The Benefits of Self-Lubricating Bushings Made of Plastic

iglide® plastic bushing materials consist of base plastics, fibers and filling materials, and solid lubricants. These components are not applied in layers, but homogeneously compounded.

The advantage of this construction becomes clear if you consider the following:

1. The coefficient of friction, determined by the surface of the plastic bushing, should be as low as possible

2. The surface must not be pushed aside by forces acting on the plastic bushing

3. The plastic bushing should be particularly resistant to wear forces acting on its surface.

There is no universal material available that can fulfill all these tasks equally well.

The traditional solution is a hard shell with a soft coating. Traditionally, every lubricated bushing works according to this principle, including a number of maintenance-free bearings equipped with special sliding layers. However, this soft sliding layer is not strong enough; with high edge loads or oscillations it is stripped away. iglide® plastic bushings function differently.

One component of the iglide® plastic bushing material acts for each function:

• The base plastics are crucial for wear resistance
• Fibers and filling materials reinforce the bushing so that it can withstand high forces or edge loads
• Solid lubricants automatically lubricate the bushings and reduce friction in the system.

Unlike traditional bearings that require external grease, microscopic lubricant particles are permanently embedded within millions of tiny chambers throughout the plastic material. This design ensures that the lubricants cannot be pressed out even under heavy loads; instead, they are consistently released in minute quantities as soon as the shaft is set in motion. By maintaining a constant presence at the contact interface, these integrated lubricants effectively lower the coefficient of friction and provide a maintenance-free solution for the entire lifecycle of the component.

Base Plastics and Technical Fibers

The radial pressure acting on the bearing is taken by the plastic base material. It provides shaft support at the contact surface. The plastic base material ensures that the solid lubricants do not receive a surface pressure that is too high. The base material is also reinforced by technical fibers or filling materials. These additional materials stabilize the bushing for applications involving continuous stress.

The Start-up Phase

In the initial phase, the shaft and the iglide® plastic bushing become mated to one another. During this period, the surfaces of both partners are fitted to each other. The specific load of the system lowers as the contact surfaces of the shaft and plastic bushing expand during start-up. Simultaneously, the wear rate lowers and approaches a linear curve. In this phase, the coefficients of friction continue to change, until finally assuming a value that is — for the most part — constant.