Metal filing
Goal of the work: Familiarize yourself with the main methods of filing metal. The main tools used for filing. Acquire practical skills in filing metals.
Equipment, tools, devices. Bench vices, files of various types, control and measuring instruments for checking the quality of filing, marking frames and copiers.
Theoretical part
Filing is a cutting method in which a layer of material is removed from the surface of the workpiece using a file.
A file is a multi-edged cutting tool that provides relatively high accuracy and low roughness of the processed surface of the workpiece (part).
By filing, parts are given the required shape and size, parts are adjusted to each other during assembly, and other work is performed. Using files, planes, curved surfaces, grooves, grooves, holes of various shapes, surfaces located at different angles, etc. are processed.
Allowances for filing are left small - from 0.5 to 0.025 mm. The achieved processing accuracy can be from 0.2 to 0.05 mm, and in some cases - up to 0.005 mm.
File(Fig. 1, A) It is a steel bar of a certain profile and length, on the surface of which there is a notch (cut).
Rice. 76. Files:
A- main parts (1 - handle; 2 - shank; 3 - ring; 4 - heel; 5 - edge;
6 - notch; 7 - rib; 8 - nose); b- single notch; V - double notch;
G - rasp notch; d - arc notch; e - pen attachment; and - Removing the file handle.
The notch forms small and sharp teeth, having a wedge-shaped cross section. For files with a notched tooth, the sharpening angle β is usually 70°, the rake angle γ is up to 16°, and the rear angle α is from 32 to 40°.
The notch can be single (simple), double (cross), rasp (point) or arc (Fig. 1, b - d).
Single cut files remove wide chips equal to the length of the entire notch. They are used for filing soft metals.
Double cut files used when filing steel, cast iron and other hard materials, since the cross cut crushes the chips, which makes the work easier.
Files with rasp cut, Having spacious recesses between the teeth, which contributes to better placement of chips, very soft metals and non-metallic materials are processed.
Arc cut files have large cavities between the teeth, which ensures high performance and good quality processed surfaces.
Files are made from U13 or U13 A steel. After cutting the teeth, the files are subjected to heat treatment,
File handles usually made from wood (birch, maple, ash and other species). Techniques for attaching handles are shown in Figure 1. e And and.
According to their purpose, files are divided into the following groups: general purpose, special purpose, needle files, rasps, machine files.
Used for general plumbing work general purpose files. By the number of notches per 1 cm of length; they are divided into 6 numbers.
Files with notches No. 0 and 1 (garnish) have the largest teeth and are used for rough (rough) filing with an accuracy of 0.5-0.2 mm.
Files with notches No. 2 and 3 (personal) are used for finishing filing of parts with an accuracy of 0.15-0.02 mm.
Files with cuts No. 4 and 5 (velvet) are used for final precision finishing of products. The achieved processing accuracy is 0.01-0.005 mm.
The length of files can be made from 100 to 400 mm.
By shape cross section they are divided into flat, square, triangular, round, semicircular, rhombic and hacksaw (Fig. 2).
Small-sized needle files are used for processing small parts. They are produced in five numbers with the number of notches per 1 cm of length up to 112.
Processing of hardened steel and hard alloys is carried out with special needle files, in which artificial diamond grains are fixed to a steel rod.
Rice. 2. Shapes of file sections:
A And b- flat; V - square; G- triangular; d - round; e- semicircular;
and - rhombic; h - hacksaws.
Improving conditions and increasing labor productivity when filing metal is achieved through the use of mechanized (electric and pneumatic) files.
In training workshops, it is possible to use mechanized manual filing machines, which are widely used in production.
Universal grinder(see Fig. 4, G), powered by an asynchronous electric motor 1, has a spindle to which a flexible shaft is attached 2 with holder 3 for securing the working tool, and interchangeable straight and angular heads, allowing, using round shaped files, filing in hard-to-reach places and at different angles.
Metal filing
When filing, the workpiece is secured in a vice, and the surface to be filed should protrude 8-10 mm above the level of the jaws of the vice. To protect the workpiece from dents when clamping, jaws made of soft material are put on the jaws of the vice. Working The posture when filing metal is similar to the working posture when cutting metal with a hacksaw.
With the right hand, take the handle of the file so that it rests against the palm of the hand, four fingers cover the handle from below, and thumb placed on top (Fig. 3, A).
The palm of the left hand is placed slightly across the file at a distance of 20-30 mm from its toe (Fig. 3, b).
Move the file evenly and smoothly over its entire length. The forward movement of the file is the working stroke. The reverse stroke is idle, it is performed without pressure. At reverse stroke It is not recommended to tear the file from the product, as you may lose support and damage correct position tool.
Rice. 3. Grip the file and balance it during the filing process:
A- right hand grip; b- left hand grip; V - pressure force at the beginning of the movement;
G- pressure force at the end of the movement.
