Processing on cylindrical grinding machines. Device for processing on cylindrical grinding machines Layout diagrams of cylindrical grinding units

A grinding machine is a device used to process workpieces made of various materials with an abrasive tool and can provide surface roughness from 0.02 to 1.25 microns. Grinding machines, which can have different designs, allow you to effectively solve problems associated with processing the surfaces of parts made of different materials.

Application of grinding machines

Using a grinding machine, you can carry out a number of technological operations:

• grinding of internal and external surfaces of parts having different shapes and purposes;
• sharpening of tools for various purposes;
• peeling, grinding, as well as cutting of metal castings and products with complex profiles;
• processing of gear parts and threaded parts;
• formation of keyed and spiral-type grooves on steel bars.

A grinding machine is practically indispensable when working with parts made of ceramic and magnetic materials that are difficult to process and highly fragile. In addition, grinding machines are capable of performing technological operations of grinding and roughening at high speed modes, which makes such equipment efficient and productive. On these machines, it is possible to remove a large amount of metal from the surface of the workpiece in a short period of time during processing.

The video below shows the operation of a CNC cylindrical grinding machine:

All grinding machines operate on the same principle: metal processing is carried out by simultaneous rotation and movement or rotation of the workpiece. The working surface is the periphery or end of the abrasive wheel, and the workpiece moves relative to it along a straight or arc path. Any grinding machine contains in its design several kinematic chains that provide:

• movement of the work table in the longitudinal and transverse directions, which is possible thanks to a hydraulic drive;
• rotation of the working tool - the grinding wheel, carried out due to the individual drive of the working tool;
• feeding the workpiece or tool in the transverse direction due to a hydraulic or electromechanical drive;
• wheel dressing, which can be done manually using an electromechanical or hydraulic system;
• rotation of the workpiece or work table;
• supply of the working tool to depth, which can be performed using a hydraulic or mechanical drive.

Classification of grinding equipment

Depending on the application, grinding machines are divided into a number of types.

This equipment is designed for grinding cylindrical (Ø 25–600 mm) and conical workpieces. Such machines have in their design a spindle that rotates in a horizontal plane, which can move on a special slide. The part to be machined may be clamped in the chuck or between the centers of the tailstock and headstock.

Such machines are used for grinding the outer and end surfaces of cylindrical workpieces (Ø 25–300 mm), as well as conical parts. To perform processing, workpieces can be fixed in centers or in a chuck.

Grinding machines of this type are used for processing cylindrical (Ø 150–400 mm), conical and profile workpieces, which are fixed in the centers of the equipment. Processing is carried out due to the transverse movement (cutting) of the abrasive wheel.

Processing on such equipment can be carried out according to two schemes: by pass (cylindrical surfaces (Ø 25–300 mm)) and by plunge method (cylindrical, conical and profile surfaces). A distinctive feature of grinding machines of this type is that their design does not provide centers for fixing workpieces.

This includes machines for grinding rolling rollers of cylindrical, conical and profile configurations. Fixation of workpieces on machines of this type is carried out using equipment centers.

For grinding crankshaft journals

On such machines, working using the plunge method, simultaneous or sequential grinding of the crankpins of crankshafts is performed.

These devices allow the processing of cylindrical and conical holes in a wide range of sizes (with a diameter of 1–10 cm on a bench grinder and up to 100 cm on a production one).

Surface grinding

Processing on such equipment is performed with the end or periphery of the abrasive wheel. Grinding machines of this type can be equipped with additional devices, which makes it possible to process metal workpieces of complex configurations. Depending on the location of the spindle, they can be horizontal or vertical. The design of such devices may also include one or two columns.

This equipment can simultaneously process two flat surfaces, which significantly increases its productivity. Such grinding machines, in which the workpieces are fixed on a special feeding device, can be of a vertical or horizontal type.

The maximum length of guides that can be machined with these grinding machines is 1000–5000 mm. Guides of these types are equipped with beds, work tables, slides and other equipment components for various purposes.

Such grinding machines are used for sharpening various tools with a maximum diameter of 100–300 mm (taps, reamers, countersinks, cutters, etc.). The technical capabilities of equipment of this type make it possible to equip it with additional devices for processing cylindrical workpieces, as well as for internal and end grinding.

This grinding equipment is used for roughening and cleaning the surface of workpieces by grinding. These machines use abrasive wheels with a diameter of 100–800 mm.

This grinding equipment is used to grind workpieces with flat and cylindrical surfaces. The diameter of the abrasive discs that are installed on such machines is 200–800 mm.

This equipment is used to grind in calibration and measuring instruments made of metal. The maximum diameter of gauges and tools that can be processed on machines of this type is 50–200 mm.

With the help of such equipment, holes are ground in, the maximum diameter of which is 100–300 mm.

These are machines designed to perform finishing (lapping) operations. Such devices process various metal products: crankshafts with a maximum diameter of 100–200 mm, equipment spindles, pistons, etc.

