The type of end on a compression spring can vary and your choice of end type can greatly influence your design's performance. Several factors come into play such as precision requirements, application context, and cost. This guide will deliver straightforward information on five common end types for compression springs: closed and ground, closed and squared, double closed, general closed, and open ends. For example, high-precision applications might require a closed and ground end. However, if the application isn't as demanding, a simpler, more affordable option could be suitable.
Advantages and Disadvantages - Closed and Ground
Advantages : Closed and ground springs have flat and smooth ends. This characteristic allows the springs to stand on their own and decreases the possibility of buckling, making them more stable. In applications where heavy loads are involved, like in the automotive suspension systems, these stable springs prevent failure under such conditions. This end type is most common in larger springs.
Disadvantages : The process of fabricating closed and ground ends adds an additional production cost. This might make these springs less appealing for applications without high mechanical load requirements, but require a high production quantity. For example, in simple door lock systems, springs without ground ends could be a more economical option that still meets the necessary requirements. Ground ends are also uncommon for smaller size springs due to the diminishing returns of flattening a small spring relative to a large one.
Advantages and Disadvantages - Closed and Squared
Advantages : Closed and squared end springs have flat ends, which improve balance in mechanical applications. An example is a valve system, where these springs sustain the system's function. The design of these springs permits upright usage in numerous contexts without grinding. This aspect reduces production costs, as it removes the additional grinding necessary for other spring types like closed and ground springs. This end type is most common in small to medium size springs.
Disadvantages : Closed and squared springs have limits. While the flatness of the spring surface aids balance, it does not provide the same stability as closed and ground springs. Typically, for smaller springs or springs that require less precision or robustness, closed and squared is preferred over closed and ground. However the closing process may add a small additional cost, like the grinding step.
Advantages and Disadvantages - Double Closed
Advantages : The design of double closed springs involves closing an extra turn of coil on each end, helping to improve stability. This characteristic is beneficial in applications requiring high durability like automotive suspension systems. Double closed springs can absorb and distribute shocks better than their single closed counterparts.
Disadvantages : The production of double closed springs involves a slightly more intensive process to close twice the normal number of coils, which leads to increased manufacturing costs. While this makes them more expensive compared to other spring end types, the improved performance in high-stress situations can justify the added cost, given this cost is often extremely small. That being said, this is a fairly rare end type that is only used in very specific applications, and is offered by very few manufacturers. Most often, it is best just to mount your spring with a rod or tube to increase stability rather than choosing this end type.
General Closed springs on CoilsDB is the nomenclature used to describe all three closed end types. Searching for this type of spring will yield results from all 3 categories, and is useful if the end type of the design is not particularly critical, which is the case for most non-production level applications.
Advantages and Disadvantages - Open Ends
Advantages : Open-ended compression springs are straightforward to design and cost-effective to produce due to the uncomplicated production process. In applications where the spring ends are not required to make flat contact with a surface, the lack of flat contact does not interfere with the spring's function. This end type is also common for exceptionally large and long springs, where the buyer will post process the spring ends with something custom.
Disadvantages : The primary drawback of open-ended springs is their limited stability. Their absence of a flat contact end restricts their use to applications that do not demand high load support or vibration resistance. In general, it is more difficult to design a surface to work with an open ended spring compared to the other end types. Given that the cost savings vs other types tends to be minimal, this end type (or rather, lack of end type) tends to be the least commonly used in practice, typically being used as a "cut to your own length" product.
The compression spring end type that you select has a direct impact on the spring's performance, cost, and suitability for different applications. Each type of end has its unique advantages and disadvantages. Closed and ground ends, for example, are generally more stable but may be more expensive due to the added grinding process. The best choice of spring end type is one that meets your application needs and fits within your budget. The specifics of your engineering applications, including their operational requirements and lifespan, should greatly influence your final selection. Make sure to base your design decisions on the actual requirements of your application to achieve the best outcomes.