Working principle of pillow packaging machine Pillow packaging machine is a continuous packaging machine with strong packaging capacity, which is suitable for all kinds of food and non-food packaging. It can be used not only for packaging non-trademark packaging materials, but also for high-speed packaging of roll materials with trademark patterns printed in advance. In packaging production, due to the error between the positioning color marks printed on packaging materials, the stretching of packaging materials and the influence of mechanical transmission, the predetermined sealing and cutting parts on packaging materials may deviate from the correct position, resulting in errors. In order to eliminate errors and achieve the purpose of correct sealing and cutting, the problem of automatic positioning must be considered in packaging design. Most methods to solve this problem are to design a continuous photoelectric automatic positioning system according to the positioning marks of packaging materials. According to the working mode of error compensation, continuous photoelectric positioning system can be divided into forward and backward, braking and dual-drive system synchronization. This paper mainly introduces the design of photoelectric automatic positioning system with forward and backward braking. 1 Basic principle of braking photoelectric automatic positioning system In the process of continuous feeding, molding, bagging, filling and sealing of packaging paper on automatic packaging machine, the conveying speed of packaging paper is out of sync with the cutting speed of horizontal sealing paper due to the printing error of positioning color label and accidental fluctuation of machine operation and operation, resulting in the deviation of sealing and cutting position, which needs to be corrected at any time and compensated continuously. Comprehensive error is a variable, but for packaging materials with high quality and high printing accuracy, at a certain packaging speed, this error should be kept in a very small range in each test cycle. In this way, the paper feeding speed and sealing and cutting speed can be measured and compared regularly (once every two packs) through the photoelectric positioning system. If the wrapping paper is too fast, the positive error system gives negative compensation, that is, the paper feeding mechanism slows down to realize compensation; If the wrapping paper is too slow, it is a negative error, and the system will give positive compensation to speed up the paper feeding mechanism. However, the given compensation value can not completely eliminate the error, and it is possible to compensate excessively or inadequately. Even if the mistake is eliminated, it will appear next time. Therefore, the design always makes the system compensate a little more, giving a compensation amount slightly larger than the absolute error value, which artificially exceeds the tolerance. When the measurement error is negative, the excessive positive value is compensated. There must be a positive error after the next measurement and comparison. After the positioning system automatically compensates the given negative value, the negative error is restored. In this way, the error is controlled within a certain range by alternating positive and negative. The cut part of this wrapping paper jumps around the right position. This continuous positioning mode of wrapping paper is called "advance and retreat" automatic positioning mode. Because its compensation is beyond the clutch, the mechanical paper feeding mechanism is designed to have the lag effect of wrapping paper when it enters the work, so the positioning system based on this principle is called "braking forward and backward" automatic photoelectric positioning system. Taking the transverse sealing and cutting speed that determines the speed of wrapping paper as a reference, adjusting the paper feeding speed to synchronize with it to control the sealing and cutting position error of wrapping paper, which is the most basic principle of continuous positioning system. 2 Analysis of positioning system before and after braking Next, the photoelectric positioning system before and after braking is analyzed, and the transmission system diagram of packaging machine is 1. The packaging process is as follows: the sheet wrapping paper is led out from the drum 1, formed by the former 5 through the photoelectric detector 2, and packaged by the pulling roller 6 and the longitudinal sealing roller 7. The packaging bags filled with packaging materials are shaped up and down and output, and sent to the horizontal head 8 by the conveyor belt for transverse sealing, and the finished products are cut off and discharged. The transmission part is: the main motor M 1 transmits the movement into the transverse sealing transmission shaft, and then drives the transverse sealing head to drive through the unequal speed mechanism 9, so as to adjust the instantaneous sealing and cutting speed of the transverse sealing head 8 to synchronize it with the moving speed of the packaging bag. The other route is adjusted by stepless speed change differential mechanism 13, which can be controlled manually or by single-phase servo motor. The required bag length can be obtained by adjusting the stepless speed change differential mechanism 13. The last path passes through the differential mechanism 18 to reach the hook and claw conveyor chain. Differential 18 is an automatic adjustment mechanism, which is mainly used to adjust the synchronization of hook-and-claw conveyor chain and transverse head. In the packaging process, the moving speed of the wrapping paper detected by photoelectric sensor is compared with the transverse sealing speed to judge its speed, and the electric system of the overrunning clutch controls the operation or braking of the overrunning motor M3 to achieve the purpose of error compensation. 