Such machines are used to polish metal parts. This universal equipment can be used to polish flat, cylindrical, conical, internal surfaces, as well as workpieces of complex configurations. An endless belt with a width of 100–200 mm or a soft polishing wheel with a diameter of 100–200 mm can be used as a working tool on these machines.

There are also honing machines that are used to perform fine grinding (0.04–0.08 mm per diameter).

Making a simple grinding machine with your own hands

Considering the fact that serial grinding equipment is not cheap, it makes sense to think about making such a machine yourself. Even the simplest homemade machine, which is not at all difficult to make, will allow you to grind workpieces of various configurations with high efficiency and quality.

The supporting element of a homemade machine for performing grinding work is a frame on which two drums and an electric motor are mounted. To make the frame, you can use a thick steel sheet, from which a platform of the required size is cut out.

With the engine, everything is much simpler: it can be removed from an old washing machine that has already served its useful life. The drums can be made in sets; for this it is convenient to use a chipboard, from which discs of the required diameter are cut.

Drive shaft mount Driven drum Motor mount

As an example, we will analyze the sequence of steps for manufacturing, the frame of which has dimensions of 50x18 cm. First of all, the frame itself is cut out of a steel sheet, as well as the work table on which the electric motor will be mounted. The dimensions of such a table will be approximately 18x16 cm.

It is important that the ends of the bed and work table, which will be connected, be cut as evenly as possible. The thick sheet of metal from which you will make the frame and work table is difficult to cut by hand, so it is better to perform this procedure on a milling machine. It is necessary to drill three holes in the frame and work table and securely connect them with bolts. Only after this is the motor installed and securely connected to the surface of the work table so that the base of the motor fits snugly to the surface of the platform.

When choosing an electric motor for your homemade grinding equipment, it is important to pay attention to the power: it should be at least 2.5 kW, and the rotation speed should be about 1500 rpm. If you use a drive with more modest characteristics, the machine will have low efficiency. You can avoid the need to use a gearbox if you correctly select the diameters of the drive and tension drums.

The diameters of the drums should be selected depending on the speed at which the abrasive belt will move. So, if the belt speed should be approximately 20 m/sec, then it is necessary to make drums with a diameter of 20 cm. To install the tension drum, a fixed axis is used, and the drive one is fixed directly on the electric motor shaft. To make rotation of the tension drum easier, a bearing assembly is used. It is best to make the platform on which the tension drum is installed with some bevel; this will ensure smooth contact of the abrasive belt with the workpiece being processed.

It won’t be particularly difficult to make drums for a homemade grinding machine. To do this, you need to cut square blanks measuring 20 by 20 cm from chipboard, and drill a hole in the center of each of them. These blanks are then assembled into a 24 cm thick package, which is machined to form a cylindrical drum with a diameter of 20 cm.

To prevent the abrasive belt from slipping on the drums, you can stretch wide rubber rings onto their surface, which are usually cut from the inner tube of a bicycle or moped. The width of the abrasive tape, which you can make yourself, should be about 20 cm.

Belts for belt sanding machines

Both in production and at home, grinding machines are often used, the working tool of which is a cloth belt with a layer of abrasive powder. The basis of such tapes is dense material (calico, twill) or special paper, and the abrasive layer is fixed on them using an adhesive composition.

The effectiveness of using such a tape depends on a number of parameters: the density of application of the abrasive powder and the composition of its grains. Belts on which the powder occupies no more than 70% of their area are more effective. This is explained by the fact that the material being processed does not get clogged between the abrasive grains of such a tape. Both natural and artificial materials can be used as an abrasive powder applied to the working surface of the belt, but all of them must have high hardness.

Belts installed on a grinding machine are classified by a number indicating the size of the abrasive grains, expressed in hundredths of a millimeter. The reliability and effectiveness of such a tape also depends on the type of glue that is used to fix the abrasive grains. Today, two types of such glue are used: flesh and synthetic resin.

As a rule, they are used in woodworking enterprises. The belt on such machines can also be attached to reels, which allows them to be classified as cylindrical grinding equipment. But in most cases, these machines are made universal; they can be used to process wooden parts either using a belt or using grinding wheels.

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Assembling and preparing circles. Before installation on the machine, the wheels should be checked to ensure that their hardness and grain size correspond to the values ​​​​specified in the technological map. Each circle must be carefully inspected and checked by lightly tapping it with a wooden hammer for cracks (the sound should be clear, without rattling).

