Drilling and ongoing. Drilling methods

Drilling

When drilling, distant, deaf and incomplete holes are distinguished. The high.quality hole is ensured by the correct choice of drilling techniques, as well as the correct location of the drill relative to the processed surface and the combination of the drill axis with the center (axis) of the future hole.

The drilling of the deaf opening to a given depth is carried out along the sleeve cut on the drill or measuring line mounted on the machine. To measure the drill to contact the part of the part, drilled to the depth of the drill cone and marked on the arrow (pointer) initial position on the ruler. Then, a given depth of drilling is added to this indicator and a figure is obtained, to which it is necessary to drill.

Some drilling machines on the measuring line are emphasized: its lower line is installed on the figure, which needs to be drilled, and the emphasis is fixed with a screw.

Many drilling machines have automatic supply mechanisms with limits that determine the course of the drill to the required depth.

When drilling deaf holes, it is necessary to periodically remove the drill from the hole, clean the last one of the chips and measure the depth with a standard.

Drilling incomplete holes (semi.firmness). In cases where the hole is located at the edge, a plate of the same material is put to the processed part, clamped in a vice and drill a full hole; Then the plate is removed.

Drilling the through hole in the square is carried out after fixing the latter in a vice on a wooden lining (rice. 230.5). First, complete easverization is performed and a hole in the control circles is checked. Having discovered the drill, eliminate it, and then finally drill a hole. After that, a square is stopped to drill the next hole and t. D.

Drilling holes in the planes located at an angle to each other. So that the drill does not deviate and does not break, begins to prepare the site perpendicular to the axis of the drilled hole (milling or zenkut), wooden liners or lining are inserted between the planes, then the hole is drilled in the usual way.

Drilling holes on the cylindrical surface

First perpendicular to the axis of drilling on a cylindrical surface

make a platform, nimble the center, after which they drill a hole in the usual way.

Drilling holes in hollow details. When drilling, the cavity into the part is clogged with a wooden cork.

Drilling holes with ledges can be carried out in two ways:

First, the hole is drilled with a drill of the smallest diameter, then it is drilled into one or two large diameters within the depths, each stage; Drills are changed according to the number of steps, consistently increasing their diameter;

First, the hole is drilled with a drill of the largest diameter, and after that. smaller diameters by the number of steps

In both ways, the drill does not take aside. It is well centered. To measure the depth of drilling is easier in the second method, since the depthmer rests on the bottom of the hole.

Drilling exact holes. To obtain accurate holes, drilling is carried out for two work movements. In the first working move, drill with a drill “The diameter of which is on I. 3 mm is less than the diameter of the hole, which excludes the harmful effects of the jumper. After that, the hole is drilled in size. The drill should be well sharpened.

To obtain cleaner holes, drilling is carried out with low automatic supply during abundant cooling and continuous divert of chips.

Drilling holes of small diameters is carried out on marching accuracy machines with appropriate feeds, as well as an ultrasound or electro.isk method.

Drilling holes of large diameters is carried out by drilling drilled holes. However, the holes obtained by casting, stamping and other similar methods are not recommended, since the drill is greatly led away due to the mismatch of the center of the hole with the axis of the drill.

Ring drilling allows you to get holes F 50 mm or more on machines, without resorting to drilling. Ring drilling is carried out using cutting heads having a hollow case with incisions mounted on it, located diametrically and evenly around the circle. The number of incisors is even. from 6 to 12 for heads f 30. 150 mm.

With ring drilling into parts, the grooves are cut with incisions, and the inner part (core) remaining in the hole in the form of the rod is broken off. The rod is usually broken not along the entire length of the hole at once, but in parts, as the head deepens. The depth of the ring back, necessary for breaking up, depends on the diameter of the hole.

Drilling holes in sheet metal. It is very difficult to drill a hole in thin sheet metal, since the drilling depth is less than the length of the fence cone. the cutting edges of the drill will cling to the processed material and tear it. The holes in sheet metal are drilled with feather drills, and most often pierced on hole.propelled presses. The large hole is obtained not by drilling, but by cutting with incisors fixed in the mandrel. To do this, use the mandrel with a guide rod 3 and a conical shank 5, in which two (or four) incisors 2 are fixed. The guide rod enters the finished hole and provides a reliable direction. Cutting with incisors, rotating and having a feed, cuts out a hole in the details

Drilling deep holes. Deep drilling is the drilling of holes to a depth exceeding the diameter of the drill by 5 times or more. Depending on the technology, continuous and ring drilling are distinguished.

