Flexible turning with FANUC CNC

Vertical pick-up lathe NXT is Schuster's entry into the "future class" of modern production machines

The 100 employees of Schuster Maschinenbau GmbH, Denklingen, achieved a turnover of around 25 million euros in the past business year. Approximately 90 per cent of the turnover was generated with turnkey systems with a focus on turning.

Automation and assembly, which used to be a separate business field, are now an integral part of the systems, most of which are supplied to the automotive industry and subcontractors. Schuster has also long been involved in projects related to electromobility. With the so-called centre turning unit for the complete machining of motor shafts, Schuster has, according to its own statements, even created a certain unique selling point.

In order to become less dependent on the fluctuations of the previous target markets, the company decided to create an additional mainstay alongside the customised solutions with a standardised machine series.

How flexible is the NXT?

Schuster defines the new machine as an "entry into the future class". That is why many things were put to the test during the development of the new machine, such as the cooperation with FANUC as a worldwide, reliable supplier of CNC and robot technology. The result of the intensive development process is the NXT, a machine for flexible machining of workpieces up to 200 mm in diameter and usually for a part length of 200 mm. 

Here, "flexibility" is a very decisive design criterion, as Matthis Rühle explains: "Every operator has different framework conditions in his production. This realisation is not new.  But we are now reacting in such a way that we have designed all assemblies, such as the workpiece supply or the chip conveyor, in such a way that we can build many combinations. With our standard, we offer a tailor-made solution, so to speak."

Already under discussion for a long time

The Schuster developers had been talking about using the FANUC CNC for a long time in order to benefit from FANUC's globally recognised turning-specific CNC experience. This is where Christian Herzog, head of software development, intervenes in the conversation: "The new FANUC 0i-TF Plus - the "T" stands for turning/rotating - is a control with an optimal price-performance ratio." Rühle adds from a sales perspective: "In the market we are targeting with this machine, the control fits perfectly." Not least because Schuster exports between 15 and 20 per cent to the USA, the choice of a globally available control system including the entire servo drive technology from a single source was a first choice. Rühle: "In many regions of the world, it's simply easier to do things with FANUC." The situation is similar in the growth regions of southern Europe.

FANUC's "Service First" strategy fits in well with Schuster's principles of building machines with the longest possible service life. Matthis Rühle: "What speaks in favour of FANUC is not least the spare parts management and the availability of parts worldwide at short notice. In the combination of performance/technology/service, the CNC 0i-TF Plus in conjunction with the iHMI operating concept was the first choice, especially since the basic package of the 0i control already contains "all" the important turning functions.

Regarding the role of the interface, Christiane Appelbaum says: "The FANUC iHMI was developed to ensure that the machine is very user-friendly. Intuitive menus, modern design and animated functions facilitate complex machine operation. Sophisticated programs and a wide variety of functionalities can be used in an uncomplicated manner." Therefore, not only FANUC-experienced users will quickly find their way around the new operating concept.

The central element is an A6 spindle with 5,200 min-1, whereby the spindle can handle a torque of up to 256 Nm. It combines the machining functions with automation in the vertical pick-up lathe. The limiting elements are actually the clamping devices and the material/cutting material combination, for which a separate tool concept was developed with tool manufacturer Ceratizit. Also integrated is a measuring system from Renishaw, which enables measurement at the highest level with a resolution of 1 µm.

"The machine is ideal for medium batch sizes," says Rühle, defining the area of application - knowing full well that "medium batch sizes" are quite different from operator to operator. The machining times and whether the production process has already been automated or whether the machine is loaded manually always have an influence.

A total of twelve tool stations are available in the NXT, whereby driven and non-driven tools can of course be used as desired. The two interfaces VDI40 and BMT55 are available for this purpose. In keeping with the modular standards, there are also two variants for the workpiece feed, a trailing frame conveyor or an NC-timed conveyor with workpiece carriers. Matthis Rühle: "Which variant is chosen depends more on the preferences of an operator than on technical reasons. You can't make a blanket statement about which is the better solution."

As far as the design of the user interface is concerned, Schuster naturally also wanted a standard solution, but with customised features. "FANUC Picture", a software for the individual design of the user interface, gives free rein to integrate graphics and pictures into the operating functions. This can be useful for troubleshooting. In the event of a fault, for example on the chip conveyor, the corresponding component or assembly is displayed graphically on the operator interface. This means that the operator or setter does not have to search for the correct programme line, but simply taps on the graphic shown and is then forwarded in the menu.

Matthis Rühle: "This is our first machine that feels customised, but is still standard. In terms of control and user interface, there's still a lot we haven't exhausted yet."

As far as the cooperation during development and especially during commissioning is concerned, both sides, Schuster and FANUC, have nothing but praise for each other. Matthis Rühle: "There was very open and constructive cooperation at all levels." At an in-house exhibition - as a substitute for the AMB - the premiere of the NXT took place in front of the public. Judging by the interest, the optimistic goal of selling the first 20 machines in 2021 could well be achieved.