compression spring is a type of mechanical spring designed to resist compressive forces. When subjected to a load, it compresses and stores mechanical energy. Upon the release of the load, the spring returns to its original shape, releasing the stored energy.

Storage and release of energy: When compressive force is released, energy is also released. This characteristic enables them to absorb shocks or impacts, cushion vibrations, and maintain consistent forces in various mechanisms.
Provide resistance: Compression springs provide resistance to compressive forces, resist applied loads, and maintain specific pressure or tension. They help maintain the normal operation of mechanical systems by applying specific forces or pressures as needed.
Absorption and distribution of force: Spring compression absorbs and distributes the force generated during motion or operation. It helps prevent component damage by absorbing impact and vibration, thereby extending the service life of the equipment.
Control motion: Compression coil springs are used for applications that require control and predictable motion. They provide precise force and motion control in various mechanisms, such as automotive suspensions, valves, and industrial equipment.

These are very common and are found in the automotive, aerospace, and consumer industries. This type of spring can take many forms – conical, barrel, hourglass, or cylindrical – but the most common is straight cylindrical. Energy storage capacity is greater for the round wire springs than rectangular, but these other shapes have advantages like reduced solid height, buckling, and surging, or to produce nonlinear load-deflection characteristics.
As you squeeze a compression spring, it pushes back to return to its original length. Spring rate is the amount of force required for every inch of compression or, for metric springs, millimeter of compression. The higher the spring rate, the harder it is to compress the spring.

Compression springs have different end types to accommodate various installation and functional requirements for different applications. The choice of end type will affect the interaction between the spring and the surrounding environment, as well as its performance in specific mechanisms. The choice of compression spring end type depends on the specific requirements of the application, including available space, installation method, required load distribution, and type of mating components. Spiral compression springs with different end types have different advantages and characteristics:

Closed end:
The two ends of the compression spring are closed, which means that the last coil at each end is tightly wound around the adjacent coil.
The closed end provides a stable and flat surface for the spring to rest on the supporting components, ensuring correct alignment and load distribution.
Usually used when the spring needs to be securely installed in a specific position.
Open ended ending:
Contrary to the closed end, the two ends of the compression spring remain open without any tight wrapping at the end.
The open end is suitable for applications that require the installation of springs on shafts, pins, or other cylindrical objects.
The open end allows for more flexible installation and is typically used when the spring must slide or rotate on its mounting point.
Ground end:
The polished end refers to a closed end that has been ground flat and smooth.
Grinding the end provides a good load distribution surface and reduces the risk of spring "popping out" under certain conditions.
When the spring needs to come into contact with a flat or mating component, a grinding end is usually used.
Double closed end:
Both ends of the spring are closed and ground flat.
It has excellent stability and load distribution, making it suitable for applications where precise alignment and consistent performance are crucial.
Double sealed ends are commonly used in high-precision equipment and machinery.