Wälzlager - 2010-08-10
NSK’s SPACEA range of bearings for special environments has solved a problem of premature failures of stainless steel bearings used in the manufacture of carbon graphite and composite materials for aerospace applications.
Operating in a solution of Ammonium Bicarbonate, the stainless steel bearings were lasting around six weeks; however, the Spacea replacements have been operating for 8-months with no problems, providing savings for the manufacturer of €11,763 per annum.
The SPACEA Bearings are situated at both ends of five rollers over which the carbon fibre material passes in a surface treatment process before being submersed in the bath of Ammonium Bicarbonate. This is an arduous application for bearings, as illustrated by the fact that the ten stainless steel 6205 bearings that were used previously were failing and requiring replacement every six- weeks, at an annual cost of €2,524 p.a. In addition, analysts calculated that the frequent replacement was costing €13,697 in lost production time.
Keen to remove these costs and improve productivity, the manufacturer contacted NSK to enquire about the company’s cost saving programme, and find out how the technical consultancy aspect of the programme might be able to help. Following the enquiry, NSK engineers visited the manufacturer’s plant to assess the application. Subsequently, they recommended replacing the stainless steel bearings with units from NSK’s SPACEA series for special environments.
The SPACEA series is a range of bearings, ball screws and linear guides that provides high performance and reliability under all types of demanding operating conditions: super-clean, vacuum, non-magnetic, corrosive, high/low temperature, nuclear and high speed. Products in the range meet the widest range of technical requirements with a programme of high performance materials, surface finishes and specially developed lubricants, including solid types.
The SPACEA bearings recommended for the surface treatment application were 6205 units with martensitic stainless steel inner/outer rings and balls; the latter supplied with an MoS2 solid lubricant coating. In addition, the cage of the bearings is self lubricating and the bearings are provided with shields of Austenitic stainless steel.
Initially, two SPACEA bearings were fitted to one of the rollers to assess the performance. After a trial period of three-months, the customer was confident enough to replace the remaining eight bearings, these are still operating successfully after eight-months, and subsequent orders for SPACEA bearings have been placed for an alternative machine.