Bend sheet metal. How is sheet metal bending done by hand? Key principles of bending

08.06.2020

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How is metal bending done by hand? While doing construction works often need to fold metal elements. For example, it may be necessary to bend sheet metal or pipes. Pipes with a small diameter are bent with a vice.

Bending of metal sheets on a bending machine occurs without welding and does not violate the structure of the metal.

Often, when performing construction work, it becomes necessary to bend pipes of large diameter. For such work, special machines are needed that bend pipes and metal sheets. The bent element does not receive damage.

When bending parts, the plasticity of the material, its thickness are taken into account, and the radius of curvature is determined.

What is metal bending technology?

Assembly diagram of a home-made sheet bender: 1 - base; 2 - handwheel nut; 3 - clamp; 4 - bending sheet; 5 - clamp; 6 - crimping punch.

bending sheet metal- this is the performance of certain actions, as a result of which the metal sheet acquires the desired shape. The bending of the part occurs without the help of welding or any other connections that reduce the strength and durability of the material.

When the product is bent, its outer layers are stretched and the inner ones are compressed. The bending technology is to bend one part of the part in relation to the other to the required angle.

During bending, the material is subjected to deformation. The amount of possible deformation depends on the thickness of the material, bending angle, plasticity and bending speed.

Bending is performed by means of equipment for bending parts. This equipment bends the element in such a way that the finished structure is not damaged.

If the element is not bent correctly, then various defects will occur on its surface, as a result of which the material will receive such damage on the bending line that the finished structure may break. Bending is carried out for sheets of various thicknesses.

The bending stress of the material must be greater than its elastic limit. As a result of bending, plastic deformation of the material should occur. In this case, the finished structure after the bending operation will retain the shape that was given to it.

Drawing of a sheet bender (detailing): 1 - clamp; 2 - cheek; 3 - base; 4 - bracket; 5 - welded clamp; 6 - axis; 7 - corner of the punch.

Benefits of the bending process:

The process is highly productive.
As a result of bending, a workpiece is obtained that does not have a seam.
The finished structure is highly resistant to corrosion.
The product is highly durable.
Rust does not appear at the bend of the product.
The structure is solid.

Flaws:

The process of manual bending is quite laborious.
Bending equipment is expensive.

Unlike structures made by bending sheet metal, welded structures have a weld that is subject to corrosion and rust.

The bending of products is carried out manually or with the help of equipment. Manual bending is very labor intensive. It is done with a hammer and pliers. The bend of the material of small thickness is performed with a mallet.

Bending of sheet metal is carried out using rollers, presses or roller machines. To form a sheet into a cylinder, manual, hydraulic or electrically driven rollers are used. Pipes are made in this way.

Scheme of assembly of the working stroke: 1 - insert made of wood; 2 - base; 3 - right cheek; 4 - bending sheet; 5 - clamp; 6 – punch axis; 7 - punch; 8 - punch lever.

Metal bending is used in home construction for the manufacture of gutters, profiles, metal frames, pipes and other structures. When bending sheet metal with your own hands, you can make pipes of various diameters. With the help of machines, zinc-coated material is bent.

If you need to bend metal at home, you can make a bending machine with your own hands. For the manufacture of the machine, you need to make a template made of wood, having a contour of a certain, curved shape.

When bending the product, you need to determine its dimensions. The length of the structure is calculated taking into account the bending radius of the sheet. For workpieces that are bent at a right angle, without creating roundings, the bending allowance should be 0.6 of the sheet thickness.

With your own hands, you can bend structures made of ductile metals: copper, brass, aluminum. The bending radius depends on the quality of the material and the bending method. Products with a small radius of curvature are made of plastic materials.

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Do-it-yourself metal bending

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How to make a bracket by bending

When bending a steel strip on a roller machine, the top notch on the bar must match the size of the strip.

Materials and tools:

a metal sheet;
vise;
a hammer;
frame;
bar;
electric saw for metal.

First, you need to calculate the length of the workpiece strip according to the scheme and calculate the bending of the metal sheet.

