ã€introduction】
China is a big manufacturing country, and the packaging industry has also developed rapidly with the manufacture of industrial products. At present, China's production of corrugated packaging products, composite flexible packaging, metal barrels, containers, plastic woven bags and other major production has been among the world's forefront. China's packaging industry has basically formed an industrial system with paper, plastics, metal, glass, printing, and machinery as the main components, with certain modern technology and equipment and relatively complete categories.
In the packaging industry, corrugated paper is used in a wide range of applications. Almost all light industrial products are used in corrugated cardboard boxes for packaging such as food, beverages, tobacco, electronic products and electrical appliances. The crosscutting machine is a very important part of the end of the corrugated board production line, and it is also the last link before the manufacturing of the packaging box. Therefore, the performance of the cross cutter is an important factor affecting the product quality and yield. At the same time, the crosscutting machine is also one of the higher automation levels in the corrugated board production line.
ã€business background】
Due to the requirements for vehicle speed, reject rate and flexibility of exchange orders, the current computer crosscutting machines have been increasingly popularized. According to the different control systems, there are two types of computer crosscutting machines:
The first type is to use single-chip microcomputer and ordinary frequency converter to control. Position the closed loop in the MCU and send the speed command to the inverter to drive the feed of the motor and board to follow. The advantage is low cost, but due to the long scanning cycle of the closed-loop control of the position of the single-chip microcomputer, the accuracy of the speed given at high speed is low; at the same time, the follow-up characteristic of the ordinary frequency converter is poor and cannot follow the given completely, thus further bringing error. The second category is the use of professional motion control systems and servo drives for control. The closed loop position is directly controlled by the motion control system. Milliseconds or even microsecond operation cycles guarantee high-accuracy position setting; at the same time, the excellent follow-up characteristics of the servo system ensure higher accuracy.The crosscutting scheme that will be introduced in this article is the second type of solution that uses Siemens motion control systems and servo drives.
ã€Mechanical structure】
In the current corrugated paper production line, the cross-section is generally referred to as a cross cutting machine. In general, there is only one knife roller motor in the cross cutting machine and there is no active feed section. Even if there is a feed motor, servo drive will not be used, but it will be driven by an ordinary inverter. Therefore, the feeding amount of the corrugated board needs to be detected by the measuring roller and transmitted to the motion control system, and the knife roller driver is controlled through the synchronous or electronic cam function.
ã€System Configuration】
The following figure shows the system configuration using the Simotion D410 Siemens motion control system and the Sinamics S120 servo drive.
The configuration diagram contains the following components:
The upper control IPC serves as the man-machine interface, receives the user's settings and settings, manages the orders at the same time, and communicates with the entire line control system; the Simotion D410 is the latest single-axis motion control system of Siemens and passes through the upper IPC. Standard Industrial Ethernet (D410 PN type) for communication: Receiving settings and orders, and real-time information of the status of the machine, such as the vehicle speed, motor current, motor temperature, etc., is transmitted to the IPC for processing or display; The servo drive Sinamics S120 receives the Simotion D410 The position command is issued, and the position of the roller is sampled in a cycle of 125 microseconds, and the position is closed-loop controlled (when the dynamic servo control function DSC is activated), the roller motor is driven; the external encoder is mounted on the measuring roller, It is used to detect the feeding amount of corrugated board as the spindle position value of the electronic cam. When it is necessary to cross-cut the corrugated paper, the color mark sensor can be connected to the fast input point on the Simotion D. Simotion D can be programmed to implement the color scale compensation function.ã€Performance indicators and highlights】
According to the different mechanical parts and motor power, the cross cutting machine equipped with this solution can achieve the following performance indicators:
å¹… Width: 1400 mm ~ 3300 mm  Speed: 120 m/min ~ 350 m/min  Cutting length: 300 mm ~ ∞ è£ Cutting accuracy: ±1 mmThe performance highlights of this solution include:
 Electronic cam cutting;  The fifth-order polynomial cam curve reduces the impact on the mechanical system; 刀 The knife roll and material are synchronous when cutting, synchronous overspeed is adjustable; 切 The cutting length does not stop change, and it takes effect immediately; Color tracking tracking.