Stepper motor control gear pumps can also achieve accurate metering. Gear pumps are widely used in the delivery of viscous bodies, such as syrup, bean paste, white wine, oil, ketchup, etc. At present, piston pumps are mostly used for the measurement of these materials, and there are disadvantages such as difficulty in adjustment, complicated structure, inconvenient maintenance, large power consumption, and inaccurate measurement. The gear pump metering is measured by a pair of gear meshing rotations, and the space of the material passing through the teeth and teeth is forcibly sent from the feed port to the discharge port. The power comes from the stepping motor. The position and speed of the stepping motor are controlled by the programmable controller. The metering accuracy is higher than that of the piston pump. The stepper motor is suitable for running at low speeds. When the speed is increased, the noise of the stepping motor will increase significantly, and other economic indicators will drop significantly. For a gear pump with a relatively high speed, it is better to use a speed-up structure. We started the structure of the stepping motor direct-coupled gear pump on the viscous packaging machine. As a result, the noise is difficult to avoid and the reliability is degraded. Later, the spur gear speed-up method was adopted to reduce the speed of the stepping motor, the noise was controlled, the reliability was also improved, and the metering degree was guaranteed.
First, the application of stepper motor in the supply of packaging film
In the packaging machine that integrates bagging, filling and sealing, it is required to position the fixed length of the plastic film for packaging, and whether it is intermittent supply or continuous supply, it can be reliably completed by a stepping motor.
1, for intermittent packaging machine
The intermittent packaging machine uses a stepping motor to supply the film, and the reliability can be improved. In the past, the packaging film was fed by the method of intermittently pulling the crank-link mechanism, and the structure was complicated and the adjustment was difficult. Especially when the product needs to be replaced, not only the adjustment was difficult, but also the packaging film was wasted a lot. The stepping motor and the draw belt roller are directly connected to the drawstring, which not only simplifies the structure, but also is very convenient to adjust, as long as the button on the control panel can be realized, which saves the adjustment time and saves the packaging material. In the batch packaging machine, the feeding control of the packaging material can adopt two modes: a bag length control mode and a color mark control mode. The bag length control mode is suitable for the packaging film without color standard. It is realized by setting the stepping motor speed in advance, and the setting of the turning ratio can be realized by the dial switch. The color mark mode is equipped with a photoelectric switch, and the photoelectric switch detects the position of the color mark. When the color mark is detected, the control switch signal is issued, and after the step motor receives the signal, the rotation is stopped, and after a certain time delay, the film is rotated, and the film is re-started. , to ensure that the film is fixed according to the position of the color mark.
2, for continuous packaging machine
In the continuous packaging machine, the stepping motor is continuously rotated, and the packaging film is uniformly and continuously conveyed. When the length of the bag is changed, it can be realized only by dialing the code switch.
Second, the application of stepper motor in horizontal seal
In continuous packaging machines, cross-sealing is an important actuator and one of the more complex mechanisms in packaging machines. Especially for the color-coded packaging film, the sealing and cutting position requirements are extremely strict. In order to improve the cutting accuracy, people have developed the eccentric sprocket mechanism, the crank guide mechanism, etc., but these mechanisms are very troublesome and reliable. Low disadvantages. The main reason for these shortcomings is that the process requires a fixed-width transverse seal and a positioning cut.
The stepper motor directly drives the transverse seal wheel to achieve speed synchronization. The film supply wheel of the continuous packaging machine is continuously supplied with film. When the horizontal sealing is required, the linear speed of the horizontal sealing is synchronized with the feeding speed of the film to avoid the occurrence of tear film and film accumulation. Since 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 transverse sealing wheel, but the horizontal sealing requires a certain time, that is, the transverse sealing wheel and the film need to be constant from contact to leaving. Time, otherwise the seal is not strict. 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 in one week, and some of them first meet the requirements of speed synchronization. In addition, the unloaded part meets the requirements of 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, which is limited to the length, and will not be stated here.
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. Conversely, 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 application of stepper motors in packaging machinery has just begun. Many traditional mechanical control methods can be replaced by stepper motors. In addition to some of the applications described above, they are also available in printing, filling, wrapping, etc. The application, I believe that in a relatively short period of time, China's packaging machinery industry will be able to leap to a new level in the stepper motor technology platform. Partially meet the requirements of 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, which is limited to the length, and will not be stated here.
The application of stepper motors in packaging machinery has just begun. Many traditional mechanical control methods can be replaced by stepper motors. In addition to some of the applications described above, they are also available in printing, filling, wrapping, etc. The application, I believe that in a relatively short period of time, China's packaging machinery industry will be able to leap to a new level in the stepper motor technology platform.