Product category:
Milling cutters
News Release from: LMT Fette | Subject: Special solid carbide roughing cutter at Varel
Edited by the Manufacturingtalk Editorial
Team on 20 December 2007
Roughing cutter raises Al alloy feed
rates 50%
A special solid carbide roughing cutter with fully integrated chip breakers increased axial feed rates by 50% when 5-axis machining wrought aluminium alloys and eliminated erratic tool performance.
LMT Fette developed a special solid carbide roughing cutter with fully integrated chip breakers increased axial feed rates on a Doerries Scharmann 5-axis machining centre by 50% to 13.5mm/rev when machining wrought aluminium alloy The Airbus plant in Varel, also reported that the cutter totally eliminated previous erratic tool performance
This article was originally published on Manufacturingtalk on 20 Jun 2007 at 8.00am (UK)
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* Eliminating 'bird nests' - Airbus also said that the LMT Fette cutter totally solved the problem of swarf forming 'bird nests' (when a swarf tangle looks like a bird's nest - Ed) around the spindle and cutting tool.
LMT Fette told manufacturingtalk.com that this was the original reason why Volker Dittmar, Airbus' manager of pre-production, called in LMT's specialist to try to solve the problem during the machining of air inlet flanges for the Typhoon aircraft.
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The Varel site in Germany produces complex structural components and tooling, for all seven German Airbus sites.
Varl employs 1,100 people and produces more than 2.5 million single components a year.
Of this number there are 19,000 different components that require milling at the site and more than 4,000 parts are destined for the A380 Airbus.
LMT's development engineer Matthias Maack said how the previous tooling, based on solid shank endmills, could not reduce the 'bird nest' problem.
Bird nesting caused problems with quality of the workpiece and the cutters continuously drew excessive power from the machine.
He said: "It was clear that we had to develop with Airbus' engineers a solid carbide tool where a fluid transition from the radius to the milling teeth could be used to form an effective chip breaker".
Simulations were performed on LMT Fette's CAD system to try and optimise cutter geometry, cutter length, number of teeth and the geometry of the chip breaker.
Regular trials on the Doerries Scharmann machine at Airbus provided the chance to optimise the cutters with the material and the machine under production conditions.
Added Maack: "It's a bit like F1, despite all the work behind the scenes, the driver makes a crucial contribution to the team's success".
The final 25mm diameter tool from LMT's Airline Series, specially developed for aluminium processing, incorporates the special chip breaker and has helical internal coolant passages.
While the geometry of the chip breaker actively breaks up the swarf, the emulsion coolant fed direct to the cutting zone also helps to prevent built-up edge on the tool.
The tool also has three helical cutting edges 22mm long and a cutting angle radius of 4mm.
In producing the Typhoon air inlet flange, the Doerries Scharmann ACM-H HPC machining centre initially performs solid groove cutting at a depth of cut of 25mm followed by line machining at 17mm/min using a coolant pressure of 25 - 50 bar.
Cutting speed is maintained at 1492m/min using a spindle speed of 19,000 rev/min and a feed rate of 9m/min.
The axial edge of cut is 13.5mm and pitch is set at 0.16mm.
Although successful, Airbus and LMT engineers are now attempting to further improve milling performance.
Currently they are experimenting to see the effects of a reduction in the radius of the cutting angles to 2mm.
If that can be achieved, it would enable the radial depth of cut to be increased further and by introducing LMT Fette's micro cutting edge geometry, even higher performance should be achievable.
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