Technical calculations of springs is one of the most important tasks for the Lesjöfors Group's technicians and sales staff. With an advanced calculation program most calculations can easily be performed with the highest accuracy.
Sometimes the purpose of a calculation is only to check that the dimensions on the drawing matches the specified load requirements, but equally common is that the calculation is made to select the appropriate material and spring dimensions to meet the requirements of spring forces or spring torsion. In the latter case a proposed technical solution is presented for the customer, usually in the form of a data sheet from a calculation program.
"We use our self-developed software OptiSpring. The advantages of a customized program are many, but the most important is the ability to update calculation models and material databases based on our continuous testing and development work. In this way, we can use the latest knowledge in our daily technical cooperation with our customers", says Stefan Musslinder, Technical Manager at the Lesjöfors Group.
Fast advanced calculations
Another important advantage of a special designed program is that the user interface is adapted to the needs of the company. OptiSpring allows Lesjöfors' technicians to make a control calculation of a single spring geometry in just a few seconds, while the same program can be used for much more complex design work.
Most spring types are included
OptiSpring includes modules for most of the spring types that Lesjöfors manufactures: compression springs (linear, conical, cylindrical progressive and spring kits with linear compression springs), tension and torsion springs, disc springs, wave springs and flat coil springs (tension springs and clock springs). For wire and strip components with complex geometry and/or highly non-linear characteristics, the finite element program Ansys is most often used.
Detailed description in data sheet
The detailed data sheet is for all spring types divided into four sections. The first section describes the characteristics of the material and the second contains spring dimensions including tolerances. The sections "Load Data" and "Stress Analysis" describe the spring under load in its' application.
"Forces or moments should ensure proper function, while the tension in the spring is what we use to assess whether the spring will fulfill lifetime demands, especially regarding relaxation and/or a requirement for fatigue lifetime, i.e. the number of load changes between the two modes", says Stefan Musslinder.
Spring details as manufacturing specification
In addition to these four sections, some extra information is available depending on the spring type. Goodman Fatigue Chart is available for linear compression springs, while a principal sketch of the spring is presented for other spring types.
The data sheet from OptiSpring is in many cases an unambiguous specification of the spring and can be used as a manufacturing specification after the customer's approval. Special end geometries (such as loop forms of tension springs or skänklar of torsion springs) and requirements for additional testing, purity, packaging etcetera, however, requires an additional specification.
OptiSpring is only for internal use within the Lesjöfors group, but if you want to learn more about spring calculations in general, you are welcome to contact Mattias Hartvigsson on +46-370 694 506 or e-mail firstname.lastname@example.org
Lesjöfors is one of the leading spring suppliers with internationally well known customers. The products are demanded in many markets, in diverse industries. The assortment of springs, stampings and pressings has a unique range, where one of the largest selections of standard springs are combined with high-tech, customized solutions.
Lesjöfors has both manufacturing and sales offices in several European countries, China, United States and Mexico.