Profile grinding machines. Profile grinding Profile grinding machine

Profile grinding machines are used for grinding parts with a complex profile, such as templates, shaped cutters, punches, matrices, etc. These machines come with a pantograph and an optical device or with two pantographs and a screen. The detail profile is ground according to its drawing, enlarged 50 times or more.

The machines have the following main components: a grinding support, a coordinate (cross) support for a part, a table for setting a drawing and an optical device. On such machines, the following movements are carried out: rotation of the grinding wheel, reciprocating movement of the support with the grinding wheel, adjusting movements of the coordinate support with the workpiece in three directions, movement of the grinding head.

Profile- grinding machine with pantograph and optical device shown in Fig. 16, a. The shape of the part is copied from the drawing using a pantograph. The part is installed on the coordinate support 13, which has longitudinal, transverse and vertical movements, respectively, from the handles 15, 14 and 16. The support is fixed with the handle 17.

The grinding wheel 12, located in the headstock of the grinding support 7, in addition to rotation, also receives reciprocating motion from the eccentric mechanism. The Be-face of the caliper stroke is adjusted by changing the eccentricity. The number of moves is set by the gearbox located in the headstock 6. The support can be rotated in the longitudinal and transverse directions. The grinding wheel rotates from Fig.16. Profile grinding motor 5 through a belt drive.

pantograph machine.

The drawing is placed on table 4 mounted on stand 3. The stand is fixed in bracket 2, which, together with the stand and table, can be moved vertically and fixed in the desired position with handle 1. Pantograph 8 is made on a scale of 50:1. To monitor the accuracy of the profile being ground, there is an optical device with a 20x magnification, the main part of which is a microscope 9, mounted in a bracket 10 and kept from angular movements by a rod 11.

The mechanical and optical axes of the microscope pass through the point of intersection of the rotary cross threads of the optical device. When the pantograph bypass pin is manually moved along the contour of the drawing, the intersection of the microscope filaments moves in the same direction by an amount 50 times smaller than the profile value in the drawing (Fig. 16.6). At point A, there is a bypass pin of the pantograph, and at point B, the intersection of the microscope threads; point C is the fixed axis of the pantograph. Other designations: 18 - grinding wheel; 19 - polished part; 20 - enlarged drawing of the part; 21 - pantograph arms with hinges F, G, E, D.

It is tedious to work on a machine with a pantograph and an optical device, because it is necessary to drive the bypass pin of the pantograph according to the drawing, observe the roughness of the surface to be machined through the microscope eyepiece, and simultaneously control several handles of the machine. Observation of the processing of the part is facilitated when working on profile grinders with a screen.

Screen profile grinder shown in fig. 17, a. The workpiece is fixed on the coordinate table 23, which has longitudinal, transverse and vertical movements from precise lead screws. The longitudinal movement of the sled 18 is performed by the handle 19, the transverse movement of the sled 20 - by the handle 21, the vertical movement of the table - by the flywheel 22. The part is installed on the working table 17, which is mounted on the upper longitudinal sled of the coordinate table and, together with the table, is located under the lens 13 of the optical device. The optical system projects an enlarged image of the part profile onto screen 14. A drawing of the part profile, made on a scale of 50:1, is fixed between two screen glasses and illuminated by illuminators 15 and 16.

The grinding head 24, together with the spindle 8 of the grinding wheel, has an installation and working movement. The spindle, mounted in a vertical slide 10, reciprocates when the lever 11 is turned on. The stroke length of the slide is 0 - 50 mm. Using screw 12, the grinding wheel is set in height relative to the profile of the workpiece. The movable flange 4 serves to rotate the circle in the horizontal plane, and the circular slide 6 and 7 - to set it at an angle in the horizontal and vertical planes. The grinding head is mounted on the upper longitudinal slide 3, moving along the lower transverse slide 1 with the help of handles 2 and 5. The grinding wheel rotates from the electric motor 9. Periodic dressing of the circle is carried out using a device mounted on the side wall of the circular slide 10.

The machine allows you to grind the profiles of flat and round parts with precision

Fig.17. Profile grinding machine.

up to 0.01-0.02 mm.

Processing is done like this.

The worker manually moves the grinding head relative to the profile of the part and ensures that the cutting edge of the grinding wheel always coincides with the corresponding point of the enlarged image of this profile, combined with the profile of the drawing on the screen.

