These products are generally designed for customers in different shapes and are generally used as accessories or components. (1) Variable diameter spiral spring: it is used in some special occasions. The material of variable diameter spring is generally circular section material, and most of them bear compression load. (2) Slice spring: the material of this spring is strip (or plate) for spring, which is processed by corresponding mould on special equipment or general pressure processing machine. The material thickness of leaf spring, wave spring and light spring is relatively thin, while the material thickness of medium or large disc spring is usually relatively thick, and this kind of spring is also widely used. (3) When the installation space is limited, the spring with rectangular cross-section is often used, because the spring made of rectangular cross-section material can obtain larger load under the same space and the same deformation. Compared with the spring of circular section material, this kind of spring has large sectional area in the same space, so it absorbs more energy, as shown in the figure below. It can be used in heavy machinery, stamping die or spring with great rigidity.