Deployment presentation. Reamer Reamer is a cutting tool that is needed for finishing holes after drilling, countersinking or boring. deployment

Deployment

Reaming is the process of making a cylindrical hole
the most accurate dimensions and high-grade surface roughness.
Figure 1 - Types of reaming holes

Deployment is designed to remove a small allowance - 0.15 ... 0.5
mm per side for rough reaming and 0.05 ... 0.25 mm for
finishing. At the same time, the accuracy of the holes reaches the 2nd ... 3rd class, and
surface roughness - 7 ... 9th class.
Figure 2 - Hole Machining Scheme

Deployment Accuracy
depends not only on
allowance and accuracy
sweep, but also from
axis matches
axis reamers
hole to be
deployment.
Axis Mismatch
reamers and holes
leads to breaking
holes. Therefore, when
deployment
holes apply
self-centering
sweep and oscillating
mandrels, which
compensate
axes mismatch
holes and reamers.
Figure 3 - Oscillating mandrel
Figure 4 - Self-centering reamer

For the processing of precise conical holes, a kit is used
from conical countersinks and reamers. For diameters over 25 mm
it is recommended to drill sequentially with several drills
different diameters to form a stepped hole,
approaching in shape to a conical countersink and a reamer
Figure 5 - Tapered reamers

Mechanical reaming is carried out on turning and
drilling machines. Cutting speed, feed and speed
when deployed is shown in Table 1.
Table 1 - Cutting speed (m/min)
feed (mm/min) and speed
(rpm) when deployed

1. The essence of the processes of drilling, countersinking, countersinking, countersinking and reaming.

2. Tools and fixtures used in the processing of holes. Drills, wear and forms of sharpening drills. Basic rules for sharpening drills. Countersinks, countersinks, countersinks, reamers. Devices for installing tools. Devices for installation and fastening of blanks. Machine vise. Conductors for fixing workpieces. Devices for limiting the depth of drilling.

3. Hole processing equipment. Manual equipment. Basic rules for drilling with a hand drill. Basic rules for drilling with a manual electric drill. Stationary drilling equipment. Basic rules for working on a drilling machine. Drilling safety rules.

4. Cutting conditions and allowances when machining holes. Typical defects in the processing of holes, their causes and methods of prevention

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Discipline "Technology of plumbing work" College ISTiD (branch) NCFU in Pyatigorsk Goncharov Oleg Yuryevich College teacher

Topic 9. HOLEWORKING 1. The essence of the processes of drilling, reaming, countersinking, countersinking and reaming. 2. Tools and fixtures used in the processing of holes. Drills, wear and forms of sharpening drills. Basic rules for sharpening drills. Countersinks, countersinks, countersinks, reamers. Devices for installing tools. Devices for installation and fastening of blanks. Machine vise. Conductors for fixing workpieces. Devices for limiting the depth of drilling. 3. Hole processing equipment. Manual equipment. Basic rules for drilling with a hand drill. Basic rules for drilling with a manual electric drill. Stationary drilling equipment. Basic rules for working on a drilling machine. Drilling safety rules. 4. Cutting conditions and allowances when machining holes. Typical defects in the processing of holes, their causes and methods of prevention. Study questions:

1. The essence of the processes of drilling, countersinking, countersinking, countersinking and reaming. When processing holes, there are three main types of operations: drilling, reaming, reaming and their varieties: reaming, countersinking, countersinking. Drilling is an operation to form through and blind holes in a solid material, performed using a cutting tool - a drill. There are manual drilling - manual pneumatic and electric drilling devices (drills) and drilling on drilling machines. One of the varieties of drilling is reaming - an increase in the diameter of a previously drilled hole.

Continuation of question 1 Countersinking is an operation associated with the processing of pre-drilled, stamped, cast or other holes obtained by other methods in order to give them a more regular geometric shape (eliminate deviations from roundness and other defects), as well as to achieve a higher, compared to drilling, accuracy (up to 8th grade) and lower roughness (up to Ra 1.25). The types of countersinking include countersinking and countersinking. Basic rules for countersinking holes: -drilling and countersinking of holes must be done from one installation of the part (workpiece) on the machine, i.e. changing only the processing tool; - when countersinking untreated holes in body parts Special attention should pay attention to the reliability of the installation and the strength of the fastening of the part;

Continuation of question 1 - it is necessary to strictly observe the value of the reaming allowance, guided by the corresponding table; - countersinking should be carried out in the same modes as drilling; - it is necessary to observe the same labor protection rules as when drilling. Countersinking is the processing at the top of drilled holes of cylindrical or conical recesses for the heads of screws and rivets, as well as chamfers. The operation is performed using a special tool - a countersink. Basic rules for countersinking holes: must be observed correct sequence countersinking holes: first drill a hole, and then countersink it; - drilling of a hole and its countersinking should be carried out from one installation of the workpiece (part), changing only the tool;

Continuation of question 1 - countersinking should be performed with manual countersinking and a low spindle speed (no more than 100 rpm) using an emulsion, the depth of countersinking should be checked with a caliper or machine ruler; - when countersinking holes with a cylindrical countersink, when the diameter of the trunnion is greater than the diameter of the hole, you must first drill a hole according to the diameter of the trunnion, and then countersink the hole. The final operation is drilling a hole to a given size. Forging is an operation for cleaning end surfaces when processing bosses for washers, nuts, lock rings. The operation is performed with the help of a special tool - counterboring, which is installed on special mandrels.

