In the machine tools and production systems sector, Innse-Berardi is confirmed as one of the main partners of Rete Ferroviaria Italiana, a company of the Ferrovie dello Stato Italiane Group responsible for the overall management of the national railway network thanks to the recent award of the tender for the supply of a gantry milling machine with double RAM and double mobile table.
Over time, therefore, a successful collaboration has repeated between the RFI Group and the Brescia manufacturer, which has already supplied 6 machines, installed at the production plants in Pontassieve and Bari.
Innse-Berardi represents one of the main industrial companies, at an international level, in the design and construction of machine tools and boasts a history of over a century. Together with the American company Ingersoll it is part of the Machine Tools division of the Camozzi Group, which deals with the engineering, production and commissioning of specific high-tech machine tools for the heavy mechanical sectors such as energy, transport, aeronautics and aerospace.
The railway sector is certainly a strategic sector for the Camozzi Group which also operates in this sector with the supply of pneumatic and electromechanical components for the fitting of trains, metro and infrastructural systems according to stringent safety, reliability, energy efficiency and operational requirements even in the most problematic environmental conditions.
The new Innse-Berardi gantry milling machine is the most recent investment that RFI has made for its production plants and represents for the Brescia-based company the culmination of an important design commitment that has led to promptly satisfying all the requirements indicated in the tender specifications, in some cases going far beyond.
From requirements to the solution
The need for the RFI to expand the internal production chain by producing the " frogs" in total autonomy prompted the strategic acquisition of the Puglia company BFM, Bari Fonderie Meridionali, in 2015.
The frogs are made from a single block of cast steel with a high manganese content, subsequently, heat treated and then milled in order to guarantee a safe rail switch at both low and high speeds. These are components with very particular technological characteristics, whose machining difficulty requires the choice of, particularly robust and precise machines.
After a series of machine tools installed in the Bari plant, completely renovated in recent years, RFI has issued a tender for the supply of a gantry machine with two rams and two hydrostatic mobile tables essentially capable of milling frogs with lengths of up to 11,000 millimeters.
"The needs to be met - explains Sergio Leoni, Product Development Manager of Innse-Berardi - were to obtain high production volumes with minimum manpower commitment and maximum machining accuracy to create a product capable of guaranteeing minimum vibrations at the time of wheel/rail contact on the switch; this in order to significantly reduce the wear of the frogs and the related maintenance interventions, also ensuring greater safety of railway vehicles".
To meet these needs, the solution proposed by Innse-Berardi has resulted in a technologically advanced machine that takes advantage of the great experience gained by the company in the processing of cast steels with a high manganese content; processing which, in order to achieve high production volumes, requires particular attention to the design and construction.
In this case, the solution provides for oversized machine structures, calculated through finite element analysis methods, to ensure maximum stability and overall rigidity.
To achieve maximum damping of vibrations, long life, minimum maintenance and, therefore, lower operating costs, the linear axes are hydrostatic or hybrid; in particular, the Z-axis and the Y-axis slide on guides with preloaded roller shoes and connected to anti-friction materials with forced lubrication.
«The vibrations problem - stresses Leoni - was particularly critical in consideration of the fact that to work that type of material and obtain productivity, it was necessary to use large diameter cutters with numerous inserts; this caused great strain on the machine».
The polar axes are equipped with a multiple pinion system on a toothed wheel to obtain maximum rigidity and high movement dynamics in the absence of play. The solution adopted, with electronic backlash recovery, guarantees a constant preload of the system without the need for periodic adjustments and with minimal maintenance requirements.
Two oversized independent heads, with main spindle and C axis integrated with the kinematic chains for the rotation of the spindles, as simple as they are reliable, have planetary gearmotors and large rotating masses to uniform the motion during machining with the aforementioned cutters and to increase the duration of the inserts.
"Being a machine that works with two heads and performs the simultaneous processing of two pieces that must be aligned with each other with extreme precision - adds Leoni - the presence of electronic probes for piece probing is even more necessary than it normally is.
Furthermore, the milling machine integrates a robotic tool magazine with 30 seats in which as many tools are housed; this number corresponds to more than double those required for machining; therefore, part of the tools in the magazine are twins. The magazine has ergonomic tool change stations that allow the replacement of worn tools without stopping machining and in total operator safety".