Here at European Springs, most types of springs we manufacture are produced by plastic deformation of the material. We could compare this method with forging, but not with machining as during plastic forming, the material springs back to a certain extent and residual stresses are created.
The plastic deformation and the spring back depends both on the accuracy of the tools and their specific positions as well as the elastic and plastic properties of the material. In today’s industry, the accuracy of the tools and their positions are high, therefore depending more on the geometric tolerances and evenness of the material.
We like to advise our customers that material properties can vary to a greater or lesser extent between material heats, material manufacturing batches and even material coils. The consequence is that tolerances below the capability of the material and process lead to extra costs.
For spring tolerances, we normally comply with the DIN standard for springs since this is the standard that best reflects real life conditions. We regularly use also other standards depending on customer demands, and requirements.
We have a big number of different types and designs for springs therefore please contact one of our expert advisers for any information on tolerance examples. European Springs manufacture our products by following the material and process capabilities regularly with statistical methods. We aim to provide knowledge and information about types of distributions, probabilities, Cpk values and other statistics for the factors/measurements in spring specifications to all of our customers, regardless of order size.