caliper. This is a measuring instrument in the form of a compass with arched legs (Fig. 22, a).
It is used to compare the diameters of parts with the dimensions taken according to the ruler (Fig. 22.6, c).
It is advisable to produce short cylindrical parts (up to 100...150 mm long) by sawing a long part into pieces.
When marking a square block, the thicknesser is set to a size equal to ²/ 7
sides of the square.
Practical work
1. Draw students’ attention to compliance with safety rules and caution when manufacturing the product.
2. Caution against mistakes when marking.
3. Show the progress of work, techniques, commenting on your actions. Protect from haste, direct to thoughtful work.
Presenting lesson results, viewing work, grading.
Let's see what we made and how, let's mentally go through the entire technological process - what was and what has become!
Viewing works, analyzing them, grading. If anyone didn’t have time, they will finish it at the next lesson.
Lesson summary:
In general, well done everyone! Now we know how to make a cylindrical product from a block of wood, how to creatively translate a drawing or sketch into a product.
In the next lesson we will look at the basics of product design and modeling.
The experience of domestic and foreign mechanical engineering shows that it is advisable to increase the accuracy of manufacturing precision parts to a level that ensures their non-adjustable assembly. The most difficult to manufacture is the sprayer, which has cylindrical and conical precision surfaces. To ensure the smooth movement of the needle in the body (mobility), the diametrical gap in this pair must exceed the total combination of deviations from the correct geometric shape of the cylindrical guide surfaces and the curvature of their axes. The values of deviations from the geometric shape of the cylinder and the curvature of its axis achieved in manufacturing practice are, separately for the analyzed parameters, 0.2-0.6 µm for the housing opening and 0.1-0.3 µm for the guide needle. Taking into account possible deformation changes in these geometric parameters in the housing upward to 0.2 -0.5 µm due to installation loading forces, the minimum diametrical gap in the injector nozzles of locomotive diesel engines should be at least 3 µm. In this case, the highest probability of collection of 1 spray will be ensured, with the exception of sticking and needle hanging.
The maximum diametrical clearance for nozzles during manufacture should not exceed 4.5-5.0 microns, in operation in nozzles operating in fuel systems without unloading the fuel injection pipes from a residual pressure of 6.5 to 7.5 microns and in systems with complete unloading 11 - 15 microns. It should be noted that an increase in the diametrical gap should not be accompanied by an increase in the tolerances for the geometric accuracy of the shape of the cylindrical surfaces of the nozzle, since these surfaces are also basic when processing a conical precision surface.
The performance and assembly of the sprayer also depend on the ratio of the total value of the radial runout of the conical locking surfaces and the diametrical clearance. For constructive
1 Ensuring performance requirements for the dimensional configuration of precision parts in a pair.
For the standard sizes of locomotive diesel injector nozzles, the total value of the radial runout should not exceed the diametrical clearance. Otherwise, the tightness of the conical seal of the nozzle is compromised due to the mismatch of the centers of the sealing sections, and there is a possibility of increased unevenness at low flow rates. This circumstance is associated with a change in the shape of the slit of the conical flow part (from annular to crescent-shaped) during small lifts of the needle, caused by installing the needle skewed in the guide hole of the housing. The total runout of the cones is 2-4 microns (in the body 1 - 3 microns, in the needle 1 microns) is practically achievable in mass production.
Radial runout is a complex geometric parameter representing the vector sum of deviations from coaxiality and roundness. When the centers of the sections coincide along the sealing belt, deviations from roundness, determining the gap area at the point of contact, independently affect the quality of the tightness of the spray cone. In accordance with experimental data, in the injector nozzles of diesel locomotive diesel engines, the complete absence of moisture, assessed according to the GOST 9928 - 71 method, is achieved when deviations from the roundness of the sealing section of the conical surface of one of the parts are no more than 0.8-1.0 microns, and their total combination of deviations roundness at the point of contact should not exceed 1.6 µm at the injection start pressure p 0 = 30...32 MPa and 2 µm at p 0 = 20...22 MPa.
In addition to dimensional deviations, the quality of fuel atomization and the injection characteristics of the nozzle are also influenced by geometric parameters.
meters that determine the shape of the flow cone part of the sprayer. These parameters include the difference in the angles of the sealing cones and deviations from the linearity of their generatrices. According to experimental data, the optimal difference in angles, ensuring high-quality atomization, starting from low injection start pressures, is 30-50". When the difference in angular ratios decreases until the angles merge (at a cone length of more than 0.6 -0.8 mm) or increases differences in angles up to 1°40"-1°50" there is a sharp deterioration in the quality of atomization. Permissible values of deviations from the linearity of the forming cones, measured at a length of 1.5 -2.0 mm below the large diameter section, which do not affect the quality of atomization and deviations flow characteristics in the minimum flow zone are 1.5 - 2.0 microns.
