Designing a drive train for winding equipment requires a comprehensive approach. Lenze assures you that, based on our years of practical experience, we can help you avoid costly mistakes in the engineering design process. Therefore, Lenze has designed DSD, a drive selection software that integrates our extensive practical experience and expertise. This practical experience report explains how to easily select the right winding equipment for different winding materials and how to use planning data to simplify subsequent commissioning.
First, it is essential to understand the winding process.
Winding drives are used to store continuous material before and after the processing. Depending on the winding process, these drives operate primarily in a quasi-static manner. Synchronous winding drives can be used in intermittently operating equipment (presses, cutting units, etc.). The types and shapes of materials to be wound are very diverse. They can be flat (paper, plastic, metal foil, woven fabric, mesh fabric, or fabric board, etc.) or round (silk, rope, yarn, thread). Depending on the material and equipment type, flat materials are handled using center winding machines or end-face winding machines. In a center winding machine, the drive is located at the center of the spool; in an end-face winding machine, the drive is located at the periphery. Mathematically speaking, winding material (a spool) is a helical motion; in flat material mesh, it is one layer wound on top of another; in round material, each layer is adjacent to the next and then stacked. The material is wound with a defined variable or fixed tension, and the production speed depends on the material quality and the current diameter. Depending on the product, the winding system offers a wide range of tensions, from approximately 0.5 N to 30,000 N. Production speeds also vary widely, from approximately 5 to 2,000 m/min. Drive power ranges from 0.1 kW to 400 kW.
Selection controlled by DSD
The specifications of a motor are determined by its torque. For center winding machines, the maximum required fixed drive torque occurs at the maximum spool diameter, reaching its lowest speed at that point. For these requirements, asynchronous motors operating within a weak magnetic field range offer significant advantages. The drive system installed on a center winding machine, generated by tension speed, has a unit rating significantly greater than the actual process power during winding. Although high speed and high torque do not occur simultaneously during winding, the drive must be capable of handling such a scenario. This combined power is called the base process power. Center winding machines with defined material tension are primarily designed for fixed operating conditions. The inverter's dynamic overcurrent capacity usually allows the drive to decelerate rapidly within the desired timeframe in emergency situations. However, considering the high moment of inertia and short braking distance, the braking torque parameter must be considered during selection. In intermittent operation modes of the winding machine, this dynamic drive torque typically dictates the selection process. Because selecting the right winding drive, choosing the correct drive components, and controlling the winding machine and motor are complex and require extensive experience, we've incorporated all this relevant experience and application knowledge into DSD. This allows every equipment engineer to easily navigate the selection process and find feasible solutions at any time simply by using the software. In addition to physical drive selection and product configuration, our new "DSD Winding Technology Assistant" can help you check for system limitations and provide valuable suggestions on multiple alternative solutions.
Sample selection for center winding of printing press
The task is to wind paper with a base weight of 80 g/mm² onto tubes ranging from 80 mm to 800 mm in diameter. The paper travels at a speed of 400 m/min on the printing equipment. The required tension is 250 N for the minimum diameter and 200 N for the maximum diameter.
DSD guides users step-by-step through all the necessary selection steps. First, engineering engineers can choose the simplest and most efficient "open-loop torque tension control mode." In this mode, DSD performs background technical checks on the equipment, followed by input of the reel's dimensions and material, tension, speed and acceleration data, number of stationary phases, and equipment efficiency values. Once the main and environmental data are input, the process description is complete. DSD uses this process description to confirm the specific requirements (torque, speed, and power) for the reel. Furthermore, diameter modifications during the acceleration phase are automatically included in the calculations; this is a helpful tip for obtaining the optimal solution. This results in a fixed winding power of 1.5kW and a base process power of 11kW. After determining the drive shaft's electrical and mechanical design and the drive concept, the most suitable motor is selected. Here's another tip: in this crucial selection step, a weak magnetic field can be interactively adjusted in DSD to generate minimum drive system power. All operations can be performed using torque-speed characteristic curves. This completes the selection of the reducer, brake, encoder, frequency converter, and optional electric braking circuit. It's worth mentioning that DSD's online help can also continuously provide valuable operational advice for the best selection process.
In our example, we used asynchronous technology to calculate and generate a 4kW energy-efficient motor (MH series) with a rotary encoder, a 45Nm spring brake, an i=3 toothed belt, a servo-controlled 5.5kW frequency converter (9400 series), and a 120W braking resistor for emergency stop. After completing the selection process, DSD will perform a comprehensive system analysis using variable charts, utilization rates, and technical coefficients. The entire selection process and document generation take only about 10-20 minutes—there's no faster or more convenient method! We also suggest you consider different solutions. This data can be quickly generated by DSD. DSD can help you list these solutions in a compact format and compare them. This allows you to evaluate the advantages and disadvantages of different drive concepts and products, and provides a clear basis for determining the suitable solution.
