Frantz® Manufacturing Company
-Technical
Information-
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Our Quality
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Technical Information
Frantz
Technical Information
At Frantz,
Quality matters. The following
information is designed to assist our customers in understanding the value
that Frantz brings to them and their customers. A quality Frantz
product will outlast our competition and result in a lower total cost of
ownership for our customer’s end-users. This website contains Frantz
standard products. Contact our Customer
Service department for custom designs and variations.
The
following contains technical information that is the underpinning of Frantz
Quality.
LOAD RATINGS
All Frantz bearings and wheels are
designed for use in roller type conveyor installations, where use does not
exceed load ratings. For optional stainless steel bearings, load
ratings may be less than those published for carbon steel bearings.
The Conveyor Equipment
Manufacturers Association (CEMA) has developed, in CEMA Standard No.
401-1994 Section 3, a formula which enables manufacturers to estimate the
load carrying ability of Commercial Unground Non-Precision bearings and wheels.
Given that bearing load failure occurs not only in the ball and race
combination, but also in the ability of the housing to grip the inside of
the tube, Frantz, in addition, applies the CEMA standard to its Semi
Precision and Precision offerings.
If the diameter and number of balls used in a bearing are
known, this formula may be used to estimate the “Basic Conveyor Bearing Load
Rating”, which is defined as that constant, radial bearing load which a
group of apparently identical bearings can endure for 1,000,000 revolutions
with 90% of the bearings surviving.
Through extensive in-house testing on custom designed
life load test equipment, Frantz bearings and wheels meet the CEMA standard
and most exceed the standard.
Actual “Service Life” is dependent
upon conditions surrounding the use of a bearing or wheel, such as mounting
procedures, lubrication, temperature, dust, moisture, shock, side thrust,
and excessive speeds.
The CEMA Standard 401-1994 attempts to insert a
“Service Factor” to allow for these elements in the calculation of load
ratings. The determination of service conditions is however best done
by the customer considering each application individually. It is for
this reason that Frantz does not attempt to apply a Service Factor to our
load ratings.
However, we stand ready to collaborate with our
customers to understand the end-user’s environment in order to best match
the proper Frantz bearing or wheel for the application. This is part
of Frantz value to our customers.
Another key point to remember is that Bearing capacity does not dictate Roller capacity. Bearing capacity is usually the limiting factor on short rollers. As rollers lengthen, roller capacity becomes a function of the axle deflection, rather than the bearing capacity. Heavier bearings will not necessarily improve the load carrying capacity in longer rollers. Commercial Unground Non-Precision bearings allow for approximately 1 degree of axle deflection through the cone before load rating is affected. Precision bearings allow for only ¼ of 1 degree of axle deflection before load rating is affected.
The two key factors in our ability
to meet and exceed CEMA Standards and to stand behind our bearing
and wheel load ratings are due to 1) our
understanding and control of the heat treating of bearing components and 2)
our strategies for the minimization of rolling friction between the balls
and the ball raceways.
HEAT TREATING
The single greatest cause of failure in competitor
products is the lack of uniform standards in heat treating operations and
the lack of adequate case depth that provides the durability necessary for
bearing longevity.
Frantz has manufactured bearings
since 1937 and manufactured steel balls since 1947. In both
operations, heat treating has been vital to produce a quality product since
the beginning. Soft bearing races and/or soft steel balls will eat
away at each other resulting in bearing failure. (Click
here
for photos of failed bearing components due to inadequate heat treating.)
Frantz still maintains internal heat treat operations to control the process
for the majority of our components. We maintain a sophisticated test
lab to measure case depths and Rockwell hardness on the products we
manufacture and the products that we source. (Click
here for
testing equipment examples.)
This provides our customers with assurance that
products that they purchase from Frantz will meet American expectations.
ROLLING FRICTION
Heat is generated from ball to ball
rubbing or from balls rubbing or wiping on the raceways.
This can be the result of a) poor mounting of
bearings in the roller tube, b) balls fighting the ball grooves due to axle
deflection, or c) improper shape of the ball groove. Frantz has
developed mounting specifications and has assisted customers in their
efforts to improve roller assembly. Click
here for Mounting Specification details. As mentioned above,
axle deflection is a function of roller length. As rollers lengthen,
the axle deflects the bearing races and the axial forces increase friction
and reduce bearing life. Conveyor manufacturers have developed charts
for guidance on load ratings to minimize axle deflection at various roller
lengths. Finally, Frantz ISO9001 compliant quality standards provide
assurance that ball groove shapes are manufactured to specification with
minimum variation to assure that the components appropriately mate in our
bearing assemblies.
LUBRICATION
Lubrication is also a critical factor in the minimization of rolling friction and for bearing life. Frantz engineers have extensively tested lubricants for our bearings and wheels for performance in various environments and have selected the following as our standard factory bearing and wheel lubrication offering.