During the filing process, it is necessary to coordinate the efforts of pressing on the file (balancing). It consists of gradually increasing, during the working stroke, a slight initial pressure with the right hand on the handle while simultaneously decreasing the initially stronger pressure with the left hand on the toe of the file (Fig. 3, c, d).
The length of the file should exceed the size of the workpiece surface to be processed by 150-200 mm.
The most rational rate of filing is considered to be 40-60 double strokes per minute.
Filing As a rule, they begin with checking the processing allowance, which could ensure the manufacture of the part according to the dimensions indicated in the drawing. After checking the dimensions of the workpiece, determine the base, i.e. the surface from which the dimensions of the part should be maintained and mutual arrangement its surfaces.
If the degree of surface roughness is not indicated in the drawing, then filing is carried out only with a hog file. If it is necessary to obtain a more even surface, filing is completed with a personal file.
In the practice of manual metal processing, the following types of filing occur: filing of planes of mating, parallel and perpendicular surfaces of parts; filing curved (convex or concave) surfaces; sawing and fitting surfaces.
Sawing wide flat surfaces is one of the most complex species filing. To achieve a properly filed, straight surface, the main focus should be on ensuring that the file moves straight. Filing is carried out in a cross stroke (from corner to corner) at an angle of 35-40° to the sides of the vice. When filing diagonally, you should not extend the file into the corners of the workpiece, as this reduces the file support area and removes a large layer of metal. A so-called “blockage” of the edge of the treated surface is formed.
Checking the correctness of the plane is carried out using a ruler “in the light”, for which it is applied along, across and diagonally to the treated surface. The length of the straight edge should cover the surface being tested.
In the case of filing parallel flat surfaces, parallelism is checked by measuring the distance between these surfaces in several places, which should be the same everywhere.
During processing narrow planes On thin parts, longitudinal and transverse filing is used. When filing across the workpiece, the file comes into contact with a smaller surface, more teeth pass through it, which allows you to remove a large layer of metal. However, during cross-filing, the position of the file is unstable and it is easy to “fill up” the edges of the surface. In addition, the formation of “blockages” can be facilitated by the bending of a thin plate during the working stroke of the file. Longitudinal filing creates better support for the file and eliminates vibration of the plane, but reduces processing productivity.
For creating better conditions and increase labor productivity when filing narrow flat surfaces, special devices are used: filing prisms, universal basting marks, basting frames, special jigs and others.
The simplest of them is a frame mark (Fig. 4, a). Its use eliminates the formation of “blockages” on the treated surface. The front side of the basting frame is carefully processed and hardened to high hardness.
The marked blank is inserted into the frame, lightly pressing it with screws to the inner wall of the frame. The installation is clarified, ensuring that the marks on the workpiece coincide with the inner edge of the frame, after which the screws are finally secured.
Rice. 4. Filing of surfaces:
A - filing using a frame mark; b - filing technique convex surfaces; V - method of filing concave surfaces; G- filing using a universal grinder (1 - electric motor; 2 - flexible shaft; 3 - holder with tool).
Then the frame is clamped in a vice and the narrow surface of the workpiece is filed. Processing is carried out until the file touches the upper plane of the frame. Since this frame plane is processed with high precision, the sawn plane will also be accurate and will not require additional checking using a ruler.
When processing planes located at an angle of 90°, first the plane taken as the base is filed, achieving its flatness, then the plane perpendicular to the base. External corners are processed with a flat file. Control is carried out by the inner corner of the square. The square is applied to the base plane and, pressing against it, is moved until it comes into contact with the surface being tested. The absence of clearance indicates that the perpendicularity of the surfaces is ensured. If the light slit narrows or widens, then the angle between the surfaces is greater or less than 90°.
Internal corners are processed as follows. Mark the workpiece using the outer surfaces as bases. They will also be the bases for control. Then the excess metal is cut out with a hacksaw, leaving an allowance for filing of about 0.5 mm. If the sides of the internal corner must meet without rounding, a hole with a diameter of 2-3 mm is drilled in it or a shallow cut is made at an angle of 45° (it is almost impossible to process an internal corner without rounding inside). By filing the sides of the corner, first of all, they achieve their flatness, and then perpendicularity. The filing of surfaces along the inner corner is carried out so that the edge of the file, which does not have a notch, faces the second surface. The correctness of the internal angle is also checked using a square.
Surfaces located at an angle of more or less than 90° are treated in the same way. External corners are processed with flat files, internal corners with rhombic, triangular and others. Processing control is carried out using protractors or special templates.
When processing curved surfaces, in addition to the usual filing techniques, special ones are also used.
Convex curved surfaces can be processed using the technique of rocking the file (Fig. 4, b). When moving the file, first its tip touches the workpiece, the handle is lowered. As the file advances, the toe lowers and the handle rises. During the reverse stroke, the movements of the file are opposite.
Concave curved surfaces, depending on the radius of their curvature, are processed with round or semicircular files. The file makes a complex movement - forward and to the side with rotation around its axis (Fig. 4, V). When processing curved surfaces, the workpiece is usually periodically re-clamped so that the processed area is located under the file.