When calculating for each bend, a margin of 0.5 strip thickness and 1 mm per bend of the ends to the side is performed.

According to the scheme, the workpiece is cut out, marks are made for the place of bending. The workpiece is bent in a vise with squares.

First you need to clamp the workpiece in a vice at the level of the bend. Then, using a hammer, the first bend is made.

Then the workpiece is rearranged in a vice and clamped with a frame along with a bar. Then make a second bend.

After that, the workpiece is pulled out, marks are made for the length of the legs of the bracket.

A bracket with a bar frame is bent in a vice, while both of its legs are bent. The bend is specified with a triangle. If the bend is not made correctly, it is corrected with a hammer and a frame bar. After the bending process, the structure is sawn off to the desired dimensions.

There are several ways to bend sheet metal, all of them have certain features. The automated method allows you to give the blanks the desired shape without the use of welding equipment. The main advantage of the bending technique is the absence of seams, which improves appearance and increase the strength of products. The bending method contributes to the acceleration production process. As a result of bending, the mass of products, metal consumption are significantly reduced, labor costs and prime cost are reduced, and profitability is increased.

Sheet metal bending has the following advantages:

saving– is achieved due to the absence of waste;
maintaining the strength of the product – welds and other connections are absent;
corrosion resistance- achieved due to the absence of changes in the structure of the material;
attractive appearance.

Sheet bending price

The cost of bending sheet metal depends on the thickness and length of the product. An important role is also played by the shape of the part, the type of steel, the features of the bending contours, etc.

Bending length, mm	100	200	500	1000	1500	2000	2500
Sheet thickness, mm	Price per sheet metal bend (minimum order from 100 bends)
0,8 - 1	9 rub.	11 rub.	16 rub.	29 rub.	40 rub.	50 rub.	76 rub.
1,2-1,5	9 rub.	11 rub.	17 rub.	30 rub.	40 rub.	50 rub.	76 rub.
2	9 rub.	11 rub.	17 rub.	30 rub.	42 rub.	51 rub.	77 rub.
2,5	9 rub.	11 rub.	19 rub.	31 rub.	44 rub.	51 rub.	77 rub.
3	9 rub.	13 rub.	20 rub.	32 rub.	49 rub.	56 rub.	95 rub.
5	14 rub.	18 rub.	25 rub.	44 rub.	69 rub.	88 rub.	139 rub.
6	15 rub.	21 rub.	28 rub.	53 rub.	81 rub.	106 rub.	166 rub.
8	17 rub.	21 rub.	33 rub.	59 rub.	105 rub.	-	-
10	19 rub.	23 rub.	38 rub.	66 rub.	-	-	-
12	23 rub.	28 rub.	45 rub.	-	-	-	-

Where sheet metal bending is used

This metal sheet processing technology is widely used in various fields due to its advantages. Bent elements with the same strength as solid-rolled pipes and profiles are light in weight. Areas of application for bending:

construction industry (roofing, components, ventilated facades);
mechanical engineering;
transport industry (cladding);
metal profiles;
production of sliding furniture;
parts of equipment cases, household appliances.

Basic Sheet Metal Bending Methods

Sheet metal bending possible various methods hot and cold. The most common methods are the transformation of cold products on bending machines, rollers. The manual method is used quite rarely, it is used for bending thin sheet metal up to 0.6 mm thick. Automatic bending methods:

On a hydraulic press(air universal). A metal strip (up to 10 mm thick, up to 6 m long) is installed on the lower table with a matrix. The product of the desired shape is obtained due to the action of the punch directed from above to the required depth.
On rollers. The metal passes through the rollers, the effect of bending is achieved due to their gradual displacement, this approach is used to obtain a shape in the form of a cone, cylinder, sphere, etc.
By matrix. The technology is distinguished by increased accuracy, it is used in the processing of sheet metal up to 5 mm, deforming the workpiece at an angle of less than 90 degrees.
With the use of a swivel beam. It is used for bending sheets up to 1 mm in order to bend products in different directions.
Slip processing. During the procedure, a separate tool is used for the workpiece of each thickness.

