Drilling holes on the cylindrical surface. Techniques of mating through through and deaf holes
Drilling, zenketing, deployment
Drilling is one of the frequently performed operations during assembly and locksmithing work. To do this, use manual, pneumatic and electric drills, rattles, drilling heads with a drive from a flexible shaft, as well as drilling machines, if the conditions allow for their use. The main manual non.elevated tools for drilling are a columnar, a spiral drill, a hand drill and a rattle.
Kolovorot (Fig. 1, a) are used to drill small holes in a tree, fiber and soft metals, as well as for unscrewing and screwing screws and screws, nuts, and valve grinding.
It consists of a curved steel rod, at the upper end of which there is a freely rotating stubborn hat, and the cartridge is strengthened at the lower end. A freely rotating wooden handle is planted on the knee. When working with a collar, pressed on the emphasis with the left hand or chest (create an effort to serve drill), and the columgot rotates by the handle with their right hand by the hand.
Hand drill with conical transmission. This drill (rice. 1, b) use to drill holes with a diameter up to 8 mm. It consists of a steel rod 2, on which the handles 3 and 7 and the hat 1 are motionless. During the rotation of the handle 7, the movement is transmitted by a large conical gears 8, freely sitting on the axis, and from it to a small conical gear 4, motionlessly sitting on the sleeve 5, and the cartridge 6, which was fixed by the drill. When working, the drill is held with the left hand by the handle 3, the right handle is rotated by the right. When drilling holes of large diameter, if necessary, you can press the head on the hat 1. A gear drill can make up to 300 rpm.
Electric drilling machines. These electric drills are powered by constant or alternating current of normal frequency and alternating current of increased frequency (high.frequency drills). Electric machines produce three types: heavy (for holes with a diameter of 20–32 mm), medium (for holes with a diameter of 10-20 mm) and light (for holes with a diameter of up to 8–10 mm). Heavy drilling machines usually have two side handles or two handles and emphasis on the housing; medium. one closed handle on the back of the case (rice. 1, c), lungs. pistol.shaped handle (rice. 1, d).
Pneumatic drills. In the factory, pneumatic drilling machines (pneumatic drills) are used in the factory. Pneumatic drills in their capabilities and form (ergonomics) of executions in many respects coincide with manual electric machines (rice. 1, d).
Repair work, depending on labor capacity, can be performed on drilling machines (mainly in the manufacture of parts during repair). For this purpose, table-drilling and single-pindle vertical plants are used.
Drilling and drilling
The most common method of obtaining holes in continuous material is drilling a hand drill or using a desktop drilling machine. Cutting movement during drilling. rotational, supply movement. progressive.
Before drilling, the position of its center on the workpiece is determined. At the intersection of the lines drawn by the devil, Kern is pierced by the position of the center of the hole.
For attaching drills with cylindrical shanks (up to 16 mm in diameter), drilling cam cartridges are used by fists 6, which can be reduced and diluted, moving in the grooves of housing 2. At the ends of the cams, slats are made, which are engaged in a thread with a thread on the inner surface of the ring 4. From key 5, through conical gear, a sleeve 3 with ring 4 is rotated, along the thread of which fists 6 move up or down and at the same time in the radial direction. To install the cartridge on the conical shank 1 spindle of the drill or machine cartridges are equipped with a conical hole.
Lecture course on EC.02 Fundamentals of metalworking technology. Lecture 12 “Drilling, zenching, zenketing and deployment of holes
Drilling. a type of machining of materials with cutting, in which, with the help of a special rotating cutting tool (drill), holes of various diameters and depth, or multifaceted holes of various sections and depths are obtained.
Drilling. the necessary operation to obtain holes in various materials during their processing, the purpose of which is:
Making holes for cutting threads, zenketing, deploying or pulling.
The manufacture of holes (technological) for placing electric cables, anchor bolts, mounting elements, etc.
Departure (segment) of blanks from sheets of material.
Laying of an explosive charge when obtaining natural stone.
Machines and tools for drilling holes
Drilling cylindrical holes, as well as drilling 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.
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).
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.