When manufacturing a batch of parts, it is advisable to make a special copier, similar to a marking frame, the front part of which has the shape of a curved surface. In this case, the copier with the workpiece fixed in it is clamped in a vice and filing is carried out until the file touches the hardened surface of the copier.
Sawing is called processing of holes (armholes) of various shapes and sizes using files. In terms of the tools used and work methods, sawing is similar to filing and is its variety.
Files are used for sawing various types and sizes. The choice of files is determined by the shape and size of the armhole. Armholes with flat surfaces and grooves are processed with flat files, and for small sizes - with square files. The corners in the armholes are sawed with triangular, rhombic, hacksaw and other files. Curvilinear armholes are processed with round and semicircular files.
Sawing is usually done in a vice. In large parts, the armholes are sawed at the installation site of these parts.
Preparation for sawing begins with marking the armhole. Then excess metal is removed from its internal cavity.
At large sizes the armholes and the greatest thickness of the workpiece, the metal is cut out with a hacksaw. To do this, drill holes in the corners of the armhole, insert a hacksaw blade into one of the holes, assemble the hacksaw and, stepping back from the marking line by the amount of sawing allowance, cut out the internal cavity.
A medium-sized armhole is drilled along the contour with a drill diameter
3-5 mm near the marking lines, then cut through the remaining jumpers with a cross-section or chisel.
To prepare for sawing small armholes, it is often enough to drill one hole with a diameter 0.3-0.5 mm smaller than the diameter of the circle inscribed in the armhole.
Direct sawing is carried out, as already noted, using techniques similar to filing.
Control is carried out using calipers and special templates.
By fitting is called the mutual fit of two parts that mate without gap. Both closed and semi-closed contours are fitted. The fitting is characterized by high processing accuracy. Of the two fitting parts, the hole is usually called, as when sawing, an armhole, and the part included in the armhole is called an insert.
Fitting is used as a final operation when processing parts of hinged joints and, most often, in the manufacture of various templates. Fitting is carried out using files with a fine or very fine notch.
First, the blanks for the liner and armhole are processed. Mark them, saw the armhole and file the liner, leaving an allowance (0.1-0.4 mm) for fitting.
The first to be prepared for fitting is the one of the mating parts that is easier to process and control, so that it can then be used for control during the manufacture of the mating part.
The accuracy of the fit is considered sufficient if the liner fits into the armhole without distortion, pitching or gaps.
Possible types of defects when filing metal and their reasons:
Inaccuracy in the dimensions of the sawn workpiece (removal of a very large or small layer of metal) due to inaccurate markings, incorrect measurement or inaccuracy of the measuring tool;
Non-flatness of the surface and “blockages” of the edges of the workpiece as a result of the inability to correctly perform filing techniques;
Dents and other damage to the surface of the workpiece as a result of improperly clamping it in a vice.
When filing metal with hand and mechanized tools, safety regulations should be followed. Use only proper tools. File handles must be firmly seated. Do not use files without handles or with cracked or chipped handles. The shavings formed during the filing process should be swept away with a special brush. Do not blow it off or brush it away with bare hands to avoid hurting your hands or clogging your eyes. When working with power tools, follow electrical safety rules. Monitor the serviceability of the conductive parts of the tool.
General rules for handling and caring for files:
Use files only for their intended purpose;
Do not process materials with a file whose hardness is equal to or exceeds its hardness;
Protect files from even minor impacts that could damage the teeth;
Protect files from getting wet, which causes corrosion;
Periodically clean the files from shavings with a cord brush;
Store files on wooden stands in a position that prevents them from touching each other.
Exercise
As instructed by the teacher, file workpieces with narrow and wide surfaces with independent selection of the necessary files and control and measuring tools. File curved surfaces on the proposed workpieces, pre-select files of the required profile and tools to control the work.
Questions:
1. What method of metal processing is called filing?
2. In what cases is metal filing used?
3. What types of notches are there to form file teeth?
4. What material are files made of?
5. What groups are files divided into according to their purpose?
6. What are needle files and what are they used for?
7. What are general rules Handling and caring for files?
8. What is the technique for performing filing techniques?
9. What mechanized tools are used when filing metal?
10. What types of defects are possible during filing and what are their reasons?
11. What safety rules must be followed when filing metals?
Dimensional processing refers to the processing of a workpiece (part) to give it a given shape, size and roughness of the machined surfaces. As a result of processing, a finished product is obtained, which may have independent use(for example, a chisel, a square), or a part suitable for installation in an assembled product (for example, handles and levers various designs). Dimensional metalworking operations include filing, hole processing (drilling, countersinking, countersinking, counterbore, reaming) and cutting external and internal threads.
