Control processes ensure the highest spring quality

Springs of the highest quality are the characteristic of Lesjöfors. In order to meet customers’ expanding requirements, major investments have been made in measuring equipment. At the plant in Swedish Herrljunga there are instruments that can measure and document each spring´s characteristics.

 Lesjöfors manufacture all types of springs with a wire diameter between 0.03 and 65 mm. Each production unit is specialized in its own market and product line, but a common requirement for all is the high quality standard each Lesjöfors spring must live up to. With theoretical models spring properties can be calculated with good accuracy.
"For all traditional types of springs, we use our own developed software and for more complicated geometries, we use specially adapted FEM programs. Rapid pulsed load and transient phenomena are areas who in some applications are of importance, says Anders Berntzen", Quality Technician at Lesjöfors Industrial Springs in Herrljunga, Sweden.

 Investments in measuring equipment
To become even better at measuring that the manufactured products are top class, a major investment has been made in new equipment. All production in Herrljunga is now carried out in fully automated processes. Measuring equipment is placed in the production line so operators are able to perform their spring tests in direct connection to their workplaces. Previously they had to go with the springs to a special test chamber.

 Accurate measurements with documentation
The new measuring equipment has been supplied by Italian Micro Studio which specializes in the measurement needs for spring manufacturers. The company is at the forefront and is continuously developing their products to live up to the high and changing requirements of the end-users´ requirements.
"We follow an overall control plan and it says check the first and the last piece with continuous inspections during the process. Have we, for example, 250 000 springs in a series, which is not unusual, the measurement takes place continuously for approximately every 30 minutes. If we have a small series of 3 to 5 springs we measure all of them in most cases", says Anders Berntzen.

 All-round spring competence
To get the requested spring properties, you need a good knowledge of manufacturing materials, after-treatments such as heat treatment, grinding and shot peening and other performance-enhancing measures.
"Lesjöfors´ strength is when a customer comes to us with an immediate problem ´we want a spring with this or that characteristic´. We can then participate from the project start and, based on our extensive experience, develop optimal solutions for the customer", says Henry Berner Strategic Sales Manager for all Lesjöfors´ units in Sweden.