Continuation of question 1 Reaming is the operation of machining previously drilled holes with a high degree accuracy (up to the 6th grade) and low roughness (up to Ra 0.63). Basic rules for reaming holes: - it is necessary to strictly observe the size of the reaming allowance, guided by the corresponding table; -manual deployment should be performed in two steps: first roughing, and then finishing; in the process of reaming a hole in a steel billet, it is necessary to generously lubricate the surface to be treated with an emulsion or mineral oil, cast iron billets should be reamed dry; - manual reaming should be carried out only clockwise to avoid scuffing of the hole walls with chips; - in the process of processing, the reamer should be periodically cleaned of chips;

Continuation of question 1 - the accuracy of processing reamed holes should be checked with gauges: cylindrical - through and through; conical - according to the maximum risks on the caliber. The expanded conical hole is allowed to be checked with a “pencil” control pin; -drilling and reaming holes on a drilling machine with a machine reamer must be done from one installation of the workpiece, changing only the processing tool.

2. Tools and fixtures used in the processing of holes Fig. 2.1. Spiral drill: a - drill design; b - design of the working part; c - design of the cutting part; 2φ - angle at the top; ώ is the angle of inclination of the helical groove; α - main rear angle; γ- front angle; ψ - the angle of inclination of the transverse cutting edge Drills are used when processing holes in solid material. By design, there are spiral, centering, feather, gun drills with external or internal chip removal and annular (trepanning heads) drills.

Continuation of question 2 Fig. 2.2. Centering drills: a - without safety cone; b - with a safety cone Centering drills (Fig. 2.2) are designed to make center holes, they are made from high-speed tool steel grades P9 and P12. By design, center drills are distinguished without a safety cone (Fig. 3.27, o) and with a safety cone (Fig. 3.27, b).

Continuation of question 2 Fig. 2.3. Spade drills: a - with a cylindrical shank; b - with a conical shank; c - with coolant supply. Spade drills (Fig. 2.3) have a flat working part and straight grooves for chip removal.

Continuation of question 2 Fig. 2.4. Gun drills: a - with a spikelet made of high-speed steel; b - reinforced with hard alloy plates; c - with internal coolant outlet Gun drills (Fig. 2.4) are used for drilling deep and super-deep holes.

Continuation of question 2 Fig. 2.5. Ring drills: a - double-cut: 1 - body; 2,3 - replaceable cutters; 4,5,6 - guide plates; b - three-blade; c - multi-cutter: 1 - incisors; 2 - body; L is the length of the working part. Ring drills (Fig. 2.5) are used to reduce cutting forces and power consumption of equipment, increase productivity in processing solid holes with a diameter of more than 50 mm, as well as reduce chip volume and subsequent use of the central rod formed along the axis of the hole being machined.

Continuation of question 2 Fig. 2.6. Wear of drills: a - on the back surface; b, c, d - on a ribbon; d - carbide drills; h 1 - wear along the axis; h 3 - wear of the backed part; h 2 - tape wear; L - linear wear of the corner; φ 1 - angular wear of the drill Wear and shape of sharpening drills For spiral drills, wear occurs mainly along the back surface of the corner at the intersection of the intake cone with the drill ribbons (Fig. 2.6, a)

Continuation of question 2 Fig. 2.7. Sharpening form: a - single; b - single with a jumper point; c - single with a point of jumper and ribbon; g - double with a jumper point; d - double with a point of jumper and ribbon; 2φ - angle at the top; l 0 - width of additional sharpening; 2φ 0 - angle of additional sharpening

Continuation 2 questions Basic rules for sharpening drills 1. It is necessary to adjust the position of the toolholder of the grinding machine so that there is a gap of at least 2 mm between it and the periphery of the grinding wheel. It is necessary to check the presence and serviceability of the screen of the grinding machine. 2. The following requirements for sharpening drills must be observed: - sharpening should be done by the periphery of the grinding wheel; - in the left hand should be the cutting part of the drill with the cutting edges up, in the right hand - the shank of the drill; - the left hand should rest on the machine tool. 3. When sharpening, you should periodically check the correct sharpening of the drill according to a special template (Fig. 2.8):

Continuation of question 2 Fig. 2.8. Template for controlling the sharpening of drills: a - control of the angle at the top; b - control of the angle of inclination of the ribbon; c - control of the angle of inclination of the transverse cutting edge; ψ - the angle of inclination of the transverse cutting edge; the length of the cutting edges must be the same; the sharpening angle at the top of the drill must match the template; the angles between the edges and the side surface of the drill must be the same; the sharpening angles of the edges must be equal and match the template.

