Hydraulic Cylinder Case Study

Hydraulic Cylinder Case Study

The Challenge

A customer of ours was manufacturing hydraulic cylinders made of 4340 steel, using a Mazak Qualiturn CNC Lathe. The cylinders for this customer required a surface finish of 16 Ra microinch (0.4 Ra) or better. Originally, the customer was sub-contracting other firms to grind the parts to achieve the required surface finish before their chrome plating operation. This was both costly for our customer and extremely time consuming since they could not control when their parts were finished, resulting in long and uncertain lead times. Here is the data for their original turning operation:

  • Speed: 650 RPM
  • Feed: 0.008”/rev (0.2mm/rev)
  • Finished achieved: 32-40 Ra microinch (0.8-1.0 Ra)

Our Solution

Once they explained their process to us, we recommended that they use a single roll OD burnishing tool made by Elliott Tool Technologies to achieve the required surface finish. Here is the data for this burnishing operation:

  • Speed: 650 RPM
  • Feed: 0.004”/rev (0.1mm/rev)
  • Radial load: 0.04” (1mm)
  • Finish achieved: less than 12 Ra microinch (less than 0.3 Ra)

Final Results

The burnishing tool we recommended achieved the required surface finish all in-house, getting rid of the need for sub-contracting to grind the cylinders. This greatly reduced the cost of manufacturing the hydraulic cylinders, and was very consistent and repeatable. The burnishing tool also greatly reduced lead times, resulting in our customer winning a lot more business.