Drilling multifaceted and oval holes.
League of cylindrical holes (diameter increase).
Central: drilling a small amount of material for the positioning of another drill (for example, with deep drilling) or to fix the details with the rear center.
Deep drilling: drilling to a depth of 5 or more diameters of the hole. Often requires special technical solutions.
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 lubricant-cooping liquids (Co.chef). 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 a manual tool, drilling from time to time interrupt and dipped the drill into a container with a liquid (the lower its heat capacity and more heat-proceeding, the better the cooling of the drill).
Zenkovka is perennial cutting tool for processing openings in details in order to obtain conical or cylindrical recesses, supporting planes around the holes or removing the chamfers of the center holes.
Used for processing drilled holes under the heads of bolts, screws and rivets.
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Clean is a perennial tool, which is a body of rotation, on the surface of which cutting teeth, a structure, geometry and the purpose of cutting teeth of cutters are similar to the cutting part of the turning cutters.
When processing with cutters, black, semi.final, finish, and with end cutting and thin milling are distinguished. Black milling is used for processing castings and generations, the allowance for preliminary processing of which exceeds 3 mm. Black milling of flat surfaces provides accuracy in rectilony 0.15–0.3 mm per 1 m of length and roughness Ra = 50–12.5 μm. Receiving milling is used to reduce the errors of geometric shapes and spatial deviations.
With output milling, roughness Ra = 25–6.3 μm and a deviation from flatness 0.1–0.2 mm per 1 m of length are ensured. Financial milling is used as final processing after black milling or as an intermediate processing method before subsequent finishing processing. Glee of finished milling allows you to obtain roughness Ra = 10–1.25 μm and deviation from flatness 0.04–0.08 mm per 1 m of length.
Thin milling is carried out as a method of final processing of flat surfaces with end cutters. Allowance for thin milling is taken in the range of 0.2-0.5 mm. Subtle milling provides roughness Ra = 2.5–0.4 μm and deviation from flatness 0.02–0.04 mm per 1 m of length.
Single milling is used in cases where the errors of the original workpiece determine a slight release for processing (less than 2 mm). With this processing, roughness Ra = 12.5–2.5 μm and a deviation from flatness 0.06–0.1 mm per 1 m of length are ensured. Applying speed modes for milling, reduce the height of micronerings by 1.5–2.5 times.
End mills are used to process large open flat surfaces; a set of cylindrical, rubberized and angular milling fixtures, fixed on one mandrel. for the processing of shaped surfaces; shaped mills. for processing complex surfaces; finger and disk mills. for processing grooves and nests. Cylindrical milling against the supply is characterized by large forces. With end milling, the supply force is insignificant, but the lateral force shifting the workpiece is great. With multi-tool fertilizers carried out on longitudinal milling and aggregate machines, they reach high labor productivity.
The drill is a cutting tool for processing holes in continuous material or for drilling holes with two simultaneously occurring movements: rotation of the drill or workpiece around the axis and the progressive movement of the supply along the axis.
The drill consists of the working part of L1, the neck L3, the shank L4 and the paw L5. Small diameter drills are made mainly with a cylindrical shank, and more with conical.
The working part distinguishes the cutting L2 and the guide L1 parts. The guide part directs the drill along the axis and allows you to carry out its multiple launch. Narrow guide ribbons 5 are made along the entire length, which serve to send the tool into the hole.
The cutting elements of the drill are the main cutting edges 1, the transverse cutting edge 2, as well as the front 3 and the rear 4 surfaces. The front angle γ facilitates the cutting of the cutting edges into the processed material, the rear angle α helps to reduce friction forces when cutting.
When choosing a drill, it is necessary to give preference to modern carbular types of drills, which has high resistance and performance compared to drilling steels. In table. 1 shows recommendations for the choice of tools for various sizes of holes and requirements for the quality of the processed surface.