Detection method: Applying a tuner
The selection process for a drive typically involves using a reference scenario and a worst-case scenario. In reality, the equipment will handle a variety of products and formulas. For winding equipment, the winding speed varies depending on the material thickness. To ensure that the winding equipment can also use the operating scenario, after the main selection process has been completed, an application tuner is used to support the equipment, which can select process and motion variables and automatically calculate alternatives. A direct comparison of all relevant results reflects changes on both the process and drive sides. This allows you to immediately establish a clear understanding of utilization, limit ranges, or energy efficiency balance.
Energy efficiency assessment
In recent years, there has been increasing emphasis on energy consumption and its resulting environmental impact and operational cost transparency. Lenze responded to this issue early on by providing professional support for equipment engineering through its "Drive Solution Energy Efficiency Performance Certification" in DSD and its well-designed related functions. This means that once energy efficiency requirements, energy efficiency costs, CO2 emissions, and optimization potential are determined, and the user has graphically prepared the inputs for the winding application and the selected drive system in the background, these are ultimately mirrored based on usage. Through this comparative operation, different solutions can be evaluated and questions such as "Which motor efficiency level is best suited for this application?", "Which gearbox type minimizes losses?", "What affects acceleration in the energy efficiency balance?", "How much energy is generated during braking?", "What are the investment costs and the resulting operating costs?", and "How long will it take to develop a specific solution?" can be answered.
In particular, winding applications offer enormous potential for energy efficiency optimization solutions. Operations such as calculating multi-axis systems, selecting power supply modules, and expressing them in an energy-efficient manner can all be performed within DSD. This allows the regenerative energy from unwinding to be utilized in other drive axes interconnected with the equipment. The main load is minimized while energy efficiency is maximized.
Energy efficiency for the engineering chain
After selecting and optimizing the drive solution, DSD provides multiple connection points to perform further engineering design work. For example, DSD can define various product characteristics, such as the color of the geared motor, the location of flanges and terminal boxes, plugs, accessories, sensors, and other special design requirements, thus providing all price-related factors and ensuring content availability. The applied CAD browser immediately displays the drive selection to the user and provides design engineers with CAD data in different formats. Users can also check the mechanical integration of the geared motor and frequency converter in their own CAD structure. Specific protocols for different ranges and layouts are key here. They not only document the solution but also provide information for many other engineering design tasks, enabling the implementation of many other functions. For example, they provide most of the important commissioning data instantly. This starts with the process description, including the input process parameters as well as the minimum and maximum reel diameters, acceleration times, linear speeds, etc. However, calculated parameters are also useful, such as the total moment of inertia for torque feedforward control; this provides better stability and more precise control response. Furthermore, a thorough understanding of the selected product facilitates successful commissioning.
To simplify the engineering design process, Lenze provides standard, mechatronic modules throughout the entire process (requiring only parameter settings). The mechanical process description for winding can be found on the DSD planning page. During the commissioning phase, a FAST technology module for winding is provided. This module contains functional block structures and logic control for the winding process and allows for parameter settings using stored information in the DSD. This accelerates and simplifies the equipment engineering process, giving it more room to focus on its specific needs.
In terms of its simplicity, DSD is minimalist yet sophisticated. The success of this engineering software also stems from the fact that all its functions and workflows are designed based on planned tasks, making debugging faster and simpler through data preparation. This makes interaction between Lenze and mechanical engineers more efficient, while ensuring optimal equipment engineering results, simplifying and efficiently reducing the total cost of equipment, and enabling faster market response. It's worth noting that DSD can be used not only for the engineering design of winding equipment but also for almost all other types of equipment.
DSD selection software provides the following functions:
o Provides the best support for handling driver selection tasks
o Plan the drive chain from the perspective of mechatronics systems o Involve engineering design through equipment description (process, action, environment)
o Supports calculation of physical requirements, utilization, and performance values
o Create the required driver structures
o Fully integrates Lenze's many years of industry experience, expertise, and related solutions experience
Product selection and testing are goal-oriented.
o System testing technology feasibility and optimal solution
o Product configuration ensures the solution is both designable and marketable.
o Supports comparison and optimization between driver solutions
o Application Tuner: A Solution for Quickly Comparing Different Application Parameters
o Energy Efficiency Performance Certification - Driven Solutions: Supports computational calculations for specific solutions
o Provide solutions and related documentation (selection records, bills of materials, etc.)
Generate CAD data for the selected product.
o Supports processing of international projects (supports 13 languages, uses internationalized units)
Working principle of a center winding device for smooth materials
Central winding unit of printing equipment
Selection of DSD winding equipment
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