Modern technologies for metal cutting in industry

Cutting is one of the most common technological operations in metalworking. Metal cutting is carried out in 2 ways: manually using saws, scissors, and other tools, and mechanized using machines and special equipment.

The first method is used for the manufacture of single copies or small batches of products. The mechanized type of metal cutting is used in serial and mass production. Let's consider methods of cutting sheet and rolled metal.

Waterjet cutting of metal

This method was one of the first to be used for cutting metal. Blanks of a given shape were cut out of a metal sheet with a stream of water mixed with abrasive and supplied under pressure of up to 5000 atmospheres.

The method has a number of limitations regarding the grade of the metal alloy and the thickness of the sheet material being cut, although it allows cutting parts with a complex trajectory.

To increase the productivity of the process, it is possible to simultaneously cut thin sheet materials in a stack of several layers.

Sheet metal cutting speeded up significantly with the advent of thermal cutting equipment. Nowadays plasma cutting machines are used for cutting. Another option for cutting equipment is a laser machine. The cutting function, as a rule, is one of the options included in the software product of such machines.

High-speed cutting, carried out according to the program, allows you to arrange the parts on the sheet in the most advantageous way and minimizes waste. At the same time, laser or plasma automated cutting is safe, economical, and does not harm the environment.

Method 7 Cutting with a reciprocating saw

A reciprocating saw or electric hacksaw is a relatively new tool on our market. Like a jigsaw, this saw can change its blades, therefore, along with cutting wood, it is used for cutting soft and hard metals (stainless steel, aluminum), as well as aerated concrete, plastic, craton, etc. This tool is more powerful than a jigsaw. In addition, the saw is more mobile and does not require support during operation. Can be used for quickly cutting iron pipes with a diameter of 2-3 centimeters or more (see video below).

Manual metal cutting

This method of cutting material is carried out by a master using slotted metal shears, an angle grinder - an angle grinder or a pipe cutter.

For cutting with a grinder, special abrasive wheels “for metal” are used.

Pipe cutters, in which the cut is performed with steel disc cutters-rollers, are used for cutting pipes.

The speed and accuracy of manual work depends entirely on the person. The thickness of the metal being separated (especially with slotted shears) is limited.

The manual method is ineffective and is practically not used on an industrial scale. The main area of ​​use for manual cutting is in everyday life.

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Thermal cutting of metal

The following types of thermal cutting are used:

• oxygen gas;
• laser;
• plasma.

All these methods are non-contact, i.e. When working, there is no direct contact between the workpiece and the cutting tool. The workpiece is separated using a gas jet, plasma or laser beam.

Oxygen gas cutting

The technological process is based on the ability of metal to heat up, melt and burn out in pure oxygen at high temperatures (more than 1000 °C).

Before starting the technological operation, it is necessary to heat the cut site to a temperature at which the material ignites. This heating operation is carried out by the flame of the torch. Acetylene is most often used as a heating gas. The heating time depends on the thickness, brand and condition of the metal surface being processed. Oxygen is not used at this stage.

After warming up, oxygen is added to the operation. The flame jet, moving evenly along the cutting line, cuts through the entire thickness of the semi-finished product. The oxygen used in the process not only cuts, but also removes oxides that form on the surface of the semi-finished sheet product being cut.

An important criterion for obtaining a high-quality cut is maintaining the same distance between the cutter and the surface being cut throughout the entire operation. This is difficult to achieve if metal cutting is done with a hand-held oxy-fuel torch. With an automated process (high-speed, oxy-fuel cutting with increased quality, high-pressure oxygen cutting), the cutting speed increases and the quality of the cut increases.

Uniqueness of the method:

• ability to cut thick workpieces;
• ability to cut titanium sheets.

Some disadvantages of oxy-fuel cutting:

• Non-ferrous metals such as aluminum, copper, as well as high-carbon or chromium-nickel steels cannot be cut;
• large cutting width, low quality, formation of oxides, sagging,
• it is impossible to work with curved surfaces;
• change in physical properties in the cutting area.

Laser cutting

This technology involves cutting and cutting metal using a focused laser beam produced using special equipment.

The laser beam is concentrated at a specific point on the part being cut. Under the influence of the thermal energy of the laser beam, the surface warms up, boils and evaporates. The beam moves smoothly along the cut boundary, dividing the metal workpiece into parts.

Laser cutting is used to separate metals with low thermal conductivity. It is used for cutting, cutting thin sheets (from 0.2 mm), non-ferrous metals (aluminum, copper), stainless steel, and pipe products.

The uniqueness of the method: almost all metals, metal alloys, and non-metals are processed.

A number of disadvantages of laser cutting technology:

• limitation on the thickness of the divided products;
• high energy costs during the process;
• The work can only be performed by specially trained personnel.

