Adaptable: A servo press machine is turned into a “servo measure” machine

For some years now IEF-Werner is known to produce servo presses which comply with the highest precision demands. Perfectly coordinated components form the basis therefore, as well as the special precision guides or the stiff tool steel c-frame. Exactly these characteristics are in need of industrial-suited altimeters. A lucky circumstance, as this is how IEF was able to solve a difficult task in a simple way for Bürkert Werke GmbH from Ingelfingen near at Heilbronn. In this process, the servo press machine was turned into a “servo measure” machine.

Furtwangen, 02.12.2015 – A new tendency in production and assembly industry is developing lately: Many producers move the quality determining factors away from cutting production precision to assembly precision. “This applies mainly for products which can be reduced further and further in their size”, Frank Neugart, product manager at IEF-Werner GmbH in Furtwangen, says. Normally production tolerances upwards are no significant challenge when scaling products. But when it is all about designing products smaller and more compact, they play a huge role. Where the end stop was installed before, now minimal inaccuracies complicate the established assembly possibility. The tolerance limits can be optimised by choosing suitable precision production methods, but that leads to inacceptable production costs in the most cases. Industry 4.0 is able to offer an efficient solution, as this vision is known in the precision and assembly sector for quite a while now.

Precisely the dynamically adapted assembly processes are at stake here. “Dynamic” means in this context that different production parameters are constantly adapted to the current situation during production. A therefore specialized communication system gathers measuring data, processes those very quickly and adapts the connected processes dynamically. “Our servo press uses the results of the measuring station for an offset correction”, Neugart reports. Every assembly process is different, hence every product is a precise unicom.

Also the Bürkert Werke from Ingelfingen near Heilbronn demands this precision when producing compact magnet valves. “It is crucial to exactly comply with the distances which are necessary to completely open and securely close the valves”, Ottmar Müller, series production manager at Bürkert, explains. Magnet valves consist of many small components. The functional parts often have such a complex form that it is not possible to produce those with conventional, cutting manufacturing processes in an economic way. This is why only injection moulding parts made of plastic are possible. Productions with injection moulding reach accuracies of up to 1/100 millimetres. But if it is supposed to get even more accurate, additional attention has to be laid on the assembly process. The developers from IEF-Werner addressed themselves to this task and optimized the assembly process at Bürkert. For this purpose the present precision press aiPRESS was equipped with an additional servo press. That, however, is not used to join components but to individually measure the height tolerances. The “measurePRESS”, as it is called affectionately by the engineers from the black forest, uses the precise construction of the basic system, the by default present measuring instruments for force and distance as well as the patented positioning and probe function. “We only had to integrate a pneumatic miniature lift cylinder into the part intake”, Neugart explains. “This stroke ensures that the upper and lower measuring points can be determined. The difference corresponds to the component height up to five micrometres precisely.” The measuring process can be adapted individually by means of the parameter. The user can state for example the probe force or the number of measurements. The second machine, which is responsible for joining in the target position, was connected to “measurePRESS”. After measuring results are determined, the data gets measured as well as the joining process programme, which is situated on the hard disk of the press machine, gets adapted. During this time the operator removes the part out of the measuring station and puts it into the assembly apparatus of the servo press together with further parts. After that the dynamically adapted joining process programme takes place. “The results are perfect and ensure quality controls of a 100 percent”, Müller illustrates. Now the IEF-developers work on the concept of dynamically adapted joining processes which then can be offered as an extension module for all IEF-servo presses to the clients.