The scheme of the optical device is shown in fig. 17.6. The beam of light from lamp 25, passing through lenses 26 and 27, prism 28, aperture 29, lenses 30 - 33, projects the outline of the part on the projector screen 43 in the form of a clear shadow. Illuminators 37 through lenses 34 - 36 additionally illuminate the part. Further, the rays pass through the projection lens, consisting of lenses 38, 39, 41, and are directed through the prism 42 to the mirror 40, reflected from which, fall on the mirror 46 and then on the screen, consisting of glasses 45 and 44 with a drawing fixed between them. A screen error of 1 mm corresponds to a workpiece profile error of 0.02 mm:

In addition to the types of machines described, working with a grinding wheel, there are profile grinding machines that work with a flexible abrasive belt. In such machines, a moving belt with an abrasive applied to it, fitting the shaped profile of the surface to be treated, grinds it.

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Profile grinding machines

For profile grinding, universal surface and cylindrical grinding machines of increased accuracy, profile grinding machines with manual and program control, etc. are used.

For the manufacture of tools, the most convenient are surface grinders with a longitudinal table stroke of 600..800 mm, equipped with a continuously adjustable hydraulic system and independent manual longitudinal and transverse table movements.

On a finely tuned surface grinder with a properly selected grinding wheel for finishing, it is possible to obtain an accuracy of linear dimensions of ± 0.01 mm, angular values ​​of ± 1 'and surface roughness L? a = 0.32 ... 0.16 μm.

A universal surface grinding machine model ZG71 of increased accuracy with a horizontal rectangular table is shown in fig. 1. Processing of parts is carried out by the periphery of the circle. Simple shaped parts can be machined with non-profiled and profiled wheels. The main components of the machine include bed I, column II, cross caliper III, the mechanism for manual longitudinal movement of the table IV, the mechanism for the longitudinal reverse of the table V, the table VI, the mechanism for the transverse reverse of the table VII and the cross feed VIII, the grinding head IX, the vertical feed mechanism X and drain tank XI.

Rice. 1. Surface grinding machine model ZG71.

The machine bed is a rigid box-shaped casting, on the upper part of which steel heat-treated V-shaped guides are fixed. Inside the frame there is a hydraulic unit and electrical equipment.

A gearbox is installed on the top of the column, designed to accelerate the movement of the grinding head.

There are mutually perpendicular guides on the cross support. A table with a working surface of 630X200 mm moves along the upper guides. It receives movement in the longitudinal direction from a hydraulic cylinder located between its guides. In the lower part of the table there are mechanisms for transverse feed, longitudinal movement of the table, its longitudinal reversal, as well as distribution and hydraulic panels. The grinding headstock moves along the rails of the rack mounted on the frame.

A grinding wheel measuring 250X25X75 mm, mounted on a spindle, receives the main movement from an electric motor with N - 2.2 kW and m = 2860 rpm. The spindle speed is 2700 rpm, and the cutting speed is v = 33.5 m/s. The vertical feed of the wheel can be done manually with handle 3 or automatically with handle 1. The largest vertical movement of the grinding headstock is 375 mm.

The cross feed of the table can also be manual (using the handwheel) and automatic (along the limbs). The greatest transverse movement of the table is 235 mm. The division price of the manual feed dial is 0.05 mm, and the automatic feed is 0.01 mm. The longitudinal feed of the table can be manual and automatic from the hydraulic system. The smallest movement of the table is 70mm and the largest is 710mm. The mechanism of manual longitudinal movement provides for a lock that automatically disconnects the gear wheel from the rack when the handle is set to the “Start table” position. When manually moving the table at the time of operation of the hydraulic drive, the handle must be in the “Unloading the hydraulic drive” position.

The mechanism of the longitudinal reverse of the table provides switching of the reverse spool at the extreme positions of the table, which are set depending on the length of the workpieces with the help of stops.

The controls of the machine: 1 - the handle for setting the height of the automatic vertical feed; 2 - handle of the valve for regulating the supply of working fluid; 3 - handwheel for manual vertical supply; 4 - stops of the longitudinal reverse of the table; 5 - handle speed table; 6 - handle for manual longitudinal reversal of the table; 7 - handwheel for manual cross-feeding of the table; 8 - limb of micrometric transverse feed of the table; 9 - dial for setting the value of automatic cross feed; 10 - button for turning on and reversing the cross feed; 11 - handle "Start the table", "Stop the table" and "Unload the hydraulic drive"; 12 - handle for manual longitudinal reversal of the table; 13 - button "Start spindle"; 14 - button "All stop"; 15 - magnetic plate switch button; 16 - drum switch for rapid movement of the grinding head; 17-button "Stop hydraulic drive"; 18 - button "Start" of the hydraulic drive; 19 - signaling light "The machine is on"; 20 - lighting switch; 21 - switch of the operating mode "With a plate" and "Without a plate"; 22 - introductory package switch.

