HELLER BIG PARTS
High-power precision machining of large, heavy-duty components calls for sturdy, permanently resilient machine tools. Manfred Maier, COO of the HELLER Group, explains in an interview how HELLER guarantees its customers maximum productivity, even in the challenging XL segment.
Core expertise – big part machining
For big part machining, HELLER offers 4-axis horizontal centres, 5-axis tilting heads and 5-axis swivel head centres and 5-axis turn/milling centres. What are the main applications of each machine series?
Manfred Maier: Horizontal machining centres provide an optimum solution for all requirements. The series H pallet ranges from the entry model to modular, individually configurable models to high-power production machines.
With the F series 5-axis machining centres, HELLER covers the entire range, from complete machining through to simultaneous 5-axis machining.
C series machining centres, on the other hand, offer the established HELLER process expertise for combined milling and turning tasks too. In addition, they unite performance-oriented pre-machining and high-precision finishing. This product range is able to machine workpieces weighing up to 10 t and standing 1,800 mm high productively and reliably.
Which requirements do large machines have to satisfy today?
Manfred Maier: HELLER pursues the primary goal of increasing its customer’s competitiveness on the basis of optimised piece-part costs. Especially for big part machining, this requires the machine to possess attributes such as productivity, reliability, process stability, precision, torque capability and efficiency.
Machining centres must also offer optimised availability and flexibility for big part machining. Increasingly smaller batch sizes, shorter lead times and more complex components mean that the production process has to be continuously optimised and rationalised. The trend, then, towards using one tool for the complete machining operation and hence towards multi-tasking is unmistakable.
HELLER takes a clear stance in this respect: machining centres not only need to meet current demands, they must prove to be efficient and productive throughout their entire service life. And so HELLER has developed expertise in application engineering. The complete machining operation, which is consistently lived and experienced, requires the use of production processes that are not wholly typical for a machining centre.
One example of this is the HELLER facing slide. This concept allows numerous turning operations, such as internal/external contour turning, facing or grooving, to be accomplished on machining centres economically and reliably. With just one drive, then, high process reliability can be achieved and machining and idle times can be reduced to below those of conventional solutions.
Which automation concepts does HELLER offer in the XL segment?
Manfred Maier: One core requirement of our customers is ›around the clock‹ availability of their machines wherever possible. Basic equipment such as CNC control, tool changer and chip conveyor already allow machines and systems to work autonomously. The burning question is, for how long? This in turn is dictated by the number of workpieces that are ›accessible‹ in the machine.
The automation concepts here range from the simple pallet changer or the pallet linear magazine or pallet rotary magazine to the flexible pick-and-place robot to the combination with a rack system for tools.
Tools can be fed by chain magazines for up to 150 tools or a rack-type magazine for a maximum of 425 tools. For heavy-duty machining in the big part segment, HELLER has also developed three other ›Heavy Duty Solutions‹ for rack-type magazines. These allow tools of up to 1,000 mm in length and weighing 50 kg to be loaded into the machine.
In conjunction with the new XPC units and a recently developed tool changer, as much as 80 kg can be managed. These variants also permit the use of spindle extensions, and so projecting lengths of up to 1,500 mm can be achieved in the work area. With the XPC units, HSK 100 tools with flat location 160 can also be used for heavy-duty machining.
How broadly is HELLER positioned when it comes to main spindle designs?
Manfred Maier: For 5-axis machining, HELLER offers a choice of two tilting head units and two swivel head units for the large machines, all of which guarantee high machining performance thanks to an extremely rigid construction. Speeds of up to 12,500 rpm, torques of up to 822 Nm with the tilting head and up to 1,146 Nm with the swivel head can be achieved.
The H series 4-axis machining centres feature nine different machining units. The high-performance gear spindle (HPC), with 60 kW of power and a torque of up to 2,292 Nm, was designed specifically for heavy-duty machining. Additional options are also available. Including the additional milling head, also with additional clamping for critical machining operations, as well as the spindle growth compensation are standard equipment for optimised machining accuracy. An option already mentioned in the NC-controlled HELLER facing slide. This makes HELLER machining units ideally suited for the heavy-duty cutting of cast iron, steel and titanium, as well as for the volume cutting of light alloys.
Which sectors is HELLER targeting with the XL machines?
Manfred Maier: These centres are ideal for machining large-scale pumps and housings for prime movers and turbo engines. Here, we have reference applications based on the H 14000. This has an operating range of 2,400/1,600/1,600 mm in X/Y/Z with a pallet size of 1,000 × 1,000 mm.
Thanks to the high-performance gear spindle (HPC), this is able to meet the toughest challenges presented by heavy-duty machining, with 20,000 N of feed force in the Z-axis and a workpiece weight of up to 4,000 kg. The NC-controlled facing slide from HELLER is also used here. A measuring probe for workpiece measurement in the machine and fast tool break monitoring are also integrated. And by concentrating on realistic dynamic values of 41 m/min in the X-axis and 45 m/min in the Y and Z, HELLER has achieved the shortest possible positioning times.
The available options also include a clamping system for angular milling heads. The machine is equipped with an HSK 100 tool holding fixture as standard. With all machine sizes in the H series, the precision is achieved by the reduced table
deformation and the high accuracy from the inside drive arrangement and the linear measuring scales. In terms of productivity, users now achieve production times that are 20 to 50 shorter than those of competitor machines.
Other sectors in which XL machining centres from HELLER are used include mechanical engineering, the oil & gas industry and the aviation industry, to name but a few.