By Brett Scruggs
Burnishing is one of a variety of processes for finishing features with tight tolerances and high surface finish requirements. Many processes like grinding, honing, and hard turning require metal cutting and very specialized expensive equipment. Burnishing, on the other hand, moves or displaces material and can be done on existing milling and turning equipment.
Let’s start by looking at single point finishing: many times, to achieve a fine surface finish and tight tolerance with a single point tool, you must use light depths of cut and slow feeds and speeds. A couple of major drawbacks to single point finishing are deflection and tool wear. These cause the machine operator to constantly make adjustments in order to maintain size control and finish. Longer cycle times, machine downtime, and potential for scrap are all costs built into single point finishing.
On the other hand, a multi-roller burnishing tool exerts pressure in multiple directions, eliminating deflection issues. A burnishing tool does not cut material, so it is not affected by the common wear issues you will see with a cutting tool that would affect size control and finish. Lastly, a burnishing tool does not make large size changes, so the risk of scrap is minimal.
Grinding, Honing, and other finishing processes generally involve a costly separate piece of equipment that can be a major investment as opposed to the cost of a burnishing tool. The cost savings are not hard to calculate in this situation.
We believe the cycle time reductions, process stability, and potential scrap reduction are all ways to easily show cost savings for the end-user. The elimination of capital investment, secondary operations, and/or possible subcontractor costs are also good cost savings for the end-user. In closing, there are several ways an end-user can save money by choosing to take advantage of burnishing for their finishing requirements.