Wheels 1 (Fig. 9.16) should be assembled on mandrel 2 according to the grinding machine setup drawing. Fitting the circle onto the mandrel should be easy, without using force, to avoid its breaking. The gap between the seat, the mandrel and the diameter of the circle hole should be 0.3...0.5 mm; the deviation from the perpendicularity of the ends of the circle to its axis should not exceed 0.15 mm (at the periphery of a circle with a diameter of 500...600 mm), which is achieved by turning the ends of the circle, maintaining dimensions A, B, C and D. Between the circle and the flange it is necessary to place oiled cardboard gaskets 4 up to 1 mm thick; When securing the circles to the faceplate using flanges, it is necessary that the latter be precisely centered. To avoid distortion of the flanges and destruction of the circle when assembling it on the faceplate, nuts 3 should be tightened alternately (through 180° from opposite sides).

Test of endurance. Before working on the machine, the wheels are tested for strength by test rotation at high speed. For this purpose, special machines are produced that provide wheel speeds 1.5 times higher than the operating speed. Tests should be carried out with a time delay at the specified test speed. The test mode is automated. Control is carried out from the remote control. The circle is tested according to a given program - acceleration, holding at test speed and braking until it comes to a complete stop. The rotation speed is steplessly controlled. Test stands are equipped with lifting and mounting devices. The circle is put on the flanges, and it is necessary to pay attention to the fact that the gap between the inner hole of the circle and the mounting diameters of the flanges is uniform along the entire circumference.

Balancing Circles. To ensure grinding of workpieces with high precision and without vibration, the wheels assembled with the faceplate must be balanced. When working with an unbalanced wheel, the machined surface becomes faceted and wavy, and the spindle supports quickly wear out. The reasons for the imbalance of the wheel can be uneven distribution of mass in the body of the wheel, eccentric location of the mounting hole in relation to the outer surface of the wheel, non-parallelism and non-perpendicularity of the ends, uneven impregnation of the wheel with coolant, incorrect installation - non-concentric installation of the wheel, etc.

When the circle is unbalanced, centrifugal force occurs, which causes vibration. With high-speed grinding, the risk of wheel rupture from cutting forces decreases, but the risk of rupture from centrifugal force increases.

The wheel is balanced outside the grinding machine on balancing stands. The circle, mounted on a mandrel, is mounted on supports - cylindrical rollers or disks (Fig. 9.17). Both devices (Fig. 9.17, a, b) have a common drawback - a large friction moment, which reduces the balancing accuracy. The use of the “air cushion” principle made it possible to create a rational design of the device for static balancing (Fig. 9.18). The advantage of the “air cushion” device is that the mandrel with the circle easily rotates under the influence of a small moment of force. To release a mandrel with a circle mounted on cylindrical rollers from rest, a torque is required that is 7 times greater, and with disks - 40 times greater.

The wheels are secured on the machine spindle using a faceplate, in the end grooves of which weights are placed - segments for balancing the wheels. Balancing is carried out by changing the position of three weights in the annular recess of the grinding wheel flange. The unbalanced circle will turn downwards with its heavier part. By moving weights in the faceplate, they ensure that the circle remains motionless in any position on the supports. As the wheel wears out, its balancing may be disrupted due to uneven distribution of mass in the wheel body, so it is advisable to re-balance the wheel. To do this, it is recommended to spin the wheel at operating speed for 1...2 minutes, turning off the cooling, so that the liquid does not accumulate in the pores of the lower part of the wheel and does not upset the balancing.

In more critical cases, balancing scales are used. With careful manufacturing of balance parts, the balancing accuracy can be brought to a residual displacement of the center of gravity of 5 microns. The average duration of balancing is 15...20 minutes. Balancing scales are designed for balancing grinding wheels with a diameter of 200 to 600 mm. Devices for balancing wheels directly on the grinding machine are also used.

Adjustment of center cylindrical grinding machines. It is recommended to perform adjustments in the following sequence:

• check the operation of all machine components in adjustment mode and eliminate any malfunctions;
• set the speed of the longitudinal movement of the dressing mechanism and perform (if it is necessary to install a new grinding wheel) preliminary dressing with the copier turned off (usually such dressing is done with a diamond substitute);
• balance the grinding wheel and then check the quality of balancing;
• edit the grinding wheel using a copying device (if necessary);
• install centers in the headstock and tailstock and check their alignment;
• install the headstock and tailstock at a given axial distance;
• install the workpiece in the centers (chuck) and check the reliability of its fastening;
• check the relative position of the grinding head with the workpiece in the axial and radial directions;
• place stops to change the direction of table movement during longitudinal grinding;
• set specified processing modes;
• when grinding long workpieces, install a steady rest (rests);
• install and adjust a measuring device to a standard to control the diameter of the outer surface and control the machine cycle;
• carry out test grinding of two or three workpieces, measuring their errors and adjusting the position of the grinding head and the setting of the measuring device;
• if the results of processing workpieces are positive, install an automatic cycle on the machine and check the operation of the machine by processing a batch of workpieces to ensure the required productivity and accuracy.

