Marking work in plumbing are auxiliary technological operation consisting in transferring contour constructions according to the dimensions of the drawing to the workpiece.

Marking– this is an operation of applying lines (marks) to the surface of the workpiece, defining the contours of the part being manufactured, which is part of some technological operations.

Planar marking used in processing sheet material and rolled profiles, as well as parts on which marking marks are applied in the same plane.

Planar marking consists of applying contour lines to the material or workpiece: parallel and perpendicular, circles, arcs, angles, various geometric shapes according to given sizes or contours according to templates. Contour lines are applied in the form of solid marks.

In order for traces of the marks to remain until the end of processing, small depressions are applied to the marks using a punch, close to one another, or a control mark is applied next to the marking mark. Risks must be subtle and clear.

Spatial marking- This is the application of marks on the surfaces of the workpiece, interconnected by mutual arrangement.

Planar markings are made on the workpiece using a scriber. Marking accuracy is achieved up to 0.5mm. Marking marks with a scriber are carried out once.

The depth of the core recess is 0.5 mm. When performing a practical task, the scriber and marking compass can be kept on a mechanic's workbench.

At the end of the work, it is necessary to remove dust and scale from the marking plate using a sweeping brush. When performing a practical task, you need to press the ruler against the workpiece with three fingers of your left hand so that there is no gap between it and the workpiece. When marking long marks (more than 150mm), the distance between the recesses should be 25..30mm. When marking short marks (less than 150mm), the distance between the indentations should be 10..15mm. Before setting the compass to the size of the arc radius, the center of the future arc must be marked. To set the compass to the size, you need to set one leg of the compass with its tip at the tenth division of the ruler, and the second at a division that exceeds the specified one by 10 mm. Angles less than 90º are measured with a goniometer using a square. When marking planarly, parallel marks are applied using a ruler and a square. When marking a circle of a given diameter on a plate, you need to install a compass to a size that exceeds the radius of the circle by 8..10mm.

To mark, measure and check the correct manufacture of products, the following tools are used: ruler, square, compass, vernier caliper, caliper, bore gauge, scale and pattern ruler, protractor, scriber, center punch, marking plate. Templates, patterns, and stencils are used as devices that speed up the marking process.

Scriber should be convenient for drawing clear lines on the surface to be marked and, at the same time, not spoil the working planes of the ruler or square. The scribe material is selected depending on the properties of the surfaces being marked. For example, a brass scriber leaves a clearly visible mark on the surface of steel. When marking parts from more soft materials It is advisable to use a pencil. Before marking, it is better to apply thin layer water-based paint.

Center punches are used to mark the centers of circles and holes on marked surfaces. Cores are made of solid steel. The length of the center punch is from 90 to 150mm and the diameter is from 8 to 13mm.

A bench hammer, which should be light in weight, is used as a striking tool when making core holes. Depending on how deep the core hole should be, hammers weighing from 50 to 200 grams are used.

Protractor steel with a protractor is used for marking and checking angles in the manufacture of mating pipe assemblies, fittings and other parts of air ducts.

Marking compass used for drawing circles, arcs and various geometric constructions, as well as for transferring dimensions from a ruler to a marking blank or vice versa. There are rack and pinion calipers, calipers, calipers, inside calipers, and vernier calipers.

Marking boards installed on special stands and cabinets with drawers for storing marking tools and accessories. Small marking plates are placed on tables. The working surfaces of the marking plate should not have significant deviations from the plane.

Various geometric shapes are applied to the plane using the same marking tool: ruler, square, compass and protractor. To speed up and simplify the planar marking of identical products, sheet steel templates are used.

A template is placed on the workpiece or material and pressed tightly so that it does not move during marking. Along the contour of the template, lines are drawn with a scribe, indicating the contours of the workpiece.

Large parts are marked on the plate, and small parts are marked in a vice. If the product is hollow, for example a flange, then hammer it into the hole wooden cork and in the center of the plug a metal plate is fixed, on which the center for the leg of the compass is marked with a center punch.

The flange is marked as follows. The surface of the workpiece is painted with chalk, the center is marked and circles are drawn with a compass: the outer contour, the contour of the hole and the center line along the centers of the holes for the bolts. Often the flanges are marked according to a template, and the holes are drilled according to the jig without marking.

Marking lines are drawn in the following sequence: first draw horizontal lines, then vertical lines, then inclined lines, and lastly circles, arcs and curves. Drawing arcs in last resort makes it possible to control the accuracy of the location of straight marks: if they are applied accurately, the arc will close them and the joints will be smooth.

