Chen Zujian, Application Engineer, Lenze (Shanghai) Transmission System Co., Ltd.
Abstract: With the film production line as the background, the application of the 9400HL retractable roll, the calculation of the roll diameter, and the friction compensation are emphasized. Summarized the advantages of the 9400HL in the field of drive control.
Keywords: Winding 9400HL Roll diameter calculation friction compensation moment of inertia
1 Introduction
The biaxially stretched film production line is a large-scale complete set of equipment in the production machinery of plastic products. This type of equipment is dependent on imports in the early stages of our country. With the rapid development of domestic industrial automation, domestic companies have now developed a pull-film production line with an annual output of 6,000 tons and a film thickness of 12 to 70 micrometers.
The main processes of the biaxially stretched film production line include feeding, die head, extruder system, longitudinal stretching system, transverse stretching system and traction winding system. This article mainly introduces the introduction of the traction winding system. Traction winding is the core part of electrical control. Its control is directly related to the quality of the membrane.
2 Lenze Solutions
In the migration and rewinding system, there are two servo motors controlling the two axes A and B to take turns. In the winding process, the tension of the film must be kept constant at all times or as the diameter of the coil increases, the film tension decreases according to a certain rule. That is, tension taper control. It is also necessary to automatically change the roll after roll-up. When the film is cut during the roll change, it must smoothly transition to the standby roll-winder winding, between the take-up roll and the backup roll-up roll, and the tension control and speed control conversion be completed automatically. . The winding roller adopts two working modes of contact winding and gap winding, but it must be ensured that the follow roller can automatically retreat with the increase of the winding diameter. In contact with the winding, it is ensured that the pressure of the follow roller is constant and adjustable.
Figure 1 Schematic diagram of winding control based on tension sensor
3 Lenze main algorithm
(1) Roll diameter calculation: In the winding process, the coil diameter is continuously increasing. To ensure the constant film line speed and tension, the coil diameter calculation must be used to match the line speed and the motor speed. The calculated roll diameter is applied to the set value of the tension, and the calculated resistance torque is superimposed on the torque setting according to the increase of the turning diameter.
(2) Taper calculation: According to the different materials and the requirements of the process, the taper curves are different on different occasions. Lentz offers three types of taper curves: linear mode, curved mode, and custom mode. There are various parameters to set, where custom mode customers can set 64 points to describe the automatic sense curve, which basically meets the needs of all occasions. The taper curve of the curve mode is shown in the following figure. D0 is the taper starting point and HW is the taper setting value.
(3) Friction compensation: Friction mainly acts on the transmission and guide rails. In particular, the force required for starting and accelerating and decelerating is much greater than that required during normal operation. This results in greater following error during start-up or acceleration/deceleration, and the speed accuracy of the servo system is seriously affected. The compensation for friction is based on the form and nature of the friction, using various control methods to suppress or eliminate the effect of friction on system performance. The 9400HL self-contained friction compensation block L_WndFrictionCompensation automatically recognizes the friction coefficient of the system.
(4) Identification of transmission inertia: The moment of inertia is a measure of the inertia (rotational object maintains its uniform circular motion or stationary characteristics) when the rigid body rotates around an axis, and its magnitude depends on the shape, mass distribution, and the position of the axis of rotation of the object. In the retractable roll application, the moment of inertia of the empty roll and the moment of inertia of the full roll are calculated separately. The 9400HL servo controller can automatically identify the moment of inertia through the off-the-shelf function block L_WndIdentMInertia, reducing the cumbersome calculations for engineers.
4 Lenze Project Highlights
1) The 9400HL has been very mature in the application of retractable volume, and there are ready-made templates for use. Customers only need to modify a few parameters to realize retractable volume functions. The template is rich in functionality, and some functions can be cut off or put in at any time.
2) The 9400HL is a free-programmed servo controller. Using Lenze Engineer software, it has a rich visual programming of function blocks and can tailor the corresponding functions for each project.
3) The 9400HL can execute up to three tasks at the same time. The fastest execution cycle is 1ms. Its programming function is no less than a small PLC. In many occasions, PLC can be saved, which reduces costs and reduces points of failure.
4) The 9400HL has a variety of communication options, including CANOpen, ProfiBus, ProfiNet, EtherNet, EtherCAT, and more. It can communicate with most PLC and touch screen products on the world, and has a wide openness.
5 Outlook
The 9400 HL has been used in a wide range of applications in the area of ​​reaming and unwinding, including packaging, textiles, plastics, and printing. The 9400 HL retractable roll template runs fast, has high precision control, and is flexible and reliable. It is mainly used in the field of high-precision control. With the increase in the level of manufacturing in China, more and more applications of this type will be made.
Product Name: Car Charger
Place of Origin: Guangdong, China (Mainland)
Brand Name: OEM
Output Type: DC
Connection: Other
Rated Voltage: 12V-24V
Working Temp: 0-55℃
Weight: 36g
Materials: PC+ABS
Color: White Black
Warranty: 1 year
Suitable for:Most digital devices
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