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In this
issue of Akcelerator,
Technically
Speaking looks at the most expensive
component on an extruder….the gearbox ..and what you should consider
when purchasing a new extruder. In Product
News you’ll preview American Kuhne’s new
line of high quality, low cost extruders….the AK ULTRA line.
Worth
Noting introduces the latest addition to
our technical sales team. And, take a look at AKt
Now for special pricing on replacement
barrels for all brands of extruders.
TECHNICALLY
SPEAKING...
Live long
and prosper…
Let’s
talk gearboxes!
Extruder buyers need to
pay extra attention to the design and manufacture of the gearbox
when evaluating and selecting a new single screw extruder because,
as previously noted, it’s the single most expensive component on the
machine. In this article we'll examine some of the more important
considerations. For the longer, more detailed version, please read
Tech Tip No. 5 in the Technically
Speaking section of our web site.
In
establishing the quality and suitability of a gearbox, there are
three key criteria: (1) HP rating; (2) thrust bearing type and
rating; and (3) serviceability.
1. HP
Rating Criteria
The
following four critical components combine to determine the HP
Rating: (A) Gear design, construction and hardness; (B) Shafts; (C)
Radial bearings and seals; and (D) Housing.
A.
Gear design, construction and hardness
— The gears themselves
are rated for horsepower or torque based on their strength and
durability ratings as calculated according to AGMA (American Gear
Manufacturers Association). Key factors include gear tooth pitch,
center distance, material and hardness.
B.
Shafts — The gear shafts must be
designed to transmit the full HP and torque capacity of the gears.
The length and diameter of these shafts is critical to their ability
to transmit this torque without excessive deflection, fatigue and
ultimate failure.
C.
Radial bearings and seals —
Radial bearings must be adequately designed and sized to handle the
load forces and speeds. Dynamic load capacity must also be
considered when evaluating the design and longevity of the
gearbox.
D. Housing
design and construction —
Typically cast iron is the most cost effective material of choice.
However, steel fabrications are sometimes used in low volume and/or
custom designed gearboxes.
Historically, cast iron
gearboxes have been made in two pieces, split either horizontally or
vertically. More contemporary gearbox designs have the one-piece
cast gearbox housing with an opening in one side for the insertion
of the gears. This provides a more rigid and compact design able to
handle higher HP applications.
2.
Thrust bearing — This vital
and expensive component isolates the rearward forces from the screw,
preventing damage to the gears, shafts and radial bearings. There
are three types of thrust bearings (spherical, cylindrical and taper
roller), each with its own advantages and disadvantages. In
addition, thrust bearings can have different mounting arrangements
and rating adjustment factors which must be understood before an
accurate comparison between extruder models can be
made.
3.
Serviceability — Before
selecting your next extruder supplier, be sure to determine where
your gearbox is made as well as the cost and availability of
potential parts and service. These considerations should always be
factored in to the initial purchase price in order to determine the
machine's actual Total Cost of Ownership (TCO).
Conclusion: As you
can see, gearbox selection can be a very complicated subject. It
appears that some manufacturers are quoting HP ratings based only on
the gear tooth rating without full consideration of the shaft,
bearings and housing design. To insure that your next extruder has
the best gearbox money can buy, be sure to evaluate, in detail, the
three key criteria discussed above. For a more detailed version of
this article, please see Tech Tip No. 5 in the Technically
Speaking section of our web site. To speak personally with our
resident expert, please contact Bill Kramer or call him
direct at (860) 886-7745, ext. 112. |
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--
PRODUCT NEWS --
Fully
equipped instead of stripped
Introducing
AK ULTRA, our new line of high quality, low cost
extruders!
Unlike competitive
offerings, the AK Ultra extruder line is fully equipped, not
stripped – providing far more overall value. Standard equipment
includes our proven Steward high-performance barrier screws with
full-width Colmonoy 56 hard facing and chrome plating for long life
and guaranteed performance.
Some of the more
important standard features include:
- Complete extruder
wet-testing to ensure fast, trouble-free start-up
- Complete set of
mechanical and electrical spare parts
- Heated single bolt
head clamp
- Pressure transducer
and digital indicator with hi-pressure shut-down
- Automatic heater
burn-out detection with audible alarm
ULTRA extruders are
currently available in 2.0”, 2.5”, 3.0”, 3.5”, 24:1 L/D and 30:1 L/D
size ranges. Larger and smaller versions will be added to the line
over the next few months.
In designing the new
ULTRA line, American Kuhne’s engineers applied the latest Solid
Works™ solid modeling and Auto Cad™ technology to create high
performance, robust and cost effective extruders. Additionally, we
leveraged our growing business volume (thanks to our loyal
customers!) to partner with the biggest names in the industry to
supply name brand components at new lower prices.
On average the cost of
an ULTRA extruder is approximately 20% lower than our AKcel line.
Even better, ULTRA extruders offer more standard mechanical and
electrical features plus a longer list of available options compared
with the competition. This flexibility allows you to configure the
machine to your needs and your budget.
Watch for an upcoming
special issue of Akcelerator with
more details on the exciting AK ULTRA line.
WORTH
NOTING
Welcome
aboard Kevin Miller, Mid-West Regional Sales
Manager.
We are
pleased to announce the addition of Kevin Miller to our technical
sales team. He will be supporting our experienced Mid-West sales
reps from Iowa to Ohio. Kevin is no stranger to American Kuhne,
coming to us from one of our fine customers. As Vice President of
Operations for a custom tubing facility, he selected American Kuhne
as the supplier of a new turn-key tubing system. After experiencing
the AK high level of technical quality and personalized service,
Kevin agreed to join our growing team. He’ll be based in Cleveland
and can be reached at (216) 374-4902 or kmiller@americankuhne.com |