Direct marks are applied with a scriber, which should be tilted away from the ruler (Fig. 45.6) and in the direction of movement of the scriber (Fig. 45, a). The angles of inclination must correspond to those indicated in the figure and not change during the process of applying marks, otherwise the marks will not be parallel to the ruler. The scriber is constantly pressed against the ruler, which should fit tightly to the part.

Risks are taken only once. When drawing lines again, it is impossible to get exactly into the same place; as a result, several parallel marks are obtained. If the mark is applied poorly, it is painted over, allowed to dry and applied again.

Perpendicular lines (not in geometric constructions) are drawn using a square. The part (workpiece) is placed in the corner of the slab and lightly pressed with a weight so that it does not move during the marking process. The first mark is carried out along a square, the shelf of which is applied to the side surface b (Fig. 46, a) of the marking plate (position of the square 1-1). After this, the square is applied with its shelf to the side surface a (position //-ID and a second mark is drawn, which will be perpendicular to the first.

Parallel marks (lines) are applied using a square (Fig. 46.6), moving it to the required distance.

Finding the centers of circles is carried out using center finders and center markers. The simplest center finder (Fig. 47,a) is a square with a ruler attached to it, which is a bisector right angle. By installing the center finder square on outer surface products, draw a straight line with a scriber. It will pass through the center of the circle. Having turned the square to a certain angle (about 90°), draw a second straight line. At their intersection is the desired center.

If the diameter of the marked end is small, it is inconvenient to use center finders. In this case, a punch center finder is used.

The center punch (Fig. 47.6) is used for marking centers on cylindrical parts with a diameter of up to 40 mm. It has an ordinary punch 7, placed in a funnel (bell) 3. A flange 2 with a hole is inserted into the funnel, into which the punch slides easily. The marking consists of pressing the funnel against the end of the product and hitting the head 5 of the center punch with a hammer. Under the action of spring 4, the center punch is always in the upper position.

Articulated price finder K. f. Kryuchek (Fig. 47, c) has advantages over other center finders. Using it, the position of the center lines is found not only

cylindrical, but also conical, rectangular and other holes. The center finder has four hinged bars connected by springs. When the center finder operates, springs press the ends of the strips against the walls of the hole. Points A and B, marked on the hinge axes, indicate the position of mutually perpendicular lines.

Marking of angles and slopes is done using protractors (Fig. 48, a) and protractors. When marking, the protractor (Fig. 48.6) is set at a given angle, holding its base with your left hand, and right hand, turning the wide end of the ruler until the arrow-shaped end of the ruler coincides with the division of the specified degrees marked on the base. After this, the ruler is secured with a hinged screw, then the lines are drawn with a scriber.

Pocket caliper(Fig. 49) with a ruler for measuring depths produced by the GDR, instead of the usual vernier, it has a dial indicator. This tool is successfully used by markers, as it reduces eye strain when taking readings and provides sufficient accuracy. The scale division of the indicator is 1/10 mm, the measurement limit is 135 mm, the working surfaces of the jaws are hardened along the entire length.

Center finder-protractor(Fig. 50) differs from a conventional protractor-center finder by the presence of a protractor 2, which, using a slider 4, can move along a ruler 3 and be secured on it in the desired position with a nut 5. The ruler is attached to a square 7. The protractor makes it possible to find the centers of holes located on specified distance from the center cylindrical part and from any angle. In Fig. 50, the position of point d is found, located at an angle of 45° and at a distance of 25 mm from the center.

A spirit level with a degree scale and a dial gauge (Fig. 51), produced in the GDR, can be used for marking works. It is rational to use a spirit level (Fig. 51,a) when measuring slopes with an accuracy of 0.0015° and when installing parts on a slab in cases where the plane of the marking slab is strictly level.

A dial goniometer (Fig. 51, 6) does not require much eye strain when setting angular values ​​on the scale.

The division value of the circular scale is 5 arc minutes. A full turn of the arrow corresponds to a change in the angle between the rulers by 10°. IN round hole The dial displays a number corresponding to an integer number of degrees. The auxiliary leg is used for measuring small angles.

Marking work in plumbing is an auxiliary technological operation consisting in transferring contour structures according to the dimensions of the drawing to the workpiece.

Marking– this is an operation to apply lines (scores) to the surface of the workpiece,

defining the contours of the manufactured part, which is part of some

technological operations.

Planar marking used when processing sheet material and profile

rolled products, as well as parts on which marking marks are applied in one plane.

