Design And Experiment Of An Automatic Packaging System For Cylindrical Sewing Threads

With the continuous development of technology, new and higher requirements in the level of automatic packaging equipment have been proposed by small medium-sized enterprises. The traditional mechanical drive of the packaging machine is complex, slow, and low accuracy. The machine only can package single species, and needs a long development cycle. Therefore, it can not be satisfied with the increasing diversified and personalized demand for packaging. With the rise of advanced control technology, highly automated, intelligent, versatile and efficient packaging equipments have been favored and admired in the packaging industry.This paper designs a cylindrical sewing automatic packaging system on the basis of the original packaging machinery. The manual packaging and shrink processes are transformed into automatic process. The packaging system is composed of an automatic sort unit, dual servo pillow packaging mechanism and thermal shrinkage uint. The dimension of the packaging machine is 5m×3m×1.8m. A vibration plate is used as the core of the automatic sorting line. To dock with the packing machine, a new method is designed with consideration of the feature of the cylindrical sewing threads. Based on the original single frequency conversion control system, a dual servo control system based on PLC and servo drive technology is proposed. The control system includes an electronic cam curve,485 communications between PLC and servo drives, HMI interface, and error compensation. The PLC technology, HMI technology, photoelectric technology, servo control technology, and communication technology are intergrated in the control system. In order to ensure the point of tangency close to the color sign, the system amends the cunmlative error casued by the color deviation. And the system is capable of empty packages detection and alarm, etc.The performances of the designed system have been tested in the last part of the paper. The experiments of vibration plate sorting and docking methods show that the designed automatic sorting line has achieved the corresponding functions. The sewing threads can be transported to the next mechanism in the specified direction one by one. The automatic sorting line can be docked with the packaging machine successfully. The reliable performances of the improved dual servo control system have been demonstrated based on the experiments of the communication between the PLC and servo drivers, two axis movement testing and color code tracking. The designed system has compensated the position deviation between the color signs and sewing threads in time. Finally, the qualification rate of packaging has been tested, and the relevant factors influencing the thermal shrinkage have been analyzed. The qualification rate can reach to 90.8%, which can meet the requirements of the designed system.