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News
New Drake Gear Grinder Rough and Finish Grinds Gears In One Setup
By
Jim Vosmik, President, Drake Manufacturing
(This article first appeared in August 2004 issue of
Gear Solutions)
Sometimes a new machine is just destined to happen.
Markets evolve, new technologies emerge, and an experienced machine
tool builder seizes the opportunity. The result: the right machine,
at the right time, at the right price.
Drake Manufacturing in Warren, OH is putting the finishing touches
on a highly productive 6-axis gear grinder that will be grinding
quality parts after just 15-minutes of setup. Best part is -–
like Drake’s other gear and thread manufacturing machines
– it’s priced to provide high return on investment
for the job shop owner as well as the large, automotive supplier.
Drake GS:G2-LM Gear Grinder
Drake is best known for its line of CNC gear
hobbers, thread and worm grinders, rack mills and bore grinders.
The GS:G2 is a machine that blends the best of Drake’s specialty
grinding and gear making expertise. |
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As the basis of competition in the power transmission and speed reducer
markets increasingly shifts toward quiet operation and efficiency, more
and more manufacturers are calling for precision ground gears. The Drake
GS:G2-LM enables manufacturers
to source near net-shaped or hobbed gears from low-cost suppliers and
still control the final product quality. “This is a high value-added
grinder, that with minimal capital outlay, can help our customers remain
globally competitive for years to come,” said Stig Mowatt-Larssen,
Drake’s Manager of Research and Development.
A flexible grinder
The GS:G2-LM has the flexibility
and capability to handle a variety of grinding roles: job shop work, manufacturing
cell environments, high volume grinding – even prototype work. Fast
changeovers with menu-driven setup screens—no more change gears
or dressing thread wheels—make it easy to switch from job to job.
Ideal customers for the Drake GS:G2-LM
are manufacturers and suppliers of industrial, off-highway and heavy
equipment power transmissions, speed reducers, and gearboxes. Actually,
anyone who is producing gears and has wanted ground gears but thought
an affordable gear grinder was unobtainable is a potential customer.
Drake Manufacturing Services made CNC thread grinders affordable 20
years ago and is now working to do the same in gear grinding. “We
want to take the mystery out of gear grinding and make that technology
widely available and less intimidating,” said Michael Hughes,
Systems Engineer at Drake.
Quick changeovers
The key to this grinder’s productivity is fast setups. A new part
can be running in 15-minutes or less. Wheel changes require an additional
15-minutes of setup. There are no change gears to install or complicated
wheel dressing routines. All the operator does is install the proper tooling,
enter the new part’s form, dress, and grind parameters into the
menu driven control and go–that’s all it takes to start up
a new job.
Gear job shops will appreciate the rapid changeovers from
one form to another. One job shop evaluating the new grinder is analyzing
the possibility of eliminating its stock of special hobs.
Those medium volume manufacturers that operate in lean,
make-to-order manufacturing cell environments with families of gears
to manufacture will love this machine. The GS:G2-LM
will make it economic for them to provide their customers with assemblies
that are quiet and have the efficiency that ground gears can provide
in gearboxes, transmissions, and reducers.
| Gear
Smart™ Programming
Drake makes all of its machine tools very easy
for the customer to operate. “Our customers do not want
machine tools, they want quality parts out their door,”
said Jim Vosmik, Drake president. “Our menus give an operator
the tools needed to make good parts. Manufacturers want their
people making parts—not fighting some arcane machine control
language,” he added. Drake machines provide menu entries
for the machine operator to define the part, tooth form, and dress
and grind process. This GearSmart™ programming guarantees
“good parts out your door from day one.”
All Drake machines are designed and programmed for the customer’s
specific manufacturing environment. Dressing forms, grind paths,
spindle and work RPM are all pre-calculated and stored in the
control’s memory. “In developing the menu entries,
our systems engineers use the customer’s terminology. Drake
makes it easy for the operators to enter the needed parameters
into the CNC—right off their setup sheet or part print.
Skilled machinists are hard to find. The machine has to be simple
to set up and operate,” said Rick Sanders, Manager of Systems
Engineering at Drake.
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setup and run a given part, the operator is only required to enter
specific part and process information (number of teeth, face width,
blank O.D., diametrical pitch etc.) for the part – prompted
by menu-driven screens.
The GearSmart™ grinding and dressing menu
provides entries for infinitely variable wheel speeds and feeds,
for rough and finish grinding, and for full control of wheel dressing
and truing. With the Drake Smart Spindle™ option, through
acoustical emissions monitoring, expensive superabrasive wheels
can be precisely trued and dressed at the micron level. Effects
of thermal movement do not result in wasted abrasives or poorly
conditioned wheels. Additional menu entries are available to suit
specific customer applications.
No programming knowledge is required on the shop
floor. GearSmart™ programming lets shops hire machine operators
instead of seeking increasingly hard-to-find journeymen machinists.
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| Dual
Wheel Capability
On the GS:G2-LM,
the first wheel can be used for quick removal of preformed rough
stock or even to grind from a solid blank. A robust spindle and
20 hp Fanuc spindle motor allows heavy roughing cuts. The second
wheel would then be used for final tooth profile grinding and
surface finish. This two-in-one productive capability reduces
the need to carry an expensive hobbing tool inventory, and can
eliminate special hobs entirely.
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| Technology
highlights
Drake equips the GS:G2-LM
with the latest Fanuc CNC controls and servos giving it world
class positioning and grinding accuracy. The cast polymer base,
wheel head, work table and work slide components provide a very
stiff grinding platform to take advantage of today’s state
of the art superabrasive grinding wheels. The machine will easily
produce gears that exceed AGMA 12 specs – productively and
cost effectively – from 1” to 12" diameter.
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| Cast
polymer base
Grinding accuracy begins with a machine’s
base components. The GS:G2-LM
uses a mineral filled cast polymer base to dampen vibration and
minimize thermal conductivity. The polymer base material provides
machine stability that results in better grinding accuracy.
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| Precise
work rotation and angular positioning
A Fanuc heavy-duty, enclosed synchronous torque motor provides
very smooth rotation and backlash-free position holding drives
the worktable (C-axis). When combined with 8 million-count encoder
feedback, the C-axis torque motor provides tooth-to-tooth index
positioning resolution of less than .2 arc seconds (.000,045°).
In this direct drive system, there is no coupling sloppiness,
backlash or windup that can introduce positioning errors. Profile
grinding of spur gears with exact tooth-to-tooth index is achievable
with this technology. Of course, helical gears—up to 45°
helix angle—are no problem either.
Accurate C-axis spindle positioning
combined with Drake’s SmartSpindle™ acoustical emissions
monitoring feature, allows fully automated gear tooth location
and stock division for finding precut parts without operator intervention
or dogging. SmartSpindle™ is Drake’s acoustic emission
technology that detects the sound of the grinding wheel touching
the part – to an accuracy of one micron. The wheel touches
one side of the gear tooth then the other, and centers itself
before grinding an equal amount of stock from both sides. Touch
dressing and automatic wheel balancing is also included on all
Drake grinders equipped with the SmartSpindle™ feature.
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| Linear
Axis Positioning
The linear axes move on preloaded recirculating
roller linear ways for high stiffness, long life, and ease of
repair. Precision ground preloaded ball screws provide accurate
positioning. The latest Fanuc AC servomotors with high-count encoders
and .000,004” resolution linear scale feedback drive the
contouring axes. While using the best available components is
an absolute necessity, Drake’s ISO9000:2000 registered quality
system assures that all components are installed and aligned such
that the dynamic accuracy of its machines are second to none on
delivery day as well as after years of multiple shift operations.
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SmartForm™
CNC diamond roll dressing.
The GS:G2-LM is equipped
with Drake’s SmartForm™ 2-axis CNC contour diamond
roll dresser that utilizes 115 mm diameter rolls for wheel profiling
and conditioning.
Wheel forms are generated by simultaneous CNC contouring
of X and W-axes or by plunging with the X-axis when using a profile
(form) roll. A precision diamond roll is used to create the exact
gear tooth profile on the abrasive wheel, using a continuous path
movement and holding tolerances in the tens of millionths throughout
the life of the wheel. Automatic dressing assures that the wheel
is properly shaped and sharpened at all times. Frequency of dressing
depends on such factors as the surface finish needed, wheel type
and stock removal rate.
Dressing software allows for involute profile modifications
for proto-types or custom gear teeth. Both left and right tooth
flanks can be modified independently. Drake has applied the experience
it has developed in over twenty years of CNC contour dressing
on its worm and thread grinders to the dresser of the GS:G2-LM.
“We know how to CNC contour dress a complex form in a grinding
wheel over and over again,” said Mike Hughes, Systems Engineer.
Drake had expected to show off the machine at IMTS, but not surprisingly
the machine has been sold. However, the company will have a video
presentation on the GS:G2-LM
at its booth # B-7407. |
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What
will be on display at IMTS?
What visitors will see at Drake’s booth is
its new GS:TE-LM Linear Motor Thread Grinder.
This grinder, built on a cast polymer base, will be equipped with
a host of Drake’s advanced machine design, productivity
options and grinding technologies. The linear motors eliminate
ballscrews, couplings, backlash, and other sources of reduced
accuracy, lead error, and drunkenness. On the positive side, linear
motor drives provide for rapid acceleration and motion needed
for thread relieving, crowning, and other profiling moves.
Drake wants customers to be able to grind a wide
range of threaded, slotted, or otherwise grooved parts on one
machine. The machine will be able to grind threads, splines, key
slots, rings and other forms in one setup using the latest superabrasives
with confidence.
“We want to show manufacturers globally what
intelligent machine design, coupled with a scientific approach
to grinding can do to reduce setup times, improve part quality,
and maximize productivity,“ said John Drake, CEO. “Of
course, as a Drake grinder, it will be delivered fully programmed
and ready to put customer parts out the door from day one.” |
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John
Drake, CEO, Drake Manufacturing
“The new GS:TE-LM thread grinder will be of
great interest to customers producing steering components, multi-start
worms, fast lead ball screws, taps, feed and bone screws, gear
boxes, transmissions and speed reducers,” he adds. |
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