Filing- this is an operation to remove a layer of material from the surface of a workpiece using a cutting tool - a file, the purpose of which is to give the workpiece a given shape and size, as well as ensure a given surface roughness. In most cases, filing is carried out after chopping and cutting metal with a hacksaw, as well as during assembly work to fit the part into place. In metalwork practice, filing is used to process the following surfaces:
Flat and curved;
Flat, located at an outer or inner angle;
Flat parallel ones to a certain size between them;
Shaped complex profile.
In addition, filing is used to process recesses, grooves and protrusions.
There are rough and fine filing. Machining with a file allows you to obtain precision processing of parts up to 0.05 mm, and in some cases even higher accuracy. The allowance for filing processing, i.e. the difference between the nominal size of the part and the size of the workpiece for its production, is usually small and ranges from 1.0 to 0.5 mm.
Tools used for filing
The main working tools used for filing are: are files, rasps and needle files.
Files are hardened steel bars, on the working surfaces of which a large number of notches or cuts are applied, forming the cutting teeth of a file. These teeth ensure that a small layer of metal in the form of chips is cut from the surface of the workpiece. Files are made from tool carbon steels of grades U10, U12, U13 and tool alloy steels of grades ShKh6, ShKh9, ShKh12.
The notches on the surface of the file form teeth, and the fewer notches per unit length of the file, the larger the teeth. Based on the type of notches, files with single (Fig. 3.1, a), double (cross) (Fig. 3.1, b) and rasp (Fig. 3.1, c) notches are distinguished.
Single-cut files cut metal with wide chips equal to the entire length of the tooth, which requires a lot of force. Such files are used for processing non-ferrous metals, their alloys and non-metallic materials.
Double-cut files have a main cut (deeper) and an auxiliary cut (smaller) applied on top of it, which ensures that the chips are crushed along the length, which reduces the forces applied to the file during operation. The method for applying the main and auxiliary notches is not the same, so the file teeth are located one after the other in a straight line, making an angle of 5 with the file axis. This arrangement of the teeth on the file ensures partial overlap of the marks from the teeth on the treated surface, which reduces its roughness.
Rasp-cut files (rasps) have teeth that are formed by extruding metal from the surface of the file blank using a special rasp chisel. Each rasp tooth is offset relative to the tooth in front by half a step. This arrangement of teeth on the surface of the file reduces the depth of the grooves formed by the teeth due to partial overlap of the tooth marks on the surface of the workpiece, which facilitates cutting. Rasps are used for filing soft materials (babbitt, lead, wood, rubber, rubber, some types of plastics).
The notches on the file surface are obtained various methods: notching (Fig. 3.2, a) on special machines, milling (Fig. 3.2, b) and broaching (Fig. 3.2, c). Regardless of the method of obtaining the notch, the teeth formed on the surface of the file have the shape of a cutting wedge, geometric shape which is determined by the sharpening angle p>, the rear angle a, the front angle y and the cutting angle 5 (see Fig. 3.2, a).
The rake angle is the angle between the front surface of the tooth and the plane passing through its top perpendicular to the axis of the file. The point angle is the angle between the front and back surfaces of the tooth. The clearance angle is the angle between the back surface of the tooth and the tangent to the machined surface. The cutting angle is the angle between the front surface of the tooth and the plane of the machined surface.
Files are classified depending on the number of notches per 10 mm of file length into 6 classes Notches have numbers from 0 to 5, and the smaller the notch number, the longer distance between the notches and the tooth is correspondingly larger. The choice of file number depends on the nature of the work that will be performed by it. The higher the requirements for processing accuracy and roughness of the machined surface, the finer the file tooth should be.
For rough rough filing (roughness Rz 160… 80, accuracy 0.2…0.3 mm), 0th and 1st class files (brutal) are used, having from 5 to 14 teeth per 10 mm of the cut part, depending on the length file
To perform finishing processing (roughness Rz 40...20, accuracy 0.05...0.1 mm), files with smaller teeth of the 2nd and 3rd classes (personal) are used, having from 8 to 20 notches per 10 mm of cut length file parts.
For fitting, finishing and finishing work (surface roughness Ra 2.5...1.25, accuracy 0.02...0.05 mm), chalk files and very fine teeth of the 4th and 5th classes (velvet) are used. , having from 12 to 56 notches per 10 mm of the length of the notched part.
Files with double notches, made using the on notching method, are intended for plumbing work. Such files are manufactured with different cross-sectional shapes, which are selected depending on the shape of the surface being processed.
flat files (Fig. 3.3, a, b) - for filing flat and convex wide external surfaces and sawing rectangular holes;
square files (Fig. 3.3, c) - for sawing square and rectangular openings, rectangular grooves and narrow flat outer surfaces;
triangular files (Fig. 3.3, d) - for sawing holes and grooves with angles of more than 60°;
round files (Fig. 3.3, e) - for sawing round and oval holes, as well as concave surfaces with a small radius of curvature, which cannot be processed with a semicircular file;
semicircular files (Fig. 3.3, e) - for filing concave surfaces with a large radius of curvature and fillets;
rhombic files (Fig. 3.3, g) - for filing teeth gear wheels, sprockets, for sawing profile grooves and surfaces located at sharp angles;
hacksaw files (Fig. 3.3, h) - for filing internal corners less than 10°, as well as wedge-shaped grooves, narrow grooves, gear teeth, flat surfaces and finishing corners in triangular, rectangular and square holes.