Drilling with a spiral drill is carried out, overwhelming the hole with a meek drill, and then drilling it normal with a drill to the full depth.

Drilling a deep hole, periodically remove the drill from it, without stopping and remove the accumulated rust from the grooves. The length of the drill must correspond to the depth of drilling.

Getting deep holes with trail drilling is ensured by: preliminary sprinkling (centering) of the hole with a hard shortened drill, which allow you to direct a more correct drill during the period of cut into the metal-

drilling holes with two drills. First short and then long (the first drilling. to a depth of up to five diameters of the drill)

using guide conductive bushings;

Metal processing with drilling: basic information

Drilling is carried out on special drilling machines, where the workpiece is rigidly fixed, and the cutting tool rotates and at the same time moves progressively along the axis of the hole drilled in the processed part (this movement is called the feed). Distinguish vertical-links and radial-drilling machines. The former are used to drill holes in small blanks, which during the settings are moved along the table with the calculation so that the axis of the drill and axis of the future openings coincide. To work with heavy and large blanks, radial-warlord machines are used. On them, the processed part is immediately rigidly fixed on the table, and the machine spindle is installed in the right position. Work performed on drilling machines:

Cutting tools used to process parts on drilling machines:

The main cutting tool when drilling parts is a drill. Typically, for this purpose, spiral drills consisting of the working part, neck and shank are used. The working part, in turn, consists of two parts. cutting and centering. The cutting part has two cutting working edges interconnected by a jumper. The centering part has a pair of screw ribbons that perform the guide function during the drilling of the metal, as well as two spiral grooves, along which the lubricant-coolering fluid is supplied and the chips are diverted. The shank may have a conical or cylindrical shape. The first option is intended for attaching a drill in a spindle through transitional bushings, the second option is for fastening in the cartridge. The neck of the drill carries a disguise, where, among other parameters, the diameter of the drill and the material of its cutting edge are indicated.

Safety, general advice

When working with a power tool, it is important to remember the security of a person and prevent premature wear of the tool and a possible marriage. In this regard, we have collected some useful tips:

• Before work, you need to check the fasteners of all elements.
• Clothing when working on a machine or with an electric drill should not be with elements that can fall under the rotating parts. Protect your eyes from shavings with glasses.
• When approaching the metal surface, the drill should already rotate, otherwise it will quickly dull.
• It is necessary to remove the drill from the hole without turning off the drill, if possible reducing speed.
• If the drill does not deepen into the metal, it means that its hardness is lower than that of the workpiece. Increased hardness in steel can be detected by conducting a file on the model. the absence of traces indicates increased firmness. In this case, the drill must be chosen from a solid alloy with additives and work at low speeds with a small feed.
• If a small diameter drill is poorly fixed in the cartridge, wrap several brass wire revolutions on its shank, increasing the diameter for capture.
• If the surface of the workpiece is polished, put on a felt washer on the drill, so that it is guaranteed not to apply scratches even when contacting the drill cartridge. When fixing blanks made of polished or chrome steel, use gaskets from fabric or leather.
• In the manufacture of deep holes, a rectangular piece of foam, mounted on a drill, can serve as a meter and at the same time, rotating, blow off small chips.

Holes processing

The most common method of obtaining holes in continuous material is to drill. In this case, there is a movement of rotation and progressive movement (feed movement). It can rotate both the workpiece and the drill, and the rotational movement of the workpiece and drill is also used at the same time.

The industry produces drill with cylindrical and conical (Morsa cone) shank, with different lengths of the working part. Drills with a cylindrical shank are installed in a drilling cam cartridge, a zang cartridge or a special mandrel. Drills with a conical shank are installed directly in the pinol of the rear grandmother using transitional bushings as necessary.

Before drilling, the workpiece must be highlighted using a short drill of a large diameter or a special center drill.

When drilling holes, the depth of which is more than the diameter of the drill is periodically removed from the hole. In the machines with CNC for such drilling, a deep drilling cycle is used. The program sets the total depth of drilling and the value of one pass, then the control system automatically divides the passes into passages.

To reduce friction, drilling is carried out with the supply of coolant. The use of coolant allows you to increase the cutting speed by 1.4. 1.5 times. The modern design of the ruins allows you to supply coolant through the holes inside the working part of the drill, directly into the cutting zone.

To ensure the minimum errors of the resulting hole, a number of conditions must be observed, namely: the drill axis must coincide with the rotation axis of the processed workpiece, the cutting edges of the drill should be imprisoned (at the same angle and have the same length). If these conditions are not observed, it leads to the following defects: the holes can have dimensions more than the specified, increased roughness, displacement of the center of the opening at the output.

