When it gets really big
As a manufacturer of customer-specific industrial gearboxes, Eisenbeiss GmbH is increasingly focusing on bringing a large share of production in house. With a Heckert HEC 1000 machining center tailored precisely to the needs of its application, the company, located in Upper Austria, is now set up perfectly for machining large transmission housings.
Anyone needing technically advanced industrial gearboxes simply cannot ignore Eisenbeiss GmbH from Enns. The company has a long history, having been founded in 1911, and has become one of the leading providers of specialist gearboxes for a wide range of applications. Customers of this niche provider include members of the plastic, food processing, steel, aluminum and energy industries.
Johann Panzenböck, Group Leader for Cubic Manufacturing at Eisenbeiss GmbH
“We were thoroughly impressed by the high level of flexibility shown by Starrag during design and implementation of the machine. Then, of course, we were also very satisfied with the commissioning and start-up phase running so smoothly.”
Further expanding vertical range of production
The manufacture of extruder gearboxes is an important business area for the Upper Austrian company. A high level of vertical integration allows the greatest possible flexibility and the means to achieve short lead times despite a wide variety of individual customer requirements. In 2015, Eisenbeiss decided to invest in a large machining center in order to increase both capacity and productivity. An existing machine, which is over 20 years old, will make way for the new machining center. “We have limited space available on our site. We had earmarked a certain area of the building for the machine to further optimize the production process. Finding a concept that would fit was a particular challenge. Another decision was whether to choose a machining center with four or five axes. To aid this decision, we provided an overview of the available and upcoming machines at the 2015 EMO trade fair in Milan. We looked in detail at six concepts from different manufacturers, and the final decision was between just two,” recalls Johann Panzenböck, Group Leader for Cubic Manufacturing at Eisenbeiss. A series of criteria were applied to evaluate the machines. The machining center itself, a large tool magazine and a setup point needed to be accommodated in the limited 27.9 ft × 24.6 ft space. Ideally, there also needed to be enough space available for handling large workpieces. “For us, though, the essential criterion was whether the new machine would allow us to process a particular gearbox housing, known internally as ‘part 7’. We passed this framework to the respective machine manufacturer and asked them to present a suitable space concept,” continues Panzenböck.
Modular to large parts
The described benchmark part is a gearbox housing produced as a cast blank part. With a 4409-lb clamping weight and dimensions of 67.5 × 47.2 × 31.5 inches, it rotates in a 78.7 inches circle. Part of the requirement was that it must be possible to fully rotate this part. “In assessing the requirements, we realized very quickly that we would be unable to implement this with any of our standard machine versions. That is why we selected the Heckert machine as the basis for our concept since it meets the needs of our customers through its modular design. The size of the part would have required a Heckert HEC 1250, but there was insufficient installation space for this machine. An X-axis from the Heckert HEC 1000 was therefore used as a support system, and this was expanded with the Y-axis and Z-axis from the 1250. This created a processing area of 66.9 × 59 × 72.8 inches (X / Y/ Z). The clamping surface measures 31.5 × 39.4 inches with a height of 65 inches The maximum workpiece weight is 8818 lb. A 4.9-inches spindle sleeve with 19.7-inches travel path was implemented as an additional ZP-axis” says Arno Berger, Sales Engineer at Starrag, describing the concept.
“The Heckert HEC 1000 could not have offered the required size of interference circle if used as the basis. A workaround for this was to open the loading door when rotating the component. In programming terms, this meant a safety step had to be inserted to prevent rotation while the door was closed. The machine operator must actively confirm when starting the machining that the part is not oversized in order to keep the door closed. The upstream set-up point also has an access lock so that part movement is stopped immediately upon entry to the safety area,” Berger explains further.
The system is complemented by a tower magazine, which offers space for over 300 tools. These can be up to 13.4 inches in diameter and 31.5 inches in length. With a spindle power of 74 hp and torque of 1,822 lbf ft, which is transferred to the tool via an SK50 interface, the machine has plenty of power reserves. The set-up point allows parts to be prepared in two places. Two longitudinal and one transverse conveyor ensure smooth chip removal at the front side of the machine.
A flexible control concept is needed
“That is why we selected the Heckert machine as the basis for our concept since it meets the needs of our customers through its modular design.”
The machine is controlled using a Siemens SINUMERIK 840D controller with ShopMill function. “We process more than just pre-programmed parts. We often need to machine special parts at short notice for service and repair work. In these cases, the parts need to be programmed by the machine operator directly on the machine. The ShopMill software offers comprehensive yet simple options for this. The tool difference list from Starrag also provides valuable assistance for the operator,” explains Panzenböck. Additional machining accuracy can be achieved on the new machine through a highly accurate B-axis, a warm-up program and coolant temperature control.
Precisely matched configuration
The fact that the machine was tailored precisely to their requirements meant Eisenbeiss selected the Starrag concept in the middle of 2016. “The high degree of flexibility Starrag showed when designing the machine was what impressed us in the end. We had a specified time for the benchmark part of between 27 and 30 hours. Up to 100 different tools are used to achieve this in nearly 300 work steps. On the new machine, we generally manage part 7 in under 23 hours. We have now been able to manufacture 17 parts on the new machine, many of which we would previously have had to outsource. In the future, will probably process around 100 different parts on the machine”, says the Department Head, justifying the decision-making process.
“We deliberately took a year to implement the machine to be able to manage the structural preparations properly. After all, a suitable foundation needed to be installed for the new machine. The new machine was put into operation in June 2017 and commissioned on July 1, 2017, a good two weeks ahead of schedule. Surprisingly, there were no teething problems and since then we have not needed manufacturer support once”, Johann Panzenböck concludes happily.