Process Principle and Performance Comparison of Imported and Domestic Copper Drawing Machines

Process Principle and Performance Comparison of Imported and Domestic Copper Drawing Machines

There are some differences in the structure, process principle and performance of imported and domestic RBD copper drawing machines, and each brand of large drawing machines has its own advantages and disadvantages. In this article, the process principle and performance are analyzed and compared with the 2 wires drawing machines of Nihoff in Germany, FRIGECO in Italy and Yongxiong in China, so as to find the basis for the purchase of wire drawing equipment.

Tongling Nonferrous Copper Co., Ltd. is a new high-tech copper processing enterprise. In addition to the SMS continuous casting and rolling production line imported from Germany, which produces 8mm low oxygen bright copper rods, in order to expand the product business model, expand downstream customers and form a complete copper rod and wire industry chain, it needs to be equipped with corresponding RBD copper wire drawing machines to process 8mm low oxygen bright copper rods into copper wires with smaller wire diameters, In order to match the RBD copper wire drawing machine with excellent performance, the company analyzed and compared the domestic and foreign first-class double head German Nihoff, Italian FRIGECO and domestic Yongxiong RBD wire drawing machines, and found a reliable basis for the selection of RBD wire drawing machines.

1. Classification of wire drawing machines

Copper wire drawing machine is a machine that uses the malleability of copper wire and the compression of mold to make its diameter smaller, so as to achieve the size of wire diameter we need. It can be divided into single head, double head and multi-head wire drawing machines according to the number of wire drawing heads at a time; According to the working principle, it can be divided into sliding type and non sliding type; According to the size of incoming wire and outgoing wire, it can be divided into 5 levels: RBD wire drawing machine, Intermediate wire drawing machine, fine wire drawing machine, super fine wire drawing machine and micro wire drawing machine; According to the modulus of copper wire drawing machine, there are 9, 11, 13 and 15 dies; Production process flow of copper wire: 8mm bright copper rod --- paying off --- drawing --- online annealing --- cooling --- drying --- take-up --- warehousing of finished products.

2. Process principle and performance of German Nihoff RBD drawing machine

2.1 Structure and process of Nihoff wire drawing machine

2.1.1 Wire drawing machine: Nihoff wire drawing machine is divided into sliding type and non sliding type, and its characteristics are as follows: ① The pull wire drum is completely immersed in the emulsion - the best cooling and lubrication. ② The drawing die is pressurized and lubricated. ③ Double cover sealed wire drawing machine base - no lubricant leakage(Double sealing system). ④ The casting box adopts a standardized modular structure - no vibration, bright and clean wire surface, and long service life of bearings and gears. ⑤ Wire drawing oil/gear oil sealing system: adopt safe passage and labyrinth seal. 6. Wire drawing die base: divided into standard die base, special die base (closed die base) and rotary sizing die base.

2.1.2 Nihoff RBD drawing annealing device, from the structure of the annealing machine, Nihoff RBD drawing machine is of discrete type and bedroom type; The annealing current can be divided into AC and DC. The structure and process are as follows: ① The wire route through the annealing device is simple, and there is no crossing of the wire route; ② Annealing transformers of different specifications can be combined with existing wire drawing production lines of various models for single wire and double wire production lines. ③ Mature and reliable AC annealing device is adopted. ④ The annealing shall be protected by nitrogen or steam.

2.1.3 Nihoff take-up system, which is divided into coil winding device, single reel take-up device and static reel take-up device. Features of coil winding device: ① Ceramic coating coil forming drum. ② Line pressing claw that can be centrally adjusted by pneumatic valve.

2.1.4 Nihoff MSM 85 motor. Nihoff is driven by water-cooled AC motor, which is more stable than air cooled motor and has lower noise.

3. Process principle and performance of Italian FRIGECO RBD drawing machine

3.1 Structural process of FRIGECO RBD drawing machine

FRIGECO wire drawing machine is mainly non sliding type, which uses independent motor system and has the following characteristics:

3.1.1 Wire drawing machine. ① Variability: The machine uses different surface reduction rates for wire rods of different dimensions to obtain the optimal wire rods and prolong the life of the mold. ② Energy consumption: the minimum sliding can increase the heat and reduce the energy loss due to the friction between the wire rod and the drum. The wire drawing drum behind is directly coupled with the motor, avoiding the use of a gearbox, which can reduce the total energy consumption in some cases. ③ When using fewer drums, the final wire drawing drum can be closed to minimize energy. ④ Wire quality: the sliding of low wire on the drum can significantly improve the wire quality by reducing the wear of wire. ⑤ The drawing die holder is designed to place the drawing die in a high-pressure lubrication space.

