In the traditional forging production, the material is fed manually and positioned by relying on the positioning block with simple structure and the experience of workers. The positioning is not accurate enough, the production efficiency is very low, and it brings more labor burden. With the continuous innovation of technology, programmable controller (PLC) is gradually applied. PLC programming is simple, which is convenient for technicians to operate it. The operation process is more stable, the positioning is accurate, and it is not easy to be disturbed by external factors, which greatly improves the production efficiency, The stepping beam multi station servo automatic feeding system of hot die forging press based on PLC technology is gradually applied to forging production.
1.Overall system structure
The four Station walking beam manipulator is composed of beam, longitudinal beam, end effector, sensor, driving box and driving elements. Because the installation accuracy of the stepping beam directly affects the working accuracy of the manipulator, a special stepping feeding motion control system is developed according to the working characteristics of the manipulator. The servo driving device of the stepping beam includes a feeding servo motor fixed at the end of the transmission rod on the right, and the feeding servo motor is connected with the control device through a wire.
The basic forging process of forged gear blank is as follows: firstly, heat the initial bar to the pre forging temperature, then send the drive belt to the host to cooperate with the stepping beam, and finally drive the finished product to the material box through the conveyor belt, as shown in Figure 2.
2.Manipulator design
The multi station stepping beam Servo Automatic System of the press can realize the cyclic actions of clamping, rising, advancing, falling, releasing, retreating and clamping consistent with the action rhythm of the press in the X, y and Z directions. Therefore, it can be applied to many stations, such as storage position, upsetting position, forming position, bottom cutting position, discharge position and so on Step transmission.
Three coordinate workpiece conveying system can be roughly divided into two categories: mechanical workpiece conveying system and electronic workpiece conveying system. The transmission shaft of the mechanical workpiece conveying system rotates synchronously through the connection between the sprocket and the crank shaft of the press. The transmission shaft distributes the rotation cycle of the crank to the x-direction moving part, the z-direction lifting part and the y-direction clamping part through the cam, realizes the operation cycle of clamping, rising, moving forward, falling, releasing and retreating, and transmits the workpiece to the next station, that is, realizes the automation of feeding and the automation of the work of the three station press. The electronic workpiece conveying system takes the servo motor as the power output device and works under the control of PLC. The action coordination is controlled by the electronic signal exchanged between the press and the controller. The movement track is controlled by PLC program, which can adapt to different die spacing. Compared with mechanical type, it is adjustable. Therefore, the electronic workpiece conveying system is used to program the motion trajectory of the production line.
According to the movement of the walking beam manipulator, the four Station walking beam manipulator is designed as a floor structure. Its movement is through the servo control system and the host to provide energy, so as to realize linkage. The top view of the designed four Station walking beam structure is shown in Figure 3.
3.Conclusion
The motion track of the walking beam manipulator is controlled by PLC program, which can adapt to different die spacing. The manipulator can accurately and quickly transmit the workpieces of each station, with adjustability, high degree of automation, simple operation and improving production efficiency. The equipment has good rigidity, simple structure, convenient maintenance in use and low failure rate, which reduces the cost of maintenance to a certain extent, which is very beneficial to mechanized production.
