After the successful launch of the DMU 80 P duoBLOCK® as a world premiere at the EMO exhibition, DMG MORI is now presenting the first horizontal machining centre in the proven 4th generation of the duoBLOCK® series. The newly developed horizontal machining centre is intended for high-performance heavy-duty chip removal (HPC) – and at the same time for precise all-round machining.
Alfred Geißler, Managing Director, DECKEL MAHO Pfronten GmbH
What were the reasons for carrying forward one of DMG MORI’s most successful machine concepts on the world market, now in the 4th generation, to the DECKEL MAHO horizontal machining centre range?
Geißler: At EMO 2013 with the world premiere of the DMU 80 P duoBLOCK®, we drew attention to the improved precision, performance and efficiency of the 4th generation of duoBLOCK® machines. At the same time, we said that the new improved concept would be carried forward to other machines in the range. We want to demonstrate the outstanding suitability of the duoBLOCK® machine concept, which has been improved with regard to stability and long-term accuracy, particularly in the field of high-performance cutting. When our newly developed DMC 80 H duoBLOCK® is used for efficient heavy-duty chip removal or for the complete machining of precision components, the greater machine stiffness demonstrably results in up to 30 % improved accuracy. In addition, our constantly enhanced duoBLOCK® module, which has proved its worth on thousands of occasions over what will soon be almost 15 years of applications, provides customised complete solutions for a wide application spectrum.
How have you succeeded in meeting the requirements for more efficient heavy-duty chip removal with improved accuracy with the DMC 80 H duoBLOCK®?
Geißler: At present, many of our customers require even more powerful machining centres for more economic heavy-duty chip removal. Our customers come from such widely differing areas as aerospace, automotive, energy supply and, increasingly, from the general mechanical engineering industry. The main features of the 4th generation DMC 80 H duoBLOCK® can be summarised as follows: With its larger work area and reduced space requirement for the whole machine, the DMC 80 H duoBLOCK® has increased overall stiffness. The main measures to achieve this are structural improvements to the reinforced and widened machine bed and column. Added to this are a reduced reach on the spindle head, the use throughout of high-quality castings (GGG60), and strengthened ballscrew spindles as well as 2 additional damping shoes per linear axis and hydraulic clamping on the C-axis. Furthermore, in the meantime, our modular building block offers one of the widest ranges of main drives for SK 50/ HSK 100 toolholders. Available in this range are motor spindles with design parameters between 288 Nm at 12,000 rpm and 44 kW. In the case of the power MASTER 1000 it is 1,000 Nm at 9,000 rpm and 77 kW. As an alternative, our torqueMASTER gear-driven spindles are available with 1,053 or 1,424 Nm at 8,000 rpm and 37 or 44 kW. We provide special heavy-duty chip removal packages for further increases in power up to values of 50 %.
Please explain to us how it has been possible to improve the accuracy of the duoBLOCK® machines in the 4th generation machining centres.
Geißler: As with our machining centres, we keep the machine temperature as constant as possible during the whole chip removal process. In addition to the reinforced and thermo-symmetrical machine design, we have also increased the number of cooling systems. These include the use of cooling strips in the machine bed and column, and liquid cooling of the feed drives on all linear axes including that of the rotary table with C-axis motor. These additional cooling systems supplement the intensive cooling of the main drive, headstock and electrical cabinet. Any residual displacement caused by temperature or the effects of static or dynamic forces is eliminated by electronic compensation devices. Furthermore, these devices are included in the standard scope of supply of the machine and are supplemented by the use of the “Spindle Growth Sensor” (SGS) to prevent axial spindle displacement. We also recommend our option for a tightly toleranced temperature control of the whole cooling / lubricant system during machining. With a combination of all these measures, we achieve up to 30 % better workpiece accuracy.
What specific measures are used to increase the productivity of the 4th generation DMC 80 H duoBLOCK® with regard to idle time?
Geißler: The idle times when changing tools and workpieces during production have once again come under the microscope with the 4th generation of duoBLOCK® machines. In this context, the whole supply of tools, which includes the use of space-saving wheel magazines, has been redesigned. Not only has the actual tool change been optimised, but also the space required by the inherently rigid standard machine, which now has 123 tool pockets, has again been reduced by approx. 40 % thanks to our compact design. Machine versatility can be further increased, while maintaining productivity, by means of a parallel arrangement of a maximum of 4 wheel magazines with a total capacity of 243 pockets. The new wheel magazine technology also enables the tool magazine to be replenished during production. Short traverses and the cam-controlled changer enables tool change in a maximum of 5.6 seconds. We have also improved the sequence and idle time behaviour of our pallet changer. Numerous automation devices, both from our own modular system and from our proven external partners, can be readily coupled to our horizontal machining centres. As in the past, the use of pallet magazines or connecting our machines to manufacturing systems enables extended, unattended, automatic operation to be carried out over a period of one or more shifts.
In spite of the increased productivity demanded by the market, how do you take into account energy efficiency and what measures do you employ in response to this development taking the DMC 80 H duoBLOCK® as an example?
Geißler: With machines in the DMC 80 H duoBLOCK® performance class, the cooling unit is one of the largest energy consumers. Among other things, highly efficient coolers, the power of which adjusts itself automatically to the cooling requirement of the machine, are therefore used in the 4th generation duoBLOCK® machines. The 80-bar coolant pump is also fitted with a speed controller, which significantly reduces its energy losses. As a secondary effect, this also prevents unnecessary heating of the coolant. The power indicator on the CELOS interface enables the operator to monitor and analyse the energy consumption. Overall, depending on the way the machine is used, these measures alone save 30 % energy and therefore several thousand euros in electricity costs each year.
What has been improved with regard to ergonomics and ease of operation with the re-engineered 4th generation DMC 80 H duoBLOCK®?
Geißler: The large work area is easily accessible from the side and from above. As a general principle, the machine is designed with the highest quality for maximum technical reliability. Necessary maintenance work can be carried out thanks to the central location of easily accessible valves and pumps at the rear of the machine. The DMC 80 H duoBLOCK® 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 DMC 80 H duoBLOCK®
- Precision: Up to 30 % higher component accuracy thanks to fully water-cooled feed drive
- Performance: Up to 30 % greater rigidity for maximum cutting performance
- Efficiency: Reduced energy consumption by up to 30 % with intelligent, demand-oriented power units
- Intelligent wheel magazine with up to 243 tools, 0.8 seconds tool change time and the option of retooling production or idle time
- Maximum productivity thanks to space-saving, high-speed rotary pallet changer as standard for off-line workpiece set-up