The listed methods of bending sheet metal provide an unchanged structure of the metal plate in the bend areas. Sheet metal thickness can reach 12 mm. The technology makes it possible to form products of the required sizes and shapes from a sheet. By bending, it is most simply possible to give the material the desired shape. The method is an easier and inexpensive alternative to welding. The choice of technology depends on the material used and the requirements for the resulting product. Before the procedure, calculations are made using a special formula.

Defects and difficulties in bending

During the deformation of metals, defects can appear. The most common are oblique bends, mechanical damage to the surface. This phenomenon occurs due to errors when marking or fixing workpieces above / below the marking line. A common mistake in bending is also considered a gap (crack) in the metal. It occurs due to insufficient plasticity of the material. Sheet metal bending is most often subject to this type defect, due to which it often has to be done manually. Another common bending defect is dimensional violations. It manifests itself when there is a shortage or excess of the sheet at the ends of the part, which occurs when the calculation of the length of the blanks is violated.

Video: Sheet bending machine

For the transformation of the metal sheet, a bending press is used, which greatly improves the manufacturability of the production process. This approach involves reducing the cost of production. Programmable stops significantly speed up production without loss of accuracy, all possible defects are easily corrected.

Benefits of contacting us

affordable cost;
compliance with all norms, rules and standards;
high quality of work;
use of modern technology;
an integrated approach, the ability to manufacture parts of varying complexity.

The company provides sheet metal bending services in Moscow. When carrying out metal bending, modern equipment is used, the use of which allows everything to be done with maximum accuracy. Sheet metal bending is fully automated, which greatly speeds up and simplifies the process.

Sheet metal is rarely used in its original form. For its further use, appropriate processing of the feedstock is necessary. The company "Rushar" offers bending and metal calculation services on modern equipment according to customer requirements. Such technological operation allows you to form products of the required shape and size from flat rolled products. Unlike welding, sheet metal bending is less expensive and takes less time.

Applied equipment

Hydraulic bending is used to bend metal. press brakes. Their parameters, dimensions, accuracy standards comply with the requirements of GOST 10560-88. This equipment provides adjustment of effort when bending sheet metal. The presses are equipped with a means of mechanizing the unloading of finished products.

On equipment intended for multi-junction bending, a device is installed program control. The type of the latter is determined by the characteristics of a particular order and the type of rental.

All presses are equipped with holding devices finished product under load, when the bending of the metal is completed. The design of the equipment allows it to be integrated into automatic lines for processing sheet metal.

In the process of bending sheet metal, the product receives a given shape. In this case, the outer layers are stretched, the inner ones are compressed, the middle ones retain their original structure. Mechanical and automatic bending of metal is carried out on the appropriate equipment. The essence of this technological process consists in bending the thin sheet strip at a given angle. The minimum bend radii are calculated according to OST 1 00286-78.

Modern types of sheet metal bending

Air (Air bending) . Such sheet bending is carried out by lowering the punch into the matrix to a predetermined depth. Their dimensions and angle are the same as in the finished part. The bending radius of the metal depends on the properties of the material and the opening of the matrix. The method is universal, it allows obtaining angles of various sizes.
metal bendingby matrix (bottoming) . This technology is somewhat more accurate than the previous one. It is used for sheet metal up to 5 mm. However, matrix sheet bending does not allow bending the original workpiece at an angle of more than 90°.
Machining using a pivot beam (Folding) . Used for bending thin sheet metal (up to 1 mm for structural steel). The method allows you to bend the workpiece in both directions, both up and down.
Slip processing (wiping) . Similar to the previous method. Such sheet bending requires a separate tool for each thickness of rolled products.