The processed hole is called deep if its depth exceeds the diameter by 5 times. For drilling deep holes, drills of an elongated series are used. For drilling holes of more than 10 diameters, special drilling systems include not only a special tool, but also special equipment and equipment. For deep drilling, crushing and removal of chips without package is necessary, which is achieved by the supply of coolants into the cutting zone under high pressure and subsequent removal along with chips. Deep drilling holes with a length of about 100 diameters can be successfully conducted in three methods.

Ejector system (two.tank). Consists of a cutting head, outer and inner rods, a cartridge, tsang and sealing sleeve. The coolant is fed into the beds between the outer and inner rods, and is removed through the hole in the inner rod.

STS system (classmate). Provides for the external Submarine, through the sealing sleeve, and remove the chips through the hole in the rod.

Cannon drill sealing system. Uses the oldest co.stroke. The liquid is supplied through the channel in the instrument and removed with the chip through the V-figurative groove passing along the drill.

Feed. When drilling, three feed groups are recommended: 1-drilling holes in hard details without tolerances or with the admission of the 12th qualifications for subsequent processing; 2. drilling holes in the parts of medium stiffness or drilling with obtaining the RZ = 20 ÷ 40 microns for subsequent processing; 3-sowing holes in the details of low stiffness or drilling holes with the accuracy of the 11th qualification for subsequent processing.

Supply to circulation when drilling holes with fast.cutting drills.

Correct coefficients for feeding during drilling.

The cutting speed during drilling is selected depending on the diameter of the drill, the selected feed and the processed material. For materials of the V group (carbon steels), the tabular value of the cutting speed is selected in the range of 30-40 m/min. With a larger diameter and larger feed, the smaller cutting speed is selected.

Correction coefficients for cutting speed.

Senction

The zenker process holes, previously stamped, cast or drilled. Senction can be either preliminary (before deployment) or final processing. In addition to processing holes, zenkers are sometimes used to process the end surfaces of the workpieces.

To increase the accuracy of zenketing (especially when processing cast or stamped deep holes), it is recommended to pre.waste the hole to the diameter equal to the diameter of the zenker to a depth of about half the length of the working part of the zenker.

Zenkers, like drills, are installed on turning machines most often in the rear grandmother or revolving head.

Cylindrical holes processing on a lathe

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Drilling

The main movement of cutting during drilling is rotational, it is performed by the workpiece; the movement of the feed. progressive, is performed by the tool. Before starting work, they check the combination of the peaks of the front and rear centers of the lathe. The workpiece is installed in the cartridge and check that its beating (eccentricity) relative to the axis of rotation does not exceed the allowance removed during the external grinding. Check the beating of the end of the workpiece in which the hole will be processed, and verify the blanks along the end. The perpendicularity of the end of the workpiece to the axis of its rotation can be ensured by trimming the end. At the same time, in the center of the workpiece, you can make a deepening to ensure the desired direction of the drill and prevent it from leaving and breakdown. Drills with conical shanks are installed directly in the conical hole of Pinoli of the rear grandmother, and if the sizes of the cones do not match, then the transitional bushings are used.

For attaching drills with cylindrical shanks (up to 16 mm with a diameter), drilling cam cartridges are used, which are installed in pinols of the rear grandmother.

Before drilling holes, the rear grandmother is moved across the bed to such a distance from the workpiece so that drilling can be made to the required depth with minimal pinoli from the hull of the rear grandmother. Before starting drilling, the workpiece is brought into rotation by turning on the spindle.

The drill smoothly (without impact) is brought manually (rotating the flywheel of the rear grandmother) to the end of the workpiece and drill to a small depth (overwhelm). Then the tool is removed, the workpiece stops and the accuracy of the opening location is checked. In order for the drill not to shift, the harvesting of a short spiral drill of a large diameter or a special central drill with an angle at a top of 90 ° is pre.which is pre.which. Thanks to this, at the beginning of the drilling, the transverse edge of the drill does not work, which reduces the displacement of the drill relative to the axis of rotation of the workpiece. To replace the drill, the flywheel of the rear grandmother is rotated until Pinol takes the extreme right position in the grandmother’s body, as a result of which the drill is pushed out of Pinoli screw. Then the right drill is installed in Pinol.

When drilling a hole, the depth of which is larger than its diameter, the drill (as well as when working on drilling machines), periodically removes from the processed hole and clean the grooves of the drill and the blank hole from the accumulated chips.

