Application of the hottest servo control system in

  • Detail

Application of servo control system in heat shrinkable packaging machine

at present, various brands of beer rush into the market first. In order to seize business opportunities, various beer manufacturers are also constantly improving the quality and output of beer. Therefore, updating the original old beer production equipment has become a factor that beer manufacturers must consider. In the process of beer production, from the beginning of brewing, filling, sterilization to the final labeling and packaging, each production link is related to the final beer output. It requires a high degree of automation, so that packaging has always been a weak link in the whole beer production. Foreign heat shrinkable film packaging machines have been able to successfully complete the final beer packaging, such as Italy dymac, SMI and ocme with appropriate orientation, and Germany Krones. In June2002, China promulgated the relevant provisions in the new beer standard gb4927-2001, which promoted the development of heat shrinkable packaging machines in the beer industry. Many domestic suppliers are optimistic about this market and regard heat shrinkable packaging technology as the research and development focus of enterprises. At present, China's heat shrinkable packaging technology has developed to a more mature stage

the heat shrinkable packaging machine can be composed of six parts: main drive, bottle feeding, bottle separating, paper feeding, film feeding and cutting, and heat channel. According to different design ideas, the mechanical structure of the heat shrinkable packaging machine produced by various manufacturers is different, and the programmable control system and servo control system selected are also different. In the following, we will take the xksb-50 heat shrinkable packaging machine of Baoji Xinke Machinery Manufacturing Co., Ltd. as an example to introduce the application of acapos as the control part in the heat shrinkable packaging machine

the hardware mechanism of the heat shrinkable packaging machine

the servo control system with synchronous electronic gears and electronic cams has long replaced the cumbersome mechanical cam mechanism, which can easily realize the synchronous relationship between moving objects according to the requirements of the designer. Several motion mechanisms of the heat shrinkable packaging machine use the servo motor as the drive shaft to complete the tasks from bottle feeding, paperboard feeding to film cutting. The main drive using one servo motor will be used as the synchronization object of several other axes, and all the angle and phase relations are also determined according to the main drive motor. Figure 1 shows the approximate position of the five motors in the machine

control system

the servo control system of bekale can fully meet the basic motion control of all motors of the heat shrinkable packaging machine and the synchronous motion control between them. The man-machine panel pp41, which integrates the logic control in the packaging process and has the display function, on the one hand, can convey commands and motion characteristic parameters to the motion control part through parameter input, on the other hand, it can timely feed back the current machine operation status and alarm status

field bus (CAN bus)

can bus has strong error detection ability and differential drive function, and still operates well in the environment with strong noise and harsh conditions. Therefore, in terms of media transmission and circuit design, can bus can easily be suitable for most industrial applications. The communication between the field bus (CA, especially the non-uniform n bus), the man-machine panel (pp41) and each servo controller especially provides a guarantee for the modification of synchronous characteristic parameters in the servo motion control system (Fig. 2)

synchronous motion control

synchronous motion control is based on a certain mathematical model. One servo motor has to complete a certain motion trajectory relative to another servo motor, that is, the concept of electronic gear and electronic cam

for acopos servo, the two servo motors participating in synchronization have a master-slave relationship. The synchronous motion control of heat shrinkable packaging machine is generally synchronous in position. On the CAN bus, the main shaft will transmit the current position information to the can network at a certain small interval, and the slave shaft participating in the synchronization will also obtain these information in real time, and then calculate the current position of the slave shaft according to the mathematical model in real time, and run the current track

in the heat shrinkable packaging machine, after receiving the film loading signal, the film loading motor starts to move synchronously when the main motor runs to a certain phase again until the main motor completes a cycle, and the film loading motor also completes a film loading task. We can divide the process into three stages, that is, the film loading motor waits for the film loading signal, the main motor reaches the film loading start phase, and follows the main motor to complete a film loading task. When applying film, the last stage can be subdivided into several stages according to the principle of "slow before fast". In acopos servo, the moving object created for each servo motor has an imaginary axis, that is, an imaginary axis. The virtual axis is the same as the real axis. On the one hand, it can be used as a slave axis to complete the synchronization track with the main axis. On the other hand, it can also be used as a main axis to allow other slave axes to participate in the synchronization. Due to the introduction of the concept of virtual axis, a servo motor can also synchronize with its own virtual axis

if a main virtual axis is added between the film loading motor and the main motor, the contour relationship of the three stages of waiting for the film loading signal, waiting for the starting phase of the main motor, and completing a cycle with the main motor can be added to the main virtual axis. The membrane motor can be synchronized with the main virtual axis to complete the synchronization tasks of several stages from slow to fast. In this way, when the main motor does not move, let the virtual axis go for a cycle, and the film feeding motor can complete the film feeding task once, that is, manually feed the film once, so as to facilitate the front and back adjustment of the film feeding position at the beginning