Continuation of question 2 4. It is necessary to fill the cutting edges of the drill on the bar. 5. It is necessary to make a trial drilling of the hole with a sharpened drill: - chips from both cutting edges must be of the same thickness (visually check); - the diameter of the drilled hole must exactly match the diameter of the drill; - the hole should not move more than 0.2 mm (the check is carried out according to the control risks).

Question 2 continued 6. The following safety requirements must be observed: -sharpening of small diameter drills must be done on a fine-grained wheel; - it is forbidden to sharpen drills on a grinding machine without a handpiece and with or without a faulty protective cover; it is strictly forbidden to sharpen drills “on weight”, i.e. without using a handpiece; - it is imperative, especially when sharpening large-diameter drills, to lower the protective screen;

Continuation of question 2 Fig. 2.9. Zenker: a - design; b - geometrical parameters of the working part: ώ - angle of inclination of the ribbon; φ - main angle in plan; φ 0 - the angle of the intake cone; γ - front angle; a - rear corner; t - depth of cut Countersinks, countersinks, countersinks, reamers Countersinks (Fig. 2.9, a) are designed for processing holes in workpieces obtained by casting, stamping or pre-drilling.

Continuation of question 2 Fig. 2.10. Top drill: 1 - cutting plates; 2 - body; 3 - thrust By design, countersinks are mounted and solid and can have a different direction of the helix angle (right, left, straight).

Continuation of question 2 Fig. 2.13. Wear of countersinks: h l - wear length; h c - wear width; h y - corner wear Fig. 2.12. Countersink with internal coolant supply

Continuation of question 2 Fig. 2.14. Countersinks and countersinks: a, b - cylindrical; c, d - conical; e, f - mounted counterbores; 2φ - angle at the top Countersinks and counterbores (Fig. 2.14) for processing supporting surfaces for mounting screws, unlike countersinks, have cutting teeth at the end and guide pins that provide the desired direction of countersinks and counterbores during processing.

Continuation of question 2 Fig. 2.15 Development: a - design; b - design of the intake part; c - geometrical parameters of the cutting and calibrating parts; d - cutting scheme; φ - intake cone angle; 2φ - angle at the top; α - back angle; γ - front angle; D - reamer diameter Reamers (Fig. 2.15) are made solid and mounted with a conical and cylindrical shank, equipped with plug-in knives, soldered hard alloy plates or made of high-speed steel. Reamers, unlike drills and countersinks, have more cutting edges

Continuation of question 2 Fig. 2.17. Reamers equipped with hard alloy plates: a, b - solid; c, d - mounted Fig. 2.16. Tapered reamers

Continuation of question 2 Fig. 2.18. Three-jaw drill chuck: a - general form; b - design: 1 - cams; 2 - nut; 3 - clip; 4 - key Devices for installing tools

Continuation of question 2 Fig. 2.18. Double-jaw drill chuck Fig. 2.19. Collet drilling chuck: 1- shank; 2 - cylindrical part; 3 - split sleeve; 4 - ring

Continuation of question 2 Fig. 2.20. Reducer bushings Fig. 2.21. Quick-change drilling chuck: a - chuck design: 1 - conical hole; 2 - groove of the ring; 3 - ring; 4 - balls; 5 - replaceable sleeve; 6 - body; b - replaceable sleeve

Continuation of question 2 Fig. 2.22. Self-aligning drill chuck: 1 - housing; 2 - spring; 3 - leash; 4 - bearing; 5 - retaining ring; 6 - mandrel; 7-coupling Fig. 2.23. Rocking mandrel for reamers: 1 - shank; 2 - thrust bearing; 3 - ball; 4 - body; 5 - pin; 6 - swinging part

Continuation of question 2 Fig. 2.24. Wedges for tool removal: a- flat; b - radius; c - eccentric key

Continuation of question 2 Fig. 2.25. Tacks (a), prisms (b) and squares (c): 1 - blank; 2 - screw Devices for installation and fastening of workpieces

Continuation of question 2 Fig. 2.26. Squares: a - hard; b - adjustable

Continuation of question 2 Fig. 2.27. Machine screw vice: 1 - screw; 2 - movable sponge; 3 - fixed sponge; 4 - base; 5 - handle Machine vice

Continuation of question 2 Fig. 2.28. High-speed machine vice: 1 - body; 2 - turning part; 3 - fixed sponge; 4 - set screw; 5 - movable sponge; 6 - handle; 7 - eccentric shaft; 8 - double cam; 9 - base

Continuation of question 2 Fig. 2.29. Pneumatic machine vice: 1 - pneumatic cylinder; 2 - movable sponge; 3 - multi-arm lever; 4 - piston rod; 5 - check valve; 6 - handle

Continuation of question 2 Fig. 2.30. Conductor bushings: a - permanent; b - quick-change Jigs for fixing workpieces To secure workpieces and ensure the correct position of the tool relative to the axis of the hole being machined, special devices are used - conductors.

