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igus® inc.

PO BOX 14349

East Providence

RI 02914

+1 800 521 2747

+1 401 438 7270

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iglide® H4 - Material data

Materials table

General features	Unit	iglide® H4	Test method
Density	g/cm³	1,79
Color		Brown
Max. moisture absorption at 73° F/50% R. H.	Wt.-%	0,1	DIN 53495
Max. moisture absorption	Wt.-%	0,2
Coefficient of friction, dynamic against steel	µ	0.08 - 0.25
p x v value, max. (dry)	psi x fpm	19,500
Mechanical properties
Modulus of elasticity	psi	1,088,000	DIN 53457
Tensile strength at 68° F	psi	17,400	DIN 53452
Compressive strength	psi	7,252
Permissible static surface pressure (68° F)	psi	9,427
Shore D hardness		80	DIN 53505
Physical and thermal properties
Upper long-term application temperature	°F	392
Upper short-term application temperature	°F	464
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	5	DIN 53752
Electrical properties
Specific volume resistance	Ωcm	> 10¹³	DIN IEC 93
Surface resistance	Ω	> 10¹²	DIN 53482

Permitted p x v values

For iglide® H4 plastic bushings running dry against a steel shaft. at 68° F.

iglide® H4 plastic bushings stand for high carrying capacity, good abrasion resistance and good temperature resistance, besides the obvious economic factors. Temperatures up to 392° F, permitted surface pressure up to 9,427 psi, and excellent chemical resistance are only some of the essential attributes. Solid lubricants lower the coefficient of friction and support the wear resistance, which was essentially improved compared to the likewise cost-efficient iglide® H2 plastic bushings. iglide® H4 plastic bushings are self-lubricating and suitable for all motions.

plastic bushing under load and temperature

Figure 13.2: Deformation under load and temperatures

Surface pressure

Figure 13.2 shows the elastic deformation of iglide® H4 with radial loads. iglide® H4 has excellent elasticity values. This is beneficial in applications with edge loads and is the reason for a higher mechanical loss factor that indicates the vibration dampening capacity of a material. If a high static compressive strength is required, the other iglide® H plastic bushings types are beneficial.

Surface pressure, load

Maximum surface speed

fpm	Rotating	Oscillating	Linear
Continuous	197	138	197
Short-term	295	216	393

Permitted surface speeds

In contrast to the similarly cost-efficient iglide® H2 plastic bushings, the iglide® H4 has an essentially favorable coefficient of friction. This accounts for the higher permitted surface speeds that can be attained with these bushings. In the dry operation, constant speeds of up to 138 fpm are possible. The speeds stated in Table 13.2 are limit values for the lowest bushings loads. With higher loads, the permitted speed drops with the extent of the load due to the limitations by the p x v value.

Surface speed

p x v value, lubrication

Figure 13.3: Maximum recommended surface pressure dependent on the temperature

Temperatures

iglide® H4 is a temperature-resistant material. The short-term permitted maximum temperature is 464° F, and this enables the iglide® H4 plastic bushings to be subjected for instance, to a paint drying process without further load. With increasing temperatures, the compressive strength of iglide® H4 plastic bushings however decreases.

Fig. 13.3 clarifies this connection. The additional frictional heat in the bearing system should be considered in the temperatures.

Temperature limits

iglide® H4	Application temperature
Lower	- 40 °F
Upper, long-term	+ 392 °F
Upper, short-term	+ 464 °F
Additional axial securing	+ 230 °F

Temperature

plastic bushing coefficients of friction

Figure 2.4: Coefficients of friction dependent on the surface speed, p = 108 psi

Friction and wear

As said earlier, the coefficient of friction of the iglide® H4 plastic bushings is very low. However it must be noted that an extremely coarse gliding partner can increase the friction. We recommend a shaft roughness range of 4 to 16 rms. The coefficient of friction of the iglide® H4 plastic bushings is dependent on the surface speed only to a minor extent. The influence of the load is greater; an increase in load lowers the coefficient of friction up to 0.08.

Coefficients of friction for iglide® H4 against steel
(Shaft finish = 40 rms, 50 HRC)

iglide® H4	Dry	Grease	Oil	Water
Coefficients of friction µ	0.08 - 0.25	0.09	0.04	0.04

Coefficients of friction

Wear resistance

plastic bushings coefficient of friction

Figure 2.5: Coefficients of friction dependent on the load, v = 1.96 fpm

Figure 13.6: Coefficients of friction dependent on the shaft surface (1050 hardened and ground steel)

Fig. 2.7: Wear, rotating application with different shaft materials, load p = 108 psi, v = 98 fpm

Shaft materials

In many of the usable shaft materials, the iglide® H4 is the economical alternative to many other high-temperature bushings. The important thing is however the selection of the suitable shaft material. It cannot be generally stated that iglide® H4 is better suited for hard or soft shafts. Tests have however shown that pivoting motions yield better wear data. In rotating applications, the wear increases markedly from pressures of 1450 psi.

Shaft materials

Figure 13.8: Wear with various shaft materials in the rotating operation dependent on the load

Figure 13.9: Wear with oscillating and rotating applications with shaft material 1050 hard chromed and ground steel, as a function of the pressure

Important tolerances for iglide® H4 plastic bushings according to ISO 3547-1 after the press-fit.

Diameter d1 [mm]	Shaft h9 [mm]	iglide® H4 F10 [mm]
Up to 0.5	0 - 0,025	+0,006 + 0,046
> 3 to 6	0 - 0,030	+0,010 + 0,058
> 6 to 10	0 - 0,036	+0,013 + 0,071
> 10 to 18	0 - 0,043	+0,016 + 0,086
> 18 to 30	0 - 0,052	+0,020 + 0,104
> 30 to 50	0 - 0,062	+0,030 + 0,150

Installation tolerances

iglide® H4 plastic bushings are standard bushings for shafts with h-tolerance (recommended minimum h9).

After the installation in a housing bore with H7 tolerance, the inner diameter of the bearing automatically adjusts to F10 tolerance.

Tolerances

Medium	Resistance
Alcohol	+
Hydrocarbons, chlorinated	+
Greases, oils, without additives	+
Fuels	+
Weak acids	+ to 0
Strong acids	+ to -
Weak alkaline	+
Strong alkaline	+

+ resistant 0 conditionally resistant - non-resistant

Figure 13.10: Influence of moisture absorption of iglide® H4 plastic bushings

Electrical properties

Specific forward resistance	> 10¹³ Ωcm
Surface resistance	> 10¹² Ω

Chemical resistance

iglide® H4 plastic bushings have a good resistance against chemicals. They are resistant to most lubricants. The iglide® H4 is not affected by most weak organic and inorganic acids.

The moisture absorption of iglide® H4 plastic bushings is about 0.1% in standard climatic conditions. The saturation limit in water is 0,2%. iglide® H4 is therefore the ideal material for wet areas.

Radioactive rays

iglide® H4 withstands both the neutron and gamma particle radiations without noticeable loss to its excellent mechanical properties. iglide® H4 plastic bushings are radiation resistant up to a radioactive intensity of 2 x 10² Gy.

UV-resistant

iglide® H4 plastic bushings alter under the influence of UV rays and other climatic influences. The surface becomes coarser, and the compressive strength declines. Therefore the use of iglide® H4 in applications directly exposed to climatic conditions should be tested.