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Introduction

A customer was experiencing repeated failures on bearings fitted to roller assemblies on his wire drawing machinery. This resulted in excessive downtime and high maintenance costs. This was a serious concern to the management and a solution was needed urgently. NSK was called in to investigate and found that there was a lubrication and sealing problem. A new bearing and lubrication package was tested. Results showed that this solution significantly improved the bearing performance resulting in large improvements in productivity and a reduced maintenance cost.

Key Facts

  • Continuous wire drawing process with high loads and arduous conditions
  • High failure rates of bearings up to 75 stoppages a month
  • Excessive downtime and high maintenance costs
  • Bearing Failure Analysis which showed a lubrication problem
  • NSK proposed Lithium Complex grease together with a sealed Cylindrical Roller Bearing unit which was tested in the machine resulting in improved productivity and reduced maintenance costs
  • A significant cost saving could be realised
  • Wire Drawing Machine
CRB
  • Full compliment Cylindrical Roller Bearing unit with seals

Value Proposals

  • A Bearing Failure Analysis showed that the primary cause was poor lubrication performance
  • A Lubrication Analysis identified the existing grease as graphite based which was not suitable
  • NSK proposed a trial using a specially selected Lithium Complex grease together with a Sealed Double Row Cylindrical
  • Roller Bearing Unit
  • The trial was successful with a 40% improvement in bearing life
  • The customer converted all of their roll assemblies over to the NSK proposed bearing / grease combination
  • There was a significant reduction in downtime and maintenance costs and this was documented in a substantial cost saving

Product Features

  • Improved contact seals prevent ingress of foreign particles or water
  • High load rating
  • Increased radial and axial capability
  • Highly corrosion resistant phosphate coating
  • Easier grease re-lubrication: Inner and outer ring re-lubrication holes
  • Bearings pre-greased with Lithium grease
  • Can be fitted with DIN 471 snap rings to the outer ring
  • Can be used in external environments due to coating

Cost Saving Breakdown

Before Cost p.a. NSK Solution Cost p.a.
Constant failure of bearings / 75 Rolls changed per month Significant improved reliability / 45 Rolls changed per month
0.5 hours per change / €6.000 per hour lost production cost / €225.000 per month x 12 months
€ 2.700.000 0.5 hours per change / €6.000 per hour lost production cost / €135.000 per month x 12 months € 1.620.000
378 man hours / €13.986 cost per month / €13.986 x 12 months € 167.832 108 man hours / €3.996 cost per month / €3.996 x 12 months € 47.952
Technical Support & Engineering Time € 2.575 No Technical Support needed € 0
Total Costs € 2 870 407 € 1 667 952

Reference:SS-E-2018