Continuation of question 2 Fig. 2.31. Mounting supports: a - pins: I, II and HI - respectively flat, spherical and knurled heads; b - plates: I and II - respectively flat and notched; L and B are the length and width of the plate, respectively; c - adjustable screw support

Continuation of question 2 Fig. 2.32. Laid on conductor: 1.2 - fixing fingers; 3 - conductor bushings; 4 - conductor plate; 5 - basic surface of the workpiece; b - machined holes

Continuation of question 2 Fig. 2.33. Overturned conductor: 1 - folding bar; 2 - bushing; 3, 8 - conductor bushings; 4 - movable prism; 5 - bolt; 6- cracker; 7 - blank

Continuation of question 2 Fig. 2.34. Rotary conductor: 1 - dividing disk; 2 - key; 3, 5 - nuts; 4 - blank; b - split washer; 7 - spindle; 8 - spring; 9 - latch

Continuation of question 2 Fig. 2.35. A set of universal prefabricated devices: a - basic details; b - guide elements; in - adjusting elements; d - fixture assembly Devices for limiting the depth of drilling

Fig. 3 Hole making equipment. 3.1. Hand drill: 1 - cartridge; 2,3 - gear; 4 - movable handle; 5 - emphasis-bib; b - fixed handle Manual equipment There are the following types of equipment for processing holes: manual; manual mechanized; stationary.

Question 3 continued Basic rules for drilling with a hand drill 1. It is necessary to firmly fix the workpiece in a vice, and the drill in the drill chuck. 2. It is necessary to firmly fix the handle on the drill shaft. 3. When rearranging the handle on different shafts of the drill gearbox, it is necessary to rationally adjust the rotational speed of the drill depending on its diameter. 4. When drilling, the drill should not be skewed, in addition, it is necessary to monitor the perpendicularity of the drill to the drilling plane. 5. When drilling, the drill handle should be rotated evenly, smoothly, without jerks. Pressing on the stop of the drill should be done evenly and constantly throughout the entire drilling process. 6. At the end of drilling, when the drill exits the material, loosen the pressure on the drill stop and reduce the drill speed.

Continuation of question 3 Fig. 3.3. Ratchet: 1 - drill; 2 - clamping chuck; 3 - ratchet (ratchet wheel); 4 - nut; 5 - center; 6 - clamp; 7 - bracket; 8 - handle; 9 - pawl To facilitate the drilling process and increase its productivity, a lever is used to press the drill stop (Fig. 3.2). Rice. 3.2. Lever application

Continuation of question 3 Fig. 3.4. Electric drills: a - light type; b - medium type; in - heavy type

Continuation of question 3 Fig. 3.5. Devices for holding heavy type electric drills: a - on a spring; b - on cables

Continuation of question 3 Fig. 3.6. Screw device with stop Fig. 3.7. Electric drilling machine with an angle nozzle: a - machine with a 90 ° head; b - machine with a 45 ° head; 1 - drill; 2 - three-jaw chuck; 3 - head; 4 - fastening nut; 5 - tube; b - body; 7- off button; 8 - roller

Continuation of question 3 Fig. 3.8. Pneumatic drills: a - light type; b - heavy type

Continued 3 questions Basic rules for drilling with a hand-held electric drill 1. Before starting work, it is necessary to check the serviceability of the electric wire and plug. 2. Before starting drilling, it is necessary to check the operation of the drill for Idling, and also make sure that there is no runout of the drill. If necessary, the drill should either be replaced or reattached. 3. When drilling holes in workpieces made of high strength steels, a cutting fluid should be used. 4. Stop the rotation of the electric drill only after removing the drill from the hole.

Continuation of question 3 Fig. 3.9. Manual drilling pneumatic machine D-2: 1 - cartridge; 2 - nozzle; 3 - rotor; 4 - button; 5 - nipple; 6 - handle Fig. 3.10. Manual pneumatic drilling machine USM-25: 1 - drill; 2 - three-jaw chuck; 3 - head; 4 - body; 5 - start button; 6-nut

Continuation of question 3 Fig. 3.11. Desktop drilling machine: a - general view; b - drive unit; 1 - table; 2,8,10 - handles; 3 - three-jaw chuck; 4 - spindle; 5 - clamp; 6 - limbus; 7 - casing; 9 - electric motor; 11 - head; 1 2-column; 13,15,24 - ball bearings; 14 - glass; 16, 22-pulleys; 1 7-adapter sleeve; 18 - clutch; 19 - flange; 20 - screw; 21 - thrust washer; 23 - gear; 25 - vernier

Continuation of question 3 Fig. 3.12. Vertical drilling machine MOD.2H118: 1 - foundation slab; 2 - table; 3 - spindle; 4 - feed box; 5 - gearbox; 6 - electric motor; 7- drilling head; 8 - handle; 9 - column

