A turning workshop in Berlin is taking a new direction: With the purchase of a Bumotec s181 machining centre from the Swiss company Starrag, Heinrich GmbH has embarked on the complete high-precision machining of components for respiratory protective devices.
"Welcome to the Swiss Corner" is how Christian Pooch, Managing Partner of Berlin-based Heinrich GmbH, welcomes us and leads us to his latest investment: a Bumotec s181 5-axis CNC milling and turning centre with a total of 9 CNC axes, which now stands alongside seven automatic lathes, also from a Swiss manufacturer.
A large machine park makes it possible to manage a "multitude of orders". At Heinrich, more machines work than humans, because the multitude of different orders - from a single piece batch to a large series of several million parts - requires a very large machine park with more than 30 installations. Mr. Pooch: "Where process and product allow, we also leave a few machines running at night as a ’ghost crew’. At night, two to three operators are enough. »
The Berliners want to use the new machine, 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 why managing partner Christian Pooch chose the Bumotec s181, a 5-axis simultaneous turn-mill centre with a total of nine CNC axes for the complete machining of complex and high-precision workpieces. It is fitted with a CNC FANUC 31i panel and a retaking unit. Pooch finds the main spindle to be very smart, because it makes it easier for operators to transit from a stand-alone 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.
Pooch’s have attached great importance to a high level of mechanisation, in order to be able to use the s181 24 hours a day if necessary. To do this, it has been equipped with an automatic tool and workpiece change system: the tool changer has 60 tool places, which can be loaded with any number of turning or milling tools. The part changer is a palletizing system designed for five pallets, on which 30 blanks can be placed at a time. If demand increases, both systems can be expanded to a maximum of 90 tools and 300 workpieces. The fully machined parts on all sides are unloaded onto a belt conveyor and collected in a container filled with oil (capacity: 300 parts to be machined). With this system, handling takes place without hindering the operation of production. The user can control, load and manipulate all components of the mechanization without having to stop production.
Working with a Starrag expert, the Berliners established the process for the new component in late fall 2017. "It’s incredible, but true," says Tobias Pooch. "We have been producing since start-up, without having to make any corrections in the meantime. "We voluntarily bought the machine with the installation, because we are here in unknown territory," adds his father.
No edges at corners and sides The new component is the centrepiece that connects the oxygen bottle to the respirator mask. The initial material is a forging blank made from a special aluminium alloy that contains silicon (AlSi05). "In terms of turning, it’s very unpleasant, because extremely long chips form in this case," explains Christian Pooch. "On the Bumotec, milling is much more pleasant, with shorter chips. Not only for chip removal, but also for tool cooling, the s181 has been equipped with a system that supplies the tool under high pressure (90 bar) with cooling lubricant. The supply of coolant lubricant is particularly effective through the tool, "which allows us to save real seconds with aluminium, and thus to increase productivity" (Christian Pooch). One example of the precision offered is the H7 opening, which is cut to exactly 14 μm. Christian Pooch: ”It‘s astonishing that a drilled hole can be cut so precisely – with absolute roundness and a high level of surface quality.“
A clamping system specially designed for "inaccurate" raw parts According to Michael Paulus, Product Sales Manager at the Starrag-TechCenter for Medical Technology and Precision Mechanics, Oberhausen office (Upper Bavaria), however, the biggest challenge lies in ensuring that ”there are no burrs in the many inter-connecting channels. 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,“explains Starrag employee Paulus. ”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.“ "And it was important, because of the adaptation, to get German-speaking support from a professional in the sector," adds his son. The support came from M. Paulus and the TechCenter for medical technology and advanced mechanics at the Precision Engineering business unit in the southern German city of Immendingen (Tuttlingen district). Mr. Paulus: "I have now been working in the field of precision machining of small parts for 28 years, including in the watch industry and medical technology. Because of my long experience on many projects, I can support customers and bring them my knowledge. »
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. But it is already clear - a few months after start-up with the new machine - that the profitability and growth objectives will also be achieved very quickly. "Thanks to the first order, we are already doing well in terms of refinancing the investment in the s181. And we have already received requests from very interested customers, to whom we have however explained that we only wish to start with new orders from mid-2018. »
However, it was not only potential clients who reacted positively to this investment. "Our finance company’s evaluation unit told us, in essence, that with the Bumotec machine, we are now part of the Champions League," the director is delighted. "The machine performs very well in terms of resale value and durability ».