With manual control of the machine, it is difficult to ensure the constant speed of supply. Various devices are used to stabilize the feed speed. For mechanical supply of the drill, it is fixed in the hazeller. Drill 1 with a cylindrical shank (rice. four.29, a) using gaskets 2 and 3 are installed in the reeds so that the drill axis coincides with the centers line. Drill 1 with a conical shank (rice. four.29, b) is installed in the power 2, which is fixed in the hazeller.

After alignment of the coincidence of the drill axis with the centers line, the caliper with the drill manually is brought to the end of the workpiece and the test hole of the minimum depth is processed, and then the caliper is turned on. When drilling, before leaving the drill from the workpiece, the speed of mechanical supply is significantly reduced or turned off the feed and end manually processing.

When drilling holes with a diameter of 5 30 mm, the supply speed S0 = 0.1 0.3 mm/O for steel parts and S0 = 0.2 0.6 mm/O for cast.iron parts.

To obtain more accurate holes and to reduce the drill departure from the axis, the part is used, t. e. drilling a hole in several techniques. When drilling holes of large diameter (over 30 mm), they also resort to drilling to reduce axial effort. Cutting modes when drilling holes are the same as when drilling.

Senction

The zenker process holes, previously stamped, cast or drilled. Senction can be either preliminary (before deployment) or final processing. In addition to processing holes, zenkers are sometimes used to process the end surfaces of the workpieces.

To increase the accuracy of zenketing (especially when processing cast or stamped deep holes), it is recommended to pre.waste the hole to the diameter equal to the diameter of the zenker to a depth of about half the length of the working part of the zenker.

Zenkers, like drills, are installed on turning machines most often in the rear grandmother or revolving head.

Deployment

To obtain high accuracy holes on the turning machines and a given quality of the processed surface, deployment is used.

When working with finishing scanes on turning and turning-river machines, swinging mandrels are used, which compensate for the mismatch of the axis of the opening axis. In order to ensure high quality processing, drilling, zenketing (or bothering) and opening openings are carried out in one installation of the workpiece in the cartridge of the machine.

The selection of cutting modes during the processing of cylindrical holes with rod tools on turning machines is made according to the same directory tables as when processing on drilling machines. However, given the small rigidity of the fastening of rod tools on the machines of the turning group, the calculated values ​​of the modes in practice reduce.

Backing

If the diameter of the hole exceeds the diameter of standard drills or zenker, then such a hole is pulled. Bleaning is also used when processing holes with an uneven allowance or with indirect forming.

Depending on the purpose, turning steep incisors are distinguished for processing through and deep holes. In turning boring core incisors, the console part is made round, and the rod for fastening the incisors. square; Such incisors can be pulled out holes with a diameter of 30 65 mm. To increase vibration resistance, the cutting edge of the incisors is made along the axis of the rod.

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Drilling holes on the drilled machine

Drilling holes on the drilled machine

Drinking by marking. Before starting work on the drilling machine, a workplace is prepared. The tool should be installed in the spindle reliably and correctly, and the product. motionlessly fixed on the machine table. The beating of the drill, which usually occurs due to the incorrect installation, should not be allowed. The handles (levers) of the control of the machine’s speeds are transferred to the position corresponding to the selected cutting mode.

Starting to drill, you need to let the machine and bring the drill to the product smoothly, without blows: it will be set by the vertex exactly in a nipped recess. Drinking in two doses is performed: first, trial drilling is performed, and then the final. During the test drilling, a small recess of the size of the hole diameter of the opening is stirred during manual supply, then the drill is lifted, the chips are removed and the coincidence of the condensed recess is checked with the center of the marked circle. If there is such a coincidence, you can

Continue drilling and bring it to the end. If the over-war recess moves away from the center, then it is corrected, for which they cut off from the center in the direction of the recess where you need to shift the drill, two or three grooves. Having made one more overturning and making sure of its correctness, they bring drilling to the end.

When drilling, you must be very careful. It is necessary to occasionally remove the drill from the hole and free its grooves from the chips. Enter the drill back into the hole must be carefully, since it is easy to break. If the through opening is drilled, then at the time of exit from it the drill, you need to turn off the automatic supply and switch to manually, loosening the pressure on the drill.

With diameters of more than 30 mm, the holes are drilled in two doses: first with a drill of smaller diameter, and then the drill to the final size.

If the increased cleanliness of the surface of the hole is required, then drilling is carried out with a zenker or, for even more cleanliness, by scanning, sometimes in several transitions.

