Success Story

Bumotec s181: Use in a traditional turned parts contractor

"A gateway to more growth"

A turned parts contractor from Berlin is boldly setting out on a new path: With the purchase of a Bumotec s181 machining centre from Swiss Starrag, Heinrich GmbH from Berlin entered into the field of high-precision complete processing of components for respiratory protective devices. 

"Welcome to the Swiss corner," says Christian Pooch, managing partner of Heinrich GmbH from Berlin, and takes us to his latest investment: a Bumotec s181 5-axis CNC turn-mill centre with a total of nine CNC axes, which now stands next to five automatic lathes that are also from the Swiss manufacturer. 

The large machine park allows for "order diversity"

More machines than people work at Heinrich, because the sheer variety of different orders – from batch size one to large series with several million parts – requires a very large machine park with more than 30 systems. Pooch: "Whenever the process and the product allow it, we also let some of the machines run overnight without operators in a ghost shift. 

The Berliners want to use the new machines, the company's largest investment to date, to break new ground. A regular customer asked the Berliners, after a competitor had already decided not to bid, if they would be willing to produce a distributor for a respiratory protective device. "It is a component that has extremely high demands with regard to tolerances and the absence of burrs," Pooch explains. "Because it is not acceptable for a fireman to inhale small pieces of burrs during use." 

Although much lower-priced machine tools are available, precision was not the only reason Pooch chose the Bumotec s181, a 5-axis simultaneous turn-mill centre with a CNC FANUC 31i panel and retaking unit, for the complete machining of complex and high-precision workpieces. 

"I think the main spindle is very smart," Pooch explains. "It makes it easier for our operators to transit from a standalone lathe to the machining centre." With its HSK-40 tool spindle (30,000 rpm), very small components can be machined precisely to 1.5 µm either bespoke or off the shelf (maximum diameter: 32 mm). Pooch has two sons who work alongside him, one of whom speaks very enthusiastically about the new possibilities. "On its own, our former core business of lathing nuts and screws has not been enough to sustain us for a long time," says production engineer and general manager Tobias Pooch. "But now, with the Bumotec, we can position ourselves even better than before with high-precision components, and also establish ourselves internationally." There is great resonance with the customer base, because the Bumotec has allowed Heinrich to open the gateway to completely new worlds, meaning growth.

Maximum precision: One example of the precision offered is the H7 drilling, which is cut to exactly 14 µm.

The Pooches have put particular emphasis on a high degree of automation so that they can use the s181 around the clock if necessary. For this purpose, it has been equipped with an automatic tool and workpiece change system: the tool changer has 60 places, which can be freely equipped with lathe or milling tools. The workpiece changer is a palletizing system for five pallets, each of which offers space for 30 blanks. Both systems can be expanded in case of increased demand to a maximum of 90 tools and 300 workpieces. The workpieces, which are completely processed on all sides, are unloaded on a conveyor belt and collected in a container filled with oil (capacity: 300 workpieces). Another factor in favour of this system is that handling occurs without adversely affecting the primary processing time. The user can operate, equip and handle all of the automation components without stopping production. 

Together with a Starrag expert, the Berliners adjusted the process for the new component in the late autumn of 2017. "It's unbelievable but true," says Tobias Pooch happily. "We have been producing since the commissioning and we have not had to make any corrections since then." "We also deliberately purchased the machine with set-up included, because we are entering new territory here," his father adds. 


Absolute sphericity and high surface quality

The new component is the centrepiece of the final product, connecting the oxygen cylinder with the respirator. The initial material is a forging blank from a special aluminium alloy that contains silicon (AlSi05). "It is extremely unpleasant to process on a lathe, because it results in extremely long chips," Christian Pooch reports. "In contrast, cutting on the Bumotec is much easier, with shorter chips." The s181 has a system that provides the tool with coolant under high pressure (90 bar) that not only removes the chips but also cools the tools. The internal coolant supply through the tool is particularly effective. "It saves time in the order of seconds when working with aluminium, ensuring higher productivity," says Christian Pooch. One example of the precision offered is the H7 drilling, which is cut to exactly 14 µm. Christian Pooch: "It's astonishing that a drilled hole be cut so precisely – with absolute sphericity and high surface quality."

Specially developed clamping system for "imprecise" blanks

"The biggest challenge lies in ensuring that there are no burrs in the many interconnecting channels," adds Michael Paulus, Product Sales Manager at the Starrag-TechCenter for Medical Technology and Precision Mechanics, Oberhausen office (Upper Bavaria). Heinrich even allows itself the manufacturing luxury of completely deburring the component not only on the inside but also on the outside, and then anodising it. "What's special about this is that the machine cuts not only bar parts but also inserts," Paulus explains. "The Bumotec inserts the blank automatically, processes all six sides and then automatically transports it onward." An exacerbating factor here was that the initial part is a pressed piece with very high tolerances; these parts can be cut precisely, not least thanks to a specifically designed clamping system adapted to the machine. Paulus: "We developed and ran-in the clamping system specifically for this component and this machine." 

"Because this was something new to us, it was important for us to receive German-language support from an industry expert," Christian Pooch adds. Paulus and the TechCenter for Medical Technology and Precision Mechanics, which is part of the "Precision Engineering" business unit, provide this support in Immendingen, near Tuttlingen, in southern Germany. Paulus: "I have been involved in high-precision microparts processing for 28 years, including in the watch and medical technology industry, and can therefore support customers with expertise based on years of experience from numerous projects." 

All in all, the new Swiss addition lives up to the Starrag claim "Engineering precisely what you value" in many different ways. Heinrich has put a special emphasis on profitability, reliability and growth. The Berliners have already achieved one of their goals: since its first hour of operation, the s181 has run reliably and without any tolerance deviations. "With this process reliability we can capture a new customer base," says the senior partner.

Furthermore, it has already become clear - a few months after the commissioning of the new machine - that the goals of profitability and growth will soon be achieved. Thanks to the first order, we are already in a good position in terms of recouping the investment in the s181. And we have already received some very interested enquiries from customers, although we have had to tell them that we don't intend to start any new orders until the middle of 2018."

And potential customers are not the only ones who have reacted positively to the investment. "The valuation department of our financing company essentially told us that the Bumotec puts us in the Champions League," the managing partner says happily. "The machine performs extremely well in terms of resale value and longevity." 

Ready for the ghost shift

Turned parts contractor Heinrich has put particular emphasis on a high degree of automation so that it can use the Bumotec s181 around the clock if necessary. For this purpose, the machine has been equipped with an automatic tool and workpiece change system.

Starrag, machining, milling, cutting, drilling, turning, machine tool, cnc, machining center, aerospace, energy, transportation, industrial, machine, 4-axis, 5-axis, 6-axis

Highly effective

The internal coolant supply through the tool plus external cooling shaves off seconds when working with aluminium at Heinrich, thus ensuring greater productivity.


Heinrich GmbH, Berlin

The family company was founded in 1924. It is an extended workbench with 20 employees that manufactures turned parts from metal and plastic. In addition to electronically controlled and conventional lathes, saws, milling, drilling, grinding and thread-cutting machines are also used. The company received its first DIN ISO EN 9001 certification from TÜV Süd Management Service in the year 2000 and has earned its reputation with very demanding, high-precision turned parts made from materials such as electrolytic copper, stainless steel, brass, aluminium and plastic in the µm range.

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