Premium Blended Grease: Frantz has worked with its petroleum supplier to custom blend grease to our specification. Frantz®14 provides superior performance over a wide temperature range from -40°F to 300°F. Frantz®14 is used in our GENII Semi Precision bearings as well as most light duty bearings and wheels. It provides very good corrosion protection and a substantial noise reduction (up to 6 db) compared to standard greases. For our larger bearings (2.5”-3”), we have selected and tested a state of the art lithium complex grease from Duralube to match tougher operating environments. This grease has been formulated with a special additive package which insures high film strength, and extreme pressure and anti-wear properties. Recommended operating range for Duralube is from -10° to 300°F.
Lightly Oiled:
Frantz utilizes CAPRI,
a
highly refined paraffinic base oil containing special extreme pressure,
oxidation, and rust inhibitors.
Temperature range is -10°F -400°F.
Special Lubes:
May be available
on request.
Powered Conveyor Applications.
These
applications generally use greased bearings and wheels due to the large
number of bearing revolutions.
Gravity Conveyor Applications.
These applications generally use oil due to the
premium placed on a lower co-efficient of friction for the roller or wheel
to convey the load at a reduced incline.
Freezer Applications.
Customers need to choose the
lubrication approach for freezer applications. The choice will depend
upon the need for grease in a powered application vs. the increased
co-efficient of friction necessary to turn greased rollers in the cold
environment.
Frantz°14 grease provides excellent low
temperature performance.
Oven Applications.
Oxidation of grease or
evaporation of oil lubricant are the biggest issues surrounding oven
applications. We have experienced good success using Moly Hi-Lo grease for
high temperature applications up to 550°F and above.
Frantz Engineers will work with our customers
to determine the best lubrication solution for hot environments.
OTHER SERVICE LIFE FACTORS
As mentioned above under the CEMA discussion, bearing
Service Life is dependent upon conditions surrounding the use of a bearing
or wheel, such as mounting procedures, lubrication, temperature, dust,
moisture, shock, side thrust, and excessive speeds.
Dust & Moisture
Contaminants,
particularly in dusty or mildly wet
environments, can enter bearing raceways and
shorten bearing life.
Frantz offers a variety of seals and shields in its
bearing models for customers requiring protection from outside
contamination.
GenStar® Precision Bearings – contain special front and back rubber seals that are bonded to metal washers providing effective protection against contamination such as moisture and dust particles. These seals are light contact which minimizes the seal drag allowing for lower starting torque and rolling friction. The lubricant forms a barrier between seal lip and the inner race further preventing smaller particles such as dust and moisture from entering into the rolling elements.
GENII® Semi Precision Bearings – depending upon the model
offer optional nylon front seals and rubber back seals.
Commercial Unground Non-Precision Bearings – depending upon the model offer
optional polymer seals, felt seals, labyrinth shields, sealing rings and
seal plates.
Consideration should be given to eliminating lubrication in bearings in dusty environments as a strategy for improving performance, however this will result in a shorter bearing life.
Shock
This occurs in loading zones
where loads are dropped onto conveyor rollers. In these circumstances,
select heavier rated bearings than would normally be required.
Select bearings that are less precise but
forgiving in order to withstand greater abuse. For example, most
generally rugged Commercial Unground Non-Precision bearings are
more forgiving and will outperform a Precision
bearing in absorbing shock loads.
Frantz
IronGrip metal housings with proper mounts will outperform plastic
housings in shock load situations due to their ability to more tightly grip
the tube.
We have also experienced good success with our heavy
GenStar® Precision bearing assembly in abusive environments due to the
ability of our IronGrip metal housing to absorb the shock.
Click here or Contact our Customer Service representatives to further discuss this option.
Side Thrust Bearings
are subject to side thrusts in sorting areas where product is swept to one
side or another on the roller bed or on curves or branches where the product
is forced to flow in a direction not perpendicular to the roller shaft.
Frantz engineers have designed special Radial Thrust bearings that have a
thick wall cup type outer race into which the ball complement can be thrust
by a deep groove inner race. Click here
for a selection of Radial Thrust bearings.
Excessive Speeds
Bearing selection is dependent upon the speed of the
application, otherwise, bearing life will be reduced.
For speeds exceeding 400 RPM where precision bearings are
desired, select Frantz GenStar®
Precision bearings.
For speeds up to 1500 RPM (depending upon the model), select Frantz GENII® Semi
Precision bearings.
For gravity applications or moderate speeds, select
Frantz Commercial Unground Non-Precision bearings.
PACKAGING DETAILS
Frantz Bearings can be shipped in steel drums or in
various sized corrugated boxes depending upon the contents as follows:
12” x 12” x 12” high
12” x 13” x 6” high
13” x 10” x 6” high
12” x
9”
x 9” high
The average weight per carton will vary from 60# to 150#.
We can also furnish a bulk cardboard container which is approximately.
28” x 35” x 20” high and weighs approximately 1200# to
1400#.
Sterling Steel® Ball product is available in the
following cartons:
11” x
8”
x 4” high
8 ½” x 8 ½” x 5 5/8” high
The average weigh per carton is approximately 50#.
Frantz®
Quality.
Simply
better.