The spring should be heat treated during processing. For springs of different types of materials and different methods, the purposes, methods and requirements of heat treatment are different. In order to eliminate unfavorable residuals, the stress distribution on the spring surface is improved. In order to obtain higher effective stress, mechanical strengthening process is often used in the manufacture of springs. Spring design requirements can be met by different heat treatment methods.
1. At present, the processing equipment and production lines of mechanical springs are developing towards the depth and breadth of CNC and computer control. However, as spring materials and geometries have changed, processing techniques have also evolved. With variable spring outer diameter. Suspension springs with variable pitch and variable wire diameter (three-variable) have been machined without moulds. Since the development of three-variable springs, tapered steel bars have been used in the winding process of CNC lathes, but the output and price are not ideal. At present, it has been changed to a heating state, and the speed and tension of the drum are controlled by a spring winding machine to obtain the required cone shape, and it is quenched through waste heat treatment.
2. Low carbon boron steel plate is rolled and welded to hollow stable spring rod.
3. The torsion bar is made of high-purity 45 steel. High-frequency quenching obtains high hardness, large residual compressive stress, and improves fatigue life and relaxation resistance.
4. Leaf springs, which are widely used in electronic products, are basically formed by stamping and automatic bending. At present, the bonding technology of composite materials is mainly developed.
1. One-time automation capability of cold forming process. The cold forming machine has reached 12 claws. Steel wires in the range of (0.3-14) mm are basically formed at one time using an 8-claw forming machine. At present, the development direction of molding processing equipment is as follows:
2. To increase the molding speed, the main development trend is to increase the molding speed of the equipment, that is, production efficiency;
3. By improving equipment accuracy, enhancing heat treatment effects and improving equipment durability;
4. Add a length sensor and a laser range finder to automatically control the manufacturing process of the CNC molding machine in a closed-loop manner.
5. Cold forming process capability. At present, the maximum size of large-diameter winding machines can reach 20mm=2000mpa, and the winding ratio is 5. There are still limitations to the cold forming process for miniature block springs and eccentric springs made from reduced or constant diameter materials.
1. Speed capability of the thermoforming process. At present, there are only CNC2 axial hot spring winding machines (9~25) mm in China, with a maximum speed of 17 units per minute. Compared with developed countries, the gap is huge.
2. The ability to control the hot forming process of large springs. Since there is only a CNC 2-axis hot spring winding machine, there are fewer three directions to control the shape and the accuracy is poor. In addition, since there is no automatic rotating rod control and adjustment mechanism, the molding technology level and capability of hot rolled springs are relatively low. Therefore, the accuracy level and surface oxidation decarburization level of the spring are also very low.