Installation and alignment of centers. Before installing the centers, you need to check for nicks in the conical holes in the spindles of the headstocks; they should be cleaned of dirt and lubricated with oil. Check the angles of the centers with a template, and the fit of the shanks with paint. The alignment of the centers should be determined by special mandrels 3 (Fig. 9.19) installed in the headstock 1 and tailstock 4. Check the position of the cylindrical surfaces of the mandrels with indicator 2 along the entire length of the mandrel generatrix. If the deviation is more than 0.01 mm, eliminate deviations from alignment by turning the front stock or shifting the tailstock.

Tailstock installation. Place the tailstock in the required position and securely fasten it to the table using two clamping screws. The pressing force of the part with the rear center should be moderate. The lighter and thinner the part, the less this effort should be. It should be remembered that excessive clamping force leads to rapid wear of the centers and, consequently, to a deterioration in the quality of processing. Weak pressure on the part is also unacceptable, since under the influence of the wheel pressure on the part, the rear center may shift and the processing accuracy will be impaired. When grinding long parts, set the required number of steady rests to prevent the part from bending under the influence of forces arising during processing.

Then you should adjust and check the cooling and filtering system of the working fluid.

Stop placement. After the part to be sanded is installed in the centers, it is necessary to begin arranging stops to change the direction of movement of the table during longitudinal grinding. To establish the relative position of the circle and the part in the direction of the part axis, a reference part is placed at the centers of the machine. The grinding headstock is given an adjustment movement in the direction of the axis of the part. The left end of the part is usually used as a base, the position of which remains constant for any length of the part. For trial runs during adjustment, turn on the electric motor of the wheel head and parts, then bring the wheel to the part until a spark appears and manually move the table. If the spark is uniform along the entire length of the part, then automatic feed can be turned on. After making several moves, check the diameter of the part at both ends and, if it turns out to be conical, check the position of the table.

Machine setup. When setting up the machine, you need to use the existing cross-feed dial, which makes setting easier. After making sure that the part rotates at the required speed and the position of the table travel switching stops corresponds to the required grinding length, you must carefully move the wheel towards the part until a spark appears. In this position, you should release the dial and, without moving the cross-feed flywheel, move it so that the number of divisions between the zero division on the body of the cross-feed mechanism and the zero division of the dial corresponds to half the allowance for the diameter of the part. After this, having secured the dial, you can process the part by turning on the automatic feed, which is turned off by the cross-feed stop when the zero divisions of the dial and the body of the cross-feed mechanism are aligned. Two or three divisions before the zero position, it is necessary to check the size of the part to prevent the removal of excess metal, and, if necessary, make appropriate adjustments to the setup. When grinding to the stop, it is necessary to periodically adjust the position of the wheel to compensate for wear.

Adjustment of measuring and control devices. Measuring instruments are installed along the reference part at the measurement positions. First, preliminary adjustment is made along the axis of the part, and then it is finally set to the zero position. When setting up devices with lever systems, it is necessary to independently adjust the horizontal and vertical levers. After the final adjustment of the measuring instruments, it is necessary to fix the position of the units so that the fixation is reliable and the adjusted precise relative position of the parts and units of the device is maintained even after they are fixed.

During the trial grinding process, you should check the state of the spark along the length of the ground surface using manual feed. If the spark is uniform along the entire length, then automatic feed can be turned on. After grinding the part, it is necessary to check the diameter of the journals in the two most distant sections. If there is a taper, it is necessary to adjust the position of the table in the horizontal plane by rotating its upper part relative to the lower one. To monitor the angle of rotation during adjustment, use a special dial or adjustment device with an indicator (Fig. 9.20). The device is attached to the lower table of the machine on a block 3 and has two rotating elements 1 and 4, with the help of which indicator 2 is installed in different positions along the height and width of the machine table. The table installation is finally checked by repeating test grinding.

For a pneumatic measuring device, proper adjustment of the device and appropriate calibration of the scale of the reading device, which is carried out according to standards, are of great importance. To measure scale holes, pneumatic instruments are calibrated using setting rings. The kit must include at least two installation rings corresponding in size to the maximum diameters of the part being measured for which the device is being calibrated. Using the setting rings, control points are applied to the instrument scale, intermediate values ​​are obtained by dividing the segments between the points; applied along the rings, into equal parts, in order to obtain the required division price. Proper operation of a pneumatic device is important for the accuracy and reliability of its operation.

Features of setting up surface grinding machines. Setting up machines with a rectangular table and a magnetic plate should begin with checking the operation of the machine components, as well as checking the serviceability of the magnetic plate or device for installing and clamping the workpiece. In case of deviation from the flatness of the table and magnetic plate, they must be ground to the required deviation from flatness according to the machine data sheet. Further adjustment is recommended to be carried out taking into account the following features.

When using a magnetic plate, place the workpiece(s) on the plate, ensuring that each workpiece overlaps two poles. Check the clamping force. After installing the workpiece, turning on the electromagnetic plate and feeding the table, the grinding wheel should be gradually brought into contact with the workpieces (to avoid its impact).