Rice. 2. Schemes of grinding the corner sections of the profile with a flat circle.

As already noted, on surface grinders it is possible to process shaped parts with an unprofiled, i.e., flat, circle. They process surfaces whose profile is formed by straight lines, in cases where the surface to be ground can be combined with the periphery or end face of the grinding wheel. For this purpose, special devices are used.

On fig. Figure 2 shows the processing schemes on a surface grinding machine of the corner sections of the profile with a flat circle using a sine cube (Fig. 2, a), a sine ruler (Fig. 2, b), sine centers (Fig. 2, b), a sine magnetic table (Fig. 2, d), devices for grinding multifaceted parts (Fig. 2, e), sine magnetic prisms (Fig. 2, f).

With a non-profiled wheel, any non-closed profile of a tool (part), made up of straight lines and arcs of circles, can be machined from one installation using a universal fixture for coordinate grinding. When using copiers, it is possible to process a closed profile of a part or individual curved sections of its profile.

Grinding with a profiled wheel is one of the most common ways to reproduce shaped surfaces.

To expand the technological capabilities of surface grinding and cylindrical grinding machines, they are equipped with optical devices, with the help of which the enlarged contour of the part and the circle is projected onto the screen. The optical system is fixed on the table, machine and moves along with the part.

Machine tools for processing profiles of round parts. Grinding of cylindrical parts with a complex profile can be carried out on universal cylindrical grinding machines (Fig. 3), where the headstock and head with a grinding wheel can be rotated around a vertical axis and set at any angle with an accuracy of ± 5 '. Since the circle is set at an angle, the inclined sections of the profile can be processed by its periphery or sides without profiling.

Rice. 3. Circular grinding machine.

The machine has a movable stop for limiting the longitudinal movement of the table, a support for end measures of length, an indicator pointer for the longitudinal movement of the table, and a tailstock. The controls are: the handle of the reverse of the table, the handle of the stop, the handwheel of the longitudinal feed of the table, the handwheel of the grinding headstock feed mechanism, the handle for resetting the dial of the grinding headstock mortise feed, the handle for retracting the tailstock quill and the handle for clamping the tailstock quill.

The machine has a stepless regulation of the frequency of rotation of the part. It is equipped with a balancing mechanism mounted on the circle flange. Coolant is cleaned from metal chips and abrasive dust using a magnetic separator.

Profile machining of parts of small diameter is carried out on specialized machines with a double-sided grinding head.

Modernized universal grinding machines type ZA64M are convenient in that they have a rotary grinding head with a double-sided grinding spindle and a rotary table. It is recommended to process parts on them with circles with a diameter of 250 mm so that the circle protrudes beyond the limits of the grinding head. The spindle speed should be reduced to 1900-2000 rpm. The machine must be equipped with a headstock with a drive for rotating the part and a tailstock with a center.

Profile grinding can also be carried out on thread grinding machines. They are used in cases where the profile is ground to a shallow depth and has small radii with tight tolerances. Grinding is carried out with a circle of a relatively large diameter, which retains sharp edges longer.

On thread grinding machines, flat parts can also be machined if there is a fixture with a reciprocating table movement.

The Model 395M Profile Grinding Machine is designed for processing complex outer profiles of punches, composite dies and other similar parts of any profile.

The profile processing method is based on visual alignment of the contour of the workpiece, magnified 50 times by a special optical system and projected onto a screen, with a drawing of a given profile drawn on a transparent tracing paper with a magnification of 50 times and fixed on the screen.

The optical scheme of the profile grinding machine model 395M is shown in fig. 4. From the light source, the rays fall on an obliquely mounted reflector, which directs them to the workpiece.

Rice. 4. Scheme of the optical profile grinding machine model 395M.

From the part, the beam of rays is reflected in the opposite direction, passes through the slot in the reflector and the magnification system, and is projected in a direct working image onto mirror 6, which reflects the rays onto a glass screen. The drawing is fixed between screen glasses. The profile of the workpiece is projected as a sharp dark image on a brightly lit screen.

