Digital drives: Synchronous motors cold form precision profiles
Using a cold forming process to manufacture high-quality gear teeth calls for a drive system that can guide movements precisely and in absolute synchronism.
Using a cold forming process to manufacture high-quality gear teeth calls for a drive system that can guide movements precisely and in absolute synchronism. Applying pressures of up to 30 tons, two rollers press both sides of a profile onto a workpiece. The teeth of the left-hand and right-hand roller must mesh perfectly: if pressure were to be applied unevenly, following errors and defective gear teeth would be the result.
Building CNC profile rolling machines is one of the specialties of Rollwalztechnik Abele + Höltich GmbH , based in Engen, Germany. Not only does the mid-sized company manufacture these profile rolling machines, it also fills commission orders for slip-on gears, for example, on behalf of automotive and other customers. This field demands the highest standards of quality, which can only be met through exact and synchronous drive movements.
The precision cold-forming gear fabrication process presses a gear blank between two rotating formers that must turn in perfect synchronization. Source: Baumuller
The company'she tool axes have been set, the electrical drives are set in motion and rotate at a synchronous rotational speed, thereby ensuring that the opposing teeth mesh perfectly.
This method of manufacturing rotationally symmetrical profiles using a non-cutting cold forming process involves applying a maximum pressure of 30 tons to compress the material, thereby strengthening the surface. To ensure that the gear teeth in the finished product do not exhibit any following errors, the two thread rollers must be moved together in absolute synchronism: The teeth of each roller must be imprinted on the workpiece like a mold. To facilitate this, the machine operator enters a synchronization angle on the human machine interface (HMI) that the drives adopt and adhere to precisely. The depth of the two rollers must be just as precise to ensure 100% true running of the finished product.
"Here, everything depends on getting things accurate to 0.001 Baumüller
To guarantee the necessary level of drive synchronization, as well as rapid and precise communication between the machine control and drive technology, Rollwalztechnik is using SERCOS fieldbus communication. A plug-in fieldbus card is used for communication with the Baumüller drive system and is inserted directly into a Baumuller b maXX controller. The two electrical axes on the 30 X CNC/AC are driven by a combined system of DSO 100 three-phase synchronous motors and servo controllers.