LMT Boehlerit, the sister company of LMT (UK) of Coventry, has answered a request from a fellow precision engineering firm.

 
Weingartner Maschinenbau called on the firm to tool-up a turn milling process on its multi-product machining centre to produce seven metre-long ship engine crankshafts with a swing of one metre.

The milling cutter had to be able to side mill the full length of each piece with a 5mm depth of cut and accommodate the progressive increase in spiral orbit from the minimum diameter to the full apex, as the crankshaft is rotated in the CNC lathe.

"As the web of the crankshaft is swung past the rotating milling cutter, the circumferential speed varies significantly due to the length of the throw in contact with the tool which also means the shank end of the tool is subjected to a far greater feed rate and chip size than at its free end," the firm explained.

The solution was an endmill-style cutter able to carry 80 cartridges for the square inserts, each strategically arranged to account for varying contact area and speed during rotation.

http://www.machinetooldirect.co.uk/machine-tool-news/LMT-tools-up-turn-milling-macine-2009-7-10.asp