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igus® inc.

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iglide® G300 plastic bushings: Material data

Materials table

General features Unit iglide® G300 Test method
Density g/cm³ 1.45
Color dark gray
Max. humidity absorption at 73° F/50% R. H. Wt.-% 0.7 DIN 53495
Max. water absorption Wt.-% 4.0
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

p x v values

Click to enlarge

 
Permissible p x v values

Permissible p x v values for iglide® G300 plastic bushings running dry against a steel shaft at 68°F.

radial load plastic bushings

The elastic deformation of iglide® G300 under radial loads.

 
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.

Maximum surface speed

fpm Rotating Oscillating Linear
Continuous 196 137 787
Short-term 393 275 984

Permissible surface speeds

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.

Temperature limits

iglide® G300 Application temperature
Lower - 40 °F
Upper, long-term + 266 °F
Upper, short-term + 428 °F
Additional axial securing + 212°F

bushing surface pressure

The maximum recommended surface pressure is dependent on the temperature

 
Temperatures

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

coefficients of friction

Coefficients of friction dependent on the surface speed, p = 108 psi

 
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).

bushing load

The coefficient of friction is dependent on the load, v = 1.96 fpm

 
shaft surface bushings

The coefficient of friction is dependent on the shaft surface (Shaft - 1050 hard chromed)

 
bushing shaft material

Wear, rotating application with different shaft materials, load p = 145 psi, v = 59 fpm

 
wear and load bushings

Wear during rotational movement is dependent on different shaft materials. The harder the shaft, the higher the maximum possible load.

 
wear load of bushings

Wear for pivoting and rotating applications with shaft material 1050 hard chromed, as a result of the load.

 
Shaft materials

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.

Medium Resistance
Alcohol + to 0
Hydrocarbons +
Greases, oils without additives +
Fuels +
Weak acids 0 to -
Strong acids -
Weak alkalines +
Strong alkalines 0
+ resistant      0 conditionally resistant      - not resistant

Moisture absorption of bushing

How moisture absorption affects iglide® G300 plastic bushings

 

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.