Planar marking consists of applying contour lines to a material or workpiece: parallel and perpendicular, circles, arcs, angles, various geometric shapes according to given dimensions or contours according to templates. Contour lines are applied in the form of solid marks.

In order for traces of the marks to remain until the end of processing, small depressions are applied to the marks using a punch, close to one another, or a control mark is applied next to the marking mark. Risks must be subtle and clear.

Spatial marking- This is the application of marks on the surfaces of the workpiece, interconnected by mutual arrangement.

Planar markings are made on the workpiece using a scriber. Accuracy at

marking is achieved up to 0.5mm. Marking marks with a scriber are carried out once.

The depth of the core recess is 0.5 mm. When performing practical

tasks, a scriber and a marking compass can be kept on a metalworking bench.

At the end of the work, it is necessary to remove dust and scale from the marking plate using a sweeping brush. When performing a practical task, you need to press the ruler against the workpiece with three fingers of your left hand so that there is no gap between it and the workpiece. When marking long marks (more than 150mm), the distance between the recesses should be 25..30mm. When punching short marks (less than 150mm), the distance between the recesses should be 10..15mm. Before setting the compass to the size of the arc radius, the center of the future arc must be punched. To set the compass to the size, you need to set one leg of the compass with its tip at the tenth division of the ruler, and the second at a division that exceeds the specified one by 10 mm. Angles, less

90º, measured with a goniometer using a square. For planar marking

parallel marks are applied using a ruler and a square. When marking on

plate of a circle of a given diameter, you need to set the compass to the size

exceeding the radius of the circle by 8..10mm.

The following tools are used to mark, measure and check the correct manufacture of products: ruler, square, compass, vernier caliper, caliper, bore gauge, scale and pattern ruler, protractor, scriber, center punch, marking plate. Templates, patterns, and stencils are used as devices that speed up the marking process.

Scriber should be convenient for drawing clear lines on the marked surface and, together

in order not to spoil the working planes of the ruler or square. Scribler material

selected depending on the properties of the marked surfaces. For example,

The brass scriber leaves a clearly visible mark on the surface of the steel. At

When marking parts made of softer materials, it is advisable to use

pencil. Before marking, it is better to apply a thin layer of water-based paint to the surface.

Center punches serve for marking the centers of circles and holes on marked

surfaces. Cores are made of solid steel. The center punch length ranges from 90

up to 150mm and diameter from 8 to 13mm.

It is used as a percussion tool when making core holes.

a plumber's hammer, which should be light in weight. Depending on

How deep should the core hole be? Hammers weighing from 50 to 200 grams are used.

Protractor steel with a protractor is used for marking and checking angles when

manufacturing of mating pipe assemblies, fittings and other parts

Air ducts.

Marking compass used for drawing circles,

arcs and various geometric structures, as well as for transferring

sizes from a ruler to a marking blank or vice versa. There are rack and pinion compasses,

thicknesser, calipers, internal calipers, vernier calipers.

Marking boards installed on special stands and cabinets with storage drawers

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marking tools and devices. Small marking plates are placed on tables. The working surfaces of the marking plate should not have significant deviations from the plane.

Various geometric shapes are applied to the plane using the same marking tool: ruler, square, compass and protractor. To speed up and

To simplify the planar marking of identical products, templates made of sheet steel are used.

A template is placed on the workpiece or material and pressed tightly so that it does not move during marking. Along the contour of the template, lines are drawn with a scribe, indicating the contours of the workpiece.

Large parts are marked on the plate, and small parts are marked in a vice. If the product is hollow, for example a flange, then a wooden plug is hammered into the hole and a metal plate is fixed in the center of the plug, on which the center for the compass leg is marked with a center punch.

The flange is marked as follows. The surface of the workpiece is painted with chalk, the center is marked and circles are drawn with a compass: the outer contour, the contour of the hole and the center line along the centers of the holes for the bolts. Often the flanges are marked according to a template, and the holes are drilled according to the jig without marking.

Marking- the operation of applying marking lines (marks) to the workpiece being processed, which determine the contours of the future part or place to be processed. The marking accuracy can reach 0.05 mm. Before marking, it is necessary to study the drawing of the part to be marked, find out the features and dimensions of the part, and its purpose. The marking must meet the following basic requirements: exactly match the dimensions indicated on the drawing; Marking lines (marks) must be clearly visible and not erased during processing of the workpiece. To install the parts to be marked, marking plates, pads, jacks and rotating devices are used. For marking, scribers, punches, marking calipers and surface planers are used. Depending on the shape of the blanks and parts to be marked, planar or spatial (volumetric) markings are used.

