Gearbox Drive Shaft – Case Study

Gearbox Drive Shaft Case Study

The Challenge

A customer of ours was manufacturing gearbox drive shafts using a Mori Seiki CNC Lathe. The shafts required a surface finish of 16 Ra microinch (0.4 Ra) or better on the central diameter and the fillet radii of the driveshaft. The customer previously transferred the drive shafts to another machine to grind down excess material and achieve the required surface finish which was quite time consuming. Here was their pre-burnishing process:

  • Speed: 1250 RPM
  • Feed: 0.008”/rev (0.2mm/rev)
  • Finished achieved: 48 Ra microinch (1.2 Ra)

Our Solution

Once we were in contact with the customer, we suggested that they use a Single Roll OD “Top Hat” Burnishing Tool with a 0.125” (3.175mm) radius carbide roll made by Elliott Tool Technologies. Here were the statistics of the burnishing operation:

  • Speed: 1250 RPM
  • Feed: 0.004”/rev (0.1mm/rev)
  • Radial load: 0.04” (1mm)
  • Finish achieved: 12-14 Ra microinch (0.30-0.35 Ra)

Final Results

The single roll burnishing tool produced a surface finish of 12-14 Ra microinch (0.30-0.35 Ra), all while allowing the part to be finished on one machine. This saved 30 minutes per part and freed up the grinding machine for other operations, which resulted in huge financial savings.