Roller burnishing
Encyclopedia
Roller burnishing is a method of cold working metal surfaces to induce compressive residual stress
es and enhance surface roughness qualities. The tooling typically consists of a hardened sphere or cylindrical roller. These tools are pressed onto/across the part being processed. The part (or the tool in some applications) must be moving at a constant rate of speed, for example in the case of roller burnishing a part on a lathe, the part is spinning and the burnishing tool is moved across the surface as a constant rate; therefore, producing a very consistent finish across the part. Another application is thrust bearing surfaces of some production crankshafts. A dual roller (cylindrical) tool is moved into the thrust bearing journal of a crankshaft, while the crankshaft
is spinning the tool is indexed (so each roller is perpendicular to the thrust surface while backing each other up) deforming the surfaces. So the diameters of each roller added together (compensated for elastic deformation) equals the finish dimension of the thrust
bearing.
In deep hole machining, a roller burnishing tool is often combined with skiving knives on the same tool. The skiving knives pass first, scraping the inside layer of metal, followed by the burnishing rollers, which cold work the tube to create a mirror surface finish. Skive-burnishing is often used in hydraulic cylinder
applications. This process can happen on a deep hole drilling machine or a dedicated skiving machine
.
Residual stress
Residual stresses are stresses that remain after the original cause of the stresses has been removed. They remain along a cross section of the component, even without the external cause. Residual stresses occur for a variety of reasons, including inelastic deformations and heat treatment...
es and enhance surface roughness qualities. The tooling typically consists of a hardened sphere or cylindrical roller. These tools are pressed onto/across the part being processed. The part (or the tool in some applications) must be moving at a constant rate of speed, for example in the case of roller burnishing a part on a lathe, the part is spinning and the burnishing tool is moved across the surface as a constant rate; therefore, producing a very consistent finish across the part. Another application is thrust bearing surfaces of some production crankshafts. A dual roller (cylindrical) tool is moved into the thrust bearing journal of a crankshaft, while the crankshaft
Crankshaft
The crankshaft, sometimes casually abbreviated to crank, is the part of an engine which translates reciprocating linear piston motion into rotation...
is spinning the tool is indexed (so each roller is perpendicular to the thrust surface while backing each other up) deforming the surfaces. So the diameters of each roller added together (compensated for elastic deformation) equals the finish dimension of the thrust
Thrust
Thrust is a reaction force described quantitatively by Newton's second and third laws. When a system expels or accelerates mass in one direction the accelerated mass will cause a force of equal magnitude but opposite direction on that system....
bearing.
In deep hole machining, a roller burnishing tool is often combined with skiving knives on the same tool. The skiving knives pass first, scraping the inside layer of metal, followed by the burnishing rollers, which cold work the tube to create a mirror surface finish. Skive-burnishing is often used in hydraulic cylinder
Hydraulic cylinder
A Hydraulic cylinder is a mechanical actuator that is used to give a unidirectional force through a unidirectional stroke. It has many applications, notably in engineering vehicles.- Operation :...
applications. This process can happen on a deep hole drilling machine or a dedicated skiving machine
Skiving machine
Skiving or scarfing machines cut material off moving strips, usually metal, but also leather or laminates, to leave a desired edge shape or cross section...
.