Consider several examples of drilling holes on drilling machines.

Drilling in a cast.iron bean of a through hole with a diameter of 20 mm. When performing this work, you should adhere to this sequence of actions: 1) get a blank and a drill; 2) prepare the workplace; 3) mark the bar, applying to its wide plane along the diagonals (from angle to angle) two risks, tap the center of the hole; outline the circuit with a control circle with a diameter of 20.5 mm and tap it; 4) put a machine vice on the table of the drilling machine and squeeze a bar in them, having previously cleaned the machine table, a vice and a block of shavings; 5) determine the most productive drilling mode; 6) configure the machine for the selected number of spindle revolutions and the selected feed; 7) install a drill in the spindle of the machine; 8) set the machine and check if the drill beats; 9) bring the drill to the center intended by Kerner and sprinkle a test recess, take the drill from the bar;10) check the coincidence of a superfluous recess with the center of the control circle; If you find the led to the side, eliminate it; 11) correcting the over.war recess, finally drill the hole; 12) Stop the machine, remove the bar, remove the drill out of the spindle and clean the machine from the chips.

Drilling through through holes with a diameter of 8 mm. Material. soft steel.

Work on each hole must be performed as follows: 1) squeeze the square in a vice or in a special device; 2) select the processing mode; 3) configure the machine for the selected spindle revolutions and the selected feed; 4) insert a drilling cartridge or transitional bushings into the spindle of the machine; 5) fix the drill and check it for beating; 6) bring the drill to the intended depression; 7) let the machine; 8) spill a trial depression and check it through the control circles; stop the machine and fix the depression, if any; 9) let the machine, again spill a small recess, check whether the departure is eliminated; 10) finally drill a hole; 11) rearrange the square in a vice for drilling a hole on its other shelf; 12) repeat the operations specified in the PP. 8-11; 13) stop the machine; 14) Remove the square with a vice, remove the drill, clean the machine.

Drilling in a roller of the non.bloody hole. The center of the hole is marked.

This work is performed as follows: 1) prepare a tool and devices; 2) install and fix the roller on the table of the machine; 3) determine the required number of spindle revolutions; 4) set up the machine for the established number of spindle revolutions and to a given depth of drilling; 5) fix the drill in the cartridge and check it for beating; 6) plunge a trial depression and check its coincidence with a control risk; 7) finally drill a hole; 8) Stop the machine, remove the drill and cartridge, remove the roller from the table, clean the machine of the shavings.

In Fig. 5 shows other cases of drilling holes.

The conductor is applied to that part of the surface of the product where you need to drill holes. The conductor is attached to the product with lateral screws or presses of various designs.

The box conductor has the shape of a box with a folding lid. The processed product is laid inside the box and attached with a lid. For drilling, the drill is introduced into the appropriate guide sleeve of the conductor and drilled in the product a hole. The use of the conductor reduces the time for the installation and alignment of products; In addition, the need for marking and trial overwhelming disappears.

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Drilling holes

Drilling holes

Drilling is the operation of obtaining round holes in the workpiece using special tools. drill. The holes can be through and undeveloped (deaf). In the first case, the workpiece is drilled for the entire thickness. In the second case. when performing deaf holes. the tool does not drill the material through.

You can manually drill holes with a drill. But much faster and easier to perform this operation on drill machines,

When drilling, distant, deaf and incomplete holes are distinguished. The high.quality hole is ensured by the correct choice of drilling techniques, the correct location of the drill relative to the processed surface and the combination of the drill axis with the center (axis) of the future hole.

Drinking by marking. Single holes are drilled by marking. Previously, axial risks, a circular risk that determines the contours of the future hole, and the control risk with a diameter, with a slightly large diameter of the future hole; Then the depression in the center of the hole is naked. The core hole of the circle is made deeper to give preliminary direction to the drill. Drilling is carried out in two doses: first, trial drilling is performed, and then the final. With test drilling with manual supply, a deepening of the size is obtained, about 1/4 of the future opening. After that, the chips are removed and the concentricity of the hole and circular risks are checked. If the contours of the recess (holes) are shifted relative to the risks of the future opening, then from the center of the hole in the direction where the center of the opening is necessary, 2 to 3 grooves cut through the cruiser. Then the hole is drilled again and, making sure of its correctness, is finally drilled.

The drilling of deaf holes to a given depth is carried out along the sleeve cut on the drill or measuring line mounted on the machine. To measure the drill to contact the part of the part, drilled to the depth of the drill cone and marked on the arrow (pointer) initial position on the ruler. Then, a given depth of drilling is added to this indicator and a figure is obtained, to which it is necessary to drill.

