Speed, precision and longterm process reliability
The new Heckert 500 D machining centre delivers impressive levels of profitability, safety and growth at Brabant Alucast
Companies that supply pre-finished parts to the automotive industry need a high-performance, machining-driven production facility. One such company is Brabant Alucast, a specialist in lightweight die casting. A facility of this type can be found at the company’s headquarters in Oss in the Netherlands. It is equipped with eight Heckert horizontal machining centres that, because of their dynamics and sophisticated design, ensure high quality and short cycle times. The two new HEC 500 D machining centres achieved particularly impressive results in benchmark testing.
20 % faster machining time, 40 % higher overall productivity
Brabant Alucast specialises in the design, development and production of high-pressure aluminium and magnesium die cast parts for the automotive industry. It is one of Europe’s top companies in this sector in terms of quality ranking and annual sales. The company is headquartered in Oss in the Netherlands and has four other branches in the Netherlands, Germany, Italy and the Czech Republic. It employs a wide variety of production methods in order to manufacture highquality parts for its customers. These methods include the Exactfit Casting™ and Vacural® Casting technologies, both of which were developed in-house. But Brabant Alucast offers more than just its die casting capability of 300 to 4,000 tons. What really makes the company stand out is its complete range of solutions, which include CNC machining and assembly of automotive components. Quality and customer focus are particularly important in this regard. Brabant Alucast obtained ISO/TS 16949 (2009) Automotive Certification for its QM system and has been awarded the European Aluminium Award (automotive) six times for its customer-oriented approach. Brabant Alucast employs around 300 people at its location in Oss, which focuses on die casting and machining of large parts made from various magnesium and aluminium alloys. The parts produced are mostly engine and gearbox components or structural components that are delivered pre-finished to BMW, GM/Opel, PSA, DAF, VW/Audi, Toyota, ZF and others.
Dynamic Heckert machines for machining die cast aluminium and magnesium parts
As Development Engineer for parts and processes, Christiano Sala is responsible for CNC machining in Oss. The machines in this area include eight from Heckert: six CWK 500 D and, as of recently, two HEC 500 D. “I have known Heckert for quite some time as a global leader in machining centres that are suitable for milling, drilling and turning complex workpieces. It was a stroke of luck for us when Benny Van Haver from the Heckert sales department came to us in 1999 to recommend the CWK 500 D machining centre for machining a flywheel housing. That’s because this machine, with a rapid traverse of 82 m/min and 1 g acceleration, allowed us to achieve the shortest production time by some distance”. The robust machine design, the size of the collision circle and the hydraulic clamping options met the expectations of Christiano Sala and his colleagues. Benny Van Haver, responsible for Brabant Alucast in the Netherlands as Head of Sales for the Benelux countries at the Starrag Group, confirms that this successful partnership has expanded in the subsequent years: “We worked together to build a robot loading system for the CWK, then there were another five CWK 500 D orders for machining oil pans, valve housings, ladder frames, crankcases and gearbox housings. All machines are designed with a robot automation interface, and some feature fire protection equipment for magnesium machining”. The six Heckert CWK systems still work in three-shift operation, with no notable decline in precision or performance. “The long-term quality of these machines makes the investment particularly worthwhile”, believes Christiano Sala.
Much faster than comparable machines
As Christiano Sala explains, “We of course conducted extensive research into which machines would be best for this application in the long term before purchasing the two new HEC 500 D machines. After all, we are talking about quantities of 100,000 parts per year, probably over a period of several years”. Using the exact same programme, Sala and his colleagues compared the production time per part on a Heckert CWK 500 D built in 2005 (402.0 s) with that of a Japanese machining centre built in 2013 (388.4 s) and the new Heckert HEC 500 D built in 2015 (321.2 s). The results (see values in brackets) were clear: The HEC 500 D was 20 % faster than the previous CWK 500 D model and 17.3 % faster than the Japanese machining centre, which is only two years younger. For Benny Van Haver, this is confirmation of the successful development work at Heckert: “The R&D division has retained proven qualities such as the robust, durable machine construction, but upgraded essential details to the latest technological standard, for example with highly dynamic feed drives and extremely precise profile rail roller guides in all linear axes”. Christiano Sala is also very satisfied with the result: “It is nice to see that Heckert takes our suggestions and those of other users seriously and incorporates improvements accordingly”. For him, this success is paying off in hard cash, as the shorter cycle times ensure the capacity of the two HEC machines is sufficient for the volume of the latest order. With the previous machines, it would have been necessary to invest in a third machining centre.
