At FRANTZ Manufacturing, Quality
matters. The following information is designed to assist our bearing and wheel customers in understanding the value that FRANTZ brings to them and to their customers. A quality FRANTZ conveyor bearing or conveyor wheel 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 Bearing/Wheel Quality.
All FRANTZ conveyor bearings and conveyor wheels are designed for use in roller type conveyor installations, where use does not exceed load ratings. For optional Stainless Steel conveyor 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 conveyor bearings and conveyor 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 conveyor bearing 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 conveyor bearings and conveyor wheels meet the CEMA standard and most exceed the standard.
Actual “Service Life” is dependent upon conditions surrounding the use of a conveyor bearing or conveyor 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 conveyor bearing or conveyor 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 conveyor 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 conveyor bearing and conveyor 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.
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 conveyor 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 for photos of failed conveyor 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 for more information on our heat treat testing
capabilities.) This provides our customers with assurance that products that they purchase from FRANTZ will meet American expectations.
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 for details on Conveyor Bearing Mounting
Specifications. 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 IATF 16949:2016 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 is also a critical factor in the minimization of rolling friction and for conveyor bearing life. FRANTZ engineers have extensively tested lubricants for our conveyor bearings and conveyor wheels for performance in various environments and have selected the following as our standard factory conveyor bearing and conveyor 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. (Note: GenII®
Semi-Precision bearings such as the 1815 that contain static discharge inserts have a temperature range of -20°F to 180°F) FRANTZ®
14 is used in our distinctive 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 heavier duty GenII®
and Commercial Unground conveyor bearings (2.5”-3”), we have selected and tested a state of the art lithium
complex grease to match tougher operating environments, especially when used in higher temperatures while also providing excellent mechanical stability. This grease has been formulated with a special additive package which insures high film strength, and extreme pressure and anti-wear properties. Recommended continuous operating range is from -22° to 355°F.
Our Engineers have specified our GenStar®
Precision ABEC-1 Conveyor Bearings and CB14 Precision ABEC-1 Conveyor Bearings with a premium lithium and calcium based grease providing an operating range from -4° to 180°F . These conveyor bearings have good low temperature properties including low starting and running torque, as well as good rust and corrosion resistance properties.
Lightly Oiled: FRANTZ utilizes PERLUBE, 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 conveyor bearings and conveyor 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 in powered applications up to 550°F and above. Gravity applications may require dry bearings in high temp stationary situations. FRANTZ Engineers will work with our customers to determine the best lubrication solution for hot environments.
Re-Lube Features. Certain FRANTZ conveyor bearing models provide ports in the bearing races for customer re-lubrication. Click for information on Regreasable Conveyor Bearings
Other Service Life Factors
As mentioned above under the CEMA discussion, bearing Service Life is dependent upon conditions surrounding the use of a conveyor bearing or conveyor 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 Conveyor 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 Conveyor Bearings
– depending upon the model offer optional nylon front seals and rubber back seals.Commercial Unground Non-Precision Conveyor Bearings
– depending upon the model offer optional polymer seals, felt seals, labyrinth shields, sealing rings and seal plates. For dirty and gritty environments, Straight Faced Counterbore Bearings
may afford the best protection.
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 conveyor 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 Conveyor bearings are more forgiving and will outperform a Precision conveyor 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
Conveyor 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 Conveyor Bearings
that have a thick wall cup type outer race into which the ball complement can be thrust by a deep groove inner race.Excessive Speeds
Conveyor Bearing selection is dependent upon the speed of the application, otherwise, conveyor bearing life will be reduced.