Coefficient of surface friction, dynamic, against steel
µ
0.08 - 0.15
p x v value, max. (dry)
psi x fpm
12,000
Mechanical properties
Modulus of elasticity
psi
1,131,000
DIN 53457
Tensile strength at 68° F
psi
30,450
DIN 53452
Compressive strength
psi
11,310
Permissible static surface pressure (68° F)
psi
11,600
Shore D hardness
81
DIN 53505
Physical and thermal properties
Max. long-term application temperature
°F
266
Max. short-term application temperature
°F
428
Min. application temperature
°F
-40
Thermal conductivity
[W/m x K]
0.24
ASTM C 177
Coefficient of thermal expansion (at 73° F)
[K-1 x 10-5 ]
9
DIN 53752
Electrical properties
Specific volume resistance
Ωin
> 1013
DIN IEC 93
Surface resistance
Ω
> 1011
DIN 53482
Permissible p x v values
Permissible p x v values for iglide® G300 plastic bushings running dry against a steel shaft at 68°F.
Compressive Strength
The graph (left) shows the elastic deformation of iglide® G300 plastic bushings under radial loads. Under the maximum recommended surface pressure of 11,600 psi, the deformation amounts to less than 5%. A plastic deformation can be ignored until a pressure of about 14,500 psi. It is, however, also dependent on the period of exposure.
iglide® G300 plastic bushings were developed for low to medium surface speeds. The maximum values stated in the table (left) can be attained only with low pressure loads. At the specified speeds, an increase in temperature up to the long-term permissible value can occur due to friction. In practice, these limits are not always reached due to the alternating effect of influences.
Ambient temperatures influence the properties of iglide® G300 plastic bushings.
The maximum short-term permissible temperature is 428°F, and this enables the iglide® G300 bushings to be used in applications where they are used without any additional load: for instance in a paint-drying process. With increasing temperatures, the compressive strength of iglide® G300 plastic bushings decreases. The graph (left) illustrates this connection. Under the long-term permissible application temperature of 266°F, the permissible surface pressure is 5,800 psi.
Temperature can also have an influence on wear. An iglide G300® bushing's wear increases with rising temperatures and the influence can especially be seen from temperatures of 248°F upwards.
Coefficients of friction for iglide® G300 against steel (Shaft finish = 40 rms, 50 HRC)
iglide® G300
Dry
Grease
Oil
Water
Coefficients of friction µ
0.08 - 0.15
0.09
0.04
0.04
Friction and wear
Just like wear resistance, the coefficient of friction - or µ - also changes dependent on the load. Interestingly, the coefficient of friction decreases with increasing load, whereas an increasing surface speed causes he coefficient of friction to rise. This correlation confirms the extraordinary capacity of iglide® G300 plastic bushings for high loads and low speeds.
Very smooth shafts increase the coefficient of both friction and wear of the bearing. A smoothed surface with an average surface finish Ra = 32 rms is best suited for iglide® G300 (see graph left).
The graphs (left) display a summary of tests conducted with iglide® G300 using different shaft materials. It can be seen that iglide® G300 can be combined with many different shaft materials. Low cost machined steel and St37 shaft materials are proven to be the most suitable for low loads.
It is important to note that, with increasing loads, the recommended hardness of the shaft increases. Soft shafts tend to wear more and increase the overall wear of the system if loads exceed 290 psi. Note that the wear rate is markedly reduced with hardened shafts.
The comparison of rotating versus pivoting movements shows that iglide® G300 wears less in pivoting applications. The higher the load, the greater the difference. This means that iglide® G300 plastic bushings can be used for pivoting applications involving far more than the specified maximum load of 11,600 psi. So, for high loads, the use of hardened shafts is strongly recommended.
Besides the shaft materials presented here, many others were tested. Please contact us in case the shaft material you would like to use is not included here.
Important tolerances for iglide® G300 plastic bushings after pressfit, according to ISO 3547-1 for plain bearings / wrapped bushes
Diameter
d1 [inch]
Shaft h9
[inch]
iglide® G300
E10 [inch]
Up to 0.019685
0 - 0.0009843
+0.0005512 + 0.0021259
> 0.1181 to 0.2362
0 - 0.0011811
+0.0007874 + 0.0026772
> 0.2362 to 0.3937
0 - 0.0014173
+0.0009843 + 0.0032677
> 0.3937 to 0.7087
0 - 0.0016929
+0.0012598 + 0.0040157
> 0.7087 to 1.1811
0 - 0.0020472
+0.0015748 + 0.0048819
> 1.1811 to 1.9685
0 - 0.0024409
+0.0019685 + 0.0059055
> 1.9685 to 3.1496
0 - 0.0029134
+0.0023622 + 0.0070866
> 3.1496 to 4.7244
0 - 0.0034252
+0.0028346 + 0.0083464
> 4.7244
0 - 0.0039370
+0.0033465 + 0.0096457
Installation tolerances
iglide® G300 plastic bushings are standard for shafts with h-tolerance (recommended minimum h9). After the installation in a housing bore with H7 tolerance, the inner diameter of the bushing automatically adjusts to the E10 tolerance.
+ resistant 0 conditionally resistant - not resistant
Electrical properties
Specific forward resistance
> 1013 Ωcm
Surface resistance
> 1011 Ω
Chemical resistance
iglide® G300 plastic bushings have excellent resistance against chemicals. They are also resistant to most lubricants.
iglide® G300 is not affected by most weak acids.
The moisture absorption of iglide® G300 bushings amounts to about 1% in standard atmospheric conditions. The saturation limit submerged in water is 4%. This must be taken into account for these types of applications.
Radioactive rays
iglide® G300 plastic bushings are radiation resistant up to a radioactive intensity of 3 x 10² Gy.
UV-resistant
iglide® G300 plastic bushings are permanently resistant against UV rays.
Vacuum
iglide® G300 plastic bushings outgas in a vacuum. Use in a vacuum environment is only possible for dehumidified bushings.
Electrical properties
iglide® G300 plastic bushings are electrically insulating.