With drilling spiral drills, holes are made in diameters up to 80 mm in a continuous workpiece. Drilling provides 1-5th class of accuracy and roughness of the surface Ra = 25–2.5 μm; It is used as preliminary processing of exact holes. Processing of rough holes for bolts and rivets is limited to one drill. With a diameter of a hole of more than 30 mm, the holes of a small diameter (one third of the given) are drilled, and then it carries it out. The position of the axis of the hole provides drilling according to the marking, the conductor and on the coordinating links. Drilling according to the conductor reduces the axis displacement and increases the diameter (breakdown) of the hole.
Zenching and Tseking
When performing zenching, a special tool is used. Zenkovka. In this case, only the upper part of the hole is subjected to processing. Apply such a technological operation in cases where in this part of the hole it is necessary to form a recess for the heads of fasteners or simply remove the chamfer from it.
How the zenching and dimension differs
When performing zenching, they also adhere to certain rules.
- Perform such an operation only after the hole in the parts is completely drilled.
- Drilling and zenching are performed in one installation of parts on the machine.
- Small spindle revolutions (no more than 100 revolutions per minute) are installed for zenching and use manual submission of the tool.
- In cases where the zenching is carried out by a cylindrical tool, the diameter of the tsapfa of which is larger than the diameter of the processed hole, the work is performed in the following sequence: first, a hole is drilled, the diameter of which is equal to the diameter of the troops, the zenching is performed, then the main hole is drilled into the specified size.
The purpose of such a type of processing as cecum is stripping the surfaces of the part that will be in contact with nuts, bolts heads, washers and locking rings. This operation is also performed on machines and with the help of the grip, for the installation of which mandrels are used on the equipment.
The deployment procedure is subjected to holes that were previously obtained in details by drilling. The element processed using such a technological operation may have an accuracy, the degree of which reaches the sixth qualifying, as well as low roughness. to RA 0.63. Scanes are divided into draft and finishing, they can also be manual or machine.
Cylindrical manual scanes 24N8 0150
The recommendations that should be followed when performing this type of processing are the following.
Processing of cylindrical holes and centering
Holes are divided into through and deaf. The former are processed to the passage, the latter. to a certain depth. On the shape of surfaces, cylindrical holes are smooth, stepped, consisting of sections of different diameters, and with grooves. Holes, the length of which exceeds 5-6 diameters, is called deep. To create a certain nature of the connection with the shaft, the holes are performed with a certain accuracy in size, shape, mutual arrangement of surfaces and purity of processing according to the technical requirements of the working drawing. On turning machines, holes are treated with drilling, drilling, boring, zenkering and deployment. Each of these methods is characterized by a certain accuracy of processing and, therefore, is applied depending on the requirements for the accuracy of the opening. § 2.
Appointment and applied tools. With drilling, holes are performed in continuous blanks with an accuracy of the 5th class and cleanliness to the 3rd class. Drilling increase the diameter of the pre.drilled hole and increase its accuracy and cleanliness by about one class. As cutting tools for the methods of processing holes considered, spiral drills are mainly used. In some cases, drill drilling is used. 2. Spiral drill. The design of the drill. A spiral drill is a double.toothed cutting tool consisting of three main parts: the working part, neck and shank, the working part, in turn, is divided into the cutting and guide parts. On the working part of the drill (rice. 66, a) Two shake grooves are made, the screw form of which facilitates the output of the chips
From the hole. To reduce the friction on the wall of the opening of the back of the teeth, they are left along each of them, narrow guide ribbons are left, for the same purpose, a small reverse cone was made along the length of the guide part (0.03-0.12 mm for every 100 mm length). To increase the strength of the drill, the depth of the chips in the direction of the shank gradually decreases. The cutting part has two cutting edges, which are formed by the intersection of the front and rear surfaces of the teeth. In the center, the cutting edges are connected by a jumper (transverse edge). The front surface of the teeth is part of the screw surface of the chip groove, and the back is the surface of the cone formed when sharpening the drill. The shank is designed to fasten the drill. It is performed by conical, in the shape of a cone.morse, or cylindrical. Drills with a diameter of 6 to 80 mm have conical shanks ending with a paw that serves to knock out a drill from a transition sleeve. Drills with a