Lemken GmbH & Co. KG is a family-run company that specialises in the production of agricultural machinery for tillage, sowing and plant protection. The Lemken range includes, among others, the "Karat 9", an intensive cultivator, which can be used in several stages both shallow and medium deep and deep. Its main use is mainly to loosen the fields, to mix organic matter and to prepare for the next sowing.
The previously used metallic solution had to be lubricated up to 1 hour daily, depending on the size of the cultivator. If the numerous lubrication points, depending on the working width, were not sufficiently lubricated, the resulting lack of lubrication led to considerable problems with corrosion and greatly increased wear of the bearing point, which ultimately resulted in damage to shafts and housing holes.
Due to plain bearings made of iglidur® G, any lubrication could be dispensed with. The elimination of lubrication saves valuable time for the farmer. The dirt resistance and stability of the plain bearings increased the dependability. In addition, the plain bearings themselves saved costs due to the more cost-effective procurement and longer service life compared with the previous solution.
During use, it is possible that large stones can be on the ground in the path of the tractor and its tillage equipment. For this reason, the Karat 9 has maintenance-free overload elements, whereby the tines, which work on the ground in normal operation, automatically dodge backwards and upwards and then automatically return to the working position.
The overload element is maintenance-free with the use of lubrication-free iglidur plastic plain bearings from igus. "Insufficient lubrication was a real problem for applications in the cultivators," says Lars Heier, Director of Marketing at Lemken. "With metallic solutions the bearing points had to be lubricated once a day, so that the bearings can perform their duties properly. This constituted, depending on the working width of the cultivator, up to one hour of work per day. " The iglidur high-performance materials from igus don't require a subsequent lubrication at all, because self-lubricating solid lubricants are already incorporated in the bearings. At the same time the iglidur plain bearings easily withstand the high forces in the overload element of the cultivator.
In 2008, the Karat was the first application by Lemken implemented with lubrication-free iglidur plain bearings. Earlier Lemken used DU bushings in its machines. "All laughed at us about the Karat cultivator in the beginning, because we wanted to use plastic at the bearing point," Lars Heier admits. "Today, the plastic plain bearings have to be replaced only every few years depending on the load, which accounts for, in addition to the lubricant saved, an additional cost advantage. " After this pioneering project, numerous other machinery from Lemken were equipped with iglidur plain bearings. The collaboration between the two companies worked very well in the process: igus tested their own materials very extensively in the in-house test laboratory in Cologne, where various bearing materials are combined with different shaft materials in order to calculate coefficient of friction and wear as precisely as possible.
Moreover, Lemken tests the products specifically for their needs at its own site. "It is of much value for us to work with a company from the area. Because, it is possible to sit together without losing time and without complications to discuss new projects or to try new solutions," says Lars Heier.
High forces are often at work particularly in agriculture with the use of heavy equipment, which need to be very tough. Therefore, in earlier times, metallic bearings were the first option. These bearings have a very limited service life, especially with pivoting movements, because lubricants may not be evenly distributed and the same points on the bearing are stressed again and again. Here, plastic plain bearings display their advantages, as pivoting movements do not harm them and there is no lubricant to displace. Another advantage lies in the dry operation of the bearings, since dirt cannot accumulate on them igus can bank on over 50 catalogue materials for the most varied requirements, such as for heavy-duty applications found in the agricultural sector.
Plain bearings from the all-rounder material iglidur G prove themselves in the cultivator Karat 9 by withstanding a compressive strength of 80 MPa. For higher loads igus also provides, for example, catalogue materials up to 120 MPa, such as iglidur Q2 or iglidur TX1 up to 250 MPa. In addition to the standard range, a multitude of special solutions are also available, with which more specific applications can be implemented.
Lemken is certain that it wants to rely on the advantages of lubrication-free plastic plain bearings for future applications. "The working time saved by using maintenance-free bearings, is a very strong argument for plastic plain bearings today," says Lars Heier. "In the future we will continue to rely on the plain bearings from igus. For what has been proven is retained by us, that is certain. "
Here, you can find the products used:iglidur G plain bearings
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