Motor spindle: From 0 rpm to 20,000 rpm in one second
The shorter production time is due in no small part to the rapid traverse of 100 m/min and accelerations of 1 g in the linear axes. And the motor spindle also delivers impressive performance data: Its speed range is between 50 rpm and 20,000 rpm, its power (40/100 % duty cycle) is 50/48 kW and its torque (40/100 % duty cycle) is 85/60 Nm. It accelerates (in accordance with VDI 2852) from 0 rpm to 20,000 rpm in just one second. With the same NC programme, setup and tools, this significantly reduced the non-productive time. “If the programme is optimised in terms of machining data, the cycle time could probably be shortened by another 10 %”, estimates Head of Sales for the Benelux countries at the Starrag Group, Benny Van Haver. Development Engineer Sala also understands the potential that the spindle has: “The oil pan, for example, contains numerous M6 threads. It took us 109 seconds to produce these on the CWK. On the HEC, we only need 77.5 seconds. These numbers do not take any optimisation of the spindle speed into account either. We can probably use PCD tools to achieve even higher cutting speeds and shorten the main time”. However, the new components are still in the initial phase. This means that, in addition to the upper oil pan parts, cylinder head covers and possibly another product will run on the HEC machines in future in order to ensure round-the-clock utilization. Accordingly, production is still alternating between HEC and CWK machines, and the NC programs must be geared to the “weaker” machine. Machining cannot be optimised until the machining managers have agreed on a fixed assignment.
Greater process reliability with the new Heckert HEC machines
The highly dynamic HEC horizontal machining centres replaced their predecessor, the CWK series, in 2011. They are so fl exible in their configuration that a wide range of materials can be machined for all sectors of the metalworking industry. Heckert offers HEC centres with a dynamic package specially for machining light alloys. They are characterised by the high values mentioned above for speed, rapid traverse and acceleration. As they have a (thermally) stable structure, extensive control and monitoring devices and a state-of-the-art service and diagnostic system, Heckert guarantees users long-term machining accuracy in tolerance class IT5. For Christiano Sala, this is an important benefit as his components generally run in automated three-shift operation for many years — robot loading is also planned for the HEC 500 D. That means a high level of process reliability is essential. “We must achieve regular dimensions with a process capability index CpK of 1 and critical characteristics with CpK 1.67”, says the Development Engineer. The upper oil pan parts contain numerous H7 fits, such as OCV holes, which must hold high-precision valves for camshaft adjustments. Accordingly, precision is important with regard to diameter and concentricity, as well as surface quality, which is Ra = 0.8 μm.
Quality down to the last detail
Starrag Group representative Benny Van Haver mentions some key improvements to the details of the HEC 500 D in comparison with the predecessor model: “The telescopic covers of the previous model have been completely replaced with fixed sheet metal in the machine. This makes greater acceleration and rapid traverse possible as the sheet metal does not have to be carried along with the linear axes. The working space also now has a funnel shape in the crosssection, meaning that chips fall in the middle onto a chip conveyor. That means there are no more piles of chips, as these endanger process reliability”. In addition, the new tool magazines offer excellent cleanliness. To achieve this, all hydraulic assemblies were removed from the surrounding area, and chips and cooling water are kept away from the changer. Christiano Sala is convinced that the Heckert HEC 500 D will prove to be just as durable as the CWK centres, which have maintained their high quality level in three-shift operation at Brabant Alucast for ten to fifteen years.
SUMMARY
The new HEC 500 D machining centres allow Brabant to increase its profi tability over the long term. The machines achieve 17.3 % faster machining times for the expanded product range. Only two machines are needed to handle production tasks, with no third machine required. Maximum process reliability was already assured with the predecessor machines, with no losses in quality in demanding three-shift production.
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