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iglide® L250 - Material data

Materials table

General features Unit iglide® L250 Test method
Density g/cm³ 1.50
Color Beige
Max. moisture absorption at 73° F/50% R. H. Wt.-% 0.7 DIN 53495
Max. moisture absorption Wt.-% 3.9
Coefficient of friction, dynamic against steel µ 0.08 - 0.19
p x v value, max. (dry) psi x fpm 11,500


Mechanical properties
Modulus of elasticity psi 282,800 DIN 53457
Tensile strength at 68° F psi 9,718 DIN 53452
Compressive Strength psi 6,817
Maximum recommended surface pressure (68° F) psi 6,527
Shore D hardness 68 DIN 53505

Physical and thermal properties
Upper long-term application temperature °F 194
Upper short-term application temperature °F 356
Lower 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 ] 10 DIN 53752

Electrical properties
Specific volume resistance Ωcm > 1010 DIN IEC 93
Surface resistance Ω > 1011 DIN 53482


Plastic Bushings Permitted p x v values Permissible p x v values for iglide® L250 running dry against a steel shaft, at 68° F.

Permitted p x v values

For iglide® L250 plastic bushings with 0.03 inches (1 mm) wall thickness in dry operation against a steel shaft, at 68° F, installed in a steel housing.

iglide® L250 is a bushing material for high rotary speeds, fast gliding movements and super coefficients of friction. The iglide® L250 material can feature these advantages particularly with low loads. Applications which feature these advantages are fans, small motors, fast-running sensors or the magnet technology.


Deformation under load and temperatures Deformation under load and temperatures

Surface pressure

With increasing temperatures, the compressive strength of iglide® L250 plastic bushings decreases. The graph shows this inverse relationship. However, at the long term maximum temperature of +194 °F the permissible surface pressure is almost 2901 psi.


Maximum surface speed

fpm Rotating Oscillating Linear
Constant 197 137 393
Short-term 295 216 591

Permitted surface speeds

iglide® L250 has been developed especially for high surface speeds with low loads. Besides the physical limit, which is preset by the heating of the bushing, the coefficients of wear also act limitingly if rapidly high glide paths emerge at high peripheral speeds and the permitted wear limit is thus reached earlier. The great advantages of the iglide® L250 plastic bushings are seen right here. The wear rate is very low, thus making the material an ideal solution for extreme glide paths. The maximum speeds are show in the table to the left.


Maximum recommended surface pressure dependent on the temperature Maximum recommended surface pressure dependent on the temperature

Temperatures

The iglide® L250 plastic bushings can be used in temperatures from -40° F up to 194° F. The short-term maximum temperature is 356° F. Note that a mechanical securing of the bushing is recommended from temperatures of 131° F. Higher temperatures can also cause the bushing to lose its press-fit seating and move in the housing.

Temperature limits

iglide® L250 Application temperature
Lower - 40 °F
Upper, long-term +194°F
Upper, short-term +356 °F
Additional axial securing +131 °F


Coefficients of friction of iglide® L250 as a function of the running speed Coefficients of friction of iglide® L250 as a function of the running speed; p = 108 psi

Friction and wear

Low coefficients of friction are a big influence on the excellent characteristics of iglide® L250 plastic bushings. The best pairing of iglide® L250 is with 304 stainless steel shafts where coefficient of friction of 0.14 are already attained at low loads. Coefficients of friction below 0.1 have already been measured for values below 1,450 psi. In order to convey the excellent wear values to the application, loads in excess of 725 psi should be avoided.

Coefficients of friction for iglide® L250 against steel
(Shaft finish = 40 rms, 50 HRC)

iglide® L250 Dry Grease Oil Water
Coefficients of friction µ 0.08 - 0.19 0.09 0.04 0.04

Coefficients of friction dependent on the load Coefficients of friction dependent on the load, v = 1.95 fpm
Coefficients of friction dependent on the shaft surface Coefficients of friction dependent on the shaft surface (1050 hard chromed)

Wear, rotating application with different shaft materials Wear, rotating application with different shaft materials, load p = 108 psi, v = 98 fpm

Shaft materials

As shown in the graphs, a variety of shafts can be used at low loads and low rotation. The good coefficients of friction are maintained across a wide range of recommended shaft roughness values. With regards to loads greater than 145 psi the shaft material selection becomes more important.

Wear with various shaft materials in the rotating operation Wear with various shaft materials in the rotating operation
Wear with different shaft materials, oscillating and rotating movement Wear with different shaft materials, oscillating and rotating movement p = 290 psi

Important tolerances for iglide® L250 plastic bushings according to ISO 3547-1 after the press-fit.

Diameter
d1 [mm]
Shaft h9
[mm]
iglide® L250
E10 [mm]
Up to 0.5 0 - 0,025 +0,014 + 0,054
> 3 to 6 0 - 0,030 +0,020 + 0,068
> 6 to 10 0 - 0,036 +0,025 + 0,083
> 10 to 18 0 - 0,043 +0,032 + 0,102
> 18 to 30 0 - 0,052 +0,040 + 0,124
> 30 to 50 0 - 0,062 +0,050 + 0,150

Installation tolerances

iglide® L250 plastic bushings are standard bushing 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, chlorinated +
Greases, oils, without additives +
Fuels +
Weak acids 0 to -
Strong acids -
Weak alkaline +
Strong alkaline +
+ resistant      0 conditionally resistant      - non-resistant

Influence of moisture absorption Influence of moisture absorption of iglide® L250 plastic bushings


Electrical properties

Specific volume resistance > 1010 Ωcm
Surface resistance > 1011 Ω

Chemical resistance

iglide® L250 plastic bushings are resistant to diluted alkalis and very weak acids as well as to solvents and all kinds of lubricants.

Please take into account the humidity absorption in applications in which very minor bushing clearances occur.

Radioactive rays

iglide® L250 plastic bushings are radiation resistant up to a radioactive intensity of 3 x 104 Gy. Higher radiation affects the material and may potentially lead to a notable lowering of value of an important mechanical property.

UV-resistant

iglide® L250 plastic bushings change color under the influence of UV rays. However the hardness, compressive strength and the wear resistance of the material do not degrade.

Vacuum

In application in vacuum, the potentially existent humidity is degassed. For this reason only the dry iglide® L250 plastic bushings are suitable for vacuum.

Electrical properties

The bushings are electrically insulating.