It should be noted that the considered geometric parameters of the cones ensure high-quality operation of the nozzles only in combination with correctly selected roughness parameters, which for a conical seal should not be higher than Ra = 0.100 µm.
In table 22 shows the basic technical requirements for the geometry and roughness of precision surfaces of nozzles in accordance with GOST 9928 - 71, as well as those recommended on the basis of experimental research data for use in the manufacture and restoration of nozzle nozzles for locomotive diesel engines using non-fitting assembly technology. For comparison in table. 22 shows similar parameters achieved in the serial production of diesel injector nozzles of type D49 and obtained as a result of selective measurements of nozzles from some leading foreign companies.
State standard 9927 - 71 provides the following requirements for the accuracy of the geometry of the precision surfaces of the plunger pair parts:
spray surfaces
| Radial runout of the cone, µm | Deviation from roundness of the cylinder, µm | Average diametrical clearance, µm | Roughness Yaa, | MKM | ||||
| cylinder | cone | |||||||
| needles | housing | needles | housing | needles | needles | housing | ||
| 2 | 3 | 0,5 | 0,5 | At least 2 | 0,040 | 0,160 | 0,32 | |
| 1 | 2 | 0,3 | 0,5 | 3,5-4,5 | 0,040 | 0,080 | 0,100 | |
| 1,0-1,3 | 1,2-2,0 | 0,3-0,6 | 0,3-0,5 | 2,5-3,5 | 0,040-0,050 | 0,145-0,18 | 0,040-0,065 | |
| 0,4-0,8 | 1,0-1,4 | 0,2-0,3 | 0,2 | 3,3-4,2 | 0,034-0,052 | 0,078-0,090 | 0,052 | |
| 0,8-1,0 | 0,9-1,6 | 0,3-0,6 | 0,2-0,5 | 4,0-4,8 | 0,038 | 0,040 | 0,045 | |
| 0,6 | 1,4-3,1 | 0,2-0,3 | 0,1-0,4 | 4,2-4,8 | 0,034-0,040 | 0,063-0,070 | 0,042-0,059 | |
| - | - | 0,3-0,4 | 0,2 | _ | 0,044 | 0,075 | - | |
| 0,8-1,2 | 1,2-2,0 | 0,1-0,3 | 0,3-1,0 | - | 0,060 | 0,088 | - |
Deviations in the shape of the working surfaces, plunger/bushing:
Similar requirements are provided for the valve pair:
Deviations in the shape of cylindrical working surfaces (valve/valve body):
from roundness, µm 3/3
cone shape, µm 3/3
Radial runout of conical and on- 5
external cylindrical surfaces relative to the valve axis, µm
Radial runout of housing cone 4
valve relative to the cylindrical guide surface, µm
When manufacturing plunger pairs using non-adjustment assembly technology (pair grinding), the tolerance for taper shape can be reduced by 1.5 - 2 times. The technological diametrical gap for pairs with a plunger diameter of 13 - 20 mm is 2.5 - 3.5 µm, the roughness of the mating surfaces is no more than: for the cylinder Ra = 0.04 µm, for the sealing end Ra = 0.125 µm. For valve pairs, the diametrical gap along the collar and the guide cylindrical part is 10-15 microns, the roughness of the cylindrical and conical surfaces is no more than 7?d = 0.16 microns.
Improvement of metrological control means has a significant impact on increasing the accuracy of manufacturing and assembly of precision pairs. Measuring tools must provide not only barrier control, but also operational control of technological processes, which allows us to consistently obtain high-quality products. At domestic factories, acceptance control measuring instruments of the unified series such as TsNITA-82 and TsNITA-36 have found widespread use. VNIIZhT has developed acceptance and inspection control devices for standard sizes of parts of diesel locomotive diesel fuel equipment using the circuit diagrams created at TsNITA.
When measuring diametrical dimensions, shape deviations and curvature of cylinder axes, the following are used: for external precision surfaces of type S-1 racks (GOST 10197 - 70) with spring-
Rice. 109. Schematic diagram of the measuring device of the TsNITA-8243 device:
1 - measured part; 2 - measuring lever; 3 - regulatory sector; 4 - spring; 5 - scale; b - optical system; 7 - sensitive element; 8 - support for an optical measuring head (opticator) of type 01-P or 02-P, having a division value of 0.1 and 0.2 microns, respectively; for internal precision surfaces - devices such as TsNITA-8243 (Fig. 109) or pneumatic length gauges (rotameters) DP.
