Problem
Spars and ribs of wings, frames, bulkheads, and other large structural aerospace aluminum components are manufactured by milling solid monolithic blocks, often exceeding 1.5 x 3 meters, to produce lightweight yet robust parts.
The material removal times required for these applications are a critical bottleneck in the production process of a sector where the two main players, Airbus and Boeing, currently face multi-year production backlogs.
Solution
This has driven the demand for new 5-axis machining centers capable of combining high material removal rates with exceptional precision, reducing handling time and difficulty, and efficiently evacuating the large volumes of chips produced.
Self Group Comi developed and produced Monnalisa, an innovative high-speed horizontal 5-axis machining center specifically designed to meet these requirements.
Benefits
A fundamental requirement for a machining center in this application is maximum rigidity and precision, which is why the structure is entirely cast iron, box-in-box, reinforced at strategic points to achieve optimal stiffness and dynamic performance with minimal thermal distortion.
Significant attention has been given to axis movement, which is evident upon observing the machine: the X-axis double-column carriage has a Gantry configuration with two Twin Drive systems to compensate for backlash via electronic preload. The Y and Z axes slide on roller guides, while the position of all axes is measured using pressurized, coded optical scales.
To accelerate material removal and meet specific operational requirements, Monnalisa can be equipped with a spindle delivering 29 Nm torque for aluminum parts, or an 83 Nm torque spindle capable of milling titanium.
To ensure maximum efficiency at the heart of the milling machine, Self Group Comi designed its own fork-style continuously interpolated head, featuring through-tool cooling, air blast for spindle cone cleaning, and rigid tapping capabilities.
Another key advantage is the pallet change system, allowing fully unmanned operation: a new part can be prepared and loaded on the second table while milling continues on the part inside the machine.
Loading, clamping, and positioning of workpieces are made easy and safe thanks to the system designed by Self Group Comi engineers: the operator loads the piece onto one of two steel tables, clamps it using vacuum pumps, an innovative “reversible” clamping system, or traditional mechanical clamps, and positions it vertically through a 90° rotation of the tilting table driven by two hydraulic arms.
Rough milling of these blocks often involves removing up to 90% of the original weight. A large belt chip conveyor beneath the worktable continuously evacuates approximately 1 m³/hour of chips, while a tank below the walkable grid collects the abundant coolant.
A high-capacity tool magazine (120–240 positions) and the high-performance Siemens 840D SL CNC complete the configuration of this machine, which allows no compromises on quality.
Monnalisa is a demonstration of Italian mechanical excellence capable of competing globally—a fact that visitors to the Self Group Comi headquarters in Zingonia (Bergamo) can witness firsthand!
