PLC input on woodworking band saw machine


In woodworking machinery, woodworking machine tools suc […]

In woodworking machinery, woodworking machine tools such as woodworking band saws, woodworking circular saws, and woodworking frame saws are often used to saw logs or finished timber. The woodworking band saw machine is a ring-shaped band saw blade tensioned on two saw wheels, and the ring-shaped band saw blade is driven by a motor through the saw wheel for continuous cutting motion. According to the classification of use, band saws can be divided into sports band saws for sawing logs and in-saw bandsaws for splitting boards or squares.
In the sports car band saw, the power equipment of the sports car is an electric motor assembled on the chassis, which drives the main shaft of the sports car to reciprocate through a gear transmission. The forward movement of the sports car is the working stroke, and the backward movement of the sports car is the return stroke. The forward and reverse of the electric motor control the forward and backward of the sports car table.
In woodworking band saw machinery, PLC or single-chip microcomputer is usually used to control the operation of the feeding part. The high anti-interference and versatility of PLC make up for the shortcomings of the single-chip control system, making it more widely used.
In order to ensure the control accuracy of the system, the sports car band saw control system adopts closed-loop control. Calculate the actual distance of the sports car table based on the pulse signal fed back by the rotary encoder. When the sports car table reaches the set distance, the PLC outputs a braking signal to stop the sports car and realize the positioning of the sports car. The PLC control system has a total of 8 switch inputs, including 1 high-speed pulse signal, 1 proximity switch signal and start, stop, enter, retreat, jog, etc. The two switch outputs are the brake contactor and the reverse relay, which respectively control the stop and movement direction of the sports car.
According to the requirements of input and output, we choose HOLLIAS-LEC G3 small integrated PLC with independent intellectual property rights from Hollysys. Considering that this system requires a certain amount of spare I/O points, the CPU module chooses the LM3107 with 14-point digital input and 10 digital output. The module comes with 3 independent telling pulse inputs, the current capacity of its relay output is up to 2A, and it can directly control the brake contactor without intermediate relays.
According to the requirements of the running process of the sports car table, the PLC compares the pulse value currently sent with the set value of the touch screen. If the current value is less than the set value, the system immediately outputs the brake signal, and then waits for the next forward signal input. When the system needs saw road compensation, the program will perform saw road compensation according to the compensation amount selected by the user.
The woodworking band saw machine with PLC as the control core uses the high-speed counting function of PLC to realize the positioning control of the sports car table. The PLC control system has strong anti-interference ability, which improves the processing accuracy of woodworking band saws. The PLC-based control system can not only be used for woodworking band saws, but also can be widely used in manufacturing industries such as furniture, doors and windows, and wooden molds.