By removing the allowance, a part profile is obtained up to the 7th grade with a roughness of the machined surface Ra ~ 1.25 ... 0.63 microns.

Processing is carried out by moving the grinding wheel 10 along two mutually perpendicular coordinates due to the movement of the two supports of the grinding head manually or mechanically. In addition to rotational and two translational movements in the horizontal plane, the grinding wheel has a reciprocating motion, which ensures the processing of the profile along the entire height of the part.

The part is installed on the machine so that there is an allowance along the entire contour or part of it to be processed. Parts whose profile image does not fit on the screen are ground in sections. The transition from one section to another is carried out by moving the support of the table, on which the part is fixed.

In cases where repeating profiles are processed according to one drawing, the movement of the table supports is controlled using end gauges. When a profile of a different configuration than the previous one is polished in an adjacent section, the tracing drawing is moved or replaced, and in the new section of the drawing or in the new drawing there should be a line of the already processed part of the profile, which is the beginning of a new section. In these cases, the movement of the table supports is controlled by combining part of the contour of the machined section of the profile with the drawing line.

The machine makes it possible to process parts without removing them from the table, with significant profile dimensions that fit into a rectangle of 150X60 mm.

Editing circles. The copy method allows profile grinding on universal equipment, such as surface grinders high precision with rectangular table and horizontal spindle.

The accuracy of the machined surfaces during profile grinding depends on the accuracy of the dressing of the grinding wheels, which are profiled with diamonds or rollers. Profiling with diamonds is carried out using various devices. There are devices for profiling only inclined or only arc sections, as well as universal ones that profile both inclined and arc sections. Let's take a look at some of the tools.

For profiling a circle along an arc of a circle, devices are used in which the diamond tip is displaced relative to the axis of the diamond holder by the amount of the refueling radius. The diamond is set using a calibrated mandrel and gauge blocks. The order of editing the circle is as follows. The base (Fig. 5) is installed on the table of the grinding machine. A diamond fixed with a screw in a diamond holder is brought to a calibrated mandrel with a diameter d. In this position, the diamond holder is fixed with screw 7. Knowing the radius of the circle profile, determine the size of the block of end measures: li = d/2±R, where d is the diameter of the calibrated mandrel, and R is the radius of the surface to be ground, in mm. If the circle should have a concavity, take the “+” sign, if the convexity - the “-” sign.

A block of end measures is installed between the ring and the rack plane. After that, the ring is fixed, the screw is loosened, and the diamond holder is pulled back to remove the block of end measures and the calibrated mandrel. Then the diamond holder is moved until the end of the ring touches the plane of the stand and is fixed with a screw.

Rice. 5. Device for editing a circle along an arc of a circle.

The device is brought to the surface of the circle and, having placed the diamond perpendicular to its generatrix, the rack is fixed with a nut. First, the circle is corrected along the cylinder until a flat surface is obtained. Then the point of the diamond is set in the middle of the circle. In this position, the table is fixed with an emphasis. For profiling a circle, loosen the nut so that the stand rotates freely. By turning the stand with the diamond by the handle and imparting a transverse feed to the diamond, the circle is profiled along the circular arc.

The universal fixture shown in fig. 6 is intended for profiling circles with various combinations of straight and arc sections, as well as similar and opposite arcs. On the basis there is a rotary carriage, in the grooves of which the caliper can move. A sled with a stand carrying a diamond holder moves along the upper ledge of the caliper. In the central position, the sled is fixed with pins. With the pins extended, the sled and the diamond holder can move freely in both directions from the central position. The rotary part of the device can be fixed in the required position or rotate freely using the handle.

The profiling of circles is done element by element. For profiling arc sections, a diamond holder fixed in a stand, together with a sled, a caliper, which is locked with pins and screws, and a rotary carriage with the help of a handle, receives a rotational movement relative to the base of the fixture. The arc radius is set by the caliper by measuring the distance between the pin on the carriage and the bar on the caliper with a micrometer. If this distance is equal to constant value of this fixture, for example, 75 mm, and the diamond holder is installed according to the template, then the value of the radius R will be equal to zero. If the caliper is moved forward by size 75 - R, then the device will be set up for profiling on a circle of a concave arc section of the profile. With a reverse displacement of the caliper by 75 + /? the arc of the convex profile will be edited.

