Motion Control Resources
Out of the control cabinet, into the winder
AMK Automation Posted 12/15/2017
Space is always an issue: Kocher+Beck relies on decentralized servo technology from AMK for its matrix transfer winders.
First unwind, then rewind – and print, laminate, and die cut in between. The UR Precision U unwinding system of Kocher+Beck is designed to feed web material to printing and converting machines nonstop from the role. The system is driven by centralized and decentralized servo technology from AMK. Because the drive technology is placed directly in the process, the size of the control cabinet is minimized – and more compact systems can be designed and more easily combined with printing and converting machines. This applies, in particular, to the matrix winder that rewinds the matrix after die cutting.
Space is generally always tight in print production. In light of this fact, Kocher+Beck has now developed a matrix transfer rewinder for printed labels that is virtually free of control cabinets. The purpose of the unit is to perform nonstop rewinding of the self-adhesive matrix that is produced by the printing and die cutting of labels and is removed before the rewinding and subsequent delivery of products to the customer. The matrix winder is usually placed directly on a printing machine between the unwinding and rewinding units, which are also driven by AMK servo technology. After the printing process, the matrix winder pulls off the sheet matrix from the web before this is rewound. Given the outlined use conditions, the compact machine is designed in such a way that it requires little space and can be combined with any printing machine. The space-saving design forms the basis for modularization of print production system components, made possible by decentralized drive technology from AMK in Kirchheim, Germany.
The AMKASYN servo inverters in the machine modules of Kocher+Beck perform precise adjustment of the web speed and tension and keep them within barely perceptible tolerances during winding. The precision is important because material savings is a constant issue in the print industry. Increasingly thinner composite materials and sheets are being used that make handling more and more difficult. Against this backdrop, Kocher+Beck has pursued the clear goal from the start of the UR Precision series of controlling the web tension with high precision using the braking torque of the unwinder.
By contrast, mechanical solutions with disk brakes are still commonly used in the print industry. The disadvantage of these solutions is that they are more difficult to integrate into the highly automated print process than an electronic servo solution. In addition, they reduce energy efficiency because kinetic energy is converted unused into heat and material wear. AMK has therefore designed an axis grouping for Kocher+Beck that features regenerative inverters and a shared DC link. The braking unwinder feeds its regenerative energy into this, which the rewinder, in turn, uses for drawing. Consequently, the drives of the transfer units "waste" only the energy difference resulting from process-related friction losses.
This detail has become an increasingly important selling point in the print industry because an ever growing importance is being placed on awareness of the total cost of ownership and on comprehensive energy management along the entire production process – from the perspective of both legislation as well as economic analysis of investment decisions.
Saving energy when winding
Regardless of whether centralized or decentralized servo inverters are used, they are supplied by a centralized power supply module directly via the DC link in the space-saving Kocher+Beck design. The interconnected operation of all axes is not only more energy-efficient but also offers additional advantages: fewer components due to elimination of contactors and filters, less wiring effort, simpler system design, longer service life of all components in the control cabinet due to less heat development in the control cabinet. "Energy efficiency is becoming more and more important in our industry," said Karin Enderle, Division Manager for Winding Technology at Kocher+Beck, in particular with regard to the European printing machine business. Expectations are high and the use of modern servo technology with sophisticated motion control is also required.
AMK has integrated the software-based "Winding" motion control function as a technology function in its own AMKAMAC A5 controller with visualization. The combination of controller and rugged touch monitor with glass display is integrated in the machine enclosure of the unwinders and rewinders in the direct vicinity of the process. Generally speaking, the preprogrammed motion control provides all important subfunctions for unwinding and rewinding – web tension determination with and without sensors, signal processing of pressure measuring boxes, pressure measuring computers and monitoring as well as the widely used dancer position control with dancer monitoring. The integrated side control ensures a flawless rewinding pattern.
Optimizations through data sharing
From the networking perspective, the drive-related equipment with modern servo controllers can be easily integrated in the overall network via TCP/IP. In this way, the machine solutions of Kocher+Beck are very well positioned to process production and inspection data in real-time. Consistent communication from the drive level to the controller and even to the ERP or MES level is becoming more and more important in this context. Machine operators thus have the ability to analyze their processes meticulously, control their warehouses more efficiently, and generally save material and process costs.
Customers also have greater flexibility to adapt their machines to new products, which ultimately makes their investment more future-proof. Because the extensive options for positioning that today's modern servo technology offers broadens the solution space, a machine can convert a large range of materials much more easily.
The matrix winder of Kocher+Beck demonstrates the performance of decentralized drive technology, especially when it comes to keeping machine modules as compact as possible. The overall solution also illustrates why there is a practical demand for combination solutions of centralized and decentralized servo axes in the form of perfectly customized equipment. With a view to Industry 4.0, the device networking possibilities also establish the basis for consistent data and thus opportunities for continuous process optimizations.
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