Compression Spring Parameters and Pi

Compression spring design formulas are really only somewhat complicated algebra. They are quite precise and yield very predictable results. However, when compression springs were first becoming widely used during the industrial revolution, neither computers nor calculators existed.

In an attempt to expedite the design of compression springs, industry designers came up with a slide rule that was specifically created for the design of compression springs. With this spring design slide rule, a spring designer could more effectively create a design for a spring and get it out to production much more efficiently than before. 

There were still significant draw backs in this method of compression spring design. Compression springs have a great deal of interrelated parameters. If the physics of one parameter is not sound, it may throw off several other parameters. As a result, the spring designer could one-by-one design the individual parameters of the compression spring and then find that when all of the parameters are put together, they do not work. 

The Parameters and Pi

With the advent of the calculator, the spring designer’s work became much more precise. The formulas used were more precise than the estimates used by the slide rule. For example, one of the more important parameters of a spring involves the use of Pi. Most of us learned that Pi can be carried down as many decimal points as you want and it will not repeat. But with the slide rule, the designer was hampered by the ability of the slide rule to accurately portray Pi. With the advent of the calculator (specifically the scientific calculator), the designer could now calculate Pi to any extent that the spring design required.

Even though the calculator made the spring design more precise, the formulae were still complicated and still had to be performed one calculation at a time. And the possibility existed that when all of the parameters were calculated individually, when stacked together, they would not fit. The advent of the programmable calculator, and then the desk top computer, not only significantly increased the speed with which a compression spring could be designed, but also had the ability to perform multiple operations at once to ensure that all of the parameters fit together well.

Advent of Computerized Spring Design Program 

As desktop computers grew in speed and capacity, more and more of the engineering parameters of the compression spring could be incorporated into the design programs. I this point, many spring companies actually wrote their own spring design programs. But then the national Spring Manufacturers Institute (SMI) found that it would be advantageous for there to be one consistent spring design program authored by the trade organization. The SMI then contracted with a programming house to write such a program under its tutelage. This program is very much in use today. And internationally, there are now several other programs written by trade organizations and testing services that are very functional in the design of compression springs. 

Some of these programs are now being “taught” to interface with spring winding machines—so the compression spring can be designed and wound all using one program. This ability has resulted in the compression spring becoming far more accurate than it was in the past. Specific applications never manufacturable in the past are now every day occurrences. And more complicated equations that are necessary to design these specific applications are now incorporated into the design programs … and are never even seen by the compression spring designer. 

In spring manufacturing, we have the capacity to create virtually any shape and type of spring with a wide variety of spring steel—for an array of uses. Contact one of our spring geeks today to find out which spring steel will work best for your next project.