When setting up machines with a rectangular table, place stops that switch the direction of movement of the table, while ensuring overrun, which is determined by the size of the wheel and the grinding method (periphery or end). Place stops that limit the transverse movement of the grinding head, ensuring that the disc extends relative to the edge of the plate by no more than 0.3 of its height. Depending on the length and speed of the longitudinal stroke of the table, set the frequency of double strokes. Set the required values ​​of transverse and vertical feeds. Set up a measuring and control device that carries out the machine operation cycle and automatically stops the machine at the end of processing.

With longitudinal feed, long surfaces are usually ground: cylindrical, conical or shaped surfaces; with cross feed - short.

On to round grinding machines When processing short surfaces of hard parts, the “deep method” of processing is sometimes used, which consists in the fact that almost the entire layer of metal to be removed is ground off in one pass of the grinding wheel with a small longitudinal feed (1-5 mm per revolution of the workpiece).

Final grinding is then carried out in the usual way, with longitudinal feed or plunging.

Plunge grinding is the most productive method of precision cylindrical grinding. In this case, the width of the circle should be sufficient to cover the entire surface to be treated. The circle is fed only in the radial direction. Shaped surfaces can be sanded in this way. With several wheels operating simultaneously, you can grind individual surfaces of different diameters (Fig. 62).

Unlike grinding on centerless machines, it is performed by securing the part between centers, in a chuck or in a special device.

Grinding is the most common method of final processing of the surfaces of rotating bodies, the accuracy of which must correspond to class 2, and surface cleanliness to class 8-9.

For fine grinding, even in mass production conditions, the economic accuracy of the processing corresponds to the 1st class of accuracy, and the easily achievable cleanliness of the processing corresponds to the 10th class.

Fine grinding is characterized by the following features:

1) using soft, fine-grained grinding wheels;

2) small cutting depth (up to 0.005 mm);

3) low speed of rotation of the workpiece (2-10 m/min),

4) high rotation speed of the grinding wheel (more than 10 m/sec);

A movable stop 3, pressed against the work surface by a spring, is connected to a rod 4. When the diameter of the work surface decreases during the grinding process, the rod 4 lowers and moves the block 6, acting on the plate 5. This plate has two contacts. The same contacts are available on the swing arms 7 and 10 , the position of which is adjusted using screws 9 and 8.

When the specified size of the surface being processed is reached during the grinding process, the contacts open. In this case, the transverse feed of the wheel automatically stops.

To facilitate setting the device to size, there is an indicator 12. Signal lamps 11 provide monitoring of the moment the required size of the surface being treated is reached.

Full automation of the processing cycle on cylindrical grinding machines is carried out using loading devices. The loading device, shown in Fig. 64, a, consists of an upper loading tray 1, a lower unloading sprocket drum 3, a hydraulic cylinder 4 and levers 5 of the loading mechanism

Loading and unloading trays 2 have cutters 6, connected to each other by rods 8, which are pressed by springs 7 so that the workpieces on the trays are held by the cutters and do not allow them to move down the slope of the tray.

In Fig. 64, and the device is shown in a position where the levers 5 of the loading mechanism with the help of a hydraulic cylinder under the heels upward and the loading drum sprocket 3 is brought to the upper tray 1 to grab the workpiece. In this case, the drum presses on the rod 8, turns the cutters 6 and the workpieces laid on the tray, move one step forward The front workpiece falls on the tooth of the loading drum of the sprocket 3

In Fig. 64.6 the device is shown in a position where the levers 5 are turned down, the workpiece is moved to the line of the machine centers. In this position, the workpiece is clamped between the centers of the grinding machine by moving the tailstock

In Fig. 64, the device is shown in the third stage of operation after grinding, when the levers 5 are in the middle position, and the sprocket drum 3 is brought to the rail of the lower tray 2. In this position, the end of the lever 5 presses the rod 8, turns the cutters 6 of the lower tray, the workpieces on the lower tray move one step of the sprocket teeth forward and the outermost workpiece rolls off the tray.

Using this device, the worker, who must place workpieces on the rails of the upper tray, serves several machines simultaneously. These machines can be built into automatic lines.

Fig. 65 shows a diagram of the automatic cycle of a machine with a loading device. The work piece is fed from magazine 1 by loading mechanism 2 and is automatically clamped in the centers. Grinding wheel 3 and measuring bracket 4 are quickly brought to the surface to be processed (diagram I) Then rough grinding is carried out ( Scheme II), changing modes and finishing grinding (Scheme III), removing the grinding wheel and measuring bracket from the machined surface (Scheme IV), releasing the part from the centers and removing it (Scheme V), dressing the wheel (Scheme VI), withdrawal of the ruling mechanism from the circle (diagram VII) When the last of the parts in the first store is processed, the machine automatically turns off.

The installation of the machine automatically removes parts 1 and 2 with different allowances and an unacceptably irregular shape before processing.

