Burnishing Technology
Principals of Roller Burnishing
Roller finishing is a non- cutting surface operation. For metal parts, surfaces prepared by conventional machines are cold- worked under mechanical pressure from a series of finishing rollers and equalizing fully depending on the application of the work.In Burnishing process, the hard mirror- finished rollers first press upon the crests in the roughness profile and flatten them through plastic deformation, at the same time raising the bottom of the valleys by squeezing the material into them until peaks and at the same level.
Advantages Achieved by BurnishingAccurate sizing, a low micro- finish and hardening of the surface. Roller burnishing will obtain a high quality finish and eliminate the need for secondary operations such as honing and lapping.
- Sizing with roller burnishing is influenced by the pre-machined surface. Roller burnishig in steel can result in a 25% size improvement. A 50% improvement in high ductility materials can be expected, while in low ductility materials such as cast iron improvement is about 20%.
- The low micro finish combined with a hardened and denser surface substantially increases part wear, life and corrosion resistance. The added strength improves the parts fatigue resistance, decreasing failures. The cold rolling condenses the grain structure of metal, producing an increase of surface hardness from 50% to 100% within a penetration of .010”to.030”.
- On the p[arts surface. In roller burnishing, the material is elastically deformed to a given depth below the surface. The result is compressive stresses at the surface. This in turn increases the resistance of the material to fatigue failure, because any external forces must first over these residual stresses.
- Pistons, valves, cylinders and parts with similar functions require continuous lubrication. Roller burnishing will leave valleys in the surface of these parts, which act as oil reservoirs, extending part life. This can be achieved by controlling the burnishing size and hole size.
- The electric motor industry has deried great benefit from roller burnishing to reduce noise level in moving parts. Heat resulting from friction, has a direct effect on surface finish. This temperature rise causes dimensional changes that can have an adverse effect on the function of the parts. By roller burnishing, it is possible to reduce friction by up to 30%.
- Interiors of hydraulic oil brake cylinders Internal surfaces and taper seat surfaces of valve bodies.
- Internal surfaces of bushing for connecting rods.
- Holes for inserting bearings.
- Internal surfaces of gun barrels.
- Internal surfaces of brass liners for cast-iron valves.
- External surfaces of shafts for torque converters.
- Valve seats of fuel pumps.
- External surface tapers for joints
- Bearing Housings
- Bearing Bushes
- Connecting Rod
- GMI Bronze Bushes
- Valves guide
- Brakes Cylinder/Master Cylinder
- Fan rotor shaft, pipe etc.
