When a manufacturer of heat exchangers was experiencing frequent production stoppages due to bearing damage on the spindles of its horizontal machining centres, the company turned to NSK. After comprehensive analysis, NSK recommended fitting its sealed, high-precision, angular-contact ball bearings, which has helped the company to save EUR24,000 per annum in replacement bearings and labour costs.
When first experiencing the repeated failures, the operations manager at the heat exchanger manufacturer asked NSK to conduct a detailed failure analysis. Within the framework of NSK's AIP Added Value Programme, experts examined the failed angular-contact ball bearings, as well as the quality of the lubricant and the operating environment conditions.
It was discovered that coolant and metallic particles – both by-products of the machining process – had penetrated the bearings. The result was deterioration of the bearing lubricant, which consequently caused the bearings to fail.
To overcome the issue, NSK proposed the use of its sealed, high-precision, angular-contact ball bearings, which are deployed widely as spindle bearings in the machine tool industry. These bearings have contactless seals that are designed to deliver exemplary resistance to the penetration of contaminants without causing friction to increase or spindle performance to drop.
To help accommodate the increased axial loads exerted on spindles often present in horizontal machining centres, a further suggestion from NSK was the installation of bearings with a higher contact angle. As a result of adopting this recommendation, the heat exchanger manufacturer has been able to increase the operational life of the bearings: after fitting NSK bearings to three of its horizontal machining centres, spindle bearing operating life increased on average by a factor of 12.
Based on the previous cost of replacing bearings, plus labour costs for installation, the heat exchanger manufacturer is realising annual cost savings of EUR24,000 as a direct consequence of switching to NSK's sealed, high-precision, angular-contact ball bearings. Moreover, this figure does not include the costs incurred from any previous lost productivity or production downtime.
Along with significantly increased operational life, further benefits of NSK bearings being enjoyed by the customer include reduced noise and vibration in the drive train, as well as far quicker installation in comparison with standard bearings without seals.