Some drilling machines on the measuring line have an emphasis, the lower line of which is installed on the figure, which needs to be drilled, and which is fixed with a screw.

Many drilling machines have automatic supply mechanisms with limits that determine the course of the drill to the required depth.

When drilling deaf holes, it is necessary to periodically remove the drill from the hole, clean the hole from the chips and measure the depth with the depthmer of the standard.

Drilling incomplete holes (semi-fracture-style). In cases where the hole is located at the edge, a plate of the same material is put to the processed part, clamped in a vice and drill a full hole, then the plate is discarded.

Drilling the through hole in the square is carried out by fixing it in a vice on a wooden lining. First perform complete drilling and checked in control circles. Having discovered the drill, they correct and then finally. Drill the hole. After that, a square is stopped to drill the next hole and t. D.

Drilling holes in planes located at an angle. So that the drill does not deviate to the sides and break, first prepare the site perpendicular to the axis of the drilled hole (milling or zenkut), the wooden liners or lining are inserted between the planes, then the hole is drilled in the usual way.

Drilling holes on the cylindrical surface. At first, the axis of drilling on the cylindrical surface is perpendicular to the platform, the center is torn, after which the hole is drilled in the usual way.

Drilling hollow details. When drilling hollow parts, the cavity is clogged with a wooden cork.

Drilling holes with ledges can be obtained in two ways: the first. first, the hole is drilled according to the smallest diameter, then it is drilled into one or two large diameters within the depths of each stage; Drills are changed according to the number of steps, consistently increasing their diameter; second. first drill the drill of the largest diameter, and then with drill smaller diameter according to the number of steps.

In the second and first ways, the drill does not take aside, it is centered well. To measure the depth of drilling is easier in the second method, since the depthmer then rests on the bottom of the hole.

Drilling exact holes. To obtain accurate holes, drilling is carried out in two passes. The first passage is made by a drill, the diameter of which is smaller by 1-3 mm diameter of the hole. This excludes the harmful effect of the jumper. After that, the hole is drilled in size. The drill should be well sharpened.

To obtain cleaner holes, drilling is carried out with low automatic supply during abundant cooling and continuous divert of chips.

Drilling holes of small diameters are made on machines of high ’accuracy with appropriate feeds or ultrasound and electro.iskous method.

Drilling holes of large diameters is carried out by drilling drilled holes. However, the holes obtained by casting, stamping and other similar methods are not recommended, since the drill is greatly led away due to the mismatch of the centers of the hole with the axis of the drill.

Ring drilling allows you to get holes with a diameter of 50 mm or more on machines, without resorting to drilling. Ring drilling is carried out using cutting heads having a hollow case with incisions mounted on it, located diametrically and evenly around the circle. The number of incisions. from 6 to 12 for heads with a diameter of 30-150 mm.

With ring drilling into parts, the grooves are cut with incisions, and the inner part (core) remaining in the hole in the form of rod 1 is broken out. The rod is usually broken not along the entire length of the hole at once, but in parts, as the head deepens. The depth of the ring back, necessary for breaking up, depends on the diameter of the hole.

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Drilling holes of medium diameter

Drilling holes of medium diameter

Preparation of the workpiece. Most often, medium.sized workpieces intended for deep drilling are made by forging or renting. The dimensions of the workpiece depend on many factors.

The following factors are specific for deep drilling: 1) the presence of heat treatment before or after deep drilling; 2) Deep drilling defects.

These factors must be taken into account when establishing the final external sizes of the workpiece and DC drilling diameter. Preliminary processing of the workpiece for the operation of deep drilling depends largely on the adopted method of fastening it when drilling and on the equipment used and equipment.

The nature of production during deep drilling is accepted by serial and large.scale. Drilling is carried out on machines designed for high.speed processing of the corresponding size of workpieces.

We will analyze the case when the material of the workpiece has good prosperity, and the hardness obtained after heat treatment allows you to successfully drill. At the same time, the workpiece can enter the operation of drilling with processed ends, centering neck and control belts. The full turn after heat treatment before drilling can not be done if the workpiece does not have a large beat and drill will be carried out with the simultaneous rotation of the tool and the processed part. It should be borne in mind that before heat treatment, the blanks are always processed on top, since drafts can cause the formation of hardening cracks.

To test the properties of the material after heat treatment on both ends of the workpiece, templates (discs) are provided. In some cases, templates are prescribed for repeated tests and therefore can significantly lengthen the workpiece. After the test, the excess material from the ends of the workpiece is cut off.