Price list with sheet metal bending prices

thickness, mm	up to 100 mm.	up to 1250 mm.	up to 3000 mm.	up to 8000 mm.
0,5 - 0,8	RUB 5.00	RUB 12.00	RUB 25.00	RUB 70.00
1,0 - 1,2	RUB 6.00	RUB 14.00	RUB 25.00	-
1,5	RUB 6.50	RUB 15.00	RUB 26.00	-
2,0 - 2,5	RUB 7.00	RUB 16.00	RUB 26.00	-
3,0	RUB 7.50	RUB 17.00	RUB 33.00	-
4,0	RUB 9.00	RUB 23.00	-	-
5,0	RUB 10.00	RUB 25.00	-	-
6,0	RUB 12.00	RUB 28.00	-	-
8,0	RUB 14.00	-	-	-
10,0	RUB 15.00	-	-	-

Benefits of our services

The Rushar company provides services for bending sheet metal with a thickness of 0.5–6.0 mm. Our main advantages include:

reasonable cost. Availability own production allows us to support affordable prices for sheet metal bending;
high quality work. For sheet metal bending under the order, modern equipment is used. Hydraulic presses provide the necessary dimensional accuracy of the finished part;
A complex approach. In addition to sheet metal bending services, we provide waterjet cutting, cold stamping and other custom processing.

High quality products combined with reasonable prices Convenient location The shortest order execution times All types of sheet metal work in one place

Sheet metal bending is one of the most common cold and hot deformation operations. It is characterized by low energy consumption, and with the correct development of the technical process, it makes it possible to successfully produce three-dimensional products of various shapes and sizes from flat blanks.

In accordance with the tasks set, sheet metal bending technology is being developed for the following options:

Single-angle (sometimes called V-shaped flexible).
Two-angle or U-shaped bending.
Multi-angle bending.
Radius bending of sheet metal (sealing) - obtaining products such as loops, galvanized clamps, etc.

The bending forces are small, so it is mainly performed in a cold state. An exception is the bending of a steel sheet made of low-plasticity metals. These include duralumin, high-carbon steels (containing an additional significant percentage of manganese and silicon), as well as titanium and its alloys. They, as well as blanks made of thick sheet metal with a thickness of more than 12 ... 16 mm, are mainly hot-bent.

Bending is combined with other sheet metal stamping operations: cutting and bending, with punching or punching are often combined. Therefore, for the manufacture of complex multidimensional parts, dies designed for several transitions are widely used.

A special case of sheet metal bending is tension bending, which is used to obtain long and narrow parts with large bending radii.

Depending on the size and type of the workpiece, as well as the required characteristics of the product after deformation, the following are used as:

Vertical with mechanical or hydraulic drive;
Horizontal hydraulic presses with two sliders;
Forging bulldozers - horizontal bending machines;
Pipe and profile bending machines;
Universal bending machines.

To obtain structures that are unique in shape and size, in particular, turbine boilers, etc., exotic technologies for bending sheet steel are also used, for example, by explosion energy. In contrast, the question - how to bend tin - does not cause difficulties, since the plasticity of this material is very high.

A characteristic feature of sheet bending machines is reduced deformation rates, increased dimensions of the die space, and relatively low energy consumption. The latter is the basis for a wide production of galvanized material intended for deformation. They are particularly popular in small workshops as well as individual users.

Despite the apparent simplicity of the technology, it is difficult to determine the balance of stresses and deformations of the state in the workpiece. In the process of bending the material, stresses arise in it, first elastic, and then plastic. At the same time, the bending of the sheet material is characterized by a significant deformation unevenness: it is more intense at the bending corners, and is almost invisible at the ends of the sheet blank. Sheet metal bending is characterized by the fact that its inner layers are compressed, and the outer ones are stretched. The conditional line that separates these zones is called the neutral layer, and its precise definition is one of the conditions for defect-free bending.

In the process of bending, rolled metal receives the following shape distortions:

Change in thickness, especially for thick plates;
Springing / springing - spontaneous change in the final bending angle;
Folding of a metal sheet;
The appearance of metal flow lines.

All these circumstances must be taken into account when developing the stamping process.

Stages and sequence of technology

Here, and in the future, we will focus on the processes of stamping sheet metal in a cold state.