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Grinding (grinding) is a method of processing a part to specified dimensions. For this purpose, abrasive materials applied to grinding wheels are used. Portable cylindrical grinding machines for metal work have many design options, both manually controlled and with CNC systems (3u10a, Studer series of machines, etc.).

Cylindrical grinding machines are widely used in manufacturing enterprises that produce products in large, medium, small series and even single copies. The universal cylindrical grinding machine is designed for grinding cylindrical and conical parts both internally and externally.

As a rule, the part goes to such a machine for final processing, which ensures high precision control of parameters and surface cleanliness.

1 Modifications

All cylindrical grinding machines have their own technological precision control and production:

• P - increased;
• B - high;
• A - especially high.

Cylindrical grinding machines, which are the most often found in factories, have the following designations:

• 3a423, 3a151,
• 3b12, 3b161, 3b153, 3b151;
• 3m151, 3m175;
• 3у10а;
• numerous series of Studer machines (S21, S31, S33, S41).

All modifications have an effective method for controlling dimensions when processing a part, including the CNC method. Most machines allow you to process heavy and large parts.

There are also differences in the location of the workpiece. There are three modifications:

• centered - the part is installed in the centers;
• cartridge - the workpiece is clamped in the chuck;
• centerless - the part is installed on the surface to be processed.

1.1 Working units

The difference in technical characteristics of different sharpening models lies in power, distance between centers, permissible weight of the workpiece, maximum grinding diameter, and the width of the spindle head rotation range.

The devices are quite heavy, so it is necessary to provide a reinforced foundation for them.

Main working units:

• grinding headstock with grinding wheel spindle;
• knife support;
• cartridge (center);
• balancing device for grinding wheel;
• device for dressing the grinding wheel;
• container with cutting fluid;
• clamps.

A universal cylindrical grinding machine can be equipped with a CNC, which greatly simplifies the control method and increases the accuracy of the work performed.

On such machines it is possible process parts from almost any materials:

• steel;
• cast iron;
• alloys of non-ferrous metals;
• textolite;
• glass;
• materials of special strength (cermets).

2 Operating principle

The workpiece is clamped in a chuck or mounted on the centers of the machine, and then, rotating, comes into contact with grinding wheels that have abrasive coatings. The machine table can move in a reciprocating direction and at the end of the completed pass, the grinding wheel moves to the next specified cutting amount.

The longitudinal movement of the table is controlled by CNC (via hydraulics) or manually (by rotating the flywheel). The grinding head, which moves transversely, can also be controlled by CNC or manually. Abrasive wheels, with longitudinal and transverse movement, process the part first in roughing and then in finishing grinding.

2.1 Machine 3m151

Used for single, serial and large-scale processing of parts. When working with metal, 3m151 allows you to perform the following operations:

• grinding (plunge and longitudinal);
• external grinding of parts that have a conical or cylindrical shape.

Work can be carried out both manually and automatically (CNC) mode, while the method of controlling dimensions allows for high precision processing.

The 3m151 machine can process parts with a maximum diameter of 200 mm and a length of 700 mm, as well as a weight of up to 55 kg. The total weight of 3m151 (together with the cooling system and a set of electrical equipment) is 5600 kg with dimensions of 2170x2450x4605 mm.

2.2 Design features

The 3m151 machine has two tables (upper and lower). The first is placed in front of the bed and moves along longitudinal guides, the second is used in processing conical parts and is rotated to a certain angle using a screw, followed by fixation with clamps. The method of controlling dimensions, as well as checking them, is to adjust them using a scale and an indicator mechanism located on the tables.

The hydraulic system of the 3m151 machine allows you to:

• manual table movement blocking;
• longitudinal movement of the table (automatic reverse is activated at the end of the working stroke);
• quick approach/retraction of the headstock;
• blocking the table when performing plunge-cut grinding;
• Quill retraction.

With longitudinal and plunge grinding on 3m151, complete automation of the process is possible, which is carried out using a hydraulic drive with a clutch and a hydraulic motor. A quill, with a gear rack, brings the tailstock to the workpiece for installation in the centers. 3M151 allows such an operation to be carried out both manually and using hydraulics.

The 3m151 tailstock has a device for dressing the grinding wheel. If desired, this device can be automated, as an additional option when ordering from the manufacturer.

2.3 Universal machine 3b12

The 3B12 machine is a universal cylindrical grinding device and is used for grinding conical and cylindrical surfaces both internally and externally.

The presence of a rotary table in 3B12 allows grinding of flat conical surfaces.

For grinding steep conical internal and external surfaces, the 3B12 has a rotating front and rotating grinding head, which consists of two parts. The upper part can be moved on a slide relative to the lower part. Thus, on the 3B12 machine, it is possible to grind the end of a part fixed in the chuck with the edge of a grinding wheel.

The 3B12 machine allows you to process a part fixed in a chuck or installed in fixed centers.