Rasps in cross-sectional shape can be flat blunt-pointed (Fig. 3.4, a), flat pointed (Fig. 3.4, b), round (Fig. 3.4, c) and semicircular (Fig. 3.4, d). Rasps are made with small and large notches.
For processing small parts, special files are used - needle files having a short length (80,120 or 160 mm) and different shape cross section (Fig. 3.5). The needle files also have a double notch: the main one - at an angle of 25 ° and the auxiliary one - at an angle of 45
To provide High Quality When filing, it is necessary to correctly select the cross-sectional profile, length and cut of the file.
The cross-sectional profile of the file is selected depending on the shape of the surface to be filed:
Flat, flat side of semicircular - for filing flat and convex curved surfaces;
Square, flat - for processing grooves, holes and openings of rectangular cross-section;
Flat, square, flat side of semicircular - when filing surfaces located at an angle of 90°;
Triangular - when filing surfaces located at an angle of over 60°;
Hacksaw, rhombic - for filing surfaces located at an angle of more than 10°;
Triangular, round, semicircular, rhombic, square, hacksaw - for sawing holes (depending on their shape).
The length of the file depends on the type of processing and the size of the surface being processed and should be:
100... 160 mm - for filing thin plates;
160…250 mm - for filing surfaces with a processing length of up to 50 mm; 250...315 mm - with a processing length of up to 100 mm; 315... 400 mm - with a processing length of more than 100 mm;
100...200 mm - length: sawing holes in parts up to 10 mm thick;
315...400 mm - for rough filing;
100... 160 mm - during finishing (needles).
The notch number is selected depending on the requirements for the roughness of the machined surface.
For comfortable holding and safety, files are equipped with a handle made of wood or plastic. Pens can be disposable or reusable. Wooden disposable handles (Fig. 3.6) for files are made from birch or linden. The surface of the handle must be clean and smooth. To prevent splitting when installed on the file shank, the handle is equipped with a special metal ring mounted on its neck. A hole is drilled in the handle for the file shank. When fastening, the file shank is inserted into the hole, then, hitting the workbench or vice with the head of the handle, it is ensured that it fits tightly into the hole in the handle. Do not force the handle onto the tip of the file with a hammer, as this may cause injury.
Filing is the removal of a layer from the surface of a workpiece using a file.
Files are cutting tools in the form of hardened steel bars with a notch on the surface. Material U13, U13A, as well as chromium ball bearing steel ShKh15.
They have different shapes: flat, square, triangular, semicircular, round, rhombic, hacksaw. WITH different number notches per 1 linear cm of the working part (bastard, personal and velvet).
Three types: regular files, needle files and rasps, diamond files and needle files.
Files are:
with a single cut can remove wide chips; they are used when filing soft metals, as well as non-metals.
with double or cross notch, for steel, cast iron and other hard materials. In these files, the lower, deep notch, called the main one, is first cut, and on top of it is the upper, shallow one, called the auxiliary notch, which cuts the main notch into teeth.
The cross cut crushes the chips, making work easier.
The arc cut has large gaps between the teeth and an arcuate shape, which ensures high productivity and good quality.
Rasp cut - teeth in a checkerboard pattern. For soft metals and non-metals.
File selection:
Used for rough filing up to 0.5 mm pugnacious files that allow you to remove a layer of metal of 0.08-0.15 mm in one stroke.
Personal– for a cleaner finish by 0.15 mm. They remove 0.05-0.08 mm in one stroke. 7-8 grades of purity are achieved.
With velvet notch– the most precise finishing, grinding with an accuracy of 0.01-0.05 mm. Remove 0.01-0.03 mm. Roughness 9-12 CL cleanliness.
scrapers – steel strips or rods with working edges. There are flat, triangular, shaped with handles, with sharply sharpened working surfaces.
Requirements. A sharp, even shank, a handle with a ring, no cracks, produces a clear sound when struck on the anvil.
The handle is first drilled, then burned through with the shank of an old file and hammered by hitting the handle head on the workbench.
When filing soft and tough metals, rub them with chalk, aluminum with stearin. Protect them from moisture and oil, so do not rub them with your hand. Periodically remove chips with steel brushes.
Marriage. Unevenness of the surface and blockages of the edges, excess was removed or not completed.
Safety. You can injure your hand with the shank if the handle is faulty, or damage the fingers of your left hand during the reverse stroke. Do not clean the file from shavings with bare hands, blow them off or remove them with compressed air, as this can damage your hands and eyes. It is better to work with a hat because... hair shavings are difficult to remove.