42 Figure 1 Transmission System Room Diagram 1 Paper Roll 2 Reflective Photohead 3 Packaging 4 Drop Roller 5 Pad 6 Pulling Roller 7 Longitudinal Sealing Roller 8 Transverse Head 9 Unequal Speed Mechanism 10 Overrunning Clutch 1 Main Motor 65438+ 5438+04 Conveying Mechanism/KLOC-0 6 Paper-feeding photoelectric sensor 16 Transverse sealing photoelectric sensor 17 At the same time, the wrapping paper (each sheet) is long or short in the production process, so how to automatically measure the length of the wrapping paper in the positioning process to make it conform to our production settings is also very important. The paper speed is measured by photoelectric proximity switch 17. We record the pulse period output by the photoelectric proximity switch for measuring the paper speed as T paper, and its derivative 1/T paper is the transmission speed of the paper feed roller. The cutting speed of transverse seal is measured by photoelectric proximity switch. We record the pulse period output by the photoelectric proximity switch as t-knife, and its reciprocal 1/T-knife is indirectly calculated by the transverse sealing speed. In packaging design, the wrapping paper is tightly pressed on the paper feeding roller, and the linear speed of the pressing roller is the paper feeding speed of the wrapping paper V paper =πD/T paper, where d is the diameter of the paper feeding roller. The cutting length after transverse sealing is L paper = V paper T knife =πDT knife /T paper 4 color mark marking method and adjustment In order to ensure the automatic positioning of packaging, it is necessary to control the servo motor M2 to synchronize the paper feeding speed with the transverse head cutting speed. But for a synchronous system, the original synchronous system will be out of step due to the accidental fluctuation and disturbance of operation. Therefore, it is necessary to add a color code detection and control circuit in the basically synchronous system, and then modify it to continuously compensate the error. In order to ensure that the cutting and sealing positions remain unchanged, it is necessary to use the color code on the wrapping paper for positioning. The positioning and labeling of color code put forward certain requirements for packaging materials, photoelectric detection means and color code printing. As far as packaging materials are concerned, it is required to have high density, uniform slip thickness and certain tensile strength. There are two kinds of photoelectric detection methods: transmission and reflection, depending on different packaging materials. Transmission type is mostly used for the detection of transparent packaging materials, and reflection type is used for the detection of packaging materials that are not easy to transmit light or cannot transmit light. Generally, the design of high-speed packaging machines mostly adopts reflective photoelectric detection method because of its high detection sensitivity. For color-coded printing, the positioning color code must have the function of shading or light-passing, and at the same time, with the size of the packaged product and the different detection methods, the positioning color code should have enough shading area to ensure the reliability of the signal during photoelectric detection. With good packaging materials, correct positioning of color scale and correct method of measuring color scale by photoelectric shading reflective sensor, color scale can be calibrated and adjusted. The pillow multifunctional packaging machine designed according to the above principles and methods is equipped with a microcomputer-controlled paper length setting and adjustment and color code positioning system, which completely solves the problem of photoelectric automatic positioning. The system is stable and reliable at high speed and accurate in sealing and cutting, and it is one of the most advanced and ideal machines at present. References 1 Xu Lincheng's Principles and Design of Packaging Machinery, Shanghai Science and Technology Publishing House,199819 ~ 212 Peng Guoxun's Design Principles of Automatic Packaging Machines, An: Northwest Institute of Light Industry, 1983.85 ~ 883. (2) August 2000 ~ 1 14 Analysis of Electro-mechanical Engineering for the photoelectric automatic positioning system of the ginger pillow candy packaging machine, 200 1 (5) (208 ~ 2 10) (date of receipt: April 2002-65438+).