Profiling of straight sections is carried out by reciprocating movement of the sled. For profiling straight sections of the circle, inclined to the axis of the profile, the caliper is set to its original position, and the carriage at an angle of 90 ° - a and fixed with a locking handle.

Rice. 6. Universal wheel dresser.

Profile grinding is the grinding of precision hardened surfaces that differ in shape and position from planes parallel and perpendicular to the mounting base of the part. Profile grinding is used in all areas of tool production: in the manufacture of fixtures, dies, cutting and measuring tools.

Profile grinding equipment

Grinding of profiles is carried out on surface grinding, coordinate marking-grinding and optical profile grinding machines. Grinding of profiles on ordinary surface grinders is especially common. However, not all surface grinders are suitable for profile grinding. The machines used must be compact, precise and easy to operate. Convenient machines with a longitudinal stroke of the table, not exceeding 800 mm, with smoothly adjustable automatic and independent manual longitudinal and transverse movement. The presence of manual movements allows you to observe the nature of chip removal, the quality of the machined surface and creates the possibility of mutual, strictly defined movements of the work table and the abrasive wheel. The control of the machines is concentrated in the hands of the worker.

The machine model SK-371 satisfies these requirements. It must be equipped with a device for working with circles of small diameters, a quick-change protective cover, accurate indicator stops for the movement of the headstock and table, as well as a side stop ruler of a magnetic plate for quick installation of devices. Nevertheless, even with such equipment, this machine allows processing not profiled surfaces, but ordinary planes. Profile grinding will also require the use of special devices that will create the ability to accurately and efficiently, in a certain sequence, process straight and curved profiles and obtain the correct pairing of their elements.

Such devices according to the nature of the work performed in them can be divided into four groups:

1. devices for grinding straight sections of profiles;
2. devices for grinding arc sections;
3. devices for the exact location of the profile elements along the circumference;
4. devices for combined grinding of profile elements.

The design of the listed devices will be explained in parallel with the description of each type of work.

Profile grinding can be carried out in one of two ways: grinding with an abrasive wheel of a standard profile or with a profiled wheel, i.e. such a circle, which (is given the appropriate shape by a profiling device.

On optical grinding machines with a screen, the curved sections of the part profile are ground until their image matches the enlarged template drawing. At the same time, the processed profile is continuously monitored. Processing on such machines with a pantograph is difficult because control can only be carried out at individual points when the pantograph needle is moved along an enlarged drawing of the part profile.

Optical universal profile grinding machines allow you to process complex profiles of round and flat parts. They are indispensable for grinding small sections of part profiles in single production; this eliminates the cost of manufacturing auxiliary tools. However, grinding straight sections of considerable length and profile parts large sizes can be performed with greater productivity on a surface grinder with a horizontal spindle. Processing is carried out on the magnetic plate of the machine or on the coordinate device.

Profile parts on optical grinding machines are ground with an accuracy of 0.01 ^ -0.02 mm without further processing. When manually fitting a profile part, it can be pre-grinded on the machine, leaving an allowance of 0.015-0.03 mm, and thereby significantly reduce the complexity of operations for manual fitting of the profile.

When working on optical profile grinders with a pantograph and a screen, the grinder continuously monitors the movement of the cutting edge of the grinding wheel and makes the necessary corrections to its feed.

When profile grinding parts on optical grinding machines, the grinder must master the setup of the machine well, correctly select the grinding wheel for hardness and grain size, depending on the material being processed and the configuration of the part. In addition, the grinder must correctly control the movements of the grinding head of the machine and accurately guide the cutting edge along the enlarged drawing of the contour of the workpiece.

The accuracy of profile grinding directly depends on the accuracy of the manufacture of the enlarged drawing, which is determined by the tolerance for the manufacture of the part. For example, for processing

detail profile with a tolerance of 0.03 mm; an enlarged drawing must be made with an accuracy of 1.5 mm (taking into account 50x magnification by the optical system of the machine).

The implementation of an enlarged drawing of the profile of the part begins with the construction of a square 500 × 500 mm. The sides of the square serve as bases from which the coordinates of individual sections of the part profile are plotted, so they must be mutually perpendicular. One of quick ways checking the correctness of the drawn square - comparing the lengths of its diagonals, which should be equal. At 50x magnification with an optical system, the dimensions of the screen of the machine 500X 500 mm correspond to the dimensions of the profile of the part 10 X 10 mm.

