Imagine sitting in the dentist’s chair while they very accurately drill a hole in your tooth from the other side of the room! This gives you some idea of what Austrian machine tool manufacturer, WFL Millturn Technologies and its intelligent boring bar measuring 120mm diameter and 2.2m long is capable of.
WFL claims it is the only company worldwide which concentrates exclusively on the manufacture of multifunctional turning, boring, milling centres, focusing on the complete solution from the start. The required software solutions with adapted processing strategies, process design and programming are also provided.
Hard-to-machine materials are becoming increasingly more prevalent in the aerospace sector and titanium machining in particular is a field in which CNC machine tool manufacturers like WFL are looking to excel. According to company applications engineering manager, Reinhard Koll, the aerospace industry represents an important market segment.
“The reliable and repeatable machining of new and exotic materials, as well as very deep and accurate deep hole machining always present a process challenge,” he begins. “In addition, our customers often use a variety of live boring heads for machining cylindrical features that are not always located on the centreline of the component.
“Therefore, the most important requirement our products must satisfy is absolute process reliability. Yes, machining cycle times are important too - as is the up-time of the machines – but a WFL machine represents an important acquisition for a customer because they often eliminate the need for other CNC machining processes on the shopfloor.”
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WFL’s machine tool interface for long and heavy tools used on prismatic operations is particularly useful for tools that may be too long for a standard toolchanger. Depending on the machine size, the company says it can offer between three and 18 of these long tools in a special magazine alongside the typical line-up of chamber boring tools and live boring heads.
As part of WFL’s focus on internal machining technologies, it formed a partnership with Sandvik Coromant to examine the use of an ‘intelligent tool’ on the M120 MILLTURN at last year’s EMO Hanover event. In light of the ever-increasing importance of networking, a live demonstration of the functionality of the intelligent 18xD CoroPlus boring bar was conducted by the WFL team to interested visitors.
Here, the boring bar is integrated into a special WFL prismatic toolholder which included a data interface. Thanks to the CoroPlus technology, information and tool statuses can be transmitted to the control system or a tablet. During processing, the machine operator is provided with information regarding temperature, deviations, background noises, vibrations and the load on the tool. In this way, the chip removal process can be perfectly optimised, protecting both tool and workpiece from damage. In addition, the complete process can be logged in full. This technology is typically used in the aerospace industry and generally, for the machining of long, slim workpieces.
“Our ‘intelligent tool’ comprises a boring bar with a long 18XD overhang measuring 120mm diameter and 2.2m long,” states Koll. “The tool itself contains sensors and can be automatically changed during the machining operation if required. Previously, an operator machining a landing gear component wouldn’t know exactly what was happening inside the bore chamber, whereas our ‘intelligent tool’ can detect anomalies like deviation from the nominal diameter and correct it accordingly.
“We can also assess both the vibration and the temperature of the dampening system – especially useful when roughing out a lot of material. A dampened boring bar can usually absorb these kinds of vibrations, but if the operation happens to exceed the capability of the boring bar, our system can adapt the machine tool’s spindle speed automatically. This sensor technology allows us to understand what is happening inside a deep bore during the machining.”
Scanning measuring probe
Other new WFL innovations include its M120 MILLTURN/3,000mm, which makes use of new measuring and testing technology from BLUM-Novotest. The machining of large, heavy and complex workpieces poses significant challenges for measuring systems. With the integrated TC63-DIGILOG measuring probe, digital measurements and analogue scanning processes can be carried out directly on the machine. Analogue measurements are especially useful for the evaluation of surfaces or contours, such as the checking of the surface of a workpiece for machining errors. With a switching digital probe on the other hand, a large number of points would need to be measured in such cases to ensure that adequate resolution is achieved.
However, the new analogue probe harnesses scanning technology to generate thousands of measurement values in a fraction of the time. With the TC63-DIGILOG, quick measurements of up to 2m/min are possible with complete accuracy. Features, such as fully-automated roundness, run-out and axial run-out measurements can be ably demonstrated on the M120 MILLTURN.
“Our new probing system is not just a touch probe, but a complete measurement system probe that can evaluate features like surface roughness, for example,” explains Koll. “After turning or milling a surface, the scanning probe measures the feature and feeds back the information to the machine tool’s control, so that when the part is finished, it delivers dimensionally accurate measurement information.”
A smart alternative
WFL also used EMO Hanover as a platform to launch its new M30 MILLTURN, a complete machining centre at a top price. As a cost-effective solution for less complex or smaller applications, the M30 MILLTURN represents an economical model on the basis of its previously smallest MILLTURN, the M35.
The company says this has been made possible through healthy synergy with its existing M35 MILLTURN, as well as by concentrating on especially typical configurations that are series produced, independently of the order. Not only does the customer benefit from a significant saving in terms of cost, but from fully-perfected machine technology too.
The M30 MILLTURN can tackle machining lengths of up to 2,000mm and turning diameters of up of 520mm. The M30 MILLTURN casing has been equipped with 50% larger windows in the sliding doors to ensure optimum visibility of the working area, and special attention has also been paid to improving user-friendly access to the tool magazine from the front via the large sliding window and integrated LED lamps within the working area. Another advantage is its robust NC drive for the steady rest slide. An optimised machine base guarantees quick set-up and repositioning of the machine.