The measuring device of the TsNITA-8243 device uses a differential measurement circuit using an elastic sensing element 7 of a spring-optical converter, similar to that used in the opticator and mounted on measuring arms 2. The arms are mounted on supports 8 and move in the same plane, contacting the surface of the part being measured 1 at opposite points. Deviation of the levers from the position corresponding to the adjustment to the size leads to the activation of the elastic element of the transducer and the deflection of the mirror mounted on it. The optical system 6 with an illuminator projects the beam reflected from the mirror onto scale 5. The constancy of the gear ratio of the spring-optical converter allows you to adjust the device to the size one ring at a time with adjusting the position of the beam on the scale by adjusting sector 3. The introduction of a compensating device into the design of the device reduces the systematic temperature error. The standard deviation when measuring on the TsNITA-8243 device does not exceed 0.1 µm with a measurement range of up to 30 µm.
The disassembled diagram is also applicable for measuring external surfaces. When two measuring mechanisms for internal and external measurements, working on a common scale, are placed in one device body, it becomes possible to directly obtain information about the diametrical gap in the pair. This design solution is implemented in the TsNITA-8295 device, which allows you to assemble precision pairs without preliminary sorting into size groups. To increase the accuracy and automation of the assembly of precision pairs, TsNITA has proposed a method for automated individual selection of parts for assembly using a computer.
When measuring internal holes, it is especially important to eliminate the error in certifying the actual dimensions of the reference mounting rings. The most convenient method, which allows testing sample rings directly in factory laboratories, is a method based on measuring the gap between a cylindrical shaft of known diameter and the measuring surface of the ring. The method is implemented in the TsNITA-3840 device, where the ring and shaft alternately contact the opposite generatrices of the cylinder lying in the same diametrical plane. The measurement is carried out by an opticator head with an error not exceeding 0.2 microns.
For selective measurement of deviations from roundness of cylindrical and conical precision surfaces, universal roundness measuring machines are used, including models 218 from the Kalibr and Thalerund plants (England). Round charts of a real profile are recorded in a section, the axis of which is preliminarily aligned with the axis of the precision spindle of the round gauge. Comparison of deviations of the circular diagram points from the adjacent circle is performed by superimposing a template on the record. The device diagram for operational acceptance assessment of deviations of roundness of conical surfaces (Fig. 110) has a main base surface,
Rice. BY. Schematic diagram of a device for measuring deviations from roundness of the conical surface of a spray needle, which is an adjacent profile (circle) in contact with the conical surface of the part being tested. The base surface is made in a carbide ring 4, which has a slot for a measuring tip in contact with the surface being measured in the same contact section. The cylindrical surface of the part 7 is based on a supporting ring support 2, reinforced in the same way as the ring with the adjacent profile, in the mounting housing 3. The drive mechanism 1 serves to rotate the part and press it through a telescopic drive shaft to the base surface. When rotating the part, the tip with the measuring lever 5 will have deviations by the value of non-roundness in the measured section. The opticator head or the recording part of the profilograph is used as a deviation recorder 6.
The diagram (Fig. 111) of the device for measuring the radial runout of the cone of the spray body provides for basing the body 1 with a cylindrical hole on a rigidly fixed in the body of the device
Rice. 111. Schematic diagram of the TsNII-7003 device for measuring the radial runout of the cone of the nozzle body on a prismatic mandrel 2. The part is rotated by a drive mechanism using a seamless belt that creates a force in the vertical plane, while the longitudinal displacement of the nozzle body is limited by the spherical tip of the movable stop 3, abutting the cone . The tip of the stop is mounted in a tubular rod suspended on a hinge having two degrees of freedom. The tip of the measuring lever 4 passes through a groove in the spherical tip (stop) and contacts the conical surface in the horizontal plane. The design of the device allows measurements in any section of the cone with an offset of roller slide 5 of the entire measuring unit parallel to the generatrix of the cone. Mechanical amplitude vibrations of the measuring arm, caused by a mismatch in the shape and position (beating) of the measured conical surface relative to the cylindrical surface of the nozzle body, are converted into electrical signals using an inductive sensor 6 and an electronic unit 7, which are recorded on indicating 9 and recording 8. The disassembled circuit is applicable for measuring the runout of the conical surface of a needle and is implemented in operational control devices TsNITA-3613-TsNII-7007 with registration of deviations on the opticator head.