Development is carried out in the following sequence:

The design of the part is analyzed.
The force and work of the process is calculated.
The standard size of the production equipment is selected.
A drawing of the original workpiece is being developed.
Deformation transitions are calculated.
Technological equipment is being designed.

An analysis of the suitability of the capabilities of the source material is necessary in order to find out its suitability for stamping according to the dimensions shown on the drawing of the finished part. The stage is performed on the following positions:

Checking the plasticity of the metal and comparing the result with the level of stress that occurs during bending. For low-ductility metals and alloys, the process has to be divided into several transitions, and interoperational annealing should be planned between them, which increases plasticity;
Possibility of obtaining a bending radius at which no cracking of the material will occur;
Determination of probable distortions of the profile or thickness of the workpiece after pressure treatment, especially with complex contours of the part;

Based on the results of the analysis, sometimes a decision is made to replace the original material with a more ductile one, about the need for preliminary softening heat treatment, or to preheat the workpiece before deformation.

A mandatory point in the development of the technological process is the calculation of the minimum allowable bending angle, bending radius and springback angle.

The bending radius r min is calculated taking into account the plasticity of the metal of the workpiece, the ratio of its dimensions and the speed at which the deformation will be carried out (hydraulic presses, with their reduced slider speeds, are preferable to faster mechanical presses). With a decrease in the value of r min, all metals undergo the so-called thinning - a decrease in the initial thickness of the workpiece. The intensity of thinning determines the thinning factor λ, %, which shows how much the thickness of the final product will decrease. If this value turns out to be more critical, then the initial thickness s of the workpiece metal has to be increased.

For low-carbon sheet steels, the correspondence between the above parameters is given in the table (see Table 1).

Thus, under certain conditions, the metal of the workpiece can even bulge somewhat.

No less important is the determination of the minimum bending radius, which also depends on the initial thickness of the metal, the location of the rolled fibers and the ductility of the material (see Table 2). In the event that the bend radius is too small, the outer steel fibers can break, which violates the integrity of the finished product. Therefore, the minimum radii are usually counted according to the largest deformations of the extreme parts of the workpiece, taking into account the relative narrowing ψ of the deformable material (set according to the tables). In this case, the amount of deformation of the workpiece is also taken into account. For example, for small deformations, the dependence is used

and for large deformations, a more accurate equation of the form

The effect of possible springback can be taken into account using the data on the actual springback angles β, which are given in table 3. The data in the table correspond to the conditions of one-angle bending.

Determining the bending force

The power parameters of bending depend on the plasticity of the metal and the intensity of its hardening during deformation. In this case, the direction of rolling of the original billet is important. The fact is that after rolling, the metal acquires the property of anisotropy, when the residual stresses in the direction of the rolling axis are less than in the opposite direction. Accordingly, if along the fibers, then at the same degree of deformation, the probability of destruction of the workpiece is significantly reduced. Therefore, the bending edge is positioned in such a way that the angle between the direction of rolling and the location of the blanks in the sheet, strip or strip is minimal.

To calculate the force parameters, it is specified how the deformation will be performed. It is possible by a bending moment, when the workpiece is placed on the clamps / stops, and then freely deformed, or by force, when at the final moment of the process the semi-finished product rests on the working surface of the matrix. Free bending is simpler and less energy intensive, but bending with calibration makes it possible to obtain more accurate parts.

In the process of building a house or a summer residence, it often becomes necessary to equip drains, sewers, metal frames.

In the manufacture of such products, it is necessary to give a flat workpiece the necessary spatial shape. Tips experienced craftsmen how to bend a sheet of metal at home, will allow you to make structures good quality that will last for a long time.

Metal bending is performed without welding seams, which allows to avoid corrosion in the future and obtain a product of increased strength. Deformation does not require significant effort and is usually performed in a cold state.

The exception is solid materials, such as duralumin or carbon steels. Sheet metal bending technology is developed in accordance with the tasks set in such options as:

radius,
multi-angle,
single-angle,
p-shaped.