On the 3B12 machine It is possible to carry out the following work:

• plunge and longitudinal grinding;
• longitudinal grinding to the stop (automatic transverse feed);
• grinding the end surfaces with the periphery of the grinding wheel.

The 3B12 machine allows you to process cylindrical surfaces with a diameter of 8-200 mm and a length of 100-500 mm, and holes of 20-50 mm with a depth of up to 75 mm. Checking the accuracy of sharpening work with a 3B12 machine is carried out using the appropriate scales for setting processing parameters.

2.4 Special machine 3a423

Model 3a423 is designed for regrinding connecting rods and main journals of crankshafts of internal combustion engines. 3a423 is used in car repair plants and repair shops. The 3a423 machine can grind cylindrical surfaces and cones that have a small slope angle.

When grinding connecting rod journals on a 3A423 machine, the crankshaft is balanced by weights moved on the chuck. The 3a423 control system has mechanical, hydraulic and manual drives. It is possible to carry out grinding with automatic plunge-in.

Kinematic chains and hydraulic systems with which the 3a423 is equipped allow the following movements:

• rotate the spindle of the grinding head;
• rotate the workpiece;
• using hydraulics, quickly move/retract the grinding head;
• move the table.

On 3a423 it is possible to process parts with a maximum total cross-section of 580 mm and a length of 1600 mm (at centers); 1450 mm (in cartridges), and also weighing up to 150 kg.

The power of the electric motor of the main drive of the machine 3a423 is 11 kW. Dimensions of the machine 3a423 (width, depth and height) - 5650x2530x1830 mm. Total weight - 7250 kg.

2.5 Model 3B161

The 3B161 machine is used in external grinding of cylindrical and conical (with a gentle bevel) surfaces.

Types of grinding on the 3B161 machine:

• longitudinal and milling (with manual control);
• longitudinal (in automatic transverse feed mode);
• mortise (all the way, in a semi-automatic cycle).

Model 3B161 allows you to install additional devices, on which the accuracy of the work is checked using the method of active dimensional control. This method is possible with a special configuration 3B161 and requires additional payment.

There is a modification 3B161, which does not have a hydraulic mechanism for cutting. Plunge and longitudinal grinding on the 3B161 machine is carried out using the manual transverse feed method.

The maximum dimensions of workpieces processed on the 3B161 machine are 280 mm in diameter and 1000 mm in length. The 3B161 machine has an electric wheel drive motor - 7 kW (980 rpm). Overall dimensions in length, width, height - 4100x2100x1560 mm, with a total weight of 4500 kg.

2.6 Universal semi-automatic 3M175

The 3M175 semi-automatic machine has accuracy class P and is designed for grinding flat conical and cylindrical surfaces.

Semi-automatic grinding occurs in fixed centers. Rotating upper part of the semi-automatic table 3M175 ensures work with conical surfaces.

The 3M175 semi-automatic machine is easy to operate and maintain. Operations of moving the table, turning on the rotation of the workpiece, cooling and quickly bringing in the grinding wheel are performed with one handle.

The 3M175 machine can process parts measuring 2800 mm with a diameter of 400 mm. The grinding area is determined by a diameter of 400 mm and a length of 2520 mm.

Overall dimensions of 3M175 are 8310x3690x2135 mm with a total weight of 13850 kg.

2.7 Machines 3m175, 3a151, 3u10a, 3b153, 3b151

Models 3m175, 3a151, 3u10a, 3b153, 3b151 are used for external grinding.

On machines 3m175, 3a151, 3u10a, 3b153, 3b151 it is possible to install active control devices, so a thorough check of all parameters when working on metal is carried out automatically. This control method allows us to produce high-quality products with a smooth and clean surface.

The 3u10a machine differs from the 3m175, 3a151, 3b153, 3b151 in particularly high precision when grinding external and internal cylindrical or conical surfaces.

Characteristics of 3u10a:

• workpiece diameter - up to 100 mm;
• workpiece length - up to 180 mm;
• electric motor power - 1.1 kW;
• dimensions - 1250x1400x1690 mm;
• weight - 1850 kg.

2.8 Studer universal cylindrical grinders

Studer S41 is a unit that is equipped with a new generation CNC. Studer has many special technical additions, such as a unique guide system, high-precision linear motor drives, and a large selection of grinding wheels.

Studer S21 - suitable for grinding parts with high quality control requirements. Can be fully automated. Used to manufacture products for the aerospace industry, precision mechanics and hydraulics (pneumatics).

Studer S31 - widely used in the tool industry.

Studer S33 - has three grinding wheels that provide comprehensive processing of the part at the highest level.

2.9 How it works cylindrical grinding machine 3K12? (video)

A cylindrical grinding machine makes it possible to process the outer surfaces of rotating products using longitudinal and plunge grinding in a chuck and centers. This machine can be used to grind structures made of various materials.

