Page 27 - MMI_MarApr 2021 (high-singles)

Source: Modern Machine Shop

This comparison shows the quality of surface finish without (left) and with SGI Smoothing.

stability that is maintainable high-speed spindle enables fast become more efficient without Today’s
without undue human inter- machining of fine features with sacrificing quality. Doing that medical
vention. Two critical and inter- small tools. The spindle is also effectively requires investing in manu-
related factors here are the in- thermally controlled providing more capable equipment, which, factures
herent geometric accuracy of optimum performance over ex- of course, comes at a cost. From are under
the machine and the thermal tended periods, ensuring exact- a financial perspective, the top increasing
stability of the machine. ing cutting conditions from start companies are thinking much pressure
Common practice for machine to finish to produce tight-toler- more like high-volume produc- to become
tool builders is to address ance, high-quality workpieces. tion manufacturers with greater more
geometric inaccuracies in the consideration of factors such re- efficient
machine with electronic com- Stable processes enable turn on investment, equipment without
pensation in the control. For unattended machining utilization rates and labor costs. sacrificing
example, say the run of an X Today’s medical manufactures You cannot just be good at mak- quali-
axis isn’t perfectly straight are under increasing pressure to ing parts anymore; you must ty. This
or there is pitch, yaw or roll requires
as the axis traverses from one investing
limit to the other. These inac- in more
curacies can be mapped and capable
compensated for in the CNC’s equipment,
motion. However, this method- which
ology can become increasing comes at a
unstable as the machine heats cost.
up because the compensation
may no longer be accurate in Symmetrical machine design is an important factor in mitigating the ill effects of thermal distortion.Source: Modern Machine Shop
a state of thermal distortion with Also important is providing equal support across the entire axis travel ranges, as show in this
some machines. rendering of Makino’s DA300 five-axis machining center.
Makino’s answer for this is to
build machines with symmetri-
cal designs that minimize ther-
mal distortion and apply active
thermal management systems to
keep the machine thermally sta-
ble in the first place.
A variety of factors combine to
deliver high positioning accuracy
(±0.000060") in the DA300 and
other models designed for med-
ical machining, including core-
cooled, fine-pitch ballscrews with
0.05 micron scale feedback. The

www.mmindia.co.in | 27March-April 2021