Planar marking performed on the surfaces of flat parts, as well as on strip and sheet materials. When marking, contour lines (marks) are applied to the workpiece according to specified dimensions or templates.

Spatial marking most common in mechanical engineering and differs significantly from planar. The difficulty of spatial marking is that it is necessary not only to mark the surfaces of the part located in different planes and at different angles to each other, but also to link the markings of these surfaces with each other.

Base- a base surface or baseline from which all dimensions are measured when marking. She is chosen by following rules: if the workpiece has at least one machined surface, it is selected as the base; If there are no machined surfaces on the workpiece, the outer surface is taken as the base surface.

Preparing blanks for marking begins with cleaning it with a brush from dirt, scale, and traces of corrosion. Then the workpiece is cleaned with sanding paper and degreased with white spirit. Before painting the surface to be marked, you must make sure that the part is free of holes, cracks, burrs and other defects. To paint the surfaces of the workpiece before marking, use the following compositions: chalk diluted in water; ordinary dry chalk. Dry chalk is used to rub the marked untreated surfaces of small non-critical workpieces, since this coloring is fragile; solution copper sulfate; alcohol varnish is used only for precise marking of the surfaces of small products. The choice of coloring composition for application to the base surface depends on the type of workpiece material and the method of its preparation: the untreated surfaces of workpieces made of ferrous and non-ferrous metals obtained by forging, stamping or rolling are painted aqueous solution chalk; the treated surfaces of ferrous metal workpieces are painted with a solution of copper sulfate, which, when interacting with the workpiece material, forms a thin film on its surface pure copper and ensures clear identification of marking marks; the treated surfaces of non-ferrous metal workpieces are painted with quick-drying varnishes.

Marking methods

Template marking is used in the production of large batches of parts of the same shape and size, and sometimes for marking small batches of complex workpieces. Marking according to a sample is used during repair work, when dimensions are taken directly from a failed part and transferred to the material being marked. This takes wear and tear into account. A sample differs from a template in that it has a one-time use. Marking in place is carried out when the parts are mating and one of them is connected to the other in a certain position. In this case, one of the parts acts as a template. Markings with a pencil are made using a ruler on blanks made of aluminum and duralumin. When marking workpieces made from these materials, scribers are not used, since the marks are destroyed when applied. protective layer and conditions are created for corrosion to occur. Defects in marking, i.e. Non-compliance of the dimensions of the marked workpiece with the data in the drawing occurs due to the inattention of the marker or the inaccuracy of the marking tool, or a dirty surface of the slab or workpiece.

Metal cutting.

Metal cutting is an operation in which excess layers of metal are removed from the surface of the workpiece or the workpiece is cut into pieces. Chopping is carried out using cutting and impact tools. The cutting tools for chopping are a chisel, a crosspiece and a groover. Percussion instrument- plumber's hammer. Purpose of cutting: - removal of large irregularities from the workpiece, removal of hard crust, scale; - cutting out keyways and lubrication grooves; - cutting edges of cracks in parts for welding; - cutting off the heads of rivets when removing them; - cutting holes in sheet material. - cutting of rod, strip or sheet material. The cutting can be fine or rough. In the first case, a layer of metal 0.5 mm thick is removed with a chisel in one pass, in the second - up to 2 mm. The processing accuracy achieved when cutting is 0.4 mm.

Editing and straightening.

Editing and straightening- operations for straightening metal, blanks and parts with dents, waviness, curvature and other defects. You can edit manually on steel correct plate or a cast iron anvil and a machine on the right rollers, presses and special devices. Manual straightening is used when processing small batches of parts. Enterprises use machine editing.

Flexible.

Bending- an operation as a result of which the workpiece takes the required shape and dimensions due to stretching of the outer layers of metal and compression of the inner ones. Bending is performed manually using hammers with soft strikers on a bending plate or using special devices. Thin sheet metal is bent with mallets, wire products with a diameter of up to 3 mm are bent with pliers or round nose pliers. Only plastic material is subject to bending.

Cutting.

Cutting (cutting)- separation of varietal or sheet metal into pieces using a hacksaw blade, scissors or other cutting tool. Cutting can be carried out with or without chip removal. When cutting metal with a hand saw, on hacksaw and cutting-off lathes, chips are removed. Cutting materials with manual lever and mechanical scissors, press shears, wire cutters and pipe cutters is carried out without removing chips.

Dimensional processing.

Metal filing.

