Powerful Prototype Spindles Boost Machine
Tool Performance
- New, fast, flexible spindles could raise U.S.
productivity and spindle market share.
- One design could save the auto industry more than
100,000 hours in annual machining time for a single part.
- Benefits could extend to aircraft, appliance,
electronics, oil, and other sectors.
A wide range of U.S. manufacturing industries could reap substantial savings in
equipment and labor costs, introduce flexible manufacturing lines, and cut cycle time
using innovative spindles that in early tests appear to break new ground in machine tool
performance. Designed in a project sponsored by the National Center for Manufacturing
Sciences, Inc., and co-funded by NIST's Advanced Technology Program, the prototype
spindles are smaller, faster, and more flexible than conventional designs and offer new
capabilities as well. Spindles--the rotating shafts that hold cutting instruments in
machine tools--are critical in manufacturing because they are used to make both parts and
tools in many industries and strongly influence production rates and parts quality.
Conventional spindles cannot provide the dynamic performance and torque-speed
characteristics needed to make a machine tool sufficiently small and agile to machine
advanced materials or implement flexible manufacturing lines. The ATP project united a
synergistic team of vehicle makers, machine tool builders, spindle designers, and
lubrication and motor experts that devised solutions that have eluded industry for years.
The team designed and built three spindles, focusing initially on meeting the needs of the
auto industry.
A four-cluster hydrostatic spindle system may be capable of outperforming a benchmark
system used in a General Motors Corp. powertrain plant. The system eliminates the expense
of ball-bearing replacement and offers the potential to reduce from two to one the number
of machining stations used by the auto industry to cut four cluster holes in the trial
part. The new design has the potential to save more than $6 million annually in the
production of a single part. Its unique bearing design won an R&D 100 award for
technological innovation. A 35-horsepower (hp) prototype spindle offers high torque over a
much broader speed range than the current state of the art. Tests on a lightweight 75-hp
spindle demonstrated its capability to perform accurate boring of cylinders and milling of
flat surfaces on a Ford Motor Co. cast iron V-8 engine block at twice the metal removal
rate of current processes, a benefit that could extend to dozens more applications in many
industries. The ATP project already has provided the basis for a handful of spin-off
products, including spindles, motors, and motor drives.
ATP funding: $3,479,000
Non-ATP funding: $4,011,000
For more
information
June 1998
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