Drilling.
Drilling The process of creating holes in a cutting material with a cutting tool – a drill – is called.
Reaming– increasing the diameter of the existing hole.
Cleanliness of processing– 1-3 classes of roughness.
Applicable for obtaining non-critical holes, low degree of accuracy and low roughness class, for example for fastening bolts, rivets, studs, threading, reaming, and countersinking.
Twist drill– a two-toothed cutting tool consisting of 2 main parts: the working part and the shank. Working part The drill consists of a cylindrical (guide) and cutting parts. The cylindrical part has two helical grooves located one against the other. Their purpose is to remove chips.
To reduce friction, the drill has a reverse cone of 0.1 mm for every 100 mm of length.
Tooth- this is the protruding part of the drill that has cutting edges.
The angle between the cutting edges has a significant influence. As it increases, the strength of the drill increases, but the feed force increases. As the angle decreases, cutting becomes easier, but the cutting part becomes weaker. The angle size is selected depending on the hardness of the material.
Steel and cast iron………………………………………….116-118 o
Hardened steel, red copper……………………125
Brass and bronze, aluminum………………….…….130-140
Silumin………………………………………………………...90-100
ebonite……………………………………………………………...85-90
marble……………………………………………………………..80
plastics………………………………………………………..…50-60
Shanks
a drill up to 10 mm is cylindrical (usually) and is mounted in a chuck. The shank has a leash for additional torque transmission.
Larger diameter drills have a tapered shank. At the end there is a foot that prevents the drill from turning in the spindle and serves as a stop when knocking the drill out of the socket. Sizes 0,1,2,3,4,5,6 s different sizes cone
Manufactured – U10, U12A, chromium 9Х, chromium-silicon 9ХС, high-speed cutting Р9, Р18, metal-ceramic alloys of grades ВК6, ВК8 and Т15К6, with cases made of steel grades Р9,9ХС and 40Х.
Drills with carbide inserts are used for cast iron, hardened steel, plastics, glass, and marble.
There are drills with holes for supplying coolant to the cutting edges of the drill.
When drilling, a dull drill heats up very quickly, so much so that the steel tempers and the drill becomes unusable. Therefore, the drills are cooled.
Steel………………………………….soap emulsion or a mixture of mineral and fatty acids.
Cast iron………………………………….soap emulsion or dry
Copper…………………………………..soap emulsion or rapeseed oil
Aluminum…………………………….soap emulsion or dry
Duralumin………………………..soap emulsion, kerosene with castor or rapeseed oil
Silumin………………………………soap emulsion or a mixture of alcohol and turpentine.
Drill wear is detected by a sharp creaking sound.
Sharpening is carried out with cooling with a water-soda solution. The drill is sharpened as follows: lightly pressing the cutting edge against the surface of the abrasive wheel so that the cutting part takes a horizontal position, adjacent to the back surface of the wheel. Smooth movement right hand, without removing the drill from the circle, turn the drill around its axis, maintaining the correct inclination, sharpen the back surface, while making sure that the cutting edges are straight, have the same length and are sharpened at the same angles.
Drills with cutting edges of different lengths or with different angles will drill holes larger than their diameter.
Drill with hand, electric, pneumatic drills and El. machines.
Safety precautions for hand drills :
Work with rubber gloves on a rubber mat.
Check the wire;
The brushes must be well polished and do not spark during normal operation.
Safety precautions for drilling machines:
Work in overalls with a headgear, fasten the straps and sleeves (overhanging parts of clothing and hair can be caught in the spindle or drill)
Do not operate the machine wearing gloves.
Check the grounding for proper functioning
Check for obstruction
Check idle rotation, axial movement of the spindle and operation of the feed mechanism, table fastening
Fasten parts firmly and do not hold them with your hands during processing;
Conical drills are mounted directly in the conical hole of the spindle or through adapter conical bushings. Removed using a wedge through a slot.
Cylindrical in cartridges
Do not leave the key in the drill chuck after changing the drill;
Do not handle the rotating drill and spindle;
Do not remove the broken drill by hand;
Do not press the feed lever too hard when drilling through workpieces, especially with small diameter drills.
Place a wooden block on the table under the spindle when changing the drill;
Do not pass objects through a running machine;
Do not lean on the machine while it is operating.
Do not remove chips from the holes with your fingers or blow them away. This must be done with a pen or brush and only after stopping the machine.
Be sure to stop the machine when changing drills, cleaning or maintenance.
Filing is the operation of processing metals and other materials by removing a small layer with files manually or on filing machines.
Using a file, a mechanic gives parts the required shape and size, fits parts to each other, prepares the edges of parts for welding and performs other work.
Using files, planes, curved surfaces, grooves, grooves, holes of any shape, surfaces located at different angles, etc. are processed. etc. Allowances for filing are left small - from 0.5 to 0.025 mm. The accuracy of filing processing is from 0.2 to 0.05 mm, in some cases up to 0.001 mm.
