The compression spring is an abbreviation of spring roll formation. The compression spring is the first process of the spring manufacturing, and it is also an important process. The accuracy of the compressioning plays an extremely important role in the entire manufacturing process. It basically determines the geometry and characteristics of the spring and the utilization of the material.
The spring compressioning equipment is generally divided into a mandrel compression spring machine and a non-mandrel shaft compression spring machine. The mandrel winding spring machine and the non-mandrel winding spring machine winding spring are respectively described below.
The rolling system has a single rolling system and multiple continuous rolling systems. A single roll system is generally used for the production of springs and oil seal springs, etc.; a plurality of continuous rolls are wound into a string of compression springs at a time, and then cut into individual springs by size.
In order to obtain the required dimensional accuracy after cold forming, it is necessary to accurately grasp the springback amount of various types of springs of different materials in the spring design, the spring process device design, and the preparation of the process specification.
There are many factors that affect the springback rate, including the mechanical properties of the material, the convolutional ratio of the spring, and the process equipment.
The rebound amount is proportional to the tensile strength fb of the material and inversely proportional to the elastic modulus e. The larger the σ/e is, the greater the rebound amount is. When the mechanical properties of the material are not stable, the rebound amount is also unstable.
The greater the winding ratio and the pitch of the spring, the smaller the plastic deformation, the less stable the internal stress, and the harder the control of the spring diameter and pitch accuracy. Therefore, when winding a spring with a large winding ratio and a large pitch, special attention should be paid to the operation of each step. For example, the speed is slow when reversing, the lightness of the rolled spring blank must be light, and it should be minimized before the stress relief annealing. For a spring billet having a large convolution ratio, it is preferable to fix the spring billet after the compressioning is completed, and then remove it from the mandrel after the stress relief annealing is performed simultaneously with the mandrel.