Continuation of question 3 Fig. 3.13. Radial drilling machine: a - general purpose; b - with a movable column; c - on a special trolley; g - portable

Continuation of question 3 Fig. 3.14. Radial drilling machine mod. 2A554: 1-base plate; 2 - base. 3 - sleeve; 4-lift mechanism; 5- spindle head; b - control panel; 7 - table

Continuation 3 questions Basic rules for working on a drilling machine 1. Drilling should be done only with a properly sharpened drill, if necessary, regrind or refill the drill. Sharpening control must be carried out using a template (Fig. 3.76, a) or a special goniometer (Fig. 3.76, b). Rice. 3.15. Template for controlling the sharpening of drills: a - template; b - angle control at the top

Question 3 continued 2. It is necessary to firmly fix the drill with a cylindrical shank in the chuck: the end of the drill should rest against the bottom of the chuck, and then fix it by inserting the key into all sockets of the chuck one by one. 3. The taper shank drill (drill chuck) must be firmly fixed in the machine spindle. 4. To ensure a strong and safe fastening of the workpiece, it is necessary: ​​- to fix large body blanks on the machine table; - prismatic blanks of medium size (length 100 ... 120 mm, width 50; .. 60 mm, height 30 ... 40 mm) should be fixed in a machine vice; - fix small blanks (length 70 ... 80 mm, thickness 1 ... 5 mm) in hand vise; - Cylindrical workpieces to be installed and fixed on prisms.

Question 3 continued 5. A deep (1.0 ... 1.5 mm) core hole should be made on the part at the drilling site. 6. Drilling holes of large diameters (over 10 mm) must be performed in two steps: first with a drill with a diameter of 5 ... 6 mm, and then with a drill of the required diameter. 7. It is necessary to correctly determine the cutting speed depending on the material being processed and rationally adjust the machine to the spindle speed. 8. The correct sequence of drilling should be observed when manually feeding the drill: - align the top of the drill with the core recess on the workpiece; - turn on the machine; - drill a hole to the full depth; - when the drill exits the hole, release the pressure.

Question 3 continued 9. It is necessary to correctly determine the amount of automatic feed and adjust the machine to this amount. 10. It is necessary to observe the correct sequence of processing through holes with automatic feeding of the drill: - combine the top of the drill with the core recess on the part; - turn on the machine; - drill a hole to a depth of 3 ... 5 mm using manual feed; -without removing the drill from the hole, turn on automatic feed; -Drill the hole to full depth. 11. When drilling holes on the conductor, the following rules must be observed:

Question 3 continued - the workpiece must be firmly fixed in the jig or the jig on the workpiece; - the diameter of the drill must exactly match the diameter of the hole in the bushing of the jig. 12. When drilling steel parts, coolant should be used; 13. Cast iron parts must be drilled without cooling the drill. 14. After finishing work, you should check the compliance of the drilled holes (diameter, depth) and center-to-center distances with the requirements of the drawing.

Question 3 continued Safety rules when drilling: - it is forbidden to drill loose or weakly fixed workpiece; - you should put your hair under a headdress; - it is necessary to carefully fasten the cuffs on the sleeves; - it is forbidden to strongly press the drill feed lever, especially when drilling holes of small diameter; - it is forbidden to lean close to the drilling site in order to avoid chips getting into the eyes; - It is forbidden to blow off the chips.

4. Cutting conditions and allowances when machining holes Cutting conditions when drilling The main elements of cutting when drilling are the speed and depth of cut, feed, chip thickness and width (Fig. 3.16). Rice. 3.16. Cutting elements when drilling: S - feed; D - hole diameter; t - depth of cut; b – cut width; a - slice thickness Allowance is a layer of material to be removed during processing. The size of this layer depends on the requirements for the treated surface and the type of treatment. When drilling, the machining allowance is half the diameter of the drill.

Question 4 continued Cutting speed V - the path traveled by the point on the cutting edge of the drill, the furthest from the axis of its rotation in min. V = π d / p / 1000 (where V is the cutting speed, m / min; d is the drill diameter, mm; p is the spindle speed, rpm; π is a constant number equal to 3.14; the number 1000 for translation drill diameter in meters). Feed S is measured in millimeters per drill revolution (mm/rev). Depth of cut t is measured in millimeters and represents the distance from the machined surface to the axis of the drill. The thickness of the cut (chip) a is measured in the direction perpendicular to the cutting edge of the drill, and is equal to half the amount of movement of the drill relative to the axis of the hole being processed in one of its revolutions. The cut width b is measured along the cutting edge and is equal to its length.

