Customised spring design

One of the ways to select an appropriate spring for the job is to looks to one of the standard spring catalogues available on the market and select the spring from the  which most closely meets requirements, if possible. Alternatively, it is possible to turn to a company such as Goss, which offers a complete design advisory service – whether it is for the design of a new component or optimising an existing design.

In order to achieve optimum life expectancy, the material selected is vital. The type of application that the spring is to be used in will of course determine life expectancy, performance requirement and, depending on what the life expectancy might be, the type of material used.

As a general rule of thumb says Nick Goss, “the more expensive the material we use, the longer the life of the component”.  A typical application for a compression spring in an engine valve might involve 8000 cycles per minute and the best material to guarantee this sort of performance is chrome silicon. 

Extreme environments

The extreme environment of the offshore industry means that Inconel is usually the material of choice. Inconel alloys are oxidation and corrosion resistant materials well suited for service in extreme environments and which may be subject to pressure and heat. When heated, Inconel forms a thick, stable, oxide layer protecting the surface from further attack.

Goss Springs is equally at home selecting the appropriate design, material and manufacturing process for a spring which might not be in use constantly, but must be ready to work when called upon. There are many applications where the spring will be held and stored for long periods of time, usually in a compressed state and in such cases a high tensile spring or stainless steel will be selected.

For many standard duties the spring, which basically acts to store energy, is produced from range 3 music wire, or high tensile stainless steel.  In operation the material is subject to various degrees of stress and therefore must be highly tensile.

A standard stainless steel will operate in conditions of up to 300˚C. Some grades of stainless steel have however restricted environmental operating conditions. The basic “music wire” used for producing springs is available in different grades: type 302 stainless should not be used in conditions where acids are present and is thus unsuitable for applications processing citrus fruits where instead type 316 should be used – which is incidentally also suitable for operations where contact with blood may occur or in low salt conditions.

Indeed, components used in the medical industry will often be made from platinum; iridium or gold may also be used. A readily worked alloy, platinum–iridium is much harder, stiffer, and more resistant to chemicals than pure platinum, which is relatively soft. Platinum–iridium is also very resistant to high-temperature electric sparks and is widely used for electrical contacts.

In case you are getting the impression that Goss are only specialists in the manufacture of custom high performance components you would be wrong. High volume, simple components is bread and butter business to the company. Very simple compression springs are made in their 000’s as positional devices in oil and water filters where they “hold” in position another component of the filter.