To measure the displacement of the cone, instruments made according to the metrological scheme of TsNITA are used (Fig. 112). The sprayer rotates on a rigid cylindrical mandrel 6 with the surface of the cone resting on the circular probe tip 8. The vertical movement of the tip 8 mounted on the lever 5, caused by the displacement of the center of the cone relative to the base cylindrical precision surface, is recorded by the measuring head.
Rice. 112. Design diagram (a) of the TsNITA-3611 device for measuring the displacement of the housing cone with a circular (b) and triangular (c) measuring tip:
1,2 - adjusting screws; 3 - measuring head; 4 - hinge; 5 - measuring lever; 6 - mandrel; 7 - bean; 8 - tip; 9 - spray body; 10- handle; 11 - drive mechanism 3. The horizontal displacement of the lever is localized by the plate-shaped cross joint 4. The diameter of the circular tip, as a rule, corresponds to the diameter of the alignment of the cones when assembling the sprayer. In this case, the conditional displacement of the cone along the center of the circle inscribed in the real profile is recorded. If the circular tip is replaced with a triangular one (see Fig. 112, c), then a value averaged between runout and displacement will be recorded, giving broader information about the geometry and position of the cone. Such devices, with a speed of 400 - 600 measurements per hour, have a confidence error of 0.5 -0.6 μm (without taking into account the error introduced by superimposing deviations in the shape of the base cylindrical surface on the measured parameter).
Telescopic devices are widely used to measure the angle of the conical surfaces of the nozzle (Fig. 113). The principle of measurement with such a device is based on fixing the difference in H legs for two sections of a cone with known diameters (3 and /X). This method, with deviations in the shape of the surface, for example, nonlinearity of more than 3 - 5 μm, can give a significant measurement error exceeding 15 - 30 ".
To increase the accuracy of angular measurements in parts of fuel equipment, a new method was developed at TsNITA and TsNII MPS. The method is based on a comparison of the geometric parameters of the cone and its position when comparing images.
1 A. s. 279065 [USSR]. A method for measuring the angle of an internal cone and the non-straightness of the generatrix of this cone. G. B. Fedotov, L. V. Segalovich and others, 17 authors in total. Statement 01 - 08. 68. No. 1262056/25 - 28. Publ. in B.I., 1970, No. 26. UDC 53.083.8 (088.8).
formation of the longitudinal profile of the generatrix with the scale of linear and angular deviations from the profile of the standard, the role of which in measurements is played by a geometric straight line. Based on this method, attachments to the model 201 profiler and autonomous devices TsNITA-3821 and TsNII-7004 were manufactured for measuring the angles...and linearity of the cones of spray and valve pairs.
The attachment (Fig. 114) consists of a rack 3, on which a cradle 10 is suspended in a bearing 7. Replaceable prisms 8 are installed in the cradle traverse, on which the measured parts are based with their precision cylindrical part. The length A of the cradle lever is designed in such a way that moving microscrew 1 by 0.01 mm gives an angular rotation of the prism by 30".
The attachment is installed on the universal table of the profilograph - profilometer and the axis of the movement path of the sensor probe is aligned with the vertical plane passing through the axis of the product being measured. The parallelism of the generating cones of the reference and mounted product, the path of movement of the probe tip is set with microscrew 1. The use of a standard profilograph allows using an attachment to evaluate not only the angles of the cones with a relative error for a pair of no more than 2", but also the waviness (nonlinearity) and roughness of the generating elements.
An autonomous device (Fig. 115) consists of mechanical and electronic units. The mechanical block is designed to install the part being measured and provide
Fig. 114 Diagram of an attachment to a profilograph - a profilometer for measuring the angle and assessing the profile of the forming cones of atomizers 1 - micrometric screw, 2 - spring, 3 - stand, 4 - mandrel, 5 - atomizer body, 6 - profilograph sensor, 7 - bearing 8 - spray needle, 9 - replaceable prism, 10 - cradle for moving the measuring lever along the generatrix of the cone. The electronic unit converts the mechanical vibrations of the measuring arm into electrical signals, which are recorded on the screen of the cathode ray tube (CRT) and the tape of the recording device 9. The measuring arm 3 of the mechanical unit is connected by a backlash-free spring hinge to the guide of the movable carriage 14, which is suspended from the body of the mechanical unit on flat-spring parallelogram and receives movement from the cam of the reciprocating mechanism 13; The mechanism is driven using electric motors and a gearbox 5. The stroke of the guide carriage is changed using a rocker mechanism 12.