A separate case is flexion with stretching. This technology is used in the manufacture of parts with large bending radii, small diameter. When making parts with your own hands, the process is combined with operations such as cutting or punching.

Soft types of metals and alloys, such as brass, copper, aluminum, are well suited for home processing. The production of products by bending is carried out on rolling or roller machines, or manually.

The last procedure is quite laborious. Bending is done with pliers and a rubber mallet. If the sheet is thin, use a mallet.

How to bend at right angles

To bend a staple from a metal sheet, you will need a set of tools and fixtures, consisting of:

vise,
hammer,
electric saws,
bar,
frames.

The length of the strip is made according to the scheme, with the expectation that for each bend there should be a margin of 0.5 mm, plus another millimeter for bends on both sides. The workpiece is placed in a vise with squares. Clamping it along the fold line, it is processed with a hammer.

After that, the future bracket is unfolded in a vice, clamped with a frame and a bar, and the other side is formed. The workpiece is pulled out, the required length of the sides is measured, making bends along the bottom.

A triangle checks the correctness of the angle, correcting inaccuracies with a hammer. When performing both operations, the workpiece is pressed with a bar and a frame. The finished staple is sawn to the desired size.

How to make a bending machine yourself

To give the metal the desired configuration, tinsmiths use a sheet bender. But what about a master who does not have special equipment at hand?

In fact, the question of how to bend sheet metal at home is easily solved. It is enough to use your own ingenuity and elementary devices to make a simple machine.

To make a bender for a metal profile, you will need:

I-beam 80 mm,
fasteners (bolts),
loops,
corner 80 mm,
clamps,
pair of handles.

You will also need a stable table on which the finished machine is fixed.

The basis of the device is an I-beam, to which a corner is screwed with two bolts, holding the workpiece in the process of bending. Three door hinges are attached under it by welding. The second part is welded directly to the corner.

To make the machine turn easily during sheet metal bending, handles are attached to it on both sides. With clamps, the finished machine is attached to the table. Before laying the workpiece, the corner is unscrewed or lifted. The sheet is pressed, aligned along the edge and bent by turning the machine by the handles. A homemade device is only suitable for processing workpieces of small thickness.

Bending a metal sheet with a hammer

In order to bend a sheet up to 1.2 mm thick at a right angle, use the simplest tools - pliers (clamps) and a rubber hammer.

Processing is carried out on a flat wooden block. The fold line is drawn with a pencil and a ruler. Then the sheet is clamped with pliers so that their ends fall exactly on the marking line.

The edge is gradually folded up, moving along the fold. After the angle approaches 90 degrees, the sheet is placed on a bar and finally leveled with a hammer.

In this way, narrow parts are produced, such as sheet metal edges.

Tip: A rubber or wooden mallet is used to prevent dents from forming on the metal. If bending is performed with a conventional tool, a textolite plate should be taken as a gasket.

It is convenient to bend a sheet up to 2 mm thick on the desktop. The metal is positioned so that the marking line falls on the edge. A steel corner is placed under the material to be processed.

The sheet is clamped in a vice with two wooden bars. Bending is done with a hammer, tapping the metal from one end to the other. At the same time, the edge of the sheet is directed down so that in the end it completely lies on the corner fixed along the edge of the table. In this way, products of any width are made, including boxes or barbecues.

Making a pipe without using a machine

Home craftsmen have invented a lot of ways to bend a metal sheet into a pipe without using a machine.

We propose to consider the simplest option using a blank of a suitable size. It is made from an old pipe of a suitable diameter.

A sheet of metal is laid out on the floor, a piece of the desired length is cut off from it. To determine the correct size, the required pipe diameter is multiplied by 3.14 and added 30 mm per seam.

A pair of tubes is welded to the blank on both sides perpendicular to one another. Scrap should be freely inserted into their holes.

To use the device, the efforts of three people will be required. The blank is placed on the edge of the sheet. One person stands on top, two others wind the metal onto the blank, turning the crowbar 90 degrees.