Filing- an operation to remove a layer of material from the surface of a workpiece using a cutting tool manually or on filing machines. The main working tools for filing are files, needle files and rasps. Using files, flat and curved surfaces, grooves, grooves, and holes of any shape are processed. The accuracy of filing processing is up to 0.05 mm.

Hole machining

When processing holes, three types of operations are used: drilling, countersinking, reaming and their varieties: drilling, countersinking, counterbore. Drilling- an operation to form through and blind holes in a solid material. It is performed using a cutting tool - a drill, which makes rotational and translational movements relative to its axis. Purpose of drilling: - obtaining non-critical holes with a low degree of accuracy and roughness class of the machined surface (for example, for fastening bolts, rivets, studs, etc.); - obtaining holes for threading, reaming and countersinking.

Reaming- increasing the size of a hole in a solid material produced by casting, forging or stamping. If you want to high quality treated surface, then the hole after drilling is additionally countersinked and reamed.

Countersinking- pre-processing of cylindrical and conical drilled holes in details special cutting tool- countersink. The purpose of countersinking is to increase the diameter, improve the quality of the machined surface, and increase accuracy (reducing taper, ovality). Countersinking can be the final machining operation of a hole or an intermediate operation before reaming the hole.

Countersinking- this is the processing with a special tool - a countersink - of cylindrical or conical recesses and chamfers of drilled holes for the heads of bolts, screws and rivets. Countering is carried out using counterbores to clean the end surfaces. Counters are used to process bosses for washers, thrust rings, and nuts.

Deployment- This is the finishing of holes, providing the greatest accuracy and surface cleanliness. Reaming of holes is carried out with a special tool - reamers - on drilling and lathes or manually.

Before starting to process the material or workpiece (cutting, filing, drilling, etc.), it is necessary to make markings, i.e., transfer from the drawing to the material or workpiece according to the given dimensions the contour lines that determine the shape of the product.

During processing, a certain layer of metal is removed from the surface of the product. Therefore, when softening a material or workpiece, a certain processing allowance is given. This allowance - an increase in the size of the workpiece beyond the contour lines (marks) drawn exactly according to the drawing - should be the smallest.

Marking can be planar and spatial.

Drawing contour lines on one plane of a material or product is called planar marking.

More complex is spatial marking products, three of which apply interconnected contours on several planes conjugated at different angles.

Before marking, the plane of the part or material must be painted so that the drawn lines are clearly visible. The raw surfaces of castings, forgings and materials, after preliminary cleaning them from dirt, molding soil, sand, etc., are painted with chalk, paints or varnished. For coloring, dissolve chalk in water and add a little linseed oil and a drier so that it does not crumble. The treated surfaces are painted with a solution of copper sulfate.

Marking consists of applying parallel and perpendicular contour lines, circles, arcs, angles, various geometric shapes according to given dimensions and various contours according to templates to a part, material or workpiece. Contour lines are applied in the form of erroneous marks or in the form of punching individual points located close to each other.

The following tools are used for marking: ruler, square, compass, caliper, surface planer, scale ruler, protractor, scriber, center punch, marking plate and templates.

All marking tool must be accurate and correct, otherwise the markings will be incorrect. It should be stored in specially designated places.

The marks applied with a scribe on a ruler, square or compass should be thin and clear. On untreated surfaces, to preserve the contours of markings along the marks, a number of points are marked with a center punch.

Marking according to the template is done as follows. The template is placed on the workpiece or material and pressed tightly so that it does not move during marking. Then, along the contour of the template, lines are drawn with a scribe, along which the part will be processed in the future.

Large parts are marked on the plate, and small parts are marked in a vice. Marking must be done accurately and carefully, since the quality of the product depends on the correct marking.

Marking techniques are shown in Fig. 53.

Rice. 53. Techniques planar marking:
a - carrying out risks; b - drawing parallel lines using a square; c - drawing perpendicular lines using a ruler and a square; d - drawing a perpendicular line using a compass; d - drawing parallel lines using a compass; e - elements of the circle; g - construction of an inscribed hexagon using a compass; h - marking circles using a compass; and - construction of an inscribed square and octagon; j - marking corners using a protractor; l - construction of angles using a compass and square; l - template spread

If the product is hollow, then a wooden plug is tightly hammered into the hole and a tin is hammered into the center, on which the center for the compass leg is marked with a center punch. The flange is marked as follows. First, the surface of the flange is painted with chalk and circles are drawn with a compass - the outer contour, the contour of the hole and the center line along the centers of the holes for the bolts. After this, the centers of the holes for the bolts are marked, they are punched and circles are drawn with a compass - the contours of these holes. Typically, holes in flanges are marked according to a template.