Various factors influence the design a compression spring, and the end is one of them. The way the coils of a compression spring are constructed at the end determines their suitability for specific applications. The ends affect pitch, seating characteristics, free length, and the number of active and total coils in a spring and solid height. When purchasing Irvine springs, it is possible to get customised ends because some options may not be readily available. Before that, though a consumer must understand the different end types and how they impact the functioning of a compression spring.
Open or Closed
Compression springs can either have open or closed ends. Open ends are also called plain because there is no grounding at the end. This design allows the spring to maintain a consistent pitch along its free length. Having open ends also means that a spring does not have the stability to support itself and needs a rod to stand upright. These spring types are suitable for light duty applications. Open ends are also appropriate in instances where a device requires a weak spring to perform, but you don’t want to increase the solid height. Opening the ends means there are two more active coils on the spring that do not necessarily alter its height.
There is a reduced pitch on closed ends such that the last two coils touch. This design creates a dead coil at the end, thereby giving the spring a squared shape. Closed end springs can stand vertically very well on flat surfaces, which is why they are quite common. However, closed-end springs can only maintain stability if the slenderness ratio allows it. This ratio refers to the proportion of the spring diameter against its length. An appropriate ratio is where the length does not exceed the outer diameter more than four times. If that happens, then the spring will not stand but buckle when a load is applied. In the case of a high slenderness ratio, placing the spring inside a shaft can help.
Open Ground, Closed Ground
Compression spring ends can be ground or not. The grinding process takes place after the coils have left the CNC machines. This procedure brings additional costs to manufacturing, which is why closed and open ground springs cost considerably more than the ungrounded alternatives. Gridding the end coils of a compression spring allows it to sit very well due to the reduced threat of buckling. The process is suitable for large springs but usually, does not fit big production projects due to the high costs. Therefore, grinding becomes necessary when:
- There are specifications for high duty springs
- A need to minimise solid height
- The load or rate is required to have unusually close tolerance
- Demand for reduced buckling tendency
- A requirement of uniform bearing pressure and adequate seating
Closed and ground ends are particularly common but are very expensive. The best application is where you need springs to stand vertically without using a hole or shaft for support. Springs with closed and ground ends are suitable for applications that demand precision.
Open ends with a grinding finish are less parallel, appear flat and are used in special applications and still need support.
Another type of end that consumers can get is a double closed. The difference is not that much from a closed end. A double closed spring has two coils closed instead of one, and they are appropriate when stability is a significant factor. Manufacturing this design is similar to making torsion springs. One downside of double closed ends is the need for a lot of material to manufacture. However, they are still less expensive than closed and grounded springs.
These designs are just the basics that most applications require. Nonetheless, if a device demands a unique end, then it is possible to get Irvine springs that meet them. It’s only a matter of explaining the necessary specifications to the engineers who then create springs that cater to them.