The press brake, equipped with a hydraulic drive, can be found today in the equipment of many manufacturing enterprises operating in various industries. This device, on which a metal workpiece is processed by the cold deformation method, makes it possible to manufacture products, the geometric parameters of which exactly correspond to the specified values.
Development history and application benefits
The hydraulic sheet bending machine, which began to be used by industrial enterprises in the middle of the 20th century, replaced manual and mechanical devices designed for bending sheet metal. Along with the high efficiency and economy of use, the manual press for bending also has a number of significant disadvantages associated primarily with the impossibility of obtaining products with precise geometric parameters with its help, as well as with the application of significant physical efforts during its use.
Mechanical press brakes are also not without drawbacks, which are as follows:
The operation of such a machine is accompanied by significant noise and strong vibration.
Products made on such equipment are not of high quality.
When operating such a machine, the risk of injury to the operator who operates it is too great.
The use of such a press brake is associated with increased energy consumption.
Changeover of mechanical plate bending machines is a rather complicated procedure.
In addition to mechanical and manual press brakes, pneumatically driven press brakes are also on the market today. Such equipment, for the operation of which requires a centralized network of compressed air, has one very serious drawback: even with an increase in the size of the machine, the force it develops, with which it acts on the workpiece being processed, does not allow processing of sheet metal products of significant thickness.
Having appeared on the market, the hydraulic listogib, featuring the highest power among all equipment of this purpose, made a real breakthrough in sheet metal processing by bending. Some models are presented at https://harsle.com Such a press brake, in addition to high power, has many other advantages:
economical power consumption;
high level of security;
high reliability;
the ability to manufacture products of exceptionally high quality.
Having appeared on the market in the middle of the 20th century, hydraulic models of bending machines have acquired a number of significant improvements, which made it possible to endow these devices with additional functionality, make them more convenient and safe to use. Equipping a modern hydraulic press brake with innovative devices and additional mechanisms allows it to be used to successfully solve even the most complex problems associated with flexible sheet metal. Among such devices and mechanisms are:
a CNC system for a press brake (such a system, equipped with a graphical user interface, is able to independently determine the modes and sequence of technological operations);
mechanisms that provide increased protection of the machine operator from injury;
electronic devices that are responsible for adjusting the traverse speed;
an indicator that provides control over the angle of the bending being performed.
This is just a small list of additional elements that may be present in the design of a hydraulic press brake. The presence of such equipment significantly expands the functionality of the machine and makes it possible to use it for solving special problems.
Having appeared on the market in the middle of the 20th century, hydraulic models of bending machines have acquired a number of significant improvements, which made it possible to endow these devices with additional functionality, make them more convenient and safe to use. Equipping a modern hydraulic press brake with innovative devices and additional mechanisms allows it to be used to successfully solve even the most complex problems associated with flexible sheet metal. Among such devices and mechanisms are:
a CNC system for a press brake (such a system, equipped with a graphical user interface, is able to independently determine the modes and sequence of technological operations);
mechanisms that provide increased protection of the machine operator from injury;
electronic devices that are responsible for adjusting the traverse speed;
an indicator that provides control over the angle of the bending being performed.
This is just a small list of additional elements that may be present in the design of a hydraulic press brake. The presence of such equipment significantly expands the functionality of the machine and makes it possible to use it for solving special problems.
Design features
The press brake, equipped with a hydraulic drive, is used to solve the following technological tasks:
the formation of bent metal products, the geometric parameters of which exactly correspond to the specified parameters;
performing one of the stages of the technological process of processing products from sheet steel, the thickness of which exceeds 3.5 mm;
performing high-quality and inexpensive bending of products from sheet steel, the thickness of which does not exceed 3.5 mm;
production by bending of large batches of the same type of products from sheet steel.
According to the degree of its mobility, the hydraulic listogib can be mobile or stationary. Hydraulically driven stationary metal bending presses are highly powerful and efficient. They are used to process a large number of workpieces in a limited amount of time. In addition, stationary hydraulic bending machines, due to their technical capabilities, are successfully used for processing workpieces made of sheet metal, even of very large thickness. Mobile or mobile presses, also powered by a hydraulic drive, can be easily moved to any site where they are planned to be used for their intended purpose.
The principle of operation of a press brake is that its working body, which is a traverse, is told the required direction of movement and the level of force with which it acts on the workpiece being processed. The traverse is a rigid beam made of steel. It is on it that the working devices are fixed, with the help of which the product is formed with the given geometric parameters.
For the accuracy of the traverse movement, on which the accuracy and quality of the processing performed directly depend, two linear sensors are responsible, one of which monitors the right side of the working body, and the second - for the left. In order to be able to form a bendable edge with the required geometric parameters on hydraulic bending machines, most models are equipped with a rear programmable stop. Hydraulic bending machines are practically irreplaceable equipment in the production of products for the following purposes:
body parts for household and industrial equipment, electrical devices for various purposes;
elements of vehicle bodies;
bent metal products for any other purpose.
Principle of operation
The principle by which the hydraulic press brake works is quite simple, but nevertheless ensures both high productivity of technological operations and their safety.
The process of bending sheet metal blanks using a machine of this category is carried out in the following sequence:
The traverse of the press is fixed at the "dead center" of the plate bending equipment, located in its upper part.
In order for the traverse to start moving from top to bottom at the required speed, a foot pedal or a button is used, with which this mechanism is controlled. To a certain position, the traverse moves with a free fall speed that is higher than the speed required to perform bending. Despite this definition, as such, the free fall of the traverse does not occur, its every movement is monitored and controlled by means of appropriate equipment.
When the crosshead is as close as possible to the surface of the workpiece being processed, the working speed is imparted to the beam. Control of all movements of the crosshead, as well as the operating modes of such movements, is provided by the hydraulic system of the press brake, and hardware adjusting means or special sensors are responsible for controlling such processes.
The traverse of the machine, after communicating the working speed to it, tends to the bottom "dead point", after reaching which it is kept in this position for some time. Holding the traverse at the bottom dead center is necessary in order to ensure a uniform load on the surface of the workpiece, which is subjected to the bending process.
It is very important, after the end of the workpiece bending, to start lifting the traverse at a certain speed, which has no less effect on the quality of the processing performed than the process itself. The stage of the bending process, at which the traverse is raised above the surface of the newly processed workpiece, is called decompression.
After the end of decompression, the traverse returns to the top dead center at a sufficiently high speed.
The equipment is turned off and the finished product is removed from the processing area.
The technological process of bending a sheet metal blank, carried out on a press brake equipped with additional working mechanisms, may slightly differ from the above described scheme, but in general its essence remains unchanged.
When processing workpieces on a hydraulic sheet bending machine, they are guided by several basic parameters of both the equipment used and the technological process. These parameters include, in particular:
working length of the equipment used;
the force that the working body of the press exerts on the workpiece being processed;
the performance with which the processing is performed.
In addition to the main ones, there are also a number of additional parameters that must also be taken into account both when choosing a press and when performing processing. These parameters include:
the distance between the side racks of the machine;
the speed at which work operations are performed;
the distance to which the traverse can be raised as much as possible, etc.
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