The external transverse dimensions of the workpiece depend on the final sizes of the part and allowances for subsequent operations. With deep drilling, the external dimensions of the workpiece can be increased due to special allowances of Academy of Sciences, providing for the compensation of the departure during the drilling. During bilateral drilling, the elimination of the departure (ledges, the axis fracture) must be carried out due to the allowance on the hole, t.e. by reducing the diameter of drilling.

As it was clarified above, the departments of the axis of the holes are the tendency to increase from the entrance end, where they are zero, to the output end of the workpiece. Therefore, it is very important to have an idea of ​​which side of the workpiece will be drilled, since the compensatory allowance should not be constant along the entire length of the processed part. It must be assigned in accordance with the size of permissible departments in certain sections of the workpiece.

If the workpiece is made of round rolling, then the compensatory allowance will affect the increase in the diameter of the rental, if from an echo, then it is possible to more rationally distribute the allowance on the workpiece. It is especially important to distribute the right allowance on a conical workpiece undergoing heat treatment. The conical workpiece should be drilled from the side of the larger diameter. In this case, the workpiece for drilling may have less weight, since the compensating allowance will mainly be located from the smaller diameter of the processed part.

Heat treatment must be done after deep drilling. Harvesties must have pamphlets for testing material after heat treatment. Therefore, they are longer than the blanks used in the drilling of parts after their heat treatment.

In this case, the technologists are faced with the question of whether the full external turn of the workpiece is carried out before drilling, since when receiving the departure (in order to remove the difference) it is still necessary to grind the workpiece from the hole. They practically act as follows: if the workpiece should rotate with a high angular velocity when drilling, then the outer turn is prescribed. The outer turn is also made when the workpiece is obtained by free forging in order to be able to identify external defects after forging. In this case, it is possible to remove shallow surface defects by “transmitting centers”, t.e. transverse displacement of the workpiece axis. Когда производство заготовок хорошо отлажено, то поверхностные дефекты, подлежащие удалению, встречаются сравнительно редко и потому заготовки, если они проходят глубокое сверление с вращением на невысоких угловых скоростях, можно полностью не обтачивать поверху. However, it must always be borne in mind that the external wiping, except for the possibility of detecting defects, reduces the beating and warping of the blanks when drilling. The beating should be checked on a machine with released fists at intermediate lunets.

Sometimes the gas station is made with a small cone so that at the time of cutting the cutting end of the drill into the material, the calibrating edges of the tool prepare the base for the support guides. Cutting the drill in this case will be smooth, Bea strikes.

Refueling holes should not be performed on a deep drilling machine, but on a lathe or central machines. Only heavy blanks are economically advisable to refuel on the machines^Globy drilling using gas stations.

If the process of deep drilling is well debugged and cutting the drills into the workpiece does not cause increased consumption of the tool, then the boring of holes for entry should not be done, since this work is quite laborious.

In Fig. 2 shows the sketches of the vault for drilling for various cases of work, and in rice. 3 is given a standard sketch of the workpiece (after heat treatment), designed for processing in a conical centering cartridge and in an oil receiver with conical seal.

In order to avoid a breakdown of the cutting edges of the tool when it exits the product, cut the output end of the workpiece.

When processing blanks with drills with an external shot of chips, the entrance end should not have a seal, since in this case the oil receiver is absent.

Machines and tools for drilling

The drilling of cylindrical holes, as well as the drilling of multifaceted (triangular, square, five- and hexagonal, oval) holes, are performed using special cutting tools-. Depending on the properties of the processed material, the desired sizes from the following materials are made, depending on the properties of the processed

• Carbon steels (U8, U9, U10, U12, etc.): drilling and drilling wood, plastics, soft metals.
• Low.alloy steels (x, B1.9XS, 9XVG, etc.): drilling and drilled wood, plastics, soft metals. Increased heat resistance (up to 250 ° C) and cutting rate compared to carbon.
• High.speed steel (P9, P18, P6M5, P9K5, etc.): drilling all structural materials in an irregular state. Heat resistance up to 650 ° C.
• Correx equipped with solid alloys, (VK3, VK8, T5K10, T15K6, etc.): drilling at elevated speeds of irregular steels and non.ferrous metals. Heat resistance up to 950 ° C. Can be solid, with attacking plates, or with interchangeable plates (fastened with screws)
• Borats equipped with a borazon: drilling hardened steels and white cast iron, glass, ceramics, non.ferrous metals.
• Drill, equipped with diamond: drilling solid materials, glass, ceramics, stones.