For the manufacture of a number of parts with a complex profile, various optical profile grinding machines are used. On fig. 125 shows a profile grinding machine mod. 395. The control panel 6 of the machine is moved to the left for ease of operation, observing

deniya behind the workpiece and installation of fixtures. The main components of the machine are the spindle head /, the coordinate table 2 for fixing the workpiece 3 and its movement in three directions (vertical and two mutually perpendicular horizontal), as well as an optical device 4 for controlling the profile of the part and monitoring the process

catfish processing. All three nodes are mounted on the frame 5 of the machine. The headstock has an arched slide that allows you to change the direction of movement of the grinding wheel, and three rotary disks (on the upper longitudinal slide, on the lower cross slide and on the bed), which allows you to grind surfaces at an angle in three projections.

The optical system of the IZI-25 type projector is designed to project onto the screen the image of the contour of the workpiece with a 50-fold increase, as well as the image of the grinding wheel. An enlarged drawing of the profile of the part is made in thin lines on tracing paper and fixed between the projector glasses. Full coincidence of the profile of the part with the contour of the drawing is achieved by moving the grinding headstock.

For grinding parts of great length (exceeding the maximum

the minimum stroke of the grinding wheel of the profile grinding machine) use the device shown in fig. 126, with which you can grind profiles to a length of 48-100 mm. At the base 1 of the device there is a roller with an eccentric lever 2. Four columns 3, pressed into the base and covered with cups 9 from dust, can move the plate 4 with the table 5 to install the workpieces. The part is fixed and mounted on the table 5 with the help of screw 6, clamping sponge 7 and clamp 8. During processing, when the grinding wheel reaches its extreme position, the eccentric lever 2 is pressed, while the plate 4 with table 5 begins to move relative to the grinding wheel, which continues to (continuously) grind part 10 over the entire profile.

Details of stamps, molds and templates are processed according to the markup, while the accuracy of processing does not exceed 0.1 mm. As a result of the stepwise movement of the tool during the milling process, the part requires additional processing due to the surface quality. Performing the same work on an optical grinding machine eliminates the need for additional operations and improves the quality of the workpiece.

On an optical profile grinding machine, the processing of part profiles can be performed in two ways: 1) the profile being ground is compared with an enlarged drawing placed on the projector screen or on the faceplate of a pantograph device; 2) they use precise movements of the coordinate table over the tiles, and the position of the points of the profile to be ground is controlled at the intersection point of two straight lines drawn on the projector screen, or the crosshairs of the microscope of the pantograph device.

The first method is applicable for grinding profiles up to a size of 10X10 mm, determined by the field of view of optical measuring devices. The second method is applicable when processing profiles larger than 10X10 mm. Maximum size workpiece on the machine without re-fixing it on the desktop is 60X150 mm. The part should be installed so that its coordinate axes lie in the direction of movement of the coordinate table.

The part is verified in the following ways: a) by grinding its base sides on the machine with the movement of the longitudinal or transverse slide of the grinding head at zero readings of the rotary scales; b) installation of the part with the movement of the supports of the coordinate table while simultaneously controlling the position of the processed base side by the control point on the screen or by the crosshairs of the microscope; c) installation of the processed base sides along the lines of the drawing, oriented according to the direction of movement of the coordinate table; d) setting the base side of the part according to the indicator fixed outside the coordinate table. The part must be fixed on the working

table so that the grinding wheel has a free exit when processing any section of the profile.

An enlarged drawing - a standard part for machine tools with a projector is performed on tracing paper; for machines with a pantograph - on thick drawing paper. The scale of the enlarged drawing is 50: 1. Deviations from the drawing dimensions when drawing an enlarged contour should not exceed 0.5 mm, which corresponds to an error

0.01mm per detail. An enlarged drawing is placed between the walls of the machine screen or fixed on a tablet so that the coordinate axes of the drawing coincide with the directions of movement of the slide of the coordinate table.

When grinding profiles with straight sloping sections, after grinding the base sides, the rotary slide is set in accordance with the angles of the profile. Grinding is carried out until the visible contour of the part coincides with the lines of the enlarged drawing.

