I Precision Winding Application Solution
■ Capable of performing winding and unwinding control, with normal operation in winding mode;
■ The tension arm must remain stable throughout the entire operation;
■ The winding speed is required to be above 1200 m/min (the operating frequency of the winding inverter should be above 60 Hz);
■ Immediate brake activation upon stopping.
■ CM580 inverter terminal control as command source, two-wire terminal control: one forward command FWD (winding), one reverse command REV (unwinding);
■ Frequency source switching available between winding and unwinding modes — PID regulation during winding, AI2 input during unwinding;
■ Fast PID regulation required during winding, acceleration/deceleration time set to 0.1s, therefore a braking unit-equipped inverter is necessary.
CMC's CM580 high-performance modular flux vector control inverter ensures all the above functional requirements are met.
II Powered Pay-Off Reel Application Solution
The wire and cable industry is currently moving toward product diversification and production automation at higher technical levels. In this industry, pay-off reels are widely used, among which powered pay-off reels represent a higher level of equipment technology. Powered pay-off reels generally require inverters with bidirectional PID control capability. CMC's CM530HLS flux vector control inverter delivers excellent vector control performance and high reliability, ensuring superior results in the wire and cable industry.
As the front-end equipment of many types of machinery, powered pay-off reels have wide applications in the wire and cable industry. Generally speaking, the following process requirements apply:
■ When the take-up speed increases, the pay-off speed must also increase accordingly;
■ When the take-up speed decreases, the pay-off speed must also decrease accordingly;
■ During stable operation at any given speed, the reel’s dancer arm must remain stable;
■ In case of slack or broken wire, the pay-off reel must automatically reverse.
All the above functions must be achieved through the inverter’s PID function, and the inverter must respond quickly to speed changes.
The CM530HLS series inverter offers flexible combinations of frequency sources. Both main and auxiliary frequency sources can be selected from 10 different options, allowing combinations such as Main/Auxiliary, Main/Main + Auxiliary, and Main + Auxiliary, thus providing users with customizable frequency source selection. For powered pay-off reels, the CM530HLS selects the Main + Auxiliary mode, where the main frequency is set to zero and the auxiliary frequency uses PID control, enabling bidirectional control.
CMC’s CM530HLS flux vector control inverter system offers the following advantages:
■ Highly responsive PID control;
■ Excellent response in both line speed tracking and slack-line reverse winding.
III Direct-Drawing Wire Drawing Machine Application Solution
Wire drawing machines are commonly used in the wire and cable industry. Based on structure, they can be categorized into water tank type, vertical type, and direct-drawing type. According to output wire diameter, they include: 1) Heavy-duty drawing machine (input diameter: 8 mm, output diameter: 3–1.3 mm); 2) Medium-duty drawing machine (input: 3–1.8 mm, output: 1–0.3 mm); 3) Light-duty drawing machine (input: 1–0.2 mm, output: 0.3–0.06 mm); 4) Micro-drawing machine (input: 0.12–0.06 mm, output: 0.06–0.01 mm). Thick wires are processed through multiple dies, and common die types include round wire drawing dies, spiral dies, and polycrystalline dies.
The direct-drawing wire drawing machine is one of the more complex types due to its multi-motor simultaneous drawing process, resulting in high efficiency. Unlike traditional water tank or loop-type drawing machines that allow slippage between dies, it requires strict motor synchronization and fast dynamic response. Due to the brittle nature of stainless steel materials compared to high-carbon steel or tire cord, breakage is more likely during operation.
1. A direct-drawing wire drawing machine consists of multiple drawing heads forming a continuous production line. It draws steel, copper, welding wires, etc., down to the desired specifications in one pass and then winds them up. This results in high productivity and compact footprint.
2. After each drawing stage, the wire diameter changes, so the linear speed of each drawing head must change accordingly. Depending on the die configuration, the drawing speeds of each head must be adjusted. The basic principle is to maintain constant metal volume flow through each die. Therefore, all drawing heads operate in synchronized line speed ratios.
