The principle aim of roller burnishing is to achieve high-high quality clean surfaces or surfaces with pre-outlined surface finish. One or more rollers or balls plastify and deform the workpiece’s surface layer. This process is used when the aim is to either obtain a high-high quality surface end or when a pre-defined surface end can’t be achieved by machining. Please refer to VDI policy 2032, where also differences between roller burnishing and rolling are explained.
On the contact level, the burnishing power generates contact stresses in the materials’s edge zone. If this stress is higher than the material’s yield strength, the material near the surface begins to flow. Because the ball or roller moves throughout the workpiece surface, the surface’s peaks are pressed down, nearly vertically, into the surface zebra03 and the material then flows into the valleys between the peaks (Fig. 1). The resulting smooth surface happens not because the peaks are bent into the surface (a widely held, but false assumption), but because the material flows, eliminating surface roughness.
Almost all processes for the manufacturing of high-high quality surfaces may be replaced by roller burnishing (e.g. superb turning, grinding (superending, lapgrinding, etc.), galling, honing, sprucing, rubbing). This confirmed process entails considerable technological and economic advantages for surfaces in the roughness area Rz < 10 µm.
Burnished surfaces are special in its construction and might be characterised as follows:
Low roughness (Rz < 1 µm / Ra < zero,1µm) or outlined roughness.
Rounded surface profile.
High surface bearing ratio.
Much less friction and wear.
Elevated hardness by means of cold working.
Benefits are:
Quick cycle time and elimination of set-up and auxiliary processing time.
For use with both conventional or CNC-managed machines.
Complete processing in one setting.
Removes no materials and generates no waste.
Easily reproducible.
Low lubricant requirements.
Low noise emission.
Long tool life.
No dimensional change by way of software wear.