QOTD: What Should I Do with Old Bearings on My Shelf?
Posted by Engineering BoreCode on
Question: What Should I Do with Old Bearings on My Shelf?
Bearings stored as critical spares for a range of machines in high volume production need to be kept in "like new" condition. Some manufacturing facilities have storerooms that put distributors to shame, stocking thousands of SKUs ranging from belts and motors to bearings and entire assemblies. How do you decide whether to use the spare, or send it to the scrap bin?
Determine the Age
Bearing manufacturers have a recommended shelf life of approximately 3-5 years, and have a laundry list of prescribed conditions controlling temperature, humidity, and other influencing factors. Bearings can survive long past that period, especially when the conditions are met or special precautions are taken. One other element to consider as time passes: evolution. For most manufacturers, you are only as good as the next product you make, and the next product is likely to be the most technologically advanced yet.
For bearings, improvements in metallurgy and thermal processing, cage and seal design, and their load ratings mean that the next bearing you buy will always be the highest performance bearing. A previous model can be used, but the latest release will feature modern technology.
Determine the Condition
Some antiques have stood the test of time and become valuable collectibles. Pappy Van Winkle. Rare coins. Period specific signage. Bearings are not that. They are machine components meant to be used and consumed within a defined period of time. A visual inspection is usually all you need to get an idea of general condition. Packaging design is usually based on the cost and weight of bearing type: small ball bearings usually have thin cardboard boxes, ball screw supports with thick cardboard with insulation, and large spherical sand tapered roller bearings are shipped in wood crates. Faded boxes, opened plastic wrap, or old labels are tell tell signs.
Determine the Value
Bearings that appear to date back to the Second World War that can be easily and quickly replaced should be. This is an easy call on small, mass produced bearings. Now, if you are sitting on a one-of-a-kind $50,000 tapered roller assembly...
Recondition
Bearing manufacturers and third party repair services will recondition, or reclaim, your existing bearing, whether it’s been in operation or in its original packaging.
Scrap Bin
If your INA HK2820-B needle roller bearing or SKF 6202-2RS1 deep groove ball bearingor some other easily replaceable bearing has damaged outer and inner packaging, surface corrosion, or visible damage, redirect the bearing to the scrap bin. The $10 replacement cost of bearing will save you the pain of early failure and wasted repair time. Bearings removed from their factory packaging and put back into inventory should be immediately discarded.
FIFO
Utilizing a first in, first out (FIFO) inventory strategy will ensure that products turn and that one bearing doesn’t keep getting pushed to the back of the bin. Obsoleting and scrapping equipment specific spare parts also helps to minimize confusion and keeps spare parts fresh.
A self-lubricating bearing is a machine element which goes by many names, including sleeve bearings, bushings, journal bearings, sliding bearings, friction bearings, etc. They were in use long before practical ball and roller bearings were developed. Slide bearings, as they relate to civil engineering, are not discussed here.
Awwa Technologies is a leading supplier of self-lubricated bearings in India. We have also been a leading manufacturer and exporter of self-lubricating bushings for over two decades.
Applications of self-lubricated bearing
All About Slide Bearings
Selection and sizing
Best Manufacturer of Self-lubricated Bearings
Applications of self-lubricated bearing
Automotive and mechanical equipment – starter motors, radiators, fans, fuel pumps, brakes, steering transmissions, shock absorbers, wipers, and similar.
Electric motors and gearboxes
Household appliances include ceiling fans, washing machines, juicers, air conditioners, coffee makers, vacuum cleaners, lawnmowers, and similar items.
Industrial machinery – in carpentry machinery, assembly
Carpentry machinery, assembly line equipment, automation equipment, sewing machines, farm equipment, bottling equipment, and much more are examples of industrial equipment.
Items for home comfort and convenience, such as garage doors, automated awnings and shutters, sliding windows, and the like.
All About Slide Bearings
Slide bearings, also referred to as sliding or plain, bearings encompass a range of mechanical components that go by various names but are generally grouped as fluid-film bearings, whose purpose is to reduce friction between rotating, reciprocating, or sliding surfaces such as shafts and stationary surfaces such as housings. The lubricating film is generally oil, although water is sometimes used in special situations, and “dry running” bearings attain their slipperiness by way of PTFE or other low-friction materials. Slide bearings differ from ball and roller bearings which use rolling elements to reduce friction but, in both instances, the goal is the same. Sliding bearings may be grouped in any number of ways; for the purpose of this article, they are discussed in terms of material.
Bronze and babbitt bearings
Carbon insert bearings
Polymer bearings
Selection and sizing
Three basic influences govern fluid-film bearings: viscosity, rotating speed, and bearing unit load. Hydrodynamic lubrication itself depends on three fundamental assumptions: that there is relative motion between shaft and bearing; that a wedging action is produced as the shaft moves eccentrically up the bearing wall; and, that a suitable fluid is present in the bearing. While the steps needed to properly engineer traditional oil-film slide bearings are beyond the scope of this article, there are several important requirements for successfully deploying them.
The bearing needs to achieve thick film lubrication.
An adequate lubricant must be available.
Temperature ranges need to be maintained.
Oil needs to flow completely through the bearing.
Shaft deflection should be considered.
Starts and stops need to be at low bearing pressures, or thin-film lubrication should be considered.
The sizing of self-lubricating bearings is a somewhat different undertaking, but consideration of bearing loads, running speeds, operating temperatures, etc. are of similar importance. Manufacturers will provide design assistance in the selection of their products. Sintered and self-lubricating bearings are available in standard lengths, IDs, and ODs to meet just about any requirement, and custom products are often available. Bearings of this kind are usually pressed into housing bores, and the ID will often decrease once the bearing is installed.
Best Supplier & manufacturer of Self-lubricated Bearings
AWWA technologies is a market leader in self-lubricated bearings for the valve industry, automotive industry, plastic machinery, construction and agriculture machinery, hydraulic machinery, and general industrial machinery.
The core competencies of AWWA technologies are life-long learning and voluntary consensus standards development.