PLC on woodworking band saw machine

In woodworking machinery, woodworking machines such as woodworking band saw machines, woodworking circular saw machines and woodworking frame saw machines are mostly used to cut logs or become lumber. The woodworking band saw machine is characterized in that an annular band saw blade is tensioned on two saw wheels, and the annular band saw blade is driven by a motor through the saw wheels to perform continuous cutting motion. According to the classification of uses, band sawing machines can be divided into two types: roadster band sawing machines for sawing logs and in-process band sawing machines for cutting plates or squares. In the band sawing machine for sports cars, the power equipment of the sports car is a motor assembled on the chassis, which drives the main shaft of the sports car to reciprocate through gear transmission. The forward movement of the sports car is the working trip, and the backward movement of the sports car is the return trip. The forward and reverse rotation of the motor controls the forward and backward movement of the sports car workbench.

In woodworking band saw machines, PLC or single chip microcomputer is usually used to control the operation of the feeding part. PLC's high anti-interference and versatility make up for the shortage of single chip microcomputer control system, making it more widely used.

In order to ensure the control accuracy of the system, the control system of the sports car band saw adopts closed loop control. According to the pulse signal fed back by the rotary encoder, the actual distance of the sports car workbench is calculated. When the workbench of the sports car reaches the set distance, the PLC outputs a braking signal to stop the running of the sports car and realize the positioning of the sports car. PLC control system has 8 switch inputs, including 1 high-speed pulse signal, 1 proximity switch signal and start, stop, enter, exit, jog, etc. The two switch outputs are brake contactor and reverse relay, which respectively control the stop and movement direction of the sports car.

According to the requirements of input and output, we choose small integrated PLC. Considering that the system needs some spare I/O points, the CPU module selects LM3107 with 14-point switch input and 10-point switch output. The module is equipped with 3 independent tell pulse inputs. Its relay output current capacity is 2 A. It can directly control the brake contactor without intermediate relay.

According to the requirements of the running process of the sports car workbench, PLC compares the currently transmitted pulse value 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 input of the next forward signal. When the system needs kerf compensation, the program will perform kerf 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 workbench. PLC control system has strong anti-interference ability and improves the machining accuracy of woodworking band saw machine. The control system based on PLC can not only be used in sports car band saw machines, but also can be widely used in furniture, doors and windows, wood molds and other manufacturing industries.