The part to be measured is mounted on a base mandrel 2, which has a support ring and a spherical tip for simultaneous mounting on cylindrical and conical surfaces. Using a universal table with an installation mechanism 1, moving in three planes, the generatrix of the cone is aligned in the measurement plane and brought into contact with the tip of the measuring lever 3. The second end of the measuring lever, opposite the one in contact with the surface being measured, is the armature of the inductive sensor 6. The sensor is powered by voltage with a frequency of 970 Hz from the generator 7. The magnetic system is balanced using levers and microscrews of the measuring unit 4. The electrical signal taken from the inductive sensor, through the measuring bridge, enters the amplifiers of the electronic unit 8. The amplified signal is fed to the horizontal plates of the CRT indicating device 10. Horizontal move-
Rice. 115. Schematic diagram of an autonomous device for monitoring the angle and profile of the cone-forming parts of fuel equipment. The beam on the CRT screen is connected through an electronic unit to the longitudinal movement of the movable carriage using a horizontal scanning mechanism 11, which includes a flag, an illuminator and a photoresistor. The circuit of the electronic unit was developed on the basis of the S1-19B oscilloscope.
The most important condition for reliable and accurate operation of the devices considered is flawlessly executed standards, methods for their certification and use.
Shafts, gears, axles, fingers, rods, pistons and other parts have external cylindrical surfaces. A cylindrical surface is the simplest form of surface formed by rotating a straight line in a circle parallel to a given axis. The following requirements apply to cylindrical surfaces:
Straightness of the form - e and;
Cylindricity in any section perpendicular to the axis, the circles must be the same diameter;
Circularity: any section must have the shape of a regular circle;
Coaxiality: the location of the axes of the steps of a stepped part on a common straight line.
It is impossible to absolutely accurately meet all the requirements for cylindrical surfaces and there is no practical need for this. The drawings of parts indicate the permissible deviations in the shape and location of surfaces. These instructions are given by symbols or text in accordance with the Unified System of Design Documentation (ESKD, GOST 2.308-68).
To install and secure workpieces on the machine, general-purpose devices are used, these include chucks, centers, and clamps. Workpieces of short length are secured in chucks, which can be self-centering or non-self-centering.
Workpieces with regular outer cylindrical surfaces (rolled products, stamped forgings, high-quality castings), as well as pre-turned parts, are secured in a three-jaw self-centering chuck. Workpieces with uneven outer surfaces (open forgings, rough castings) and asymmetrical parts are secured in a non-self-centering four-jaw chuck.
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Details Mechanical engineering and materials processing1.What are the requirements for cylindrical surfaces?
1. cylindricity, straightness;2. straightness of the generatrix, cylindricity, roundness, coaxiality;
3. roundness, coaxiality, straightness;
2. What is a feed motion?
1. this is the movement of the cutter along the workpiece;2. this is the translational movement of the cutter, ensuring continuous cutting into new layers of metal;
3. this is the cutting surface during processing;
3. What is the front angle called?
1. angle between the front and back surfaces;2. the angle between the front surface and the plane perpendicular to the cutting plane;
3. angle between the front surface and the cutting plane;
4. What tool is used to finish the hole?
1. drill;2. countersink;
3. sweep;
5. The class of shafts includes parts that have:
1.length is significantly greater than diameter;2. length is significantly less than diameter;
3. length is equal to diameter;
6. What to consider when using dials:
1. presence of lubricant;2. number of marks on the limb;
3. presence of backlashes;
7. Which thread is characterized by a triangular profile pitch, profile angle 60˚
1. metric;2. inch;
3. trapezoidal,
8. What is allowance?
1. layer of metal removed from the workpiece;2. layer of metal for processing;
3. a layer of metal that is removed from the workpiece in order to obtain a part from it;
9. What is called cutter geometry?
1. cutter angles;2. shape of the front surface;
3. the size of the angles of the cutter head and the shape of the front surface;
10.What steels are called alloyed?
1. steels smelted in electric furnaces;2. steels containing alloying elements;
3. steels smelted in open hearth furnaces
11. Why is a three-jaw chuck called self-centering?
1. three cams simultaneously converge towards the center and diverge and ensure precise centering of the workpiece;2. based on the outer cylindrical surface;
3. coincidence of the workpiece axis with the spindle rotation axis;
12. How are drills with a cylindrical shank attached?
1. in the tailstock quill using cams;2. in the tailstock quill using a drill chuck;
3. in the tailstock quill using a template;
13. Blanks, what parts are installed and secured on the centers?
1. shaft blanks during finishing turning;2. shaft blanks, the length of which exceeds the diameter by 10 times;
3. shaft blanks, the length of which exceeds the diameter by 5 or more times;
14.How is the permissible overhang of the cutter from the tool holder calculated?