Continuation 4 questions Typical defects in the processing of holes, their causes and methods of prevention. Defect Cause Prevention Drilling Hole misalignment The machine table is not perpendicular to the spindle. Chip penetration under the bottom surface of the workpiece. Incorrect (non-parallel) pads. Incorrect positioning of the workpiece on the machine table. Defective and inaccurate fixtures Check the correct position of the table. When installing, clean the table and workpiece from dirt and chips. Fix or replace gaskets. Check the installation and fastening of the workpiece. Replace the tool with a good one. Hole offset Runout of the drill in the spindle. Pull the drill to the side. Incorrect installation or weak fastening of the workpiece on the table (the workpiece has moved during drilling). Incorrect marking when drilling according to the marking Eliminate drill runout. Check the correctness of the points of the drill, align it for runout and sharpen it correctly. Check the installation and fastening of the workpiece, securely fix it on the machine table. Correctly mark the workpiece

Continued Question 4 Excessive hole diameter Machine spindle play. Incorrect drill sharpening angles or different lengths of cutting edges. Displacement of the transverse cutting edge In all of the above cases, it is necessary to regrind the drill correctly. The surface of the hole walls is rough. Dull and wrong for a sharpened drill. Poor workpiece or drill installation. Insufficient cooling or incorrect composition of the coolant Sharpen the drill bit correctly. Check that the drill and the workpiece are properly fastened. Increase drill cooling or change coolant Increase hole depth Incorrect depth stop Set the stop exactly to the desired depth of cut

Continued 4 questions Defect Cause Prevention Countersinking Rough machining, scuffing on the machined surface of the hole Chips get under the teeth of the tool Holes in steel blanks are machined with coolant Lubricant misalignment of the hole countersinking in the unmachined body part Incorrect setting the workpiece on the machine table When installing the workpiece on the machine table, pay special attention to the location of the axis of the hole to be machined relative to the axis of the tool. Fix the workpiece firmly on the machine table

Continued Question 4 The diameter of the countersinking part of the hole is greater than the diameter of the countersinking The diameter of the countersinking pin is less than the diameter of the hole Carefully ensure that the diameter of the countersinking pin exactly matches the diameter of the hole being machined The depth of countersinking of the part of the hole is less than or greater than the specified Work is not finished. Inattention during measurements, inattention during work Continue work and be more attentive to measuring the depth of countersinking. In the second case, the marriage is irreparable.

Continued Question 4 Reaming Rough machining, scratches on machined surface Machining was carried out without cutting fluid. Incorrect reaming techniques were used Both for rough and finish reaming of holes in steel parts, it is obligatory to use a cutting fluid. Reaming should be performed only by turning the knob clockwise The diameter of the reamed hole is less than the specified one, the plug of the gauge does not enter the hole The work was carried out with a heavily worn reamer Change the tool

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Text content of presentation slides: DRILLING, COUNTERBOARDING, REAMING AND REAMING Drilling is the formation of holes in a solid material by removing chips using a drill that performs rotational and translational motionReaming is the increase in the size of a hole in a solid material. Classification of drills Spiral spade centering Spiral drill device On the guide part there are two helical grooves, along which the chips come off. Ribbons along the grooves serve to reduce the friction of the drill against the walls of the hole. The sharpening angle of the drill depends on the material being processed - for steel it is 116 -118o - for brass, bronze 130-140o - for aluminum -130o - for plastic -50-60 o The quality of sharpening is checked with templates with cutouts. Drills come with helical flutes, which provide better chip flow, and straight flutes, which are used for drilling holes in brittle materials. Drills with coolant holes are designed for drilling deep holes. The coolant cools the cutting edges and facilitates chip removal. Drills are made of high-speed steel R9, R18, R6M5 and carbide inserts from alloys VK6, VK, T15K6 Centering drills are used to obtain center holes. Spade drills are used for drilling non-critical holes with hand drills and ratchets COUNTERSinking is the processing of the upper part of the hole in order to obtain chamfers or cylindrical recesses (under the countersink head of a screw or rivet) Countersinking is performed using tools - countersinks stamping or drilling - to give them a strict cylindrical shape, improve the accuracy and quality of the surface. It is performed with special tools - countersinks. Countersinking can be a finishing process or preparatory to reaming Countersink countersink REAMING is the finishing of holes. Provides higher accuracy and low roughness. The reamer is a multi-blade tool. The considered operations of processing holes are performed mainly on drilling or turning machines or manually, using knobs or manual or mechanized drills, drilling machines. When working on drilling machines, machine vices and prisms are used to secure workpieces. Cutting tools with cylindrical shanks are fixed in the chuck of the machine (with square ones for hand wrenches and drills) Cutting modes 1. Cutting speed is selected depending on the properties of the material being processed, diameter and other factors. cutting tool relative to the workpiece along its axis in one revolution3. Depth of cut is the distance between the machined and machined surface, measured perpendicular to the axis of the workpiece. With an increase in cutting speed, the processing speeds up, but when working at too high speeds, the drill quickly becomes dull. Increasing the feed beyond the allowable one leads to breakage of the drill. The task is to select the optimal modes. DRILLING TECHNIQUES Drilling by marking (single holes). First, axial risks are applied to the part, a circular risk of the hole contour, a hole is punched in the center to give direction to the drill. Drilled in two stages: trial and final drilling Drilling of blind holes is carried out along the stop or measuring ruler fixed on the machine. Drilling incomplete holes (at the edge of the part). To do this, a plate of the same material is attached to the workpiece and a full hole is drilled, then the plate is removed. Drilling hollow parts. To do this, the cavity is clogged with a wooden plug. Drilling in sheet metal They are obtained with spade drills (others will tear the material) Drilling deep holes (more than 5 diameters of the part). Here, the hole is first drilled with a short drill, then normal to full depth, periodically withdrawing the drill and removing chips. The length of the drill must match the depth of the drill. SAFETY RULES FOR DRILLING The work gown must be buttoned up, on the head - takes. It is necessary to correctly install and securely fasten the workpieces, do not hold them with your hands. Before turning on the machine, make sure it is in good condition Do not grasp the rotating tool and the spindle Do not press hard on the feed lever, especially with small diameter drills a wooden lining on the machine table under the spindle when changing a chuck or drill Use a special key to change the drill Do not work with a dull tool Do not pass or receive any objects through the working table Do not work with gloves Do not lean on the machine Wear safety glasses Do not remove chips with your hands Do not lean close to the drill to look results of the work CONTROL QUESTIONS 1. What is drilling? 2. What is the design of twist drills? 3. List the types of drills 4. What is countersinking and what tool is performed? 5. What is countersinking? cutting modes should be taken into account when drilling? 8. Why are helical grooves made on drills?