Drilling operations are carried out on the following machines:

• Vertical-warlord machines: drilling-main operation.
• Horizontal-drilling machines: drilling-main operation.
• Vertically-frame machines: drilling-auxiliary operation.
• Horizontal-based machines: drilling-auxiliary operation.
• Vertically milling machines: drilling-auxiliary operation.
• Horizontal milling machines: drilling-auxiliary operation.
• Universal milling machines: drilling-auxiliary operation.
• Turning machines: the drill is motionless, and the processed workpiece rotates.
• Turning Tools: Drilling-Auxiliary Operation. The drill is motionless.
• Aggregate machine.
• Turning-river machines: drilling-auxiliary operation. The drill can be motionless (static block) or rotate (drive block)
• Mechanical drills: drilling using a human muscular force.
• Electric drills: drilling with portable power tools (including shock-feed drilling).
• Peorators

The following measures are used to facilitate the cutting processes:

• Cooling: lubricants and chipping liquids and gases (water, emulsions, oleic acid, carbon dioxide, graphite, etc.)
• Ultrasound: Ultrasonic vibrations of the drill increase the performance and fraction of the chips.
• Heating: heated weaken the hardness of hard.to.process materials.
• Blow: with shock drilling (drilling) of stone, concrete.

Types of drilling holes and their characteristic:

A big problem when drilling is a strong heating of the drill and processed material due to friction. At the place of drilling, the temperature can reach several hundred degrees Celsius.

With strong heating, the material may begin to burn or melt. Many steel, with severe warm-up, lose their hardness, as a result, the cutting edges of the steel cords wear out faster, which is why friction only intensifies, which ultimately leads to a rapid failure of the system and a sharp decrease in the efficiency of drilling. Similarly, when using a carbide drill or drill with interchangeable plates, a hard alloy when overheating loses hardness, and plastic deformation of the cutting edge begins, which is an undesirable type of wear.

To combat warm-up, cooling is used using cooling emulsions or lubricants-coolering liquids (coolants). When drilling on the machine, it is often possible to organize fluid supply directly to the drilling site. The supply of coolant can also be carried out through the channels in the drill itself, if this allows the machine. Such channels are made in many whole drills and in all corps. The internal supply of coolants is necessary when drilling deep holes (with a depth of 10 or more diameters). At the same time, it is important not so much cooling as the removal of shavings. The pressure of the coolant ishing the chips from the cutting zone, which avoids its package or re.cutting. If, in this case, it is impossible to organize the supply of coolant, then you have to drill with periodic conclusions of the drill to remove chips. This method is extremely involuntary.

When drilling with a manual tool, drilling is interrupted from time to time and dipped a drill into a container with a liquid.

Processing process

Starting the cutting process, the first thing to do is to turn on the machine. The drill supply to the workpiece should be carried out smoothly. Blows are not allowed, since this negatively affects the condition of the drill (its cutting edges quickly lose their severity, and sometimes painted).

The drill supply is usually carried out manually. For Pinoli’s advance, the corresponding flywheel should be rotated. If the depth of the hole exceeds its two diameters, then the hole is initially overwhelmed by a short drill of a similar diameter, which is rigidly fixed in the rear woman. Due to this, the subsequent drilling of the hole with a tool of normal length will be made much easier and more precisely, because the drill will be better directed.

Features of the drilling of metals

The process of cutting metal blanks differs from the processing of products made from other materials. The features of such drilling include the receipt of deep holes. This process is directly related to the thickness of the processed metal and with the hardness of the alloy. Such operations negatively affect the work of the tool:

• the intensity of friction increases;
• The temperature increases in the processing zone;
• the amount of chips formed, which contacts the drill, increases.

In this case, the tool can be avoided, provided that the coolant is used (coolant). There are situations in which you cannot do without it. These include the cutting of aluminum and steel, accompanied by the formation of elevated temperatures, which in one way or another can cause the failure of the drill. Along with this, iron.cutting of cast iron, bronze, brass can be carried out without cooling, of course, if all precautions are observed. Be that as it may, the coolant allows you to increase the speed of rotation of the tool somewhere about one and a half times.

The service life of the drill can be extended if the openings drilling operations are performed at high speeds and at low supplies. To improve the quality of processing, the tool should be periodically tightened (the length of the two cutting edges should be equal). The need for sharpening is determined by the roughness of the formed surface, that is, with unsatisfactory purity of processing, you need to immediately sharpen the drill.