CNC bending machine is a kind of machine for processing sheet metal. It mainly uses hydraulic system to fold sheet metal into different angles. This paper introduces the successful application of quadfang CA500 servo driver and CM500 servo motor in CNC bending machine.
The traditional hydraulic system of NC bending machine uses ordinary three-phase asynchronous motor to drive the oil pump, which has high energy consumption, high temperature rise, low efficiency and easy damage of components. With the increasing attention paid to energy saving and emission reduction, a new type of CNC bending machine which uses electro-hydraulic servo system to drive oil pump emerges at the historic moment. In this paper, combining the four CA500 servo driver with CM500 servo motor, an electro-hydraulic servo speed control scheme for the hydraulic system of CNC bending machine is introduced, which can effectively reduce the energy consumption of the system and the temperature rise of hydraulic oil, and improve the reliability of equipment operation.
One. Brief introduction to the process
CNC bending machine a work cycle can be divided into fast, slow, pressure, unloading, return these several states. When the equipment is working, the system controls the operation of the oil pump and works with the hydraulic oil circuit control unit, so as to control the flow of the hydraulic system and reach the reasonable pressure value under various working conditions. Its specific work process is as follows:
When the sliding block of the machine goes down quickly, the pressure oil enters the upper chamber of the oil cylinder through the hydraulic valve group, and the oil in the lower chamber of the oil cylinder returns to the hydraulic pump through the hydraulic valve group. The sliding block of the machine drops rapidly due to its weight, and the liquid filling valve is opened to fill the upper chamber of the oil cylinder. When the sliding block of the machine works at low speed, the pressure oil flows into the upper chamber of the cylinder through the hydraulic valve group to continue to push the sliding block down; When the machine slider returns, the pressure oil enters the lower chamber of the oil cylinder through the hydraulic valve group, the piston rod of the oil cylinder pulls the slider to rise, and the oil in the upper chamber of the oil cylinder flows back to the oil tank through the open liquid charging valve, so as to complete a working cycle.
Two, the system scheme
The hydraulic system of the traditional bending machine adjusts the flow of the system through a fixed pump and a proportional reversing valve. Because the actual flow required by the system is changing, and the output flow of the oil pump is constant, there must be a part of the flow to overflow, resulting in energy loss; On the other hand, the set pressure of the valve-controlled hydraulic system is always higher than the actual pressure needed, which also results in the loss of energy. At the same time, there is overflow of the main pressure valve in the throttling speed regulation mode, resulting in large noise and heat value of hydraulic oil, high temperature rise, reduce the service life of hydraulic oil, and increase the maintenance cost.
Aiming at the shortcomings of the traditional hydraulic system of the bending machine, as well as the molding process and process characteristics of the equipment, the paper designs a control system which adopts the quadrate CA500 servo driver, CM500 servo motor and gear pump to adjust the flow and pressure of the hydraulic system.
The specific system scheme is as follows:
According to the position feedback of the grating ruler, the NUMERICAL control system obtains the required flow and pressure of the system through the characteristic algorithm, outputs the corresponding 0 ~ ±10V analog control signal to CA500, adjusts the speed of the oil pump in real time, and works with the hydraulic oil circuit control unit to meet the pressure and flow requirements of different process ends.
By adjusting the speed of servo motor to change the flow rate and system pressure of the oil pump, the energy loss caused by the traditional throttle speed control scheme is avoided. Especially in the stage of pressure holding and unloading, the oil output is very small, and the oil pump can almost stop running, which greatly reduces the energy loss. At the same time, the response time of the servo drive system is shorter, the equipment is working faster, and the return journey is faster, and the efficiency is higher.
※ CA500 servo driver adopts heavy load design, low frequency torque, fast dynamic response, strong overload capacity, can operate for a long time with 120% load;
※ CM500 servo motor adopts high performance rare earth permanent magnet material, strong anti-demagnetization ability. The motor rotor adopts special structure and technology, the shell protection class is IP54, the insulation class is F, to ensure the reliability of the system operation;
※ The pump control technology replaces the conventional valve control technology to eliminate the throttling loss, the energy saving effect is remarkable, the energy saving rate can reach 25%.
※ Lower the temperature rise of hydraulic oil, prolong the service life of hydraulic oil, reduce the maintenance cost of the system;
※ The noise of each process section of the bending machine is obviously reduced during operation of fast down, slow down, pressure holding, unloading and return, and the working environment is improved.
※ Simplified debugging function (no debugging for sifang motor), minimize commissioning parameters for customers, easy to install and use.
This paper introduces a numerical control bending electro-hydraulic servo scheme based on quadrilateral CA500 servo driver and CM500 servo motor. The scheme effectively reduces the energy consumption of the system, the operation noise is small, the system response is fast, the efficiency is improved, and the operation is stable and reliable, the protection function is powerful, the operation is simple and convenient. Can not only meet the bending machine molding process requirements, improve product quality and output, but also reduce equipment maintenance costs, to create good economic benefits for users, has been batch applied in a number of CNC bending machine servo system.