Consider grinding the template profile shown in fig. 127. Processing should begin with sections of the profile located in the direction of the axes of the rectangular coordinates of the drawing. The wheelhead moves when the rotary slide is set to zero. Sections of the template profile, located at angles of 28 and 30 °, are ground when installing the rotary slide, shown in fig. 128 a. In this case, the lower rotary slide is set at an angle of 30° and the inclined section of the profile is ground to a size of 8.2 mm with an allowance of 0.1-0.15 mm for grinding the plane of the template. After that, the slide is rotated through an angle of 36° and the second inclined section of the profile is ground. Then the lower slide is rotated through an angle of 90° and, without changing the circle, a section 2 mm wide and a second section located 2.7 mm below the coordinate axis are ground to a size of 8.2 mm. Touching around the side of the arcuate cavity (R = 2 mm), they notice a size of 34.3 + 2 mm along the limb of the longitudinal movement of the sled and begin

grind the base surface and the lower section of the cavity to a size of 3 mm.

For grinding sections of the profile located at angles of 30, 45 and 50 °, the upper slide is installed as shown in fig. 128, c, d. The arc sections of the template profile are ground according to the enlarged drawing with a specially profiled circle (Fig. 128.6). The thickness of the circle should be 3-4 times less

the radius of the arc of the processed contour of the template for more convenient movement of the circle, as well as for warnings of cuts in neighboring sections. A long profile is processed sequentially, since the enlarged profile drawing does not fit on the screen.

An enlarged profile drawing is performed according to the scheme shown in fig. 129, a, b. The drawing is divided into separate sections. First, sections of the profile are ground that coincide with the base lines of the drawing. At the same time, the rotary slide of the machine must be set to zero readings of the scales.

After an approximate alignment of the profile of the template blank with the contour of the enlarged drawing in the BG section (Fig. 129), grinding is carried out until they are completely combined. When grinding the profile, it is necessary to go beyond the center O of the grid by a small amount; this will make it much easier to control the installation and movement of the template.

Having finished grinding the first section of the template profile, the coordinate table together with the template is moved along the vernier of the longitudinal movement limb. In this case, the polished section of the VG profile at point 2 will be aligned with the same point of the AD section of the enlarged drawing. After checking the installation of the sled and grinder

headstock and making sure that the axis of the machine spindle is parallel to the direction of the longitudinal movement of the coordinate table, start grinding the corner sections of the template profile. To eliminate errors when grinding the profile along the lines

drawing attached to the screen, the following rules must be observed:

1. The beginning and end of the lines in the sections of the enlarged drawing are numbered 1 and 2 (see Fig. 129). The breakpoints corresponding to one place of the profile must have the same numbering.

2. The sides of the contour are highlighted with light shading.

3. With a complex profile configuration and multiple intersections of the lines of the combined enlarged drawing, each line is underlined with its own color for each section.

4. In places where the profile breaks, arrows indicate the directions of subsequent movements of the coordinate table, as well as the magnitude of their movements.

The accuracy and roughness of the surface of curved sections largely depend on the experience of the grinder. Practice shows that due to the stepwise movement of the grinding wheel, the roughness of the machined surface does not exceed Ra = 2.5 - 0.32 microns. Therefore profiles machined on profile grinders almost always require reworking to improve the surface quality.

Fitting and patterning work is carried out at the site of the workshop or workshop, equipped in accordance with the nature of these works. Workbench 1 (Fig. 130, a) has a welded frame made of angle steel 30 x 30 mm and legs made of angle steel 50 X 50 mm. Wooden bars 70 X70 mm are installed between the legs. The workbench is sheathed on the sides

plywood, its cover is made of well-fitted boards with a thickness of 10 mm and covered with linoleum. On the back side of the workbench, above the lid, there is a shelf for laying measuring tools on it. FROM right side workbench under the cover there is a cabinet 2 with shelves for storing fixtures and finished parts on them. On the left side of the workbench there is a bedside table 6 with four wooden drawers and a lifting and swivel chair 5. On the right side, on the cover of the workbench, there are rotary parallel bench vise 3, and opposite them is a rotary electric lamp 4 (voltage 36 V) shadowless lighting. The height of the workbench with the vice installed on it is determined by the height of the worker. When choosing the installation height of a parallel vice, the bent left hand is placed on the jaws of the vice so that the ends of the straightened fingers touch the chin (or by setting the hammer head on the impact part of the chisel), while the forearm right hand should be vertical, and the elbow should be horizontal.

Behind the worker, an auxiliary workbench is installed (Fig. 130.6) for assembly and assembly work. The distance between workplaces, as well as passages between locksmith workbenches (1.5-2 m) are set depending on the technical and technological requirements and labor protection conditions.

The correct choice and placement of equipment and auxiliary equipment, tools and materials at the workplace of a fitter create favorable conditions for productive work.