Page 7 - Parker - Gearheads and Gearmotors

High-Speed Milling

High-speed milling Parker SOLUTION:
machines are
commonplace in Two Stealth® PS Helical Planetary
industries such Gearheads were used in tandem
as aerospace and to create a stiff platform for the
automotive because spindle machine head. One
they allow large gearhead, acting as the master,
structural components and the other as the slave, were
to be machined from attached to the bull gears to
one piece rather simultaneously turn the ring
than assembled from gear that positioned the machine head. While the
many smaller subcomponents. For a customer master gearhead moved the ring, the slave was
that manufactures high-speed milling machines, taking up the backlash. In this way, the precision
spindle heads are operating at speeds ranging from gears allowed for the spindle to be moved accurately,
18,000 to 40,000 RPM, so that the cutting is above while the two gearhead combination maintained
the resonant frequency of the machine. Because maximum system stiffness.
of this, many characteristics become more critical Parker’s Stealth PS gearhead features an all-helical
than with their standard machines. The extremely planetary gear design. Helical gears have a much
large size of the spindle head also posed problems higher tooth-contact ratio and greater face width
for the manufacturer in trying to keep it accurately than straight-spur gears, providing higher loads,
positioned during the milling stage.
smoother tooth engagement and quieter operation.
Application Challenge: The Stealth’s HeliCrown Gear Tooth design
provides extremely high gear tooth accuracy, while
Low Stiffness minimizing tooth wear. Parker Bayside’s Plasma
The spindle head was moved rotationally by 2 bull Nitriding heat-treating process further heightens the
gears, driving a large ring gear. Because of the gear tooth’s wear resistance.
system characteristics, it was difficult to keep the This solution can also be used in the aerospace and
spindle head absolutely stiff during the milling automotive industries.
process. The problems associated with low stiffness
are:
• Poor surface finish
• Accuracy errors
• Excessive tool chatter
• Reduced tool life

Parker Hannifin Corporation • Electromechanical Automation Division • 800-358-9070 • www.parkermotion.com 7