The news that polymer researcher and plain bearings expert igus GmbH was moving into the ball bearing business caused quite a stir. Since then, the Cologne-based company has done lots of development work: five separate "xirodur" materials (two of which were launched this year), many new dimensions and a wide range of different designs available ex stock in 24 hours, E-engineering tools for design engineers, from 3D CAD downloads through to the online service life calculation program.
Lubricant and maintenance-free "xiros" polymer ball bearings can be used at temperatures of up to 150 deg C, are highly corrosion-resistant, can be washed and cleaned, are non-magnetic and have a low weight. According to igus, they provide an economic alternative for many applications where the use of conventional metallic ball bearings are is problematic. Product manager Dirk Muller states: "These are applications where the focus is not on maximum load and speed, but on other features such as chemicals or use in liquid media. In such applications, lubricants are often washed out of the metallic, sealed and permanently lubricated ball bearings, so that corrosion becomes a problem." In addition to the lack of lubricant and corrosion, the company says that weight reduction, the avoidance of magnetism, very good friction coefficients and longer service life are further arguments in favour of the use of "xiros" polymer ball bearings.
Deflection rollers: polymer bearings replace metal bearings
The applications are varied, and range from all kinds of medical equipment, pump and measuring technology, through to transport and conveying technolology, particularly in the fields of chemicals, food, laboratories and packaging. One example is Tesa Scribos (Hamburg), expert for solutions related to protection against fraud and theft, with products such as adhesive seals. Radial deep-groove ball bearings made of the polymer material "xirodur B180" are installed for material guiding in the coated deflection rollers of various machines. The maintenance-free plastic bearings replace metal ball bearings because these could only be used in oiled versions to achieve lower rolling friction. In addition to the advantages of maintenance freedom and weight saving, "xiros" polymer ball bearings are about fifty percent cheaper and available more quickly, according to Tesa Scribos. They are now used in the deflection rollers in the pressure roller before the intermediate drive, where the pressure roller is adjusted with a defined compressive force on the drive roller. The combination of deflection roller/intermediate drive is not only used to drive the product, it also creates web tension in the material.
Already five materials with more than a hundred variants
Within only four and a half years, the range of "xiros" material has grown from one range to five. The universal range "xirodur B180" and the low-price chemical bearing "xirodur C160" have been added to the high-temperature "xirodur A500". The range of dimensions has also been significantly increased. There are now more than a hundred sizes, shapes and styles available. These range from radial and axial bearings, multi-purpose bearings for both linear and rotational movements, rotary table bearings, pedestal bearings and flange bearings through to ball bearings and bearings with dust shields. The focus is also always on fast delivery: stock being delivered in 24 hours or the same day, says the company. The standard range is supplemented by tailor-made customer-specific solutions, which are becoming increasingly important.
New: conductive and extremely wear-resistant
This year, igus has developed two new tribologically optimised "xirodur" materials. The first is "xirodur F180" for conductive polymer ball bearings. This ESD protection type provides protection from electrostatic discharge. The lubricant and maintenance-free bearings can be used permanently at temperatures of up to 80 deg C Industry sectors, include the semiconductor industry, paper, textiles and glass industry.
Service life increased by 42 times
The second new material from the Cologne-based company is "xirodur D180". It is four times more wear-resistant than the all-round material for ball bearings, "xirodur B180". The inner and outer ring are made of the new high-performance material, the cage is made of PA, the balls either of glass or stainless steel. The permanent application temperature is 80 deg C. "xiros D180" polymer ball bearings have been available ex stock since May. They are extremely wear-resistant at high rotational speeds and low loads. Tests in the company's in-house Technical Centre have shown that the new bearings can be 72 times more wear-resistant than ball bearings made of PEEK, also according to igus. ball bearings made of PE, PP, PA and POM all have significantly shorter service lives than "xirodur D180". Product manager Dirk Muller: "Ongoing material optimisation along with a comprehensive series of tests have enabled us to increase the service lives of our polymer ball bearings by a factor of 42 since 2007."
New: service life calculation on the Internet
In addition to its service life calculators for plain bearings, linear bearings, pivoting bearings and semi-finished materials on the igus websites, last year the company also developed an online expert for "xiros" polymer ball bearings. Such E-engineering tools increase speed and convenience, according to the company, and thus help to reduce process costs. The link www.igus.eu/xiros-life leads straight to the program. There, customers can choose a design size and enter the speed and loads of their application. The material combinations available in the required size are listed in the window "selection of material combinations". The customer can then print off the result, giving a lifetime in thousands of hours.
Gunter Blase began igus® back in 1964 in a double garage in Cologne. For the first 20 years, the company worked as a supplier of complex technical polymer components. However, in 1983 Frank Blase established reinforced plastic Energy Chain Systems® and injection moulded polymer bearings as two distinct product groups and set up a network of sales engineers. These seemingly unrelated products are linked together through the belief in making functionally advanced, yet affordable polymer components and assemblies.