The hydrostatically supported 5-axis machining center Starrag S1250 HD is ideally suited for titanium machining due to its extraordinary stiffness and damping. During performance tests conducted by Starrag at its headquarters in Rorschacherberg, the machine achieved almost unbelievable results: With a carbide end mill 'Cylindrical Endmill Cutter Ø40 R1.24' (18 teeth) developed by Starrag for high-performance machining (HPC), the milling specialists realized a material removal rate of 1,516 cm3/min. According to their assessment: World record in titanium machining!
Even the prototype of the Starrag S1250 HD demonstrated very efficient machining of titanium structural components. Two years ago, the hydrostatically supported machining center achieved a material removal rate up to three times higher than the roller-supported variant Starrag STC 1250 during roughing tests. In finishing, the improved damping and dynamics also ensured excellent precision and surface quality.
For the series machine, the Starrag technologists made several changes to further increase the removal rates and reduce tool wear. Since the most important adjustment factors for this are the stiffness and damping of the machine, the structure of the machine – both the beds and the column – was made even stiffer. It was also possible to increase the contact area in the hydrostatics, thereby enhancing stiffness and damping.
Another change involved the rotary table, which is now designed as a geared variant. With an enormous torque of 25,000 Nm and a clamping torque of 32,000 Nm, it perfectly meets the requirements of titanium machining. Additionally, the proven, compact swivel milling head received a one-sided enlargement. This creates space for a 50 percent reinforced A-axis with 12,000 Nm torque and 20,000 Nm clamping torque – while maintaining good accessibility.
The robust, Starrag-owned 53 kW geared spindle is used as the work spindle in the Starrag S1250 HD, offering 1,600 Nm torque and a speed of 4,500 min-1. New is the HSK-B160 interface, which provides high stiffness of the tools due to its large contact area. This is important for large cutting depths – especially with extensively overhanging tools.
With this interface, the Starrag S1250 HD is already targeting future needs. Given modern methods for producing blanks close to final contours, rough machining is likely to be reduced. The challenge will then be to dive into complicated and deep cavities with tools up to 500 mm long and deliver high performance there. Such tools are well supported by the large contact area of the HSK-B160 holder.
The new concept of the Starrag S1250 HD being a hit is confirmed not least by the order from Airbus for use at the Varel site. The company has already ordered five machines.
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