Quality is paramount
One of the difficulties with the ageing VMCs was the inability to mill by circular interpolation a sealing surface without four quadrants being visible and lines apparent at each change of axis direction, with the attendant risk of parts being rejected. Quality is paramount, with ± 1.5 μm dimensional accuracy and 0.4 mm Ra surface finish required.
The AA1165 machine, fitted with a high pressure (70 bar) coolant system, has proved itself capable of achieving the drawing tolerances when machining nickel and steel alloys. Features of the WELE that secure a combination of heavy cutting performance and precision finishing include twospeed, auto change gearbox drive to the 18.5/15 kW BIG Plus 8,000 rpm spindle, which delivers up to 469 Nm of torque, hand-scraped square-section guideways, rigid construction, up to 10 m/min cutting feed rate and 36 m/min rapids in X and Y, 20 m/min in Z.
The machine’s Fanuc 0i-MF CNC is already prepared for controlling a fourth axis, which is an optional extra offered by Whitehouse on the AA1165, whose 1,300 x 650 mm table has plenty of room at one end to accommodate it.
LB Bentley’s Operations Manager Andrew Kethro said, “We have been extremely pleased with the performance of our new machine. It is very rigid and the load monitor highlights that the machine can easilycope with the materials and depths of cut specified.
“Our machinists have commented how quiet the machine is when cutting at high torques and low speeds, 1,500 rpm being a maximum here when milling our difficult alloys.
“With limited factory space here, the small footprint of the WELE is supporting our 5S initiative and the continuing improvements we are making on our shop floor.” Machine shop supervisor Tracey Harnden was part of the team tasked with sourcing the new capacity. He commented, “We shortlisted two alternatives to the WELE and asked both potential suppliers to run a trial using one of our existing programs for cutting an Inconel part.
“The spindle stalled on one machine, while the other company were unable to point us to a single user installation where their equipment cuts our type of alloys.
“Other CNC mills we looked at were light, high-speed models that were obviously unsuitable and the original supplier of the VMCs that are being replaced did not even call us back.”