1. 1.2 N (cutter holders);2. 1.5 N (cutter holders);
3. 1 N (cutter holders);
15.Quality is:
1. range of sizes varying according to a certain dependence;2. a set of tolerances corresponding to the same degree of accuracy for all nominal sizes in a given interval;
3. list of sizes that have the same tolerance;
16.Which of the listed machine components converts the rotational movement of the lead screw into the rectilinear translational movement of the support?
1. machine guitar;2. machine apron;
3. feed box.
17.What should be the gap between the tool rest and the wheel on the sharpening machine:
1. no more than 6mm;2. no more than 3 mm;
3. not less than 10 mm,
18. Which of the following methods is more expedient to obtain a conical surface (chamfer) on the cone of the rod for cutting threads with a die:
1. by turning the upper slide of the caliper2. wide incisor;
3. displacement of the tailstock housing;
19. What affects the durability of the cutter:
1. coolant quality, tool geometry;2. cutting speed;
3. tool material, processed material, coolant quality;
20. What accuracy and surface roughness can be obtained by drilling?
1. Accuracy class 5, roughness 3;2. 3 accuracy class, 5 roughness;
3. 4 accuracy class, 2 roughness;
21. Reasons for the hole moving away from the axis of rotation:
1. end runout;2. cutting edges of various lengths;
3. displacement of the axis of centers;
22. What determines the allowance left for deployment:
1. from the diameter of the reamer;2. on the diameter of the hole, the material being processed;
3. from the material being processed;
23. Cast iron is an alloy of iron and carbon containing:
1. more than 6.67% carbon;2. more than 2.14% carbon;
3. less than 0.8% carbon;
24. How many dimensions must be indicated in the drawing for a truncated cone:
1. two;2. three;
3. four;
25. What types of shafts are there according to the shape of the outer surfaces:
1. stepped, oval;2. smooth, stepped;
3. smooth, conical;
26. Determine the hole tolerance Æ 40 N 7(0.025; -0.007):
1. 0,032;2. 40,025;
3.39,075;
27. Shaft radial runout is the result?:
1. spindle runout;2. incorrect installation of the cutter;
3. incorrect choice of cutting modes;
28. Brass is an alloy:
1. copper with tin;2. copper with zinc;
3. copper with chrome;
29. What elements are distinguished on the working part of the development:
1. cutting edge, shank, intake cone;2. calibrating part, cutting edge, shank;
3. cone, intake cone, calibrating part;
30. Determine the sharpening angle of the cutter, if the rake cutting angle is 15, the main rear angle is 8:
1. 67 ;2. 82 ;
3. 75 ;
31. Guitar replacement wheels are designed to:
1. to change the spindle speed;2. to transmit rotation to the lead screw;
3. to set the machine to the required feed;
32. What is the main alloying element of high-speed steel:
1. chrome;2. cobalt;
3. tungsten;
33. What is the lethal current strength:
1. 0.1 A;2. 0.5 A;
3. 1 A;
34.What surface is used as a mounting base in the manufacture of complex disks:
1. inner surface;2. outer surface;
3. outer surface, as well as ledges and recesses;
35. What is meant by the main dimensions of the machine:
1. diameter of the workpiece;2. overall dimensions of the machine;
3. height of centers and distance between centers;
36. What are the different types of chips:
1. fracture, chipping, drain;2. fracture, chipping, deformation;
3. chipping, breaking, cutting;
37. What does the feed rate correspond to when cutting threads:
1. pitch of the thread being cut;2. diameter for threading;
3. thread length;
38. How much carbon is contained in U12 steel?
1. 0,12%;2. 12%;
3. 1,2%;
39. Cementation is:
1. process of saturation of steel with zinc;2. the process of saturating steel with carbon;
3. the process of saturating steel with carbon and nitrogen;
45. Cutting speed increases if:
1. increase feed;2. increase the spindle speed;
3. increase the depth of cut;
4. reduce feed and increase depth of cut
46. Determine the cutting speed when turning a part with a diameter of D=60mm and the spindle speed n=500rpm
1. 94.2 m/min;2. 83.6 m/min;
3. 125.7 m/min;
47. In single production, when processing shaped surfaces, the following is used:
1. processing using a conical ruler;2. processing with passing cutters while using longitudinal and transverse feed;
3. processing using a copier;
48. Indicate what limits the largest possible diameter of the workpiece being processed:
1. spindle hole diameter;2. distance from the center line to the frame;
3. the distance of the chuck jaws from the centers;
49. Thanks to what type of processing is the strengthening of the surface layer of the part achieved?
1. grinding;2. running in, rolling out, smoothing;
3. hardening;
50. How much is the allowance for deployment:
1. 0.5 – 1mm per side;2. 0.08 – 0.2 mm per side;
3. 0.5 – 0.8 mm per side;
§ 1. General information
1. Types of external surfaces. According to their shape, the outer surfaces of cylindrical parts can be divided into cylindrical, end, ledges, grooves, chamfers (Fig. 25).
