1. Brief introduction of the equipment
A wire drawing machine, also known as a wire pulling machine, is a mechanical device that draws metal wires. It can convert thick wire raw materials into thin wires and wind them into coils for use in the next processing step. This equipment is widely used in industries such as machinery manufacturing, hardware processing, petrochemicals, and wire and cable manufacturing.
Schematic diagram of wire drawing machine
2. Introduction to the control principle of wire drawing machine
Schematic diagram of wire drawing machine
Wire drawing machines can be broadly divided into four parts: take-up and wire laying, wire drawing, wire unwinding, and tension and angle feedback. Among these, wire drawing is the most crucial step, where the metal wire is gradually stretched through a die by being guided by electronic gears. Each wire drawing process requires a motor, making its control the most complex. The specific working principle is explained below from three aspects:
01. From a mechanical perspective, a thicker wire passes through an opening smaller than its diameter and is compressed into a thinner wire by a die. The formula expressing the relationship between speed and wire diameter is:
Based on this formula, the theoretical relationship between the front and rear wire diameters and the linear velocity of each mold can be obtained.
02. From the perspective of electrical control, the speed of the motors before and after each die can be correlated by electronic gears. Under the premise of a specified wire drawing speed, the speed of each motor can be calculated based on the electronic gear ratio obtained from each die and the wire feed diameter, thus obtaining a basic control framework with electronic gears as the core.
03. In actual operation, due to various errors, the calculated theoretical speed may not be suitable. We add a feedback mechanism - tension bar. The control system quickly obtains the tension bar angle and uses an incremental PID correction algorithm to calculate a suitable correction value and add it to the theoretical value to correct the motor speed, so that the tension bar always stays in a horizontal position, thus ensuring that the wire drawing speed at each stage is stable, with less fluctuation and no wire breakage.
3. Control Scheme
The control system in this case study uses the eXtreme series high-performance motion controller developed by MOONS. This motion controller is capable of handling a variety of high-speed and high-precision motion control applications, integrating motion control, logic control, network communication and other functions, and is a powerful core of automation solutions.
Network topology diagram
Challenge 1: Multi-stage electronic gear coupling, and varied manufacturing processes.
Solution: The controller program uses arrays to represent multiple axes and their corresponding parameters, employing a single-spindle coupling mode. Based on the selected process, the corresponding electronic gear coupling ratio is dynamically calculated. Practical testing has proven that the simplified control method is simple, reliable, and easy to use.
Challenge 2: Factors such as machining affect the theoretical calculations.
There will be discrepancies between the electronic gear ratio and the actual ratio.
Solution: A tension angle sensor was added to the equipment to provide feedback on the actual smoothness of the wire drawing process. Through PID control, the electronic gear ratio was dynamically adjusted, effectively eliminating gear ratio deviations caused by machining and other factors. Practical testing has shown that the PID-adjusted electronic gear ratio meets the control requirements of the wire drawing machine.
Advantages of the solution:
01
- The entire set uses MOONS' product series -
Motion controllers, servo drives, and servo motors – one-stop service to shorten development cycles.
02
- Recipe Function -
The formula function meets various process requirements, and formula parameters are stored in real time and retained even after power failure;
03
- Process Library -
Its unique wire drawing process library is simple to use, offers precise control, and effectively reduces programming and debugging time.
04
- Communication Methods -
The control system offers diverse communication methods to meet the various communication needs of the project.
4. Summary
The entire wire drawing machine system has strict requirements for speed control, as well as high precision in the control system and coordination between each motor. This complete solution provides one-stop service, using MOONS' MCX motion controller and M3 servo system for control. It enables real-time data exchange, reduces transmission delays, improves the uniformity of the finished wire, and effectively increases production efficiency.
