Tuesday, 13 June 2017

Outstanding milling



[article by Edoardo Oldrati, original source: "Tecnologie Meccaniche" Magazine, June 2017]

The German mould maker, WFT Werkzeug- und Frästechnik, has invested in Breton milling solutions. Specifically, in the recent Flymill HD for machining superalloy, steel and aluminium parts with complex three-dimensional shapes.

Founded in 1997, but the heir of an entrepreneurial history that started in 1919, WFT Werkzeug- und Frästechnik is a German company that manufactures matrices and moulds for punching, foaming and compression moulding of all kinds for the automotive, aerospace, medical and renewable energy industries. 

State-of-the-art technology and many years of know-how”, explain Frank Elzener and Stefan Lühr, managing director and owner of the company respectively, “allow us to provide our customers with everything they need for each process phase, from design and manufacture to assembly and testing, giving them a single source procurement service”.

In the Coppengrave plant in Lower Saxony, more than 50 employees use modern production systems to machine blanks. The CNC machines have up to a maximum of 5 programmable axes and can machine workpieces up to 8 metres long and weighing up to 46 tonnes.
One of the strengths of WFT is precisely this advanced fleet of machines, which takes up four halls with an overall surface area of 3 thousand square metres. For the past three years, WFT has relied on machines supplied by Breton. Currently the company's plant houses a Breton Matrix 1000, with axis travel of 2200 x 2500 x 1000 mm, and a new Flymill HD with head change and an axis travel of 8000 x 3500 x 1300 mm.

Flymill HD in action

HIGH MILLING PERFORMANCE

A company like WFT must be able to rely on milling machines that can combine high material removal capacity with high accuracy. Precisely for this reason, a partnership was started with the Italian manufacturer Breton, which has supplied two machines in recent years.
The most recent one is the high-speed, high-performance milling machine with 5 continuous interpolated axes, the Flymill HD. It is ideal for machining superalloy, steel and aluminium parts with complex three-dimensional shapes that must be made accurately.


A sample worked by WFT with the Breton Flymill 1300 milling machine

To ensure high performance, the Flymill is equipped with sturdy shoulders made using the exclusive Metalquartz® technology, which provides high structural rigidity and a high degree of vibration damping to guarantee improved surface finish and increased cutting tool life.

The large work table size, the strength of the structure and the large operating travels make this high-speed milling machine suitable for use in a single work area or in pendulum mode, with a milling speed of up to 40 m/min for the linear axes, reaching up to 60 m/min in rapid mode. The bi-rotary heads (with continuous C-axis rotation, A-axis rotation up to 135°, power of 85 kW and rotation speeds of up to 100 rpm) allow the machine to rapidly perform even the most complex machining, working simultaneously in all three dimensions with very simple programming. In fact, considering that the A-axis can rotate up to 135°, it is easy to perform difficult undercuts without repositioning the workpiece. 

The machine model installed at the German company has an axis travel of 8000 x 3500 x 1300 mm. There are electrospindles for the Flymill HD heads that can guarantee high performance through their bilateral fork structure made of cast iron, which gives them structural strength and vibration damping ability. The Breton Flymill is equipped with the Tornado HD head, which can take a 75 kW (S1), 14,000 rpm spindle for rough machining and finishing.
Also noteworthy is the compact structure that meets the increasingly widespread demand for small-footprint systems. 



Furthermore, the Breton machine previously installed in WFT, a Matrix 1000 with an axis travel of 2200 x 2500 x 1000 mm, features high machining speed and high material removal rate.

It is a high-speed, high-precision machining centre for milling parts with complex three-dimensional shapes, ideal for applications in the aerospace, automotive, mould making and design industries. In fact, thanks to the speed of its linear axes, which can reach 60 m/min, and its Direct Drive head with a continuous C-axis rotation speed of 100 rpm, the Matrix can perform uncommon high-precision and dynamic machining of complex profiles with 5 continuous axis.


Matrix 1000 Dynamic




The bi-rotary continuous head with direct drive can be positioned at any angle within its operating range, thanks to powerful hydraulic brakes. This makes it possible to use spindles with continuous powers of up to 40 kW and 28,000 rpm, giving the machine a considerable material removal capacity.
It is also worth noting that it can easily handle high-speed machining and milling of both light alloys and other special alloys that are often used in the aerospace industry.

The completely enclosed structure with mechanisms at the top of the machine offer maximum operator safety with maximum machining reliability and precision. Its machining quality and precision are also achieved through the thermo-symmetry of the structure and the a thermal stabilisation system in the Z-axis lead screws and bearings and the axis drives, which keeps the temperature of these parts aligned with that of the machine structure during operation. 

This stabilisation system makes the machine practically immune to deformation caused by the thermal dilatation of the structure that is induced by continuous daily use for high-speed machining. Sophisticated finite element method (FEM) dimensioning integrated with global dynamic simulation has made it possible to obtain strong structural elements that combine stable geometric precision with dynamic high acceleration of the operating units.

THE KEY TO SUCCESS


WFT manufactures prototype moulds, pilot moulds and production moulds for a wide range of plastic machining technologies. Depending on the geometry of the workpiece, the number of components and the customer's needs, WFT can offer the optimal mould concept from both the technical and economic points of view, providing its customers with recognised know-how as well as intelligent and highly technological solutions. 




In addition to its versatility, another element behind the success of WFT is its ability to follow the whole implementation cycle of moulds and customised machines, from design to production. “Our personnel create the three-dimensional model of the component to be made on CAD/CAM workstations. The design department is connected with customers around the world, allowing them to see the data on line and to perfect the design through direct consultation”.

The target industries for the moulds made by the German company impose high quality standards.

“Quality is our watchword”, confirms the technical department, “and many years of experience and the constant training given to our engineers and experts guarantee the highest quality combined with reduced production times. To ensure excellent quality, every aspect of all moulds and machines is tested before being delivered to the customer. Moreover, visual inspection is an effective method, but it is not enough to meet the current requirements imposed by the manufacturers of components for the automotive and aerospace industry. 

For this reason, we reply on complete control systems and we manufacture measurement devices and test equipment from aluminium, steel or light material, to guarantee accurate measurement of every product. Here, the distinctive feature lies in making the measurement: in fact, the test and measuring devices provide assessment, documentation and display. We can also build custom test devices to meet customer requirements”.

The ability to innovate is also essential, not only by investing in a fleet of state-of-the-art machines, as we have seen, but also by developing new technologies. An example of this approach is the innovative joint technology for plastic products that WFT uses in its plant. 

To make products such as trims for doors or bumpers, dashboards or fuel tanks, packaging components or medical items, plastic components are applied to various objects. In these cases, WFT uses latest generation joining technology to integrate metal elements into the plastic, fold laminated materials or securely fasten thermoplastics by welding or riveting.

For more information please write to mail@breton.it.

Thank you for the attention and best regards.
Bye-bye

Sergio Prior

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