Reamer Reamer is a cutting tool that is needed for finishing holes after drilling, countersinking or boring. Reaming achieves accuracy up to 6-9 quality and surface roughness up to Ra = 0.32…1.25 µm. Reamers are classified: according to the shape of the holes being machined: - cylindrical - conical according to the method of application: - machine - hand-held according to the shape of the chip grooves: - spur - helical according to the type of tool material: - carbide - made of high-speed steel

Countersink Countersink is a multi-blade cutting tool for processing cylindrical and conical holes in parts in order to increase their diameter, improve surface quality and accuracy. Types of countersinks: By type of processing: - cylindrical countersinks - conical countersinks - face countersinks By type of attachment: - tail - mounted By type of construction: - one-piece - prefabricated

Countersink design - The main angle φ for countersinks made of high-speed steel is 45-60; carbide; - Rake angle for countersinks made of high-speed steel γ=8-15 when processing steel parts; γ=6-8 when processing cast iron; γ=25-30 when processing non-ferrous metals and their alloys. A carbide countersink has γ=5 degrees when machining cast iron and γ=0-5 degrees when machining steel. -Rear angle α=8-10 degrees; angle of inclination of the helical groove ω= For better guidance of the tool, the countersink teeth have a cylindrical chamfer with a width of 1.2-2.8 mm

Application Countersinking is used for "finishing drilled," cast or forged holes with an accuracy of Grade 4 and 45, as well as for their pre-treatment for deployment.

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Machining is a technological process that is carried out on metal-cutting machines by introducing a cutting tool into the body of the workpiece, followed by the release of chips and the formation of a new surface.

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Metal cutting machine - a machine designed for dimensional processing of metal blanks by removing material. History of metal cutting machines. It is believed that the history of machine tools begins with the invention of the caliper. lathe. Around 1751, the French engineer and inventor Jacques de Vaucanson was the first to use a special device for fixing the cutter - thus eliminating the direct influence of the human hand on the shaping of the surface.

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Classification of metal-cutting machine tools Machine tools are classified according to many criteria. According to the accuracy class, metal-cutting machines are classified into five classes:

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Classification of metal-cutting machines by weight:

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Classification of metal-cutting machines according to the degree of automation:

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Classification of machine tools according to the degree of specialization:

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The metal-cutting machine has a drive (mechanical, hydraulic, pneumatic), with the help of which the movement is transmitted to the working bodies: spindle, caliper, etc. The complex of these movements is called shaping movements. Shaping movements - movements carried out by the tool and the workpiece, necessary for the implementation of the cutting process, in the manufacture of parts with the removal of the allowance, on metal-cutting machines.

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Types of machining Turning (turning, boring, trimming, cutting). Drilling (drilling, countersinking, countersinking, deployment, countersinking). Planing Slotting Milling Broaching Stitching Grinding Finishing methods (polishing, finishing, lapping, honing, superfinishing, shaving).

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Turning is the machining of external and internal cylindrical and conical surfaces, facing, cutting off, chamfering, shaping, grooving, cutting internal and external threads on lathes. Turning is one of the most ancient technical operations, which was automated using a primitive lathe. Varieties of turning 1. Turning - processing of external surfaces.2. Boring - processing of internal surfaces.3. Undercutting - processing of flat end surfaces.4. Cutting - cutting the workpiece into parts or separating the finished part from the workpiece.

