1. Manufacture of compression coil spring with cold drawn spring wire
For the lathe coil spring, after the coil spring process, it is necessary to go through the cutting process to separate several connected springs into a single spring.
For some important springs, before grinding the end face, a blank height classification process can be added to ensure the grinding quality. The grinding process can also be divided into rough grinding and fine grinding, and deburring or chamfering can be performed after rough grinding.
2. Manufacture of tension coil spring with cold drawn spring wire
There are special automatic spring coiling machines abroad for the manufacture of tension coil springs. For some typical shackles, they can be completed at one time in the spring coiling process. However, this kind of machine tool has not been produced in China. The tension spring hook and loop is made with some special molds, which is a special process.
It is worth noting that the stress relief tempering process after the coil spring is to eliminate the residual stress generated during the winding process, while the tempering process after the hook ring is manufactured is to eliminate the internal stress generated during the production of the hook ring. Although these two processes have the function of eliminating internal stress, they cannot be combined into one process because the previous tempering process has the function of "shaping" to ensure the relative position accuracy of the shackle. And the heating temperature of the next tempering process must not be higher than the tempering temperature of the previous one.
Unlike compression springs, tension springs are generally not subject to "strong pulling" treatment. Since it is difficult for the shot to be sprayed on the inner surface of the spring, the shot blasting treatment is not performed.
3. Manufacture of torsion coil spring with cold drawn spring wire
Similar to the tension spring, there are also special automatic spring coiling machines abroad for the manufacture of torsion coil springs. For some typical torsion arms, they can be completed at one time in the spring coiling process. However, at present, there is only a straight tail coil spring machine in China, and the torsion arm must be completed in a special process with a special mold.
Since the direction of the residual stress generated during the coil spring is opposite to that of the working stress, the tempering process is often omitted so that these beneficial residual stresses can reduce the peak value of the working stress. However, tempering treatment is beneficial to stabilize the grain structure of the spring material and reduce the deformation of the spring torsion arm caused by collision during transportation.
The strong torsion treatment is also a process arranged for a few special torsion springs.
4. Coil springs are manufactured from spring steel wire supplied in annealed state
The alloy spring steel wire supplied in the annealed state is mainly used to manufacture the compression coil spring. Its process flow is different from the above mainly in that quenching and tempering treatment are required after forming, and normalizing treatment is required when manufacturing the spring end. Other processes are basically the same.
5. Process flow of hot coil large spring
Springs with a material diameter greater than 12mm are often referred to as large springs, which are generally manufactured by thermoforming. The large hot coil spring is basically a compression coil spring.
Hot coil springs are all cored coil springs. For the rolling conical spiral compression spring, it is difficult to "open the gear" (roll out the pitch) during the rolling process, so the calibration process also has the task of opening the gear. In addition, in order to ensure the quenching temperature, the correction process must act accurately and quickly. Otherwise, it must be reheated during quenching. In order to improve the fatigue life of hot coil spring, shot peening shall be carried out as far as possible when conditions permit.