Manual filing with a file has now been largely replaced by filing on special machines, but these machines cannot replace completely manual filing, since fitting work during the assembly and installation of equipment often has to be done manually.
A file (Fig. 134) is a steel bar of a certain profile and length, on the surface of which there are notches (cuts), forming cavities and sharp teeth (teeth), having a wedge-shaped cross-section. The files are made from U13 or U13A steel (alloy chromium steel ShKh15 or 13Kh is allowed), and after cutting they are subjected to heat treatment.
Files are divided: according to the size of the notch, according to the shape of the notch, according to the length and shape of the bar, and according to their purpose.
Types and main elements of notches. The notches on the surface of the file form teeth that remove chips from the material being processed. File teeth are obtained on sawing machines using a special chisel, on milling machines- by milling cutters, on grinding machines - with special grinding wheels, as well as by rolling, broaching on broaching machines - broaches and on gear cutting machines. Each of these methods cuts its own tooth profile. However, regardless of the method of obtaining the notch, each tooth has a rear angle a, a sharpening angle p, a front angle y and a cutting angle 5 (Fig. 135).
Files with notched teeth (Fig. 135, a) with a negative rake angle (γ from -12 to -15°) and a relatively large rear angle (α from 35 to 40°) provide sufficient space to accommodate chips. The resulting sharpening angle β = 62 (up to 67°) ensures the strength of the tooth.
Files with milled or ground teeth (Fig. 135, b) have a positive rake angle γ = 2 (up to 10°). They have a cutting angle of less than 90° and, therefore, less cutting force. The high cost of milling and grinding limits the use of these files.
For files with teeth obtained by broaching (Fig. 135, c), γ = - 5°, β = 55°, α = 40°, δ = 95°.
The extended tooth has a socket with a flat bottom. These teeth cut better into the metal being processed, which significantly increases labor productivity. In addition, files with such teeth are more durable, since the teeth do not become clogged with chips.
The fewer notches per 1 cm of file length, the larger the tooth. There are files with a single, i.e., simple notch (Fig. 136, a), double, or cross (Fig. 136, b), point, i.e., with a rasp (Fig. 136, c), and arc (Fig. 136, d).
Single cut files can remove wide chips equal to the length of the entire cut. They are used for filing soft metals (brass, zinc, babbitt, lead, aluminum, bronze, copper, etc.) with low cutting resistance, as well as non-metallic materials. In addition, these files are used for sharpening saw blades, as well as for processing wood and cork. A single notch is applied at an angle λ = 25° to the file axis.
Files with a double (i.e. cross) cut are used for filing steel, cast iron and other hard materials with high cutting resistance. In files with a double notch, the lower, deep notch, called the main notch, is cut first, and on top of it is the upper, shallow notch, called the auxiliary; it cuts the main notch into a large number of individual teeth.
The cross cut breaks up the chips more, making work easier. The main notch is made at an angle λ = 25°, and the auxiliary notch is made at an angle ω = 45°.
Distance between adjacent teeth The notch is called the pitch S. The pitch of the main notch is larger than the step of the auxiliary one. As a result, the teeth are located one after another in a straight line, making an angle of 5° with the axis of the file, and when it moves, the marks of the teeth partially overlap each other, so the roughness on the treated surface is reduced, the surface is cleaner and smoother.
Rasp (point) notching is obtained by pressing the metal with special triangular chisels, leaving capacious recesses located in a checkerboard pattern, facilitating better placement of chips. Rasps are used to process very soft metals and non-metallic materials (leather, rubber, etc.).
The arc cut is obtained by milling. The notch has large cavities between the teeth and an arcuate shape, which ensures high productivity and improved quality of the processed surfaces. These files are used when processing soft metals (copper, duralumin, etc.).
Agreed: at a meeting of the methodological commission.
"__"___________ 2015
Lesson Plan #1.5
Topic studied in the program: PM 01. Metal filing.
Lesson topic. Metal filing.
The purpose of the lesson. Teach the student how to properly file convex surfaces.
Educational purpose:
1. Fostering a production culture, love for the chosen profession, technological discipline, proper organization labor.
2. Formation of skills and abilities, readiness to correctly apply existing skills and knowledge to perform practical tasks.
3. Creating conditions for the manifestation of a person’s abilities to creatively perform work, achieving high-quality performance of a practical task.
Material and technical equipment of the lesson. Posters, samples, technological maps, workpieces, measuring and marking tools, workbenches, vices, a set of files, pattern rulers.
Lesson progress: 6 hours.
1. Introductory group briefing 50 min.
a) testing knowledge on the material covered 10 min.
- What are the causes of hacksaw blade failure?
- How to fix a hacksaw blade with broken teeth.
- Design and purpose of files for rough metal processing.
- Techniques for filing parallel surfaces.
- Cleaning files from oil and soft material.
- Safety precautions when filing metal.