1 Cylindrical grinding machine - general information

The described installations are intended for finishing and roughing of products using diamond and. Both the first and second guarantee low roughness of the processed surface, as well as decent accuracy of the geometric shape and dimensions of the part.

In most cases, such units receive workpieces that have already undergone preliminary thermal or mechanical treatment. In other words, cylindrical grinding units perform the final grinding operation of parts that have been on a drilling, milling, turning or other machine.
Based on the type of basing (this term refers to giving the workpiece the required configuration in space in relation to a particular coordinate system), all cylindrical grinding units are divided into three types:

• cartridge-type: the workpiece in them is located in the cartridge;
• center: blank in centers;
• centerless: basing the structure being processed on several or one surface to be ground.

But there are two direct basing schemes:

• on shoes (fixed type supports) with an end drive support;
• with a supporting knife on the driving circle.

Depending on how the main movements of the part are carried out relative to the circle, plunge-in, through-cut and combined grinding are distinguished. Pass-through processing provides:

• excellent surface quality after grinding;
• low heat generation;
• uniform wear of the grinding wheel.

Continuous grinding is recommended for cylindrical surfaces of significant length, since during processing the cylindricity index practically does not change. With plunge-cut grinding, the geometric accuracy of the surface being processed directly depends on the degree of wear of the wheel. It is most often used for processing shaped and stepped shapes, surfaces with shoulders, short necks, and also when simultaneous processing of the end and neck of a part is required.

Combined grinding has an important feature. It consists in the fact that the cylindrical part of the workpiece is ground using the through grinding technology, and after that the end is processed. Note: the movement of the part in the longitudinal direction with centerless mounting is limited by the stop (end).

2 Layout diagrams of cylindrical grinding units

The basing option determines the layout features of the machine equipment. The most common layout schemes for cylindrical grinding units are:

• cartridge room with two or one table;
• center with two or one table;
• centerless with fixed shoes, with a movable and fixed knife.

The most important difference between the layout of units with a centerless mounting method and other options is that the support knife in this case is mounted on the headstock (drive) slide or directly on the bed. If it is installed on a slide, the knife moves both together with the driving circle and relative to its axis. At the same time, the headstock becomes motionless in relation to the bed.

Stationary knife units are often built into automatic production lines. Such machines guarantee the constancy of the workpiece axis in any condition of the grinding (diamond) wheel. When it wears out, there is no need to adjust the transport mechanisms of the unit.

But machines with fixed knives, unfortunately, have a rather complex design due to the presence of devices that move the heads, as well as a decrease in the rigidity of the entire structure in general and the grinding head in particular. Machine equipment with a fixed headstock is characterized by higher rigidity and more modest dimensions. This arrangement is optimal for processing parts with a wide range of adjustment.

Modern cylindrical grinding machines have objectively high technical capabilities, which are achieved through the use of the principle of unification of their individual functional units, as well as the thoughtful design of all unit units without exception. A unified modular block means a number of units and elements that perform the same function in the same way in relation to processed parts of different sizes. These blocks make it possible, with a relatively small number of modules, to design many cylindrical grinding units with different modifications.

3 A few words about the components and mechanisms of cylindrical grinding machines

All cylindrical grinding units are divided into four groups. In accordance with this division, machines can be:

• Simple. The grinding and headstock, as well as the table of such equipment, are made with a non-rotating design.
• Universal. All of the above components are made with a rotary design.
• Mortise. With these installations, workpieces cannot be fed longitudinally. The grinding tool of such machines has a large width, which allows them to process the part along its entire length. The peculiarity of plunge-cutting equipment is the combination of continuous transverse feed with rotation of the workpiece.
• Special. Units for performing operations for processing any specific products (for example, cam shafts, turbine blades, tooth profiles, and so on).

The main blocks of the machines under consideration include:

• Desktop;
• grinding and headstock;
• bed.

The drive to the wheel is mounted in the grinding headstock, to the spindle in the front wheel, and to the table in the frame.

The equipment is controlled using a push-button station, stops, flywheels for moving the work table and headstock (spindle) manually, as well as a number of handles for performing:

• quick retraction and supply of the headstock (spindle);
• quill removal;
• changing the speed of table movement;
• disabling the table movement in automatic mode;
• table reverse.

The design of cylindrical grinding units also includes the following important elements:

• Grinding headstock: characterized by a rigid structure, can be moved or mounted stationary on the frame, and houses the spindle.
• Wheel balancing mechanism: necessary to correct vibrations in the “wheel – workpiece” system. Balancing, we note, is performed both non-automatically and according to a fully automatic scheme.
• Grinding tool dressing mechanism: the task of the device is to maintain the functional shape of the wheel and its cutting capabilities.
• Feed mechanism: performs the working movement of the tool, installation movements, and compensation for wheel movement.
• Tailstock: used on units with products based in a chuck and in centers.
• Steady rests: special supports, without which it is impossible to effectively process thin and long workpieces.