3.1.2 FRIGECO continuous annealing device: The structure of FRIGECO annealing device can be divided into vertical and horizontal, and the annealing current is AC annealing. ① The annealed wire is cooled by a high-pressure coolant nozzle. ② After cooling, the wire is dried by a double mold device filled with compressed gas. ③ The annealing shall be protected by nitrogen or steam.

FRIGECO paying off device. ① Automatic loop take-up. ② Single reel take-up. ③ Double reel take-up.

4. Process principle and performance of Yongxiong RBD drawing machine

4.1 Structural process of Yongxiong RBD drawing machine

4.1.2 Wire drawing machine. Yongxiong RBD wire drawing machine is a sliding wire drawing machine with the following characteristics: ① The RBD wire drawing machine adopts full immersion lubrication cooling, powered by two DC motors. ② The speed of the fixed speed wheel motor is adjusted according to the synchronous coefficient of the motor to ensure the tracking coordination between the wire drawing and the fixed speed wheel. ③ The sizing die adopts rotary design to improve the roundness of the finished product line. ④ The gear box of the wire drawing machine can choose to separate the last three drums of the wire drawing machine through a special clutch, so as to reduce the idling phenomenon of the gears in the non working part, improve the service life of the equipment and reduce the noise.

4.1.2 Yongxiong annealing machine. ① The annealing machine adopts the three section contact annealing principle and AC power supply, which is suitable for the continuous annealing production equipment of copper wire. ② The annealing machine adopts vertical and horizontal structure, and is composed of conductive system, anti oxidation protection system, cooling system, drying system, electrical system, etc. ③ The power of the annealing machine comes from the constant speed motor of wire drawing, which is driven by the clutch. When annealing is not used, it can be disengaged by the clutch to reduce mechanical wear and energy consumption. ④ The annealing shall be protected by nitrogen or steam.

4.1.3 Yongxiong take-up machine. Yongxiong take-up machine has coil take-up machine and disc take-up machine. The coiling take-up machine is composed of frame, coiling, wire dropping, wire storage, tray transport mechanism and electrical control system. The take-up machine is driven by DC motor. The wire dropping mechanism adopts eccentric rotation design, which makes the wire form a plum blossom shape, and has the characteristics of high loading density and no entanglement paying off.

5. Process principle and performance comparison of imported and domestic RBD drawing machines

① Nihoff, Germany: Sliding and non sliding wire drawing machines are used. AC/DC annealing is used for annealing. Double ended annealing with a current of about 10000 amperes. The structural types of annealing machines are vertical and horizontal; Annealing is protected by nitrogen/steam; The take-up methods include reel take-up and coil winding. ② FRIGECO, Italy: The wire drawing is non sliding, and the annealing is AC annealing. The double end annealing current is about 10000 amperes. The structural types of the annealing machine are vertical and horizontal. The annealing is protected by nitrogen or steam; The take-up mode is the moving disc take-up and the looping off. ③ Domestic Yongxiong RBD drawing machine: the sliding type is used for wire drawing, and the AC annealing is used for annealing. The double end annealing current is about 8000 amperes. The structure of the annealing machine is mainly horizontal. The annealing is protected by nitrogen or steam; The take-up methods are disc type and coil type. ④ Compared with FRIGECO in Italy, Nihoff in Germany is an old brand enterprise in the wire drawing industry. Nihoff is very mature in the sliding wire drawing technology. Its technology development on the non sliding wire drawing machine is relatively late, and the technology is still developing. On the annealing current, Nihoff adopts AC and DC. But at present, AC annealing is used better. In terms of after-sales service, Nihoff's after-sales service fees are expensive. FRIGECO developed the non sliding wire drawing technology early, and the technology is relatively mature, but its control is complex. Moreover, FRIGECO is transferred from the steel wire drawing machine, and has no experience in copper wire drawing. From the perspective of production capacity, FRIGECO wire drawing speed is higher than Nihoff wire drawing speed, and the production capacity is correspondingly high. ⑤ Compared with the imported wire drawing machine, the domestic wire drawing machine is only sliding at present, and the take-up mode is only loop winding; In terms of production capacity and technology, there is a big gap between domestic wire drawing machines and imported wire drawing machines.

6. Conclusion

The wire drawing production process is a complex system engineering, involving many links. To produce high-quality products, it is necessary not only to be familiar with the structure and performance of the equipment, but also to have qualified staff, strict raw material procurement procedures and strict testing procedures. According to the actual situation, on the basis of detailed comparative study of the structure and performance of domestic and foreign copper wire drawing machines, the company finally selected the appropriate wire drawing machine equipment.