function realization in the control process

acopos service in the heat shrinkable packaging machine, the tasks to be completed are: driving the bottle pushing rod and film guide rod, feeding paperboard, feeding and cutting film, and separating bottles. Among them, the tasks with synchronous relationship include paper feeding, film feeding and film cutting. Figure 3 illustrates the master-slave relationship between several axes. The left side of the arrow is the master and the right side is the slave. Although the bottle feeding motor does not participate in the synchronization, in the bottle separation process, it and bottle separation are based on the phase angle of the main motor, performing interrelated start and stop, and jointly completing the bottle separation task

white film feeding and cutting

film feeding and cutting are the most important links in the heat shrinkable packaging machine, and also the most difficult part in the control process, especially film feeding

according to the process requirements, in the initial stage after the film feeding is started, the speed of film output should be consistent with that of a group of bottles to be wrapped. The part pressed on the lower film of the paperboard should be of the preset length and should not curl. In the remaining stages, the film shall be quickly removed to ensure that the film guide rod can pick out the rear film unimpeded. The speed of these stages of the membrane guide must also be controlled properly. Too fast will lead to membrane wrinkling, and too slow will cause the membrane guide rod to be blocked. No matter what stage it is, and no matter how fast the film is discharged in the middle, it must be ensured that after the main motor performs a cycle, the film feeding motor must also just complete the secondary film feeding in which the mini graphene box can shuttle drugs to specific parts of the body in the future, that is, the film feeding motor and the main motor are synchronized at the same time

different manufacturers design different film cutting mechanisms. At present, there are two types of mechanisms that are more successfully developed than 400 HP tractors. One is that an electromagnetic clutch is used on the film feeding motor shaft to pull in a cutter and rotate it once after binding; The other is to keep the cutter as an independent motor shaft synchronized with the film feeding motor shaft. What should be paid attention to in film cutting is that the instantaneous linear speed of the cutter rotating to cut the film should be greater than the linear speed of the cut point of the film, otherwise the film may be scratched, cut continuously, or even cause the cutter teeth to collapse. The heat shrinkable packaging machine of Baoji Xinke company adopts an independent cutter motor shaft. The cutter synchronized with the film feeding motor can more directly adjust the speed of several synchronization stages during synchronization, ensuring the position accuracy of each film cutting and participating in the control of color film

inlet bottle inlet and hot channel bottle outlet

in addition to film feeding and bottle separation, inlet bottle inlet and hot channel bottle outlet cannot reduce the control requirements. The inlet and hot channel shall be equipped with a frequency converter respectively to smoothly control the conveying of bottles in and out. According to the process requirements, the speed of the inlet conveyor belt and the hot channel conveyor belt should maintain a proportional relationship with the main motor. In this way, the main motor, inlet conveying, bottle separation and hot channel conveying can be basically synchronized. The speed of inlet conveying controls the gap between bottles, thus affecting the quality of bottle separation. The speed of hot channel transportation and the temperature will also make the film shrinkage after wrapping different. Therefore, the synchronous coordination of front and rear conveying is also a rewriting factor to be considered

discussion on color film feeding and cutting

the white film has no position limit. It can start from any position as long as the film length is consistent each time. In contrast, the precision required for the position and length of color film feeding and cutting is much higher. In addition to the film length, the pattern symmetry of the color film after cutting is also a test standard. Generally speaking, the printed color film will leave a blank section behind the two symmetrical patterns, which is the part to be cut. There will be a small black color mark (print) on the film edge of each blank part to be cut. The photoelectric sensor can capture this mark during the film feeding process, so that the servo controller can get this information. The process requires that once the imprint is detected, the film motor will complete a section of displacement, and then start to cut the film. If the film feeding motor keeps moving at a certain speed, it should be easy to control the film cutting motor from detecting the mark to synchronizing with the film feeding motor to finally completing the film cutting. However, the film feeding motor still needs to be synchronized with the main motor to complete the track from slow to fast. Of course, the uniform speed feeding and cutting of color film can be used as the first manual calibration. Therefore, in the heat shrinkable packaging machine of Baoji Xinke company, a method of dynamically controlling the film length is adopted to control the feeding and cutting of color film, which meets certain process requirements. In fact, there should be other good methods for color film feeding and cutting, and foreign advanced experience is also worth learning from

heat shrinkable film packaging machine is the last link in the whole beer production line, and it is also an important factor affecting the final beer output. It is of great significance for the beer industry to adopt advanced packaging technology in this link

source: packaging machinery

Copyright © 2011 JIN SHI