Duplicate machines at NMH: Same same but different
C 42 U | Robot system RS 2 | Contract manufacturing
Price, quality and delivery dates are what really interest his customers, explains NMH Managing Director Christian Bulander. More recently, one robot and two virtually identical Hermle 5-axis machining centres have been helping the specialist engineering company and contract manufacturer to meet these challenging demands efficiently.
For the past two and a half years, two C 42 U machines have been sitting in the production hall at NMH GmbH in Hohentengen municipality in the district of Sigmaringen in Germany. Between the two milling centres stands a type RS 2 robot. Since Hermle installed the system at the company, which specialises in contract manufacturing, engineering and software development, the daily working routines of Matthias Eisele and Elmar Käppeler have changed fundamentally. Although they still write programs for the milling process, set up and strip the machines and load the systems with tools, the robot frees them up from the operating cycle of the milling centres. "We operate a flexible time model here, which is based on self-organisation, individual responsibility and trust. This allows both operators to be present simultaneously or at different times. Alternatively, they can split up their day so that they spend three to four hours on-site in the morning and in the evening. We have left this arrangement completely open and don’t intervene", explains Christian Bulander, Managing Director of NMH GmbH, adding that the operators themselves know best what they need to complete and when. This approach is also in line with Bulander’s high expectations: "Only those who think innovatively and contribute ideas can fully exploit the potential of an automated production cell".
NMH first entered the world of automated machining with the robot and two 5-axis milling centres by Maschinenfabrik Berthold Hermle AG. "Without them, we would have been at a competitive disadvantage", explains Bulander. Or put another way: the robot enables an economical price calculation even with series production runs. However, it also increases employee availability and maximises flexibility. It removes individual workpieces from a matrix pallet and places them into the clamping system, grips fully equipped pallets and can either supply both adjacent machining centres or swap out tools if required. The robot can handle different clamping situations just as easily. With running times of three to 20 minutes, there are many hours when staff are not required, particularly when it comes to handling individual parts. "The robot simply does everything, and its flexibility is unbeatable", remarks the managing director.
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Christian Bulander began his career at NMH as an electrical engineering apprentice in 2001. He has been running the business since 2019 and became a shareholder in the GmbH shortly afterwards. He is currently the majority shareholder. -
NMH Managing Director Christian Bulander (centre) with machining technicians Matthias Eisele (left) and Elmar Käppeler. -
The robot is controlled by the SOFLEX software – right now, everything is in the green zone. -
In 2019, Hermle installed two C 42 U machines, automated with the RS2 robot system, at NMH. -
Pallet, workpiece or tool handling: for NMH, a robot means maximum flexibility.
Just the same only different
Bulander and his team considered and calculated in advance how they wanted to implement automation – with which system, with how many machines and from which manufacturer. After several visits to reference customers, they ultimately chose Hermle – the overall concept and the fact that everything comes from a single source sealed the deal. The reason why NMH invested in two C 42 U machines at once was because of the variety of its products. That’s because the manufacturer of meat processing machinery founded in the 1940s is now a successful contract manufacturer and engineering company specialising in measuring, testing and assembly systems. For example, it designs and builds welding fixtures, load-handling devices, measuring machines, robot cells and systems for the production of agricultural machinery, automotive equipment, commercial vehicles and the construction sector. It has also established another arm of the business with its plastic injection-moulding technology. Here too, the innovative company supplies everything from a single source, from the design to the final production part. In the area of digitalisation, NMH provides software and hardware solutions to support digital paperless production, CO2 measurement and energy control.
"The machines are not entirely identical", says Bulander in response to the question about the choice of the two milling centres from Gosheim. Whereas one is designed for heavy-duty machining, the focus of the other is on precision down to five My. This can be seen, for example, from the tool spindles installed, which rotate at speeds of up to 15,000 or 18,000 revolutions per minute. Another reason for doubling up on machinery is to make optimum use of the robot: the running time of a machine is always longer than the parts handling process. If two machines are available, the robot is better utilised, and the system is therefore more productive – including during the unmanned shifts. "Although one robot and one machining centre can also be profitable, operating two or more machines in parallel naturally provides much greater leverage", explains Bulander.
Night shift on its own
The robot loads all sorts of components onto the swivelling rotary tables of the 5-axis machining centres: made from plastic, aluminised steel, cast materials and in unit numbers from 1 to 500. "The Hermle machines handle challenges such as accuracy and material complexity with ease – including the reliable removal of the various chips and shavings", confirms Bulander. As a result, the production cell also runs overnight and at the weekend – without supervision. "Why should the machine be idle at night? Surely, it’s better to have it earning money while we sleep". His argument proves to be correct in practice. "To date, we have never had a crash during an unmanned automation process. Naturally, that’s also down to the fact that our employees just know what they are doing", acknowledges the managing director.
A glance at the swivelling control panel on the RS 2 system reveals another unusual feature: a second screen with a web cam is mounted above the Hermle monitor. That’s because NMH embraces paperless production and has developed its own production software called COCO (ControlCockpit) for the purpose. This allows NMH to track and manage all manufacturing processes in real time – also with the help of cameras installed in the machining areas of the C 42 U. This means that workers can keep an eye on the process at all times even if they are not standing beside the machine. Every component and every production series is accompanied by a small white digital tag that is centrally managed and labelled by NMH. The QR code that is then generated ensures that all important data, be it the tools to be used, CAD drawings or measurement logs, is available in the latest version at any time and from any workstation.
This digital transparency also plays a key role in enabling Bulander to meet the expectations of his customers by combining on-time delivery with quality at an attractive price. The Hermle machining cells are another secret to his success. "I believe we chose the right time to invest in a system that ensures our competitiveness and provides us with reliable and precise results", says the managing director in summary. He is equally satisfied with the cooperation with Hermle, which he describes as "extremely punctual, competent and always very professional". However, he is happiest when he hears nothing from the service department: "That means everything is running smoothly. That’s the ideal scenario for both sides".