3. The speed of each drawing head is determined by the main speed plus a PID fine-tuning value. Each drawing head has a displacement sensor mounted on the tension arm to dynamically monitor the tension between drawing heads. The sensor outputs a standard signal (4–20 mA or 0–10 V), which serves as feedback for closed-loop PID control of the inverter. By adjusting motor speeds, the system maintains constant tension at each detection point, ensuring smooth multi-stage drawing and high-quality output wire.
4. Low-speed jogging for threading the dies, stable running speed. Full-load motor start-up with starting torque reaching 180%, maximum wire speed up to 20 m/s.
CMC's solution for direct-drawing wire drawing machines:
Working Principle: The operator sets the operating speed via the HMI. The analog signal is sent to the PLC, which considers acceleration/deceleration time and then outputs the signal with a certain slope. This satisfies operations like jogging and threading. The analog voltage output from the PLC is connected to the AI1 input of all inverters as the main speed reference. Each swing arm displacement sensor signal is connected to the corresponding drum drive inverter as PID feedback. With the swing arm centered, a fixed PID setpoint is defined (numerical setting). This forms a typical feedforward PID control system, cascading stages with PID as a fine-tuning mechanism.
Advantages of Using CMC's CM580 High-Performance Flux Vector Control Inverter for Direct-Drawing Wire Drawing Machines:
■ Easily achieves main speed with PID fine-tuning without additional control boards;
■ All complex control handled by inverters, reducing PLC programming and hardware development difficulty;
■ No D/A or A/D conversion modules required, lowering PLC performance requirements;
■ Optimized cost and improved system cost-effectiveness.
IV Water Tank Type Dual-Inverter Wire Drawing Machine Application Solution
Dual-inverter wire drawing machines can stretch copper or steel wires progressively and wind the finished product quickly, typically used for processing wires larger than 0.1 mm. These machines usually use passive unwinding. Raw material enters the drawing box from the pay-off reel, passes through multiple dies, and is drawn to the preset diameter. After stranding, it is wound layer-by-layer onto a bobbin.
1. **Threading the Dies:** Before starting the machine, the operator manually grinds the front end of the raw material and threads it through each die. Footswitches can be used to jog the motor at low speed while pulling the wire through each die. To pass through the next die, the wire end must be further ground or thinned. At this stage, the main drawing motor must deliver high and stable torque at startup and low speed, with no reverse rotation during deceleration shutdown.
2. **Drawing:** After manual threading, the motor speed is gradually increased to achieve continuous drawing. Note that dual-inverter drawing is usually performed by one drawing motor, followed by multiple dies for stepwise stretching. During actual operation, the motor speed range may be large, even operating in the constant power zone. At this stage, the motor must maintain minimal speed fluctuation under any load, and provide strong and stable torque even at low speeds or in the field-weakening region.
3. **Winding:** The winding section is independently driven by a winding motor, synchronized with the drawing motor via a PID-controlled tension arm. Finished wire after drawing must be evenly wound onto the bobbin. Throughout the process, whether during acceleration, deceleration, or steady-state operation, the winding and drawing motors must remain synchronized. Otherwise, wire breakage or tangled winding may occur. At this stage, the winding motor must have fast PID response and precise speed control.
4. **Layering:** Typically, finished wire is wound layer-by-layer onto a bobbin. Along the horizontal axis of the bobbin, the wire must be tightly and evenly arranged from one end to the other, forming one layer, then building up layer by layer until a full spool is completed. This requires a layering device to reciprocate the wire along the bobbin axis. Mechanical, inverter-based, or servo-based solutions can be used depending on mechanical design requirements.
5. **Start-Up and Emergency Stop:** During startup, both the drawing and winding motors accelerate. The wire overcomes friction forces, causing significant dancer arm movement. The startup must be smooth with minimal dancer arm swing and no wire breakage. In case of emergency stop during operation, the machine must halt as quickly as possible. At this point, both motors rapidly decelerate, and the stop must not cause wire breakage.
Advantages of CMC's CM530HLS Wire Drawing Winding Dedicated Inverter:
1. Fast PID response — the winding inverter responds in real-time to speed changes of the traction inverter;
2. Stable speed control — the dancer arm remains stable during normal operation;
3. Optimized dustproof, moisture-proof, and heat dissipation design — suitable for harsh environments with high metal dust and temperature;
4. Software-optimized start/stop handling — smooth startup and no wire breakage during stop.