Cylindrical surfaces 1 are obtained by rotating a straight line (generator) around a line parallel to it, called the cylinder axis. In the longitudinal section such surfaces are rectilinear, in the transverse section they have the shape of a circle.
The extreme flat surfaces 2, perpendicular to the axis of the part, are called ends.
Transitional flat surfaces 5 between cylindrical sections, located perpendicular to the axis of the part, are usually called ledges.
Reductions 4 made around the circumference of a cylindrical or end surface are called grooves.
Chamfers are small bevels 3 on the edges of a part.
2. Methods for installing workpieces on the machine. When turning, four main methods of installing workpieces on the machine are most often used: in a chuck, in a chuck and back center, in centers and on mandrels.
In chuck 1 (Fig. 26, a) short blanks are installed with the length of the protruding part l from the cams up to 2-3 diameters d.
To increase rigidity, longer workpieces are installed in chuck 1 and rear center 2 (Fig. 26, b).
The installation in the centers (Fig. 26, c) is used mainly for finishing turning of long shafts, when it is necessary to maintain strict alignment of the processed surfaces, as well as in cases of subsequent processing of the part on other machines with the same installation. The workpiece is supported by the center holes on the front 4 and rear 2 centers, and rotation from the spindle is transmitted to it by the driving chuck 1 and the clamp 3.
Installation on mandrel 1 (Fig. 26, d) is used for processing external surfaces when the workpiece has a previously machined hole (see Chapter IV). 
§ 2. Processing of cylindrical surfaces
1. Grinding smooth surfaces. Technical requirements. When processing a cylindrical surface, the turner must maintain its dimensions (diameter, length), correct shape and required cleanliness.
Dimensional accuracy is limited by the permissible deviations indicated on the drawing. Dimensions without tolerances must 
carried out according to the 7th or less often 8-9th accuracy classes. In this case, the permissible deviations for external dimensions are set to minus from the nominal size, for internal dimensions - to plus.
The accuracy of the cylindrical shape is determined by the deviations of the cylinder in the longitudinal direction - cone-shaped, barrel-shaped, saddle-shaped and in the transverse direction - ovality (Fig. 38). The first three errors are characterized by the difference in the diameters of the treated surface at the edges and in the middle, the fourth - by the difference in the diameters of one section in mutually perpendicular directions. If the drawing does not indicate the accuracy of the surface shape, then its errors should not exceed the tolerance for the diameter.
The cleanliness of the finish is characterized by the degree of surface roughness remaining on it. after turning. The permissible roughness is indicated in the drawing by a triangle, to the right of which is a number corresponding to the cleanliness class.
For example, V.5 means the fifth class of cleanliness.
The processing accuracy must comply with the technical requirements of the working drawing. It should be taken into account that the normally achievable accuracy of turning on lathes is class 3-4 and cleanliness up to class 7. Surfaces of higher precision and cleanliness are usually pre-processed by turning with an allowance of 0.3-0.6 mm per diameter for subsequent grinding. 
Incisors used. Grinding of the outer surfaces is performed with passing cutters (Fig. 39). According to their shape, they are divided into straight a, bent b and persistent c.
The first two types of cutters are mainly used for processing rigid parts; They can be turned, chamfered, and when bent, the ends can be trimmed. The most widely used in turning practice are persistent cutters, which, in addition to the above work, allow you to trim ledges. These cutters are especially recommended for turning non-rigid shafts, as they create the smallest transverse deflection of the part compared to other cutters.
Passing cutters have different durability (time of direct work from sharpening to regrinding). Under equal conditions, persistent incisors are the least resistant, since their sharp tip is less durable and heats up faster. This feature of thrust cutters should be taken into account when assigning cutting modes.
For universal work, through cutters with different tip radii are used for both roughing and finishing turning. For rough cutters, the apex is rounded with a radius of r = 0.5-1 mm, for finishing cutters - r = 1.5-2 mm. As the tip radius increases, the finish improves.
To perform only finishing turning, it is recommended to use finishing double-sided cutters (Fig. 39, d) with an increased radius of curvature of the apex r = 2-5 mm; they can be used with longitudinal feed in both directions.
