Press brakes are made on the hydraulic principle of action. The accuracy of the nodes is controlled by sensors: circular encoders or linear reading. The holding mechanisms serve as a safety unit and protect the workpieces from slipping from the clamping elements.
Features of equipment design
Press brakes are the next and more productive generation of pneumatic machines. The first designs lacked the effort to perform precise bending. Models are subdivided according to the main criteria: maximum force, workpiece length.
Press brakes for simple movements with low requirements can be made on the basis of elementary logic without monitoring the main parameters. More complex products require automated CNC systems with traverse position sensors and bending angle control. Often a backstop is used to support the workpiece in a certain position.
For example, for an Asian press brake, the price is formed by summing the costs of the machine base and a set of options. The amount of investment varies from hundreds of thousands of rubles to millions of costs for unique models. Options include additional control of parameters, positions of stops, sensors of the security system. Also, users have access to a huge number of applications that facilitate the creation of programs for products of standard forms.
Why do I need two controllers?
Press brakes are a complex type of equipment. The standard controller is applicable for processing simple signals and is not intended to control a large number of axes. At a minimum, a separate control unit is required, which affects the final price of the machine.
A special CNC controller allows the machine to be ready for operation at high speed, to position the crosshead on several axes at the same time. The process parameters, the speed of removal from the part, the pressure time and many other equipment conditions are processed in software: oil temperature, system activity, integrity control of the working parts. Hydraulic press brake provides high repeatability of the bending angle, the main quality of products depends on it. Precise rulers are indispensable here. The drive system affects the timely removal of the beam, in case of violation of the exposure time, the machine begins to produce defective products.
Extra options
CNC press brake is in most cases used for the production of rather long and thin products. Therefore, reinforced beam is used in the design. But with all the rigidity of the metal, it still sags a few millimeters.
These values must be taken into account to ensure high accuracy. The CNC system corrects for the entered parameters, excluding possible errors. Such compensation is required for machines longer than 2 meters. Energy saving mode is implemented by many press manufacturers. In moments of downtime, stationary units are turned off, pumps are turned off, and engines are powered. Of no small importance is the ability of equipment to be connected according to standard protocols for monitoring the entire technological chain of the production line.
Components of equipment
The bed carries the main load of the unit and keeps it from swinging during the operation of the upper part - the beam. A tool for press brakes is mounted on the moving part. Servomotors are connected through screw-couplers and gearboxes to a support located on sliding guides. Rolling bearings have low operational properties, but can be used in cheaper models. This is a significant design flaw.
The selection criterion is the method of fastening the tool, the type of hydraulic cylinders used, the method of installing punches, the presence of guards and automatic protection. Many manufacturers have software help in the calculations, the most successful parameters have already been entered into the database. It remains only to indicate the type of material and dimensions of the part according to the drawing. The machine will do the rest on its own after starting the automatic cycle.
Design difference
The machines are equipped with several types of beds, differing in shape. Each of them has its own advantages and disadvantages, depending on the type of part manufactured and placement in the workshop:
- The C-shaped form of the bed has a wide front part, a pocket forms behind. Manufacturers use it to service the working area, and there you can also place additional equipment: a cooler, a compressor. The disadvantages include the following: if the press load was once exceeded, the bed can lead, and it will open a little. You will need to set the alignment of the design again.
- The O-shaped form of the bed is more reliable and will not open at high loads. But along with this, the weight of the machine and the dimensions increase. If the previous forms can be combined in lines, then this model is used only as a piece of equipment. It is also difficult to remove finished products from the side, which slows down the production process.
Working part
The main interchangeable element of the machine is the tool. It depends on it the quality of parts, dimensional accuracy. For each workpiece, the corresponding material of the working part is selected.
Using the software, the tool sizes are entered into the CNC memory. The next readjustment is carried out in a few minutes, loading the required configuration into the processing area.