Just the number of 1,000 DECKEL MAHO gantry machines delivered in the last 15 years is unique in the heavy machine construction industry. At EMO 2013, with the DIXI 270, DMG MORI had already created a new model of the established DECKEL MAHO gantry machines for high-end machining of large parts up to 12 t. The successful range is now being extended further and impeccably rounded off to extend the area of application of these in-demand gantry machines. DMG MORI’s growing customer base now has an uninterrupted range of gantry machines in proven premium standard design with Y-axis of 2,100 mm to 6,000 mm at its disposal.
2.4 times more working space
Compared with the DMU 210 P, the newly developed DMU 270 P gantry machining centre has longer travels of 2,700 x 2,700 x 1,600 mm in X / Y / Z. They represent increases of 50 % in the transverse direction and by approx. 30 % in the longitudinal and vertical directions. The work area is increased by 235 %. The interference contours are also improved thanks to the newly designed milling head. A further advantage is that the space requirement has been kept low by appropriate design of the additional components. Maximum workpiece dimensions are increased to a an impressive 2,800 mm diameter and 1,800 mm height with a permissible workpiece weight of 12,000 kg. These are the highest figures in this machine class.
Maximum cutting performance thanks to optimum rigidity and dynamics
The inherently rigid structure of the proven machine concept with vertically traversing crossbeam and hydraulic weight compensation has been further enhanced. To this end, the basic machine is made entirely of high-quality castings (GGG60). The newly designed B-axis milling head with a swivel range which has been extended from 210° to 250°, and which is capable of swivelling to 30° in the negative direction, together with the larger B-axis bearing, result in a milling head housing with 20 % higher rigidity, extending the range of applications. The extended swivel range and improved interference contour with greater reach together with the cable conduit incorporated into the housing open up even more possibilities. Increased interest in the DECKEL MAHO gantry machine concept is therefore noticeable in various sectors which focus on, for example, tool making, mould making and mechanical engineering, the aerospace industry, energy management and medical engineering. Idle times are reduced thanks to the increased swivel speed of the B-axis with 30 rpm and a full swivel time of 1.5 seconds. The longer service life of the integral cables also has a positive effect on the machine availability.
The newly developed B-axis works in conjunction with a more rigid NC rotary table that can be more accurately positioned. With a larger bearing and improved tool holding, this provides a torque of 34,000 Nm and is driven at an increased maximum speed of up to 14 rpm by means of two new compact gearboxes which are electrically braked. As well
as the higher B-axis swivel speed and the enhanced NC table, the new DMU 270 P offers high dynamics and therefore also sets standards in its class.
The new powerMASTER 1000 motorised spindle with 9,000 rpm, a maximum of 77 kW and 1,000 Nm torque guarantees effective heavy-duty chip removal. As well as the standard SK 50 / HSK-A 100 motor spindle with 12,000 rpm, 44 kW and 288 Nm torque, five further spindles are available as an option – including a unit with rated at 15,000 rpm with 52 kW at 430 Nm or the 35 kW spindle with HSK 63 interface and a maximum of 18,000 rpm for High Speed Cutting. The larger-than-average range of main drives is supplemented by the offer of the HSK 100 gear-driven spindles with 1,550 Nm at 6,300 rpm and 44 kW.
As an alternative to the B-axis arrangement, the range of gantry machine modules includes an A-axis milling head housing with swivel axis parallel to the X-axis which accommodates the appropriate motor spindles.
Maximum temperature stability and 20 % higher rigidity lead to highest possible accuracy
In conjunction with the high machine rigidity, a constant overall machine temperature control with the cooling of all internal heat sources on the DMU 270 P leads to a further improved positioning accuracy compared with the smaller DMU 210 P gantry machine with Pmax < 9 / 10 / 9 µm. For this purpose, comprehensive and new cooling measures have been implemented on all ballscrews, housings and motors of the main and feed drives, all linear axes, and the B-axis and C-axis of the milling head and rotary table. A further effective measure is the temperature control of the frame and machine bed. In addition, insulation at the rear of the electrical cabinet shields any heat produced, which together with improved electrical cabinet cooling prevents any negative effects. The electronic compensation devices, which are specially matched to the DMU 270 P, effectively eliminate any residual displacement which may be caused by heat or the effects of static or dynamic forces.
The Spindle Growth Sensor (SGS), which is included as standard with the thermo-symmetrically designed gantry machine, prevents axial spindle displacement. A temperature control feature for the whole coolant system and a so-called Thermoshield for shielding the machine bed from air flow are also available.
Universal productivity for gantry machines redefined
The DMG MORI modules for the DMU 270 P gantry machine enable production time to be increased and idle times to be further reduced and provide an additional range of automation equipment. The consequential growth in universality and productivity for 5-axis milling and the future combination with turning operations in a single setup form the basis for a significantly extended range of applications. The wheel magazine, similar to the 4th generation duoBLOCK® machines, enables rapid tool changeover. An upgrade for the standard wheel with 63 pockets to 123, 183 or 243 pockets in the version with four wheels enables the machine to be ideally matched to customer requirements. The wheel magazine is also extremely compact, which results in minimal space requirement for the inherently rigid machine. The productivity of the gantry machine is also improved by the increase in NC table speed in rapid traverse mode and the increased swivelling speed of the milling head.
Planned options in the also redefined range of gantry machine models are the future DMC 270 U version of the machine with pallet changer, and the DMC 270 FD fitted with a milling/turning table to form a gantry milling/turning centre. Additional automation devices, such as the use of a pallet magazine or the integration of several DMC 270 U gantry milling centres with a linear pallet magazine to form flexible manufacturing systems, are already planned.
The new DMG MORI gantry machine saves energy
Energy savings have also been implemented by means of specific measures with the newly developed DMU 270 P. The enhanced and optimised machine temperature control necessitates the use of highly efficient, energy-saving cooling units. In addition, the cooling power required at any particular time is automatically adjusted to the instantaneous cooling requirement of the machines. Likewise, the pumps, such as the coolant pumps, are classed as energy efficient thanks to speed controllers. An automatic power display, for example on the CELOS interface, not only shows the machine operator the current energy consumption but also prompts the appropriate savings.
New DMG MORI design as prerequisite for optimum ergonomics and user-friendliness
The large work area of the DMU 270 P gantry machine with a volume of 11.7 m³ can be easily accessed from the front, the side or from above. The DMU 270 P is even more attractive with the new DMG MORI design. The improved view of the work area makes for user-friendly machine ergonomics for effective setup and in automatic mode. The work area is also fully clad in stainless steel and, if it should be necessary to change a window, this can be carried out from the outside in a service-friendly manner. The DMU 270 P will be presented with CELOS with 21.5” ERGOline® and SIEMENS and will be available from June 2014. CELOS from DMG MORI simplifies and accelerates the process from the idea to the finished product. CELOS APPs provide the user with integrated management, documentation and visualisation of order, process and machine data. CELOS is compatible with PPS and ERP systems, can be networked with CAD / CAM applications and is ready for future-oriented CELOS APP extensions. As standard, the machine is equipped with Operate 4.5 on SIEMENS 840D solutionline including 19” ERGOline®.
Highlights of the DMU 270 P
- Proven gantry design
- Large work area X / Y / Z: 2,700 / 2,700 / 1,600 mm
- Large work area for workpieces up to Ø 3,000 × 1,600 mm
- Easy machining of deep moulds thanks to optimised milling head interference contour
- 55 % higher dynamics thanks to new drive technology on NC rotary table
- High precision thanks to optimised temperature stability
- Rapid commissioning at customers’ premises without foundations thanks to 3-point support