In continuous packaging machines, cross-sealing is an important actuator and one of the more complex mechanisms in packaging machines. For the packaging film with color file, the sealing and cutting position requirements are extremely strict. Before the successful application of the stepping motor, in order to improve the cutting accuracy, people have developed the eccentric sprocket mechanism, the crank guide mechanism, etc., but these mechanisms are There are disadvantages that the adjustment is very troublesome and the reliability is low. The main reason for these shortcomings is that the process requires horizontal sealing of the sealing wheel and positioning and cutting.
The characteristics of the stepper motor are mainly attributed to three aspects, one is that the overload is good. The speed is not affected by the load size. Unlike ordinary motors, when the load is increased, the speed will drop. Therefore, the stepping motor is used in places where speed and position are strictly required. Second, the control is convenient. The stepping motor rotates in units of “steps”, and the digital features are obvious, which brings great convenience to computer control. In turn, the emergence of computers has opened up a broader market for stepping motors. Third, the structure of the whole machine is simple. The traditional mechanical speed and position control structure is complicated and difficult to adjust. After using the stepping motor, the structure of the whole machine is simple and compact.
The stepper motor directly drives the transverse seal wheel to achieve speed synchronization. The film feeding wheel of the continuous packaging machine is continuously supplied with film. When the horizontal sealing is required, the linear speed of the transverse sealing is synchronized with the feeding speed of the film to avoid the occurrence of tear film and film accumulation, because the diameter of the transverse sealing wheel is constant. When changing the length of the bag, it needs to be changed by changing the rotation speed of the horizontal sealing wheel, but the horizontal sealing requires a certain time, that is, the transverse sealing wheel and the film need a constant time from contact to leaving, otherwise the sealing is unduly. The total time per revolution of the transverse sealing wheel and the time required for the horizontal sealing are constant. To meet the requirements of speed synchronization, the speed of the stepping motor can be divided into two parts within one week, and some of them first meet the requirements of speed synchronization. In addition, the unloaded part meets the total time of the week.
In order to achieve good sealing quality, the non-equal speed control mode can be realized by the stepping motor on the transverse sealing wheel, that is, the speed synchronization is realized at every point of the horizontal sealing.
The application scheme of stepping motor in packaging machinery has matured and many applications have good feedback. In addition to the application of packaging machinery, stepper motors are also widely used in other industries.