cylindrical shank are produced with a diameter of 0.25 to 20 mm. At the end of the cylindrical shank, a leash is sometimes made that protects the drill from turning during operation. Depending on the purpose, the standards provide for the release of spiral drills with different lengths of the working part: with a conical shank. normal, elongated and long; with a cylindrical shank. short, medium and long. Drills are made of high.speed steels P9 and P18, and are also equipped with plate solid alloy VK8. The latter are mainly used to drill cast iron and labor- irrevocable steels. To save speed steels, the tails of drills with a diameter of more than b mm are made from structural steels that are welded to the working part of the drill. four. Preparation for drilling. Important conditions for high.quality processing of the hole by the drill are: a strong fixing of the workpiece without a noticeable beating of the perpendicularity of its end to the axis of rotation, the absence of irregularities and convexity on the end, the coincidence of the spindle axis and the creation of the initial direction of the drill. The workpiece installed in the lathe, if necessary, verify and firmly fixed. The end of her before drill is purely cut. To create the initial direction of the supervision, especially with the larger length, in the center of the end, it is recommended to make a small cone recess. It is performed with a stubborn cutter (rice. 75, a) or short hard drill (rice. 75, b). The angle of the center deepening is made 20-30 ° smaller than the corner at the top of the working drill. Under this condition, the jumper of the drill at the initial moment will not participate in the cutting (rice. 75, c), which much eliminates the danger of displacements of the drill to the side. To increase the stiffness of long drills, it is recommended to support them at the beginning of drilling with the back side of the cutter, fixed in the reeds so that the upper plane of the rod is 5-6 mm above the axis of the drill. Before drilling a deep hole, the workpiece must first be overwhelmed by a short drill of the same diameter to a depth approximately equal to the diameter of the hole. In this case, the main drill, having received the initial direction, will not be able to deviate to the side. The alignment of the centers of the machine is checked in earlier in the described methods (see. ch. II, § 1, p. 5). The rear grandmother is fixed on the bed in this position so that Pinoli departure when drilling is the smallest. No less important is the correct installation of the drill. Its shank and pinoli hole should be wiped dry. Fabols on the shank are removed with a file. The drill is installed in Pinol with a sharp axial impetus. 5. Drilling techniques. The usually used method of drilling on a lathe is shown in the rice. 76. After the preparatory work, the rotation of the spindle is included and manually, turning the flywheel of the rear grandmother, smoothly bring the drill to the end of the rotating workpiece. At the same time, a blow should be avoided, otherwise the drill may break. At first, the drill is moved forward slowly, when it crashes into the metal to a depth, a slightly larger length of the cutting part, the supply can be increased. The supply of the drill should be performed smoothly, without jerks. Particular caution should be shown when the drill exits the through hole. An uneven load of the cutting edges arises in this place and they can crumble. Therefore, at the output, the feed must be sharply reduced.
Before turning off the rotation of the spindle, the drill must be removed from the hole, otherwise, due to the elastic deformation of the metal, it can be jammed in it. When drilling, the chips are difficult to leave the holes. To do this, the drill must be periodically removed from the hole and cleaned with a metal brush. The depth of the dull hole is kept along the pinoli millimeter scale, according to the limb of the flying grandmother, and in their absence, by chalk risk, which is applied to the drill. To increase the resistance of the drill, it is recommended to cool it. When drilling steels, an emulsion is used, non.ferrous metals are drilled with cooling or dry, cast iron is treated without cooling, since its shallow shavings, mixing with the liquid, strongly pollutes the machine. The coolant stream is directed to the drill near the end of the processed part and included simultaneously with the start of cutting. Manual supply of the drill, especially when processing holes of large diameter, is too difficult. Therefore, in a number of models of modern lathes, there is a device for mechanical movement of the rear grandmother. The device is a castle consisting of two squares, respectively attached to the transverse salacs of the caliper and the plate of the rear grandmother. Before turning on the mechanical supply, the posterior grandmother is uncovered from the bed. 6. Leveling holes. Drilling holes of large diameter is very difficult due. Therefore, holes with a diameter of more than 30 mm are performed
In the process of drilling on a lathe, the workpiece is rotated (the main movement) fixed in the spindle of the machine, the cutting tool performs the progressive movement.
