DryLin linear guides - ASI Automatikk

DryLin ®
DryLin ® – Technical Information
DryLin ® – Technical Information
DryLin ®
Phone +49- (0) 22 03-96 49-145
DryLin ®
Fax +49- (0) 22 03-96 49-334
igus ® GmbH
51127 Cologne
Internet: www.igus.de
E-mail: info@igus.de
Coefficients of friction [µ]
Coefficient of friction [µ]
Wear in [µm/km]
Wear in [µm/km]
Graph 242.1: Coefficient of friction as a function
of the speed/DryLin ® R p = 0.9 MPa
0,2 0,2
0,15 0,15
0,1 0,1
0,05 0,05
0 0
0,15 0,3 0,6 1 ,2 2
v [m/s]
Graph 242.2: Coefficient of friction as a function
of the speed/ DryLin ® T, p = 0.46 MPa
0,170
0,165
0,160
0,155
0,150
0,145
0,15 0,3 0,6 1,2
1,2 1,2
1,0 1,0
0,8 0,8
0,6 0,6
0,4 0,4
0,2 0,2
0 0
0,8 0,8
0,6 0,6
0,4 0,4
0,2 0,2
v [m/s]
Graph 242.3: Wear in µm/km for different sliding surface,
p = 1 MPa
iglidur ® J
DryLin T
iglidur ® J
aluminum shaft
iglidur ® J
cold rolled steel
iglidur ® J
stainless steel
iglidur ® X
aluminum shaft
Graph 242.4: Load dependent wear in µm/km
iglidur ® X
cold rolled steel
iglidur ® X
stainless steel
0 0
0,05 0,1 0,25 0,5 1
Surface load [MPa]
linear guide systems have clear advantages in applications with high
amounts of dirt, the coefficients of friction in dirty applications also
increase. It was observed that the stability of the coefficients of friction
after start up is not always present in extreme application conditions.
Wear behaviour
The wear behaviour of DryLin ® is a function of the shaft material, but
it works well on many different materials. The surface load, in addition
to the shaft material and roughness, has an effect on the wear. With
decreasing surface load, the wear also decreases in µm/km.
Stick slip behaviour
DryLin ® is very resistant to the behaviour known as stick slip. Stick
slip occurs when there is intermittent movement between two sliding
surfaces. The stop and go movement is caused by frequent changes
from static to dynamic friction. The coefficients of static and dynamic
friction are close enough to each other for iglidur ® J so that the danger
of stick slip behaviour is very low.
Operating temperatures
Sliding elements made of iglidur ® J and J200 can be used in the
temperature range between -40 and +90°C. Due to of the excellent
thermal conductivity of aluminum as a shaft and housing material, a
large increase in bearing temperature only occurs in high frequency,
short stroke applications with a high load.
iglidur ® X is recommended for temperatures up to 250°C, and is offered
in DryLin ® R in combination with hardened, chrome plated or stainless
steel shafts.
Shaft materials
The maintenance free linear plain bearings can be combined with
many different shaft materials. In addition to the various steels, other
materials such as carbon fibre and ceramics are possible. The best
friction and wear properties are obtained for shaft roughnesses of
Ra = 0.1 – 0.3 µm. Rougher surfaces lead to increased wear, especially
during the start up phase.
Table 242.1: Suitability of different shaft materials
Shaft material
Suitability
Hardened, ground steel shafts
Hardened, ground stainless steel shafts
hard anodized or anodized aluminum shafts
Free cutting steel
Ceramic
GFK and CFK shafts
HR Carbon steel
303 Stainless steel/304 stainless steel
Chemical resistance
Eccentric forces
DryLin ® linear bearings are resistant to weak acids, diluted Alkalines For the successful use of the maintenance free DryLin ® R linear bearings,
and to fuels and all types of lubricants. Even the frequent chemical a few design rules must be considered. Due to the higher coefficient
washdowns of machines in the food industry are not a problem. of friction in comparison to ball bearing guides, a higher driving force
The chemical resistance of a linear bearing system is also dependent is necessary.
on the shaft material. For a system that is resistant to chemicals, a
high alloy stainless steel would be suitable, for example, 440 stainless
steel, especially when used with iglidur ® X as a bearing material.
Corrosion behaviour
The low moisture absorption of DryLin ® bearings allows design in
underwater applications. With the use of stainless steel or anodized
aluminum shafts, a corrosion resistant system is achieved. Anodized
aluminum is resistant to chemically neutral materials in the PH range
2 to 7. For special applications it is recommended to test anodized
aluminum sample parts to examine results prior to their use.
Quiet operation
Sliding elements made of polymers, which run on ground shafts or
profile rails, are extremely quiet running, as opposed to the traditional
ball guides where the noise level increases with speed.
Permissible speeds
Because of the structure of the DryLin ® linear plain bearings (rolling parts
are eliminated) extremely high speeds (more than 15 m/s) and accelerations
(200 m/s 2 ) can be achieved. DryLin ® bearings are thus suitable for
applications where acceleration and cycle times need to be increased.
The permissible average surface speed depends on the bearing load.
With decreasing surface load, higher speeds can be obtained. More
significant than the maximum speed is the average speed per cycle,
since the temperature of the bearing system is more greatly affected. To
calculate the suitability of the linear bearing systems, the average surface
speed should be determined. In applications with intermittent cycles, the
highest average surface speed is significant.This is an average taken
over a time period of 10 to 30 minutes. The use of hard anodized aluminum
as the running surface lowers the operating temperature at the bearing
surface due to the thermal conductivity of the aluminum. Thus, even for
very short stroke lengths, the system can be driven at a high frequency.
The 2:1 rule
2 x
1x
When using linear plain bearings, the 2:1 rule (see drawing above)
must be observed. If not, a non uniform movement, or even a binding
of the system occurs. Often an application can be solved by relatively
simple changes. The principle is not a function of the load or the driving
force – it is a product of the friction and always relates to the fixed
bearing. The further the drive is located from the guide bearing, the
greater the wear and necessary drive forces. If the distance of the
driving force to the fixed bearing is more than double the distance
between the bearings (2:1 Rule), the system will in theory bind at a
coefficient of static friction of 0.25. Our application consultants will be
glad to help you in creating a design that is suitable for the plain bearing.
Please send us a drawing, in which:
The distance between the rails,
The distance between the carriages,
And the distances and applied loads [N] of the acting forces
are shown.
With this information we will advise on system function, required driving
force, and the expected bearing lifetime in your application.
Table 539.1: Chemical resistance of iglidur ® J, iglidur ® J200, iglidur ® X
Medium iglidur ® J iglidur ® J200 iglidur ® X
Alcohol Resistant Resistant Resistant
Chlorinated hydrocarbons Resistant Conditionally Resistant Resistant
Ester Not Resistant Not Resistant Resistant
Greases, oils Resistant Resistant Resistant
Ketones Conditionally Resistant Conditionally Resistant Resistant
Fuels Resistant Resistant Resistant
Weak acids Conditionally Resistant Conditionally Resistant Resistant
Strong acids Not Resistant Not Resistant Conditionally Resistant
Weak Alkalines Resistant Resistant Resistant
Strong Alkalines Resistant Resistant Conditionally Resistant
Sea water Resistant Resistant Resistant
For further details see the chemical resistance table on page 115
Phone +49- (0) 22 03-96 49-145
DryLin ®
Fax +49- (0) 22 03-96 49-334
mm
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Lifetime calculation, CAD files and much more support www.igus.de/en/DryLin Lifetime calculation, CAD files and much more support www.igus.de/en/DryLin
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