I. Introduction to Multi-Wire Winding Machine:
A multi-wire winding machine is a device that combines multiple thin alloy steel wires into a relatively thick alloy steel wire, which is then wound onto a bobbin. Its operation mainly involves technologies such as parameter calculation and setting, active unwinding, wire length measurement, and equidistant wire arrangement. Because it involves multiple wires being twisted and wound together, and given the high elasticity and rigidity of the steel wire, the system requires high levels of synchronization and tension range adjustment, making the entire control system relatively more complex than that of a single-wire winding machine.
II. Analysis of the main technical requirements for winding machines:
The overall frame of the winding machine is shown in the figure below, consisting of a pay-off frame and a wire testing and winding table. Each pay-off frame can hold 8 spools of wire, and the required number of wires to be wound can be adjusted according to the actual situation.
Problems encountered in system design:
1. Because alloy steel wire has a relatively thin diameter and is relatively hard, it is easy to break when tightened during winding, and easy to run when loosened and the arrangement is not neat.
2. When multiple rollers are feeding yarn simultaneously, the yarn must be fed at the same linear speed between each roller; otherwise, problems such as yarn breakage, yarn pulling, and uneven stranding may occur.
3. During the winding process, the winding speed should not be too fast or too slow. When starting or stopping, the start and stop should not be blocked. The speed should be adapted to the physical properties of the alloy steel wire itself.
4. Large and small alloy steel wire spools have different wire widths during winding. Furthermore, the alloy steel wire is wound in a cyclical pattern from left to right and right to left on the small spool. To ensure neat wire arrangement and appropriate tension, the transmission and wire arrangement components must utilize high-precision, constantly adjustable servo motors. Due to the high precision and constantly adjustable speed, the motor's speed, start-up, running, and stop states are controlled through internal pulse signals and external sensor signals to meet process and technical requirements.
III. Winding Machine Design Scheme:
The winding machine is designed according to the processing technology and technical requirements provided by the customer company. Based on the above working principle, the winding machine system can be divided into three parts: the wire feeding system, the wire measuring system, and the winding system.
1. Laying-out system
Based on the system's requirements for the winding section, an active winding method is adopted. Options include a 750W frequency converter + tension sensor or a 750W servo drive + tension sensor. The main difference lies in control effect and accuracy; the frequency converter is cheaper but has a smaller controllable range, while the servo drive offers better control and more uniform winding, but is more expensive. In addition to working with the drive to close the tension loop, the tension sensor also detects wire breakage. If a break occurs, the drive sends a breakage signal, immediately stopping the entire winding system to prevent further losses. Therefore, if the frequency converter meets the overall system winding effect requirements, the active winding solution using a frequency converter and tension sensor is preferred.
2. Measurement line length:
After the steel wires are bundled into a single steel rope, it passes through a measuring roller, which drives the encoder to rotate. The actual winding length can be calculated based on the number of pulses output by the encoder. This data calculation can be performed using a PLC or our company's dedicated length measurement control card. When the actual length equals the set length, a winding stop signal is output to stop winding. The set length can be changed and the current winding length can be displayed via RS-485 communication.
3. Winding section
Based on the client's requirements and existing machinery, two servo drives were chosen to power the winding roller and the wire guide roller in the winding system. The wire drum section uses a 1.5kW servo drive in speed mode to pull the wire winding, with the speed adjustable by the user. The wire guide section primarily uses a 400W servo drive in position mode, winding the wire proportionally to the position of the winding servo. The wire guide operation is performed according to the wire width and drum length, cycling from right to left and then from left to right to ensure neat arrangement and appropriate tension of the alloy steel wire on the winding drum. The wire guide data can be changed via a human-machine interface, allowing the winding method and pattern to be customized according to the user's actual needs, rather than being fixed by the machinery.
IV. Simplified Electrical Connection Diagram of the System
In this multi-wire winding machine system, due to the large number of wire feeding sections, a 485 bus + port control method is adopted for convenient system connection and management. System parameters, such as wire feeding tension, winding speed, encoder wire measurement coefficient, wire diameter, winding length, wire laying method, and number of winding rollers, are input via a human-machine interface. After setting the parameters, the system starts winding. The winding servo motor gradually accelerates to the set speed, and the various frequency converters cooperate to evenly feed the wire under the pull of the winding motor. Each wire is stranded by the rollers and then rolls onto the measuring wire. The controller calculates the winding length based on the signal from the encoder. The wire laying servo driver moves evenly left and right to lay the wire according to the wire width and the real-time synchronous position signal fed back from the winding motor. When the measured wire length equals the set length, the controller issues a stop signal, stopping the winding motor and the wire laying motor. The displayed finished product count increments by 1. After manually changing the wire spool, pressing the start button resumes winding, and the process repeats continuously.
V. Conclusion
This system employs a multi-point control approach, with each driver operating independently yet cooperating with others. The servo drivers, in particular, not only drive the motors but also handle some of the control tasks, making the system more stable and reliable. This type of winding machine system has already been well-received by our customers, with excellent results.