Initially, in a certain sequence, preparation is carried out, the purpose of which is to check the accuracy of the installation of the part, taking into account the beating relative to the axis, which is allowed in the amount of not more than the value of the allowance for processing the outer surface. It is desirable that the details of the details are minimal. this will reduce the possibility of vibration of the workpiece. It is important that the alignment of the centers of the machine is observed. they should be on the same line. The end of the workpiece should be perpendicular to the rotation axis, in case of violation of this condition, it must be cut, and in its center to make a recess (bag). this will help direct the tool in the right direction. In this way, you can center the workpiece with a shortened central drill with an angle of sharpening 90 °.
During turning processing, drills with a diameter of not more than 16 mm are used, the installation site of which is pinol of the rear grandmother of the machine. Slowly bringing the fixed tool to the workpiece, turn on the rotation of the spindle, overthrow the centering hole in the workpiece to verify the correctness of its axis. This is done after the spindle stop.
The processing of the holes of the large depth is performed in several visits, periodically taking out the tool and the formed chips. You can replace the tool by turning the flywheel of the rear grandmother until it stops.
Considering that the drills can be equipped with shanks of various cones, not coinciding with the conical pinoli, you can use bushings with the corresponding cones of holes and tailings. Small diameter drills having a cylindrical shank are attached into fist cartridges installed in the rear grandmother.
The considered method of drilling involves manual process management. It is much more convenient to use automatic or mechanical supply of drill. This is possible if the cylindrical shank 1 is fixed in special devices (realmers) installed on the caliper. Dense fit and the ability to regulate the drill is provided at the expense of gaskets 2 and 3. If the shank 1 of the tool has a conical shape, a special holder 2 is suitable, for the fastening of which a reschedurator is used. The main requirement in this case is the exact alignment of the drill and the processed part along the line of the machine centers, this ensures the quality of the execution of the drilling operation.
A. with a cylindrical shank: 1. drill; 2 and 3. gaskets;
b. with a conical shank: 1. drill; 2. holding
Having checked the correct installation of the tool, they begin to drill a shallow trial hole, manually bringing the caliper to the workpiece with the tool installed in it. After that, the mechanical feed of the caliper is turned on. Before the completion of the drilling, the feed rate is gradually reduced to zero and turned off, then the feed is carried out manually. The drilling rate is depending on many factors, including on the properties of the processed material, the quality of the tool, the technical level of the machine. So, for products made of cast iron, it is smaller (from 0.2 to 0.6 mm/about.). Steel blanks are drilled at speeds from 0.1 to 0.3 mm/about. Such parameters are selected in cases where the diameter of the drill is from 5 to 30 mm.
The drilling method is used to increase the accuracy of processing, as well as to reduce the axial cutting efforts. this applies to drilling holes over 30 mm. This method involves drilling a hole in several stages, gradually increasing its size, in the same modes as during drilling.
Cylindrical holes processing on a lathe
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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.
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.
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.
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.
The use of manual tools
Manual zenketing and deployment is carried out according to a similar scheme, which involves the following technological operations.
- Based on the parameters of the initial and final opening, choose a tool for performing black and finally deployment.
- The workpiece is securely fixed in a vice if its dimensions allow this to perform. If it differs in significant size, then it is not fixed before deploying.
- A tool for black deployment is inserted into the hole in the part, which was previously obtained during the casting of the workpiece or its drilling.
- On the tail of the instrument, which has a square cross.sectional form, a cake is put on.
- The outer surface of the flaw and the inner surface of the hole are lubricated with a special liquid.
- A scan, using a cart, begin to rotate in the direction of the location of its cutting edges. During the rotation of the tool, which should be performed slowly, without sudden movements, lubricants are constantly applied to its working surface. Rotating the scan, it is necessary to carefully submit it in the direction of processing, which ends after the layer of metal left for the allowance is completely removed from the inner surface of the hole.
- After the rough deployment is completed, the tool is neatly removed, while it is not allowed to perform its reverse rotation.
