From the micro range up to dimensions of 2,000 x 800 mm, highly complex components, long cycle times ... this describes the range of workpieces manufactured by TVRmicrotec in Karlsruhe. Especially the micro range requires the necessary sensitivity for precision, as exotic materials, like titanium, invar or nemonic, are also machined with the smallest of tools up to 30 µm and tolerances of less than 5 µm. However, these projects, frequently realized for development departments, research institutions and universities, also require economical production in addition to high accuracy.  For this purpose, appropriate machinery is the basic prerequisite for the people responsible for implementing the project. For Tihomir Valentin Rupcic, it is no coincidence that TVRmicrotec meanwhile works with  two PICOMAX 90 machining centers, one PICOMAX 60 and the VERSA 825 by Fehlmann: „Based on our experience, in the smaller component segment, there are no other machines on which to produce with such precision and speed. Here, the PICOMAX 90 and the VERSA 825 are excellent examples. Our tests have shown that we are able to stay within the small tolerances, even without an additional high-precision package. High accuracy is simply built into the machines from the outset.  In my opinion, however, this applies to the entire cost/performance ratio of Fehlmann. The standard version of these machining centers, for instance, includes coolant processing with booster pump, fine filter and coolant tank. In other words - coolant as clean as necessary for an internal coolant supply system is standard at Fehlmann.“
One of the said tests in Karlsruhe involved a component with an extremely tight delivery deadline, so that the cycle time was of elementary importance.  Compared to other premium machines, the P 90 managed to machine the component in 5 hours / 10 minutes instead of the usual 6 hours, using the same program, the same tools and the same cutting data. According to Tihomir Valentin Rupcic, this saving of time became possible thanks to higher dynamics, i.e. the Fehlmann cycle surface, accuracy and speed.

High-precision machining even in the micro range
Similar results are achieved with the VERSA 825 when hard machining components. People were pleasantly surprised to see how easily and fast free-form surfaces were milled with tolerances below 20 µm. Given a lot size of 130 parts, the tool was loaded, probed and cut, results were reproducible without exception. The only requirement is a warm-up program, which lasts 20 minutes. After reaching the required temperature, the machine is absolutely stable and temperature fluctuations do not occur.
Another important aspect was the swiveling table. While comparable machining centers are offered with swiveling movements up to 108°, Fehlmann talks about +/- 115°. In one concrete case, however, swiveling up to 116.5° could be realized after consulting Fehlmann.
Apart from that, the overall concept and design of the VERSA 825 is highly convincing in every respect, especially as the standard version of the machine comes equipped with a tool changer with 44 stations and torque drives. In addition, the VERSA 825 at TVRmicrotec has already been prepared for full automation. Of special interest is the fact that components to be machined on a high-precision machining center for microtechnology may also be produced on the PICOMAX 60 without any problem. As Uwe Brenk, Manager Microtechnology, puts it: „Everything we produce on the micro machine we may technically also machine on the PICOMAX 60 without any significant difference. For instance, we have machined numerous components for minimally invasive surgery, as well as artificial joints with hydraulic or pneumatic drives for patient care with tolerances of just a few µm and a cutter diameter of 2/10 mm on the PICOMAX 60.“
Meanwhile, TVRmicrotec own four Fehlmann machining centers, even though the Fehlmann brand had been entirely unknown to those responsible in Karlsruhe until 2001.  Two of the machines have been up and in operation for 10 years now - and are still cutting reliably and with high precision; the service and the projects have been handled by Fehlmann in a perfectly customer-oriented manner. These are reasons enough for Tihomir Valentin Rupcic and Uwe Brenk to have established a strong relationship based on trust and for being convinced about Fehlmann without reservations.

TVRmicrotec GmbH
The company was founded together with the partner company I-SYS Feinwerktechnik in 1998 and is engaged in design, construction and manufacturing in the fields of micro system technology, as well as the production of pre-series parts, prototypes and small series.  Next to mold & tool making, the company has specialized in the cutting of prototypes and of all kinds of materials. One of the particular strengths is the capability to realize complete process chains, including EDM machining and grinding. Providers from medical and analysis technology, gear manufacturing and the automobile industry are mainly counted among their customers. In funded projects, together with universities and research institutions, the company also considers itself a service provider in mechanics - also with respect to planning and design.

By the way...
According to information by Fehlmann, the unique precision is, among other aspects, achieved by the scraped machine geometry, direct encoders, as well as an extremely rigid, heavily ribbed gray-cast iron construction with inherently stable three-point support system.

Interesting side note
The machining of aerospace components from PEEK with glass fiber demonstrates how exotic the materials cut in Karlsruhe may be. This component was machined on the VERSA and demanded appropriate machining know-how due the required plane parallelism of 5/100 mm.

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