Installation of cutters on the machine. The cutters must be correctly installed and firmly secured in the caliper tool holder. The first condition is determined by the position of the cutter relative to the axis of the machine centers. Cutters for external turning are installed so that their top is at the level of the center axis. In some cases, for example, when rough turning and processing non-rigid shafts, it is recommended to perform this installation above the center line by 0.01-0.03 of the diameter of the part.
The installation height of the cutter is adjusted using steel pads 1 (Fig. 40, a), usually no more than two. In this case, the dimensions of the pads should ensure a stable position of the cutter over the entire supporting surface. The turner must have a set of such shims of different thicknesses to compensate for the decrease in the height of the cutter as grinding progresses.
The height setting of the cutter is checked by aligning the tips of the cutter and one of the centers or by trial trimming the end of the workpiece. 
In the latter case, if the cutter is installed correctly, there should be no boss left in the center of the end of the workpiece.
The cutter must be securely secured with at least two screws. To increase the rigidity of the fastening, the extension of the cutter from the tool holder is set to the smallest, no more than 1.5 times the height of the rod. In addition, the cutter is positioned perpendicular to the axis of the workpiece (Fig. 40, b).
Grinding techniques. To obtain the required diameter of the machined surface, the cutter is set to the cutting depth. To do this, it is brought into contact with the surface of the rotating workpiece. When a faintly noticeable mark appears, the cutter is moved to the right behind the end of the workpiece, the transverse feed dial is set to zero and the caliper is moved transversely forward to the required size along the dial. Mechanical longitudinal feed is turned on after the cutter cuts into the metal by manually moving the caliper.
Setting the cutter to the exact size is carried out similarly by trial turning the end of the workpiece to a length of 3-5 mm. Based on the results of measuring the diameter of the resulting surface with a caliper (Fig. 41, a) or, with higher accuracy, with a micrometer (Fig. 41, b), the cutter is moved to the final size along the dial. When the required size is reached, the dial ring is set to zero so that all subsequent parts from the batch can be processed without trial readings.
The turning length is maintained by marking the workpiece or along the longitudinal feed dial. In the first case, a score is machined on the workpiece at a certain distance from the end, the location 
which is installed with a ruler (Fig. 42) or a caliper. When using the longitudinal feed dial for this purpose, the cuts are brought to the end of the workpiece, the dial is set to zero and manually 
With constant longitudinal movement, the calipers cut into the metal. Then the longitudinal feed is turned on and turning is performed. The feed is turned off before reaching 2-3 mm to the required length. The remaining part is processed by manually moving the caliper.
The cleanliness of the processing is determined by comparing the surface of the part with cleanliness standards 2 (Fig. 43).
Features of using limbs. When feeding the cutter to the depth of cut along the transverse feed dial, you should keep in mind that it moves radially to the axis of the part. Consequently, the diameter of the latter after turning is reduced by an amount twice the cutting depth. For example, if a workpiece with a diameter of 30 mm needs to be ground to a diameter of 27 mm, that is, the diameter should be reduced by 3 mm, then the cutter should be moved transversely by 1.5 mm.
To determine the required rotation of the dial, you should divide the depth of cut by the value of its division. 
The division value is the amount of movement of the cutter corresponding to the rotation of the dial by one division. Let's say you need to feed the cutter to a cutting depth of 1.5 mm with a dial division value of 0.05 mm. The number of dial rotation divisions will be equal to 1.5: 0.05 = 30.
Some machines have cross-feed dials, the division price of which is indicated “by diameter”. In this case, the amount of rotation of the dial is determined by dividing the difference in the diameters of the workpiece before and after turning by the division price. For example, a workpiece with a diameter of 25 mm is ground to a diameter of 20 mm at a cost of dividing the dial by 0.05 by the diameter. The number of divisions by which you need to turn the dial will be equal to (25-20): 0.05=100.
When using dials, it is necessary to take into account the presence and magnitude of play (gap) in the caliper movement transmissions. If, for example, a caliper that is extended forward is moved back, then with a certain part of the revolution of the manual feed handwheel it will remain in place. This characterizes the amount of play in the transmission. Therefore, when measuring dimensions on the machine, the manual feed handwheel must be smoothly turned only in one direction (Fig. 44, a). If an error is made and the dial is turned by a greater number of divisions than required, then the handwheel is turned in the opposite direction by an amount slightly larger than the backlash (about 0.5-1 turn), and then, rotating in the same direction, the dial is brought to the required division (Fig. 44, b). The same is done when it is necessary to move the cutter away from the surface of the part by a certain size. To do this, the caliper is withdrawn by an amount greater than necessary, and then, feeding it to the part, the dial is brought to the required division.