In the cable manufacturing industry, the process flow of many processing machinery is from the start of the wire pay-off to the end of the wire take-up. The most widely used is the pay-off rack, and the power pay-off rack is a kind of equipment with higher technical content. In order to ensure the processing quality, the wire tension must be kept constant during the winding and unwinding process. The traditional control method is to use PLC's A/D and D/A modules, and obtain the required pay-off speed by reading the potential of the tension pendulum potentiometer. The take-up reels of different shaft diameters correspond to different PLCs. The internal adjustment parameters of the PID, such as inappropriate PID settings, will easily make the pay-off wheel in an unstable state, resulting in uneven pay-off tension, thereby affecting the quality of the product.
At present, the use of frequency converters for constant tension control of power pay-off racks is a development trend. Generally, frequency converters are required to contain PID adjustment functions, and PID can be controlled in both directions. At present, in industry applications, only a few brands of inverters can meet this requirement without adding any auxiliary accessories.
The pay-off speed of the pay-off reel depends on the take-up speed of the reel. Since the take-up reel always has a process of starting and decelerating to stop, this gives the take-up reel an inconstant speed. At the same time, due to the change in the diameter of the take-up reel, the line speed is constantly changing under the condition of a certain speed. The tension of the wire take-up directly affects the quality of the product. If the tension is too large, the wire is too tight, and it is easy to deform or break the inner core for small diameter wires. If the tension is too small, the take-up reel will slide axially on the winding core and be misaligned during take-up, resulting in irregular take-up. All of these require the pay-off wheel to correct its own speed according to the balance position of the tension pendulum.
Generally speaking, the requirements for power pay-off racks are as follows:
1. In the process of winding and unwinding, keep the wire tension constant;
2. When the speed of the take-up reel is accelerated or slowed down, the speed of the take-up reel needs to quickly and automatically track the take-up speed and keep the line speed consistent;
3. The speed of the pay-off wheel can be automatically adjusted according to the diameter of the take-up reel;
4. When running stably at a certain speed, the tension pendulum bar of the pay-off stand should be stable; the tension pendulum bar should not swing repeatedly;
5. Need to have a broken wire detection function; when there is a loose wire or a broken wire, it is required that the pay-off wheel can be automatically reversed;
6. When the speed of the take-up reel is 0, the tension pendulum bar should be quickly stopped at the midpoint position.
Schematic diagram of retractable wire frame
After testing the power pay-off rack for low-speed pay-off, accelerated pay-off, high-speed pay-off, deceleration pay-off, etc., it can meet the customer's requirements very well, and it has also been recognized by customers. And the power pay-off stand using KE309 frequency converter has a wide speed range, high steady-state accuracy, fast acceleration and deceleration, flexible and convenient operation, and high reliability. It has excellent performance in fast speed tracking and loose wire reverse take-up. Greatly improve the efficiency of the power pay-off rack and fully meet the needs of customers. While saving the cost of the enterprise, the output and quality of the product are increased. The pictures of the application site are as follows:
The application of Micno KE309 power pay-off rack/double-frequency wire drawing machine special frequency converter in the cable industry actually solves the electrical control problems of electric pay-off racks and take-up reels in the wire and cable industry. Its superior performance (rapid response PID function, wide speed range, high steady-state accuracy, fast acceleration and deceleration, flexible and convenient operation, complete functional protection) and high reliability have been fully verified. Due to the simple wiring and the PID built in the inverter, it saves the work that had to be converted by A/D and D/A modules and the work of PLC programming, which saves customers' costs and makes customers more competitive.