Abssac Ltd

Compression spring machined from a solid piece of material

Technology Spotlights

In classical physics, a spring is seen as a device that stores potential energy, specifically elastic potential energy. Back in the 17th century the British physicist Robert Hooke developed what was to become known as Hooke’s law of elasticity. This states that the extension of an elastic rod (its distended length minus its relaxed length) is linearly proportional to its tension, the force used to stretch it. Similarly, the contraction (negative extension) is proportional to the compression (negative tension).

All spring forms adhere to this law, however it is the linear accuracy of the relationship between the compression or extension to the force applied, that separates the traditional wire wound spring from the machined spring. As the name suggests, the product is machined from a single piece of bar stock material rather than coiling wire. Due to the geometry of the machined coil, the spring rate is extremely linear in compression and extension. In fact spring rate tolerance can be as good as +/- 1% if required.

So why use machined springs?

Two main advantages are immediately apparent. Machined springs can provide very precise, linear deflection rates because virtually all-residual stresses are eliminated. Secondly, the machined spring also enables the designer to incorporate the way in which the spring attaches into the single piece design, often incorporating parts of the spring assembly into the single part construction.

Why are machined springs so unique?

Quite simply, it is possible to have one, two, three of more spring coil elements in the single piece spring construction. Multi-start springs

deliver outstanding performance advantages, since the independent helixes are in the same cylindrical plane, which provides totally enhanced spring performance. In fact, the machined multiple start spring coil configurations takes the performance and reliability to levels simply not achievable by the traditional wound spring format.

So why use machined Compression or Extension springs?

A single start spring provides a reaction force plus a moment. On multiple start springs, virtually all internal moments are resolved within the spring itself, which translates into excellent compression or extension parallelism.

The machined spring product has proven itself in medical, aerospace, semiconductor and motor-sport industries to name a few. Wherever a wound spring is not able to meet your performance criteria or a new spring design requires accuracy and repeatability, the machined spring is the ideal partner.

The next time you require a spring in a critical or high duty cycle environment, the machined spring from Abssac Limited may be the answer to your design problems.