- In a hole treated with a black scan, placed a finish tool, on the square shank of which is also planted.
- The scan for finishing processing is rotated clockwise, while such a rotation is carried out very smoothly and accurately, constantly using lubricants. The value of the tool is to obtain a hole with the required parameters of the roughness of the inner surface, there should be a minimum.
- After the final processing is completed, the scan is removed from the opening and its geometric parameters are checked using a smooth maximum caliber-pronoun.
Conic.shaped holes processing
Using the technological operation of deployment, conical holes can also be processed, which had previously had a cylindrical shape or were drilled with ledges, for which drilling of different diameters were used. The execution of the preliminary opening with ledges in such cases allows you to leave a lower allowance for further deployment.
The deployment of conical holes is practically no different from the technological scheme of processing holes of the cylindrical shape. To perform such a technological operation, as a rule, the rough, intermediate and final tools are used.
Conic holes processing sequence
A special conical caliber is used to check the results of such deployment. In this case, the check is performed both on the plane of contacts of the surfaces of the formed hole and caliber, and in the depth of the passage of the control tool.
Caliber cone of the center holes (KKSO)
Performing such a check is carried out according to the following scheme.
- Several pencil lines (usually 3-4) are applied to the side surface of the conical caliber along its axis, placing them at approximately the same distance from each other.
- Using a small pressure, the caliber is inserted into the conical hole in the part.
- Then the caliber is turned by 1/3 turnover.
- Having removed the caliber, they control the condition of the pencil lines applied to its surface.
The fact that the deployment operation is performed qualitatively is evidenced by the uniform erasing of pencil lines on all parts of the side surface of the caliber.
Types of holes and methods of drilling
In the theory of metalworking, all holes are divided according to the following signs:
According to their intended purpose, they are divided: for fastening two or more elements, subsequent cutting of threads, inserts of individual structural elements.
On the second basis, the following types are considered:
A special place is occupied by holes that are prepared to cut the internal thread. In this case, the drilling and drilling of holes is carried out taking into account the future diameter of the screwed element with external thread. For each of the holes, choose their own ways to drill.
Since drilling is the process of mechanical cutting of the metal, therefore, to obtain the desired result, you should choose the necessary methods of processing. For the production of through holes in the details, it is necessary to think over the system of their fastening, which will not allow you to damage the surface located behind the part. It is most advisable to use a vice or clamp.
For the manufacture of blind or half.holes, an accurate stop of the drill should be provided, which will provide the necessary size. Drilling large holes involves the use of special equipment. If it is necessary to obtain holes of different diameters, you should choose the required set of Sovers or use machines with numerical control. They will automatically make a drill to replace the tool with a given diameter.
Equipment and devices for drilling
For each stages, a tool for drilling holes has been developed. At the preparatory stage, the following tools are used to make accurate marking of the place of position of the future hole. To do this, use: core, special template or conductor. Kern is a well.sharpened rod made of strong instrumental steel. With its help, a recess on the surface of the workpiece is applied at the point where it is planned to drill. Once in this recess, the drill does not slip over the surface and accurate drilling is carried out.
To increase productivity at enterprises with mass production, special templates are made. They allow marking the places of future holes in the same type of blanks. Special templates are used for drilled on cylindrical surfaces. They are made from a steel strip bent at right angles. A small hole is drilled on one of the surfaces, which will further allow the core to apply on the cylindrical surface.
To obtain increased accuracy of the marking, compliance with the vertical position of the drill and compliance with a given distance, between the holes the tool called the conductor is used. In addition, it is used when drilling thin.walled products for which a strong mechanical effect is not possible (for example, a hammer blow to the core).
In addition to these products, tools and devices are used to drill a drill during its rigid fixation. To this end, I use:
The first two devices are made for a specific electrode design design. The conductor allows you to accurately direct the drill to the place of the future hole. It is successfully used for size not exceeding 20 millimeters. Therefore, in the manufacture of holes of large diameter using the conductor, preliminary drilling is performed.
