A fully automatic production cell based around two Heckert five-axis horizontal T45 machining centres from Starrag, with integrated robot handling, is manufacturing process-intensive planetary gear carriers in half the time taken by conventional methods. Plus, it is reducing tool expenditure by around 25% and halving traditional equipment costs.
The capabilities of Starrag’s T45 machining centres are combining effectively with robotised pallet, gripper and tool handling, as well as with seamless cell control technology, to ensure Germany-based mechanical engineering and automation specialist Voith increases productivity by producing gear carriers in the shortest possible lead times and with extremely high levels of precision and process reliability.
Assuming an annual output of 50,000 parts per year, the system is also enabling productivity per unit area to be increased by up to two and a half times. This improvement is thanks to a reduction in the number of machines being used compared to traditional methods plus the compactness of the T45 – the machine’s footprint is 38% smaller than a conventional horizontal machining centre.
With exceptionally smooth running and minimal friction loss, state-of-the-art automotive power transmissions must be delivered, in a range of variants and different quantities, to customers’ assembly lines at precisely the right time.
In 2018, Voith approved the construction of a plant for the automated production of planetary gear carriers. The requirements were demanding, including an annual output of several thousand parts and the production of multiple variants in just two clamping positions. The requirements for precision, fault tolerance and process reliability were also high, of course.
Starrag engineers and designers, together with automation specialist SAV, set out to develop the unique production cell. And while it was clear that Starrag’s proven Heckert T45 machining centre would meet the requirements for milling, turning and drilling, a particular challenge was to develop automated, time-saving solutions for workpiece preparation and set-up, as well as effective process handling.
The successful result consists of two compact Heckert T45 machines in an integrated robot cell where the robot is effectively the ‘master’, orchestrating everything – from checking incoming components to loading/unloading the machines. Identical or differing type variants can be machined by the cell.
Once the component is clamped, an optimally coordinated sequence of rough and smooth milling, turning and drilling operations are undertaken by machines with 15,000 revs/min and 292Nm spindles, complemented by fast start-up and deceleration rates and 60-tool magazines.
The extremely short process and throughput times for sequentially machining workpieces that may be of variable design are partly due to the robot‘s ability to automatically set up the required grippers and type-specific pallets in the storage area while the machines are cutting. When the operator approves a new series for production, the robot changes all equipment within eight seconds.
This innovative production solution halves the previous process time.
Overall throughput time is also reduced because there is no need to change workpieces between machines – thus, for example, eliminating the installation of different clamping devices and re-clamping. In addition, the system offers an optimal flow of parts and minimised work-in-process inventory.
The Heckert T45s handle all the machining tasks with an extremely high level of precision. The machines’ central element is a powerful rotary table with a maximum speed of 900revs/min, which replaces the traditional use of multiple lathes. Indeed, with the HSK T100 tool holder and five axes, the Heckert T45 is the only horizontal machining centre that can combine clamping hydraulics with milling and turning.