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Purpose of drilling Drilling is a necessary operation to obtain holes in various materials during their processing, the purpose of which is: making holes for threading, countersinking, reaming or boring. Making holes (technological) for placing electric cables, anchor bolts, fasteners, etc. Separation (cutting) of blanks from sheets of material. Weakening of destructible structures. Charge bookmark explosive in the extraction of natural stone. Drilling is a type of mechanical processing of materials by cutting, in which holes of various diameters and depths, or multifaceted holes of various sections and depths, are obtained using a special rotating cutting tool (drill).

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Types of drilling Drilling cylindrical holes. Drilling multifaceted and oval holes. Reaming of cylindrical holes (diameter increase). Cooling with the help of cooling or lubricating liquids is used to combat heating.

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Countersinking is a type of machining by cutting, in which holes or chamfers of various diameters and depths are obtained with the help of special tools (drills), after preliminary drilling. Reaming is a semi-finishing machining. Purpose of countersinking Cleaning and smoothing the surface of holes: before threading or reaming; Hole calibration: for bolts, studs and other fasteners; Chamfering: for rounding sharp corners and removing burrs, also for accommodating bolt and screw heads.

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Reaming is a type of mechanical processing of materials by cutting, in which, with the help of a special rotating tool (reamers), holes of various diameters and depths are processed with high accuracy and a low degree of surface roughness, after preliminary drilling and countersinking. Purpose of reaming Obtaining accurate calibrated holes: landing for bearings, holes for plungers, shafts, etc. Obtaining a small surface roughness of the holes: to reduce friction, for tight contact or fit.

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Purpose of chiseling Processing of external surfaces, including. Processing of internal cylindrical, polyhedral and unequal surfaces (through and "blind" holes and cavities) Cutting gears of both external and internal gearing. It should be noted that cutting a wheel with internal gearing is possible only by chiselling. Slotting is a type of mechanical processing of metals by cutting, in which the tool (saw), making reciprocating movements, cuts off the material being processed. Slotting is very close to another type of material processing by cutting, planing.

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Milling is a type of cutting with a tool called a milling cutter. The cutter is a cutting tool with several teeth, each of which is a simple cutter. Milling and milling were invented in Germany and Austria in the 17th and 18th century, since milling required a strong machine bed with precise bearings, and Leonardo da Vinci invented angular contact bearings. Official Inventor milling machine is the Englishman Whitney who received a patent for such a machine in 1818.

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Classification * Depending on the location of the machine spindle and the convenience of fixing the workpiece

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Broaching is a type of metal cutting that uses a specific tool, the so-called broaches. Broaching is preceded by preparatory metalworking operations, such as drilling, countersinking, reaming, punching (i.e., a fairly accurately machined surface of the workpiece is required to carry out broaching). Application of broaching Machining holes of rifled firearms (barrels of pistols, machine guns, cannons). Processing of landing surfaces of turbine blades of aircraft engines. Cutting slots and keyways. Processing of complex external profiles. Calibration of cylindrical, multifaceted, shaped holes. Broaching is used in large-scale and mass production of metal products, and rarely in small-scale and single. Broaches of various designs - external, internal, and mandrels, are among the most expensive tools for metalworking. As an alternative to pulling, gouging is used.

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For the manufacture of broaches, medium-alloyed tool steels, high-speed steels are used, and prefabricated broaches and mandrels are equipped with hard alloys. When pulling, abundant cooling of the tool and workpiece coolant is used. Types of broaching Main types of broaching: Internal broaching. External stretch. burnishing. incandescent

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Grinding is the cutting of metals with abrasive wheels. When grinding, the main cutting movement is the movement of the tool. Grinding is distinguished by the periphery of the abrasive wheel and the end of the circle, in the first case, the cutting part is the outer surface of the circle, and in the second case, the end of the circle. Grinding ensures high surface finish and high dimensional accuracy of the workpieces. Grinding is done with abrasive tools. The abrasive tool is solid, consisting of grains of abrasive (grinding) material, fastened together by a bundle.

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Abrasive tools are overwhelmingly used in the form of grinding wheels of various shapes. In addition, they can be used in the form of bars, skins, pastes and powders.

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Polishing or superfinishing - mechanical restoration materials with fine abrasives. It is a finishing operation for processing metal and non-metal surfaces. The essence of polishing is the removal of the thinnest layers of the material being processed by a mechanical, chemical or electrolytic method and giving the surface a low roughness and a mirror finish. Types of polishing Manual polishing (in a single production and during repair work). Manual polishing with the use of polishing wheels (small-scale and single production). Machine polishing (serial and large-scale production, precise and unique polishing). Hydroabrasive polishing (large-scale and mass production). Ultrasonic polishing (medium-scale production, polishing of hard alloys). Electrolytic polishing (mass production). Chemical-mechanical polishing (treatment of hard alloys on a cobalt bond).

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Honing is a type of abrasive processing of materials using honing heads (hones). It is mainly used for processing internal cylindrical holes (from 2 mm). One of the types of finishing and finishing cutting. Allows you to get a hole with a deviation from cylindricity up to 5 microns and surface roughness Ra=0.63÷0.04.

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