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NORGLIDE® PTFE-Bearing Compound
The sliding layer of our NORGLIDE® Bearings is a thin tape of compounded PTFE. Every compound has unique properties and is an important part of our modular plain bearing concept.
Polytretrafluorethylene (PTFE)
Pure (virgin) PTFE is a soft, electrically insulating material with a minimum coefficient of friction for solid materials.
PTFE advantages over other High Performance Materials
• Lowest coefficient of friction of all solid materials
• Wide temperature range (- 200°C/+ 260°C)
• Self-lubricating
• Excellent weathering resistance
• Essentially innert to all chemicals
Fillers
With the addition of fillers, properties like creep or electrical conductivity can be optimized while maintaining the excellent friction characteristics of PTFE.
The in-capsulation effectively avoids cold flow to Improve form stability and wear characteristics.
The compounds used in NORGLIDE® Bearings are all made in-house and tailored to the application. Some of these compounds are discussed here.
NORGLIDE® PTFE Bearing Compound Options
Glass graphite (GG)
This PTFE-compound, which is exclusively used for the NORGLIDE® MP platform, combines glass fibers. Based on its specific shape, it improves load carrying capabilities and reduces wear as well as creep. It is combined with Graphite, a modification of Carbon, which minimizes initial wear.
Glass fiber / graphite / Conductive (GC)
Also the GC-compound is solely used for the NORGLIDE® MP platform. Just like the GG compound, it combines glass fibers. Due to its special shape, it improves load carrying capabilities and reduces wear as well as creep. Also in this compound, the Graphite as modification of Carbon minimizes initial wear. Compared to the GG compound, the conductive pigment additionally improves conductivity.
Carbon / graphite (CG)
Within this PTFE-compound Carbon is utilised, which undertakes a similar function as glass fibers by improving load carrying capabilities and reducing wear as well as creep. However, it is less abrasive on the mating surface. Additionally, Graphite is used which minimizes initial wear.
Carbon, conductive (C)
Also within this compound, Carbon is used, which takes over a similar function as glass fibers. Nonetheless, it is less abrasive to the mating surface. Carbon increases the load carrying capabilies and reduces wear as well as creep. Furthermore, Graphite, a specific modification of Carbon, is utilised which minimizes initial wear. Carbon fibers moreover ensure conductivity of this PTFE compound. Due to its electrical conductivity, these materials can be used for electrostatic discharges. Therefore, they are most valuable in the cathodic dip-coating of assemblies.
Glass fiber / pigment (LR)
This PTFE-compound uses Glass fibers as a filler to increase load carrying capabilities and reduce wear as well as creep. Additionally, a red pigment is added for coloration. This material is non-conductive. Thus, bearings made of it reduce paint build-up on the bearing surfaces and help to improve paint-quality.
Ekonol® (E)
Ekonol® is a special aromatic polyester which improves the wear resistance while lowering the coefficient of friction. This PTFE-compound solution is recommended for high-speed sliding operations and soft mating surfaces.
Ekonol® / graphit (EG)
This compound combines the outstanding wear resistance of Ekonol® with the low initial wear of graphite. It is less conductive than the carbon graphite compound (CG).
Electrical conductivity
Electrically conductive compounds
With the addition of selected fillers, we can tailor the electrical conductivity of the bearing’s sliding material. The total electrical resistance depends on the contact surface between the bearing and shaft, size, active surface load and the material thickness.
Electrically conductive bearings are used for electrostatic discharge, not for conducting electrical current. They are most valuable in the cathodic dip-coating of assemblies.
Non-conductive compounds
Electrically non-conductive PTFE Bearings reduce paint build-up on the bearing surfaces and help improve paint quality. Making this the PTFE-Bearing solution for applications where e-painting is used.
There are some applications that require a current flow from a housing bore, through a bearing and onto a shaft and vice versa. Such applications could be a vehicle side door, hood and tailgate hinges.
In the case that current is required to flow between two mating components, NORGLIDE® Bearings can be made with electrically conductive PTFE compounds that contain carbon, CG for example. This allows for Smart Design of an assembly that would otherwise require an extra wire to electrically connect the two parts. This solution can, therefore, reduce cost and reduce space. Equally, some applications will require a high level of resistance between two mating components in which case a non-conductive compound, LR and E, for example, can be used for the solution. If a non-conductive PTFE layer is required but the bearing needs to allow current flow between parts, for instance with e-painting then a more innovative approach is necessary. With the introduction of notches into the bearing, there can be small areas on the bearings that provide conducting metal-to-metal contact.
Learn more about Electrophoretic deposition solution from NORGLIDE®:
https://www.bearings.saint-gobain.com/blog/e-coating