- Defects during filing and methods for correcting them.
b) explaining new material to students 30 min.
Filing the nasa varies..- an operation for processing metals and other materials, removing a small layer with files manually or on filing machines. Using a file, the mechanic gives the parts the required shape and size, fits the parts to each other, prepares the edges of the parts for welding and performs other work. Using files, planes, curved surfaces,
grooves, grooves, holes of any shape, surfaces located at different angles, etc.
File - It is a steel bar of a certain profile and length, on the surface of which there are notches that have a wedge shape in cross-section. Made from carbon steel or alloyed chromium steel.
Files subdivide P about the size of the notch, the shape of the notch, the length and shape of the bar, and its intended purpose.
Files according to the number of notches per 1 cm of length, they are divided into six numbers (0.1) - pugnacious For large layer of metal removed. (2.3) - personal days of a small layer removed (finish filing) (4.5) velvet for final finishing of the product.
Files are divided into types.
A - flat; b - flat pointed-nosed; V - square; g - triangular; d - round; e - semicircular; g - rhombic; e - hacksaw files - on special order.
According to the shape of the notch share;
With single and double notches, as well as dot notches in a checkerboard pattern (rasps)
Files are divided according to purpose into general purpose groups and
special.
Special purpose files (needles rasps, machine) - for processing
non-ferrous metals, light alloys and non-metallic materials.
Files - small files for jewelry work, stripping and have the same
shape like a file
Surface preparation To filing with brushes
The workpiece is cleaned with metal brushes from dirt, oil, scale, then
The workpiece being processed is clamped in a vice, with the sawing plane horizontally 8-10 mm above the level of the jaws.
Filing techniques the same as when cutting metal with a hacksaw. Adjust the pressure on the file, achieving a smooth surface to be filed without blockages: During the reverse stroke (idle), the file should not be torn off from the surface of the part, but should only slide. First, filing is performed from left to right at an angle of 30 - 40° to the axis of the vice, then with a straight stroke, and ends with an oblique stroke at the same angle, but from right to left.
Check the surface; straight edge, calipers,
squares, slabs in the light at eye level in several places. At first
sawing off one wide surface (it is the base), then the second parallel to the first, etc.).
Parallelism sides are checked with a caliper, and - perpendicularity to the surface - with a square.
After the base surface, file the second one at an angle of 90°. When filing and sawing curved surfaces, choose the most rational method of removing excess metal (with a hacksaw, drilling and cutting). Too large an allowance for filing leads to a lot of time spent on completing the task, and a small one is too allowance leads to defective parts. Sawing of concave surfaces. First, the workpiece is marked along the contour of the part. Most of the metal can be removed with a hacksaw or drilling, and then filed with a file of different shapes. Check for light using the template.
Filing convex surfaces . Filing the toe of a metalworker's hammer, making dowels and other parts.
Types and causes of defects during filing.
- Uneven surfaces (humps) and blockages in the edges of the workpiece - inability to use a file.
- Dents or damage to workpieces; strong clamping in a vice.
- Inaccurate dimensions of the sawn workpiece due to incorrect markings, removal of a very large or small layer of metal, as well as incorrect intent or inaccuracy of measuring instruments.
- Scuffs and scratches on the surface of a part resulting from careless work and an incorrectly selected file.
Occupational safety when filing.
- When filing workpieces with sharp edges, you should not tighten the fingers of your left hand during the reverse stroke.
- The shavings must be swept away with a hair brush. Do not throw with bare hands and do not blow off or remove with compressed air.
- When working, use only files with firmly mounted handles; Do not use files without handles or with cracked or chipped handles. When filing a workpiece with sharp edges, do not press the fingers of your left hand under the file or in reverse motion.
- The shavings formed during the filing process must be swept off the workbench with a hair brush. It is strictly prohibited to throw away chips with bare hands, blow them off or remove them with compressed air.
- When working, use only files with firmly attached handles. Do not use files without handles or files with cracked or chipped handles.
c) consolidation of material from introductory briefing 10 min. Brief student survey
- What surfaces are called convex?
- What are the general rules for the sequence of filing convex surfaces?
- Safety precautions when filing?
d) task for the day
- Exercise for filing convex surfaces.
Make a part: a universal hammer.
2. Independent work students: 4 hours.
Conduct a tour of students' workplaces in order to:
1. Checking the organization of the workplace.
2. Compliance with safety regulations and technological process when filing.
3. Quality of work performed:
Indicate the mistakes made and methods for eliminating them.
Cleaning workplaces:
1. Inspection and delivery of the tool.
2. Clean the workplace.
3. Final briefing. Analysis of the working day. 10 min.
- Celebrate the work of the best students.
- Note students' shortcomings.
- Answer students' questions.
- Submit grades to the journal.
4. Homework assignment. Familiarization with the material of the next lesson, repeat the topic “Filing metal”. Textbook "Plumbing" author Skakun V.A.
Master of Industrial Training ___________________________