All these problems are easily solved with the use of drill or lathes. Drilling machines are divided into three categories:
They are classified according to the following signs:
- table design;
- automation level;
- the number of existing spindles;
- degree of accuracy;
- the presence of additional opportunities.
The first category of machine tools allows you to solve almost the entire range of problems for the production of holes. The permissible distance is a serious restriction to which the cartridge with a fixed drill can move. This circumstance does not allow drilling to a greater depth. In this case, specialized machines are used. To increase labor productivity and increase the number of manufactured parts of the same parts, special units are constructed. They are able to perform a list of necessary operations with high accuracy and speed.
By design, such machines are produced with one or more spindles. The design of the table is diversity: ordinary, floating, lifting and others. The level of automation is determined by the way of performing drilling operations. The simplest machines are manual and mechanical. Automatic and machine tools are more advanced.
In addition to drilling machines, various lathes are used to solve these problems.
To obtain holes on a lathe in the spindle of the front grandmother, a drill is fixed, and a workpiece is fixed in the rear woman.
On the lathe, you can perform the entire list of operations related to the receipt of holes: directly drilling, drilling with subsequent deployment or zenki.
Processing of cylindrical holes
In many details of the machines, holes are an important element. The parts are connected through the holes with screws or bolts. Holes are used to install bearings, lubrication or coolant. The working cavities of engines, compressors are also holes and t. D.
The holes are divided into through (processed to the passage) and deaf (processed to a certain depth). In shape, they are smooth, stepped, with grooves. Holes, the length of which exceeds 5 diameters, is called deep.
To create a certain nature of the connection with the shaft, the holes are performed with a certain accuracy in size, shape, location and roughness according to the technical requirements of the working drawing.
Cylindrical holes are processed on lathes. The holes are treated with drilling, drilling, boring, zenkering, deployment. Each of these methods is characterized by a certain accuracy of processing and, therefore, is applied depending on the requirements for this hole.
- Drilling holes
- Hoosen centers
- Pulling holes
- Determination of holes
- Senction of holes
Various requirements are presented to the holes for accuracy, straightness of the axis, the correctness of the geometric shape, and the roughness of the surface.
The cylindrical holes are smooth, stepped, with a groove (a hide). Holes can also be through or deaf (rice. 70, a. d).
The diameters of the holes are controlled by a caliper with a reference accuracy of up to 0.1 mm or 0.25. When measuring the STC-P with an accuracy of 0.05 mm, the thickness of the sponges is taken into account. Holes with a diameter of 120 mm and above are measured with a micrometric gut meter with an accuracy of 0.01 mm. Deep holes of large diameter (for example, cylinder cavity) are controlled by an indicator gut meter, which is pre.tuned to the size along the reference ring or by the micrometer. The indicator shows the deviation from the established size with an accuracy of 0.01 mm.
In large-scale and mass production, the holes are controlled by maximum calibrations-stumps. If the passing cork PR without effort passes into the hole, and the impassable does not pass, then the size of the hole is within the tolerance. To control holes with a diameter of 80 mm or more, cut and plate plugs are used. Such traffic jams are easier, in addition, they can identify the ovality of the hole, making the control of the hole in two mutually perpendicular directions. Before controlling the caliber-test, the cavity of the hole is cleaned of chips and wiped. Wipe the hole and control the size only after the spindle rotation is completely stopped. Caliber-tests are stored in an upright position or laid on a foam panel.
Senction is used for preliminary and final processing of holes after casting, stamping, black drilling, for leveling the ends of the blanks. Before the use of zenker, holes in the details obtained by the methods of casting, forging, stamping are subject to boring with a cutter to the size of Zenker. The depth of processing can reach 50% of the length of the working part of Zenker. On a turning machine, Zenker can be installed in Pinoli of the rear grandmother, in a special device on the caliper of the machine, in the revolving head.
Processing of internal cylindrical surfaces (holes)
Making and processing holes are different processes.
The manufacture of holes is associated with their implementation in continuous metal, for example, under oil channels in the cylinder block, crankshaft and distribution shafts, for fasteners, etc.P.
Holes are processed, already made, for example, by casting, in details such as a cylinder block, etc. P.
