An important industry first for the construction and agricultural machinery industries: For the first time igus has found a way to manufacture heavy-duty bearings made from two components of high-performance plastic, using the cost-effective injection moulding process. Until now, a plastic-based multi-layer structure was only possible using a winding which is more expensive for mass production.
When an excavator bucket supporting hundreds of kilograms of sand moves, enormous loads act on bearing points – loads that plastics specialist igus has so far met mainly with igutex series plain bearings. These bearings are made of more than one material in a winding process. With integrated solid lubricants, the inner layer ensures low-friction, dry running. The outer layer provides the enormous strength.
"Now we have succeeded in producing a multi-layer structure using injection moulding and still combining materials with complementary properties," says Rob Dumayne, drytech director at igus UK.
The result is the iglidur Q3E series. "Thanks to the new technology, we can now manufacture multi-component heavy-duty bearings in volume series using very cost-effective injection moulding," he adds.
The challenge: Moulding and fusing two materials in a single operation
The new iglidur Q3E material is the result of intensive cooperation between igus’ Material Development division and specialists from the company’s toolmaking department.
"When developing iglidur Q3E, we had the goal of developing a multi-part structure similar to the igutex series, with the high-performance plastic iglidur Q3 for a lubrication-free optimised core, and a specially reinforced polymer for the mechanically high-strength shell," explains Dumayne.
The biggest challenge was to handle the two different materials in the injection moulding process in such a way that two components join as one, while combining the advantages of both materials. "We succeeded with this in the multi-component injection moulding process with correspondingly complex and sophisticated injection moulds."
Load-bearing capacity plus convincing sliding properties
The plain bearings made of iglidur Q3E are suitable for heavy-duty applications in which bearings made of metal or fibre composite bushings are traditionally used and where cost savings can be achieved, including the construction and agricultural machinery industries. The bearings’ maximum dynamic surface pressure is 75 MPa.
"This means that we can cover many heavy-duty applications with iglidur Q3E," says Dumayne.
The decisive advantage is that the new bearings do not require any lubricating grease. Microscopic solid lubricants are integrated into the polymer of the inner layer, and are slowly, continuously released during the lifetime of the bearing.
"Particularly in the maintenance of construction and agricultural machinery, lubricating the bearing points is one of the most complex tasks," Dumayne adds.
"By switching to iglidur Q3E or igutex, users of this big, heavy plant can save maintenance costs and increase the service life of their machines. Time and again, neglected lubrication of classic metal bearings leads to expensive and sometimes catastrophic damage to shafts and plain bearings."