Plasma

This technology involves the use of a plasma torch as equipment, in which the role of a cutting tool is performed by a plasma jet.

Hot ionized gas (plasma) passes through the plasmatron nozzle at high speed. The plasma heats, melts the metal, and then blows off the melt, thereby forming a cutting line for the workpiece.

Uniqueness of the method:

• process safety;
• high speed;
• slight limited heating of the cut surface.

The disadvantages of this technology are the high price of equipment, the need for personnel training, noise during operation of plasma installations, and limited thickness of the metal being processed.

Kinds

All metal cutting technologies are divided into two large groups:

• mechanical;
• thermal.

Mechanical ones are based on the separation of metal by exposing it to cutting surfaces made of a more durable material. These include:

• saws;
• guillotine and sheet shears;
• hydraulic cutting.

In hydraulic cutting, separation occurs through the action of a thin jet of water under high pressure.

Thermal cutting methods are based on melting the metal at the cut line using heat. These include:

• gas;
• plasma;
• laser

The cutting method is selected based on the thickness of the workpiece, the metal or alloy of the workpiece, its thickness, the amount of work, the location of the cutting and a number of other parameters . Many craftsmen tell how to cut metal with a welding inverter. This type of cutting by electric welding is inefficient, has a high waste rate and low accuracy.

Mechanical metal cutting

Mechanical separation is based on direct contact of the metal being processed with the cutting tool. The material of the tool, as a rule, is also metal, but of higher hardness.

There are mechanical cutting using scissors, saws, and cutters. A special case of mechanical cutting is impact cutting. Impact cutting or chopping with a guillotine is used at the stage of procurement work.

Types of equipment used for mechanical separation of materials:

• band saw machines (LPS);
• guillotines;
• disk machines;
• lathes with cutters installed on them;
• slitting units.

Band saw cutting

Cutting material with a band saw is often used to separate long, sheet metal. The band saw is the main unit on the so-called band saw machine (LPS). The essence of the work of a band saw is the same as that of a regular hacksaw. The saw blade is enclosed in a large diameter band, one side of which has special teeth. The saw blade moves continuously due to the rotation of pulleys connected to an electric motor. The average cutting speed of the machine is 100 mm/min. The material for making the saw blade is carbon steel or bimetallic alloy.

The advantages of the method: accuracy, accessibility, low price of equipment, the ability to perform not only straight, but also angular cuts; a small percentage of waste, since the cutting width is only 1.5 mm.

Modern LPS models are equipped with electronics and additional equipment with which you can include the machine in the production line.

Impact cutting of metal on a guillotine

This type is usually called felling. The main application of cutting is the separation of sheet metal. It can be ferrous metal, various types of steel - stainless, galvanized or electrical steel.

The method is based on the use of mechanical devices: scissors, knives for cutting metal sheets. The metal sheet is placed on the working surface of the guillotine. They are secured using a pressure beam and the operation is performed.

The uniqueness of the method lies in the fact that chopping (cutting metal) occurs with a single blow of a knife along the entire length of the workpiece being cut. The result is an absolutely smooth edge without unnecessary edges or burrs.

Three types of guillotines are used in industrial production:

• electromechanical;
• hydraulic;
• pneumatic.

In some industries, manual guillotine shears have been preserved, where the cutting mechanism is activated by pressing the pedal.

Disadvantages include noise during operation of the mechanism, limitations on the thickness of the workpiece, and differences in the width of the cut parts.

Cutting on a disc machine

The main advantage of this equipment is ease of operation, compactness, and versatility.

The role of the cutting tool is played by a disk with teeth protected by a casing. The disk is mounted on the surface of the desktop and driven by an electric motor.

Cutting with a circular saw is characterized by high cut quality, the ability to cut at an angle, and high processing accuracy.

A slitting unit is highly specialized equipment that is used exclusively for longitudinal separation of a metal workpiece.

The cutting process is fully automated. The operator monitors the process and controls the work from behind a special console.

The uniqueness of the method: the ability to divide sheets into narrow elements of long length (ribbons, strips, strips).

The general disadvantages inherent in all types of contact cutting can be formulated as follows:

• cuts only in a straight line or at an angle;
• It is problematic to obtain parts of complex configurations.

In modern technologies, the latest methods of metal separation are used, in particular, cryogenic (an operation using a supersonic flow of liquid nitrogen).

Cutting and cutting of metal are the primary procurement stages of processing metals and alloys. The use of straight-sided workpieces of the correct shape as the final product of metalworking is limited. After cutting by mechanical methods and gas-oxygen cutting, the parts are transferred for mechanical processing. But using thermal operations of laser and plasma cutting, you can obtain parts that are the final product. These will be parts of a complex configuration with cut holes, cuttings and other elements.