The holes in the details of the machines are cylindrical, stepy, conical, style, open and deaf.
Get the same accuracy in terms of tolerance in the manufacture of holes is much more difficult than when processing outdoor surfaces, therefore, as a rule, the qualities for holes are set in slightly larger than for shafts of the same diameters.
Holes processing are carried out with removal and without removing chips.
So, the processing of holes with the removal of the chips is carried out by a blade and abrasive tool.
The manufacture of holes without removing the chips is carried out by piercing them in stamps, stitching, rolled, calibration.
Drilling holes in continuous metal.
Equipment: drilling, radial-drilling and desktop-drilling machines.
Set: here we note the installation of both parts and tools.
The part is established taking into account the rules of basing in the device with appropriate reliable its fastening;
tool. drill. installed in the conical hole of the machine spindle so that the paw of the drill enters the groove of the spindle.
Tool: a spiral drill that has two cutting edges, a jumper and two basing ribbons; Drill for deep drilling and others.
The main defects that occur during the drilling of holes. the breakdown of the holes and the deposition of the axis of the holes. are associated with the improper sharpening of the drill.
For drilling deep holes, for example, in the distribution Val ICE, special drills are used, called cannon.
A shallow hole is drilled with a hard tool, which is then pulled under the diameter of the drill for deep drilling.
The drill has three longitudinally located guide elements (usually from a solid alloy) and an internal hole through which a lubricant-cooled liquid (cooled) is supplied to washing the chips from the cutting zone.
The front part of the drill fixed on the caliper is introduced into the wasteful hole, and the hole is drilled to any length.
For processing holes after drilling, casting or stitched on press equipment of holes, zenketing is carried out.
This operation prepares holes for subsequent deployment, bothering or stretching, ensuring the elimination of the axis of the axis.
Equipment and basing: as when drilling.
Tool: Zenker (multi.toothed hard tool) with whole or insertion carbide knives.
To eliminate the departure of the axis of the hole in parts with a diameter of more than 25 mm, it is advisable to use the upper and lower guides.
Senction is used, for example, to create a flat support.
The deployment process is indispensable in the manufacture of prize holes in two connected parts, for example, holes in the connecting an an a chronic force passing through the connecting rod and its lid.
Equipment: when manually deployed, no equipment is required, except for the device for fastening the connected parts; During machine deployment, any machine is suitable, for example, a current.
Installation: since the scan during processing moves along the axis of the available hole, it does not eliminate the opening of the axis of the hole.
Therefore, with manual deployment, the question of basing the tool does not arise.
During machine deployment, the deployment should have a hinged mount.
Tool: Scan compared to Zenker has a larger number of teeth.
Small in height of the teeth are designed to remove a slight allowance.
In some cases when it is required to remove a relatively large allowance or increase the accuracy of the hole, a set of scanes is used, which have in the upper part of the mark in the form of ring cuts.
Processing holes with grinding
All parts with holes for which planting is provided for a mating part, as a rule, are treated with grinding.
Since grinding circles of small diameters are less resistant than with round grinding, the grinding rate is much lower, and the hardness of these circles is higher.
Installation: in a magnetic or canovic cartridge, as well as in a cartridge with a hydraulic clamp.
Tool: abrasive circles of small diameter from ceramic binding and fine.grained abrasive.
At the same time, for example, for an abrasive circle with a diameter of 10 mm at a spindle speed of 10,000 min-1, a speed of 5 m/s is reached.
The grinding of holes is carried out in the following ways:
The part is fixed in a magnetic or canovic cartridge and rotates. The grinding circle is rotated using a belt transmission from an electric or pneumatic drive (drill);
The part (case) is motionless, and the grinding circle is set in motion from the spindle. In this way, you can polish the reverse cone;
Through and deaf holes with a diameter of 10 to 200 mm are polished on non-center-grinding machines. The grinding circle 4 performs the reciprocating movement (supply of SPROD) and rotates with the frequency of NSh.to. The frequency of rotation of the part and the auxiliary circle, respectively, n we. and nv.to.