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By Larry Olson,
Editor
Modern Applications News
Using dual wheels to
grind the taper, shoulder, and V-groove in one setup reduced the processing
time by 75%, eliminated a setup and an operation, and significantly improved
precision.
 Ingersoll was founded in Cleveland, OH in 1887, primarily
as a heavy machine manufacturer. The company moved to Rockford, IL shortly thereafter and
has operated at its present location for more than a century. Ingersoll International
employs about 4,000 people, worldwide: approximately 2,000 in the U.S. and about the same
number in Germany. Ingersoll subsidiaries focus primarily on the manufacture of special
machine tools and cutting tools.
 Ingersoll Cutting Tool Company in Rockford employs about
550 people and consists of three facilities: steel products, with about 40,000 sq.-ft. of
manufacturing space; carbide inserts, with about 28,000 sq.-ft. of production space; and a
prototype and repair center. Scott Wenstrom, senior manufacturing engineer in steel
products, has responsibility on the shop floor for just about all aspects of cutting tool
production; including fixture design, troubleshooting, and assigning required work to the
proper machines. With 15 years’ experience at Ingersoll Cutting Tools, and 10 years
in his current position, he supports the activities of nearly 100 people involved in
manufacturing precision cutter bodies.
The cutting tools produced in the steel
products shop are mainly for unique applications, with about 36% being standard designs
and 64% specials. During 1999, steel products volume totaled about 40,000 units, although
this figure is not entirely representative of the overall manufacturing picture. The
tooling ranges in size from small ½" diameter endmills to aluminum scalpers with
diameters in excess of 100". Typical lot sizes vary from one to 30 pieces for a wide
variety of standard, nonstandard, and engineering special tools. Much of the tooling is
manufactured specifically for its sister company, Ingersoll Milling Machines, that is
involved in making high-velocity (40,000 rpm) milling machines.
 Most of the shop’s production is batch-processed on 13 five-axis
machining centers, two CNC (computer numerical control) grinders, and an assortment of
manual grinders. Of the two CNC grinders, the Kellenberger Kel-Varia from Hardinge Inc.
(Elmira, NY) is the one used in making HSK-type high-speed tools. Otherwise, standard
tooling product is manufactured in a production cell comprised of another CNC grinder and
an assortment of other machines.
According to Wenstrom, the Kel-Varia (the
company’s first) was installed in December 1998. Previously, the shop had one CNC
grinder in its operation, with four other CNC grinders installed at Ingersoll Milling
Machines. With the pressure of increased production volume and higher precision
requirements, Ingersoll Cutting Tools decided to expand the steel products shop by adding
another CNC grinder. While reviewing the alternatives, Wenstrom narrowed the search to the
Kellenberger machine. In the final analysis, having CNC on the B-axis and an excellent
reputation for service gave the nod to the Kel-Varia.
In making the decision, Wenstrom studied
machines in North Carolina, in the Milwaukee area, and locally in Rockford that were
involved in similar applications. Based on his own experience and discussions with a North
Carolina tooling manufacturer (who was doing work similar to Ingersoll Cutting Tools), he
was able to collect some good information on the Kel-Varia’s operation. “When I
talked with their engineers and shop floor people to get their opinions on service,”
says Wenstrom, “the majority of the answers were, ‘We don’t know, since we
never had to use it.’”
What Makes Grinding Integral HSK
Tooling So Tough?
Ingersoll Cutting Tools was one of the
first cutting tool companies to pioneer in manufacturing HSK-type tooling. Early in the
1990s, the company teamed up with Ingersoll Milling Machines in a project to build a line
called the “Ford Factory of the Future.” This project featured the development
of several groups of high-speed machines and nontraditional transfer-line equipment with
HSK tooling.
Most of the tooling manufactured to HSK
designs is integral; that is, the shank and the cutting tool are one piece. This is in
direct contrast with several other makers of cutting tools that use a standard adapter
with an endmill. This two-piece arrangement often has many inherent problems such as
rigidity and runout. However, according to Wenstrom, manufacturing the tooling as a single
unit presents some unique processing difficulties as well.
Inside the HSK taper, there is a 30°
clamping angle to accommodate the drawbar in the machine tool. From the shoulder of the
tool to that angle, there is a relatively tight tolerance. Wenstrom explains, “If
that were the only dimension that had to be maintained to the shoulder (about
±0.001"), it wouldn’t be a problem. You could measure the stock, grind the
excess off the shoulder, and be done with it. By making the tool integral, we also try to
maintain a dimension over the insert at the opposite end from the same shoulder. So, we
end up holding two dimensions from the same datum (or feature point) in opposite
directions. That makes a very small window where the shoulder must be located.”
Wenstrom recalls that Ingersoll Cutting
Tool’s steel products shop learned a lot about the tight tolerances involved, right
from the beginning. “We knew what we wanted the machine to do,” he says.
“Unfortunately, the one grinding machine that we had couldn’t do what we wanted
it to do. The process was achievable, but it was very labor-intensive.” Originally,
manufacturing the HSK tooling involved two separate operations. The taper and the shoulder
were done in one operation, followed by grinding the V-groove on another machine.
“Luckily, the operator at that time was very experienced,” he adds, “which
bridged the gap between the (manual) machine’s shortcomings and what was
needed.”
Now, the Kel-Varia’s setup with
in-process gauging and automation has made life a lot easier for the shop. The
machine’s features significantly reduce the cycle time and labor involved in
producing a good part. On average, depending on the particular HSK tool design, a part
that would take as much as 1½ hours of manual grinding to complete now can be finished in
15 minutes. In addition, grinding the tooling features in one setup on the Kel-Varia has
paid dividends for Ingersoll Cutting Tools by producing parts with precision the first
time, with much less scrap and wasted effort.
Another major advantage for the Kel-Varia
is its CNC B-axis, which gives it the ability to achieve much more precise results.
Accuracy and repeatability are further ensured by having hydrostatic ways on the X- and
Z-axes, where other grinders may have this feature only on the Z-axis. Wenstrom is quick
to point out that there is nothing custom about their Kel-Varia. As far as delivery and
installation were concerned, he says, “We received the machine, and a week later the
service representative came in to train the operator and me. It went really smooth, and he
still supports the machine on a day-to-day basis, if needed.”
The Kel-Varia is presently running on one
shift, 10 hours per day, six days per week, with the ability to expand to two shifts if
needed. Most of the company’s HSK tooling is manufactured for sale with the milling
machines made by Ingersoll Milling Machines. The market for this type of tooling to other
customers is expanding as well, although it is still a relatively narrow niche. As the use
of HSK tooling becomes more prominent in the marketplace, the steel products section of
Ingersoll Cutting Tools is positioned to manufacture some of the most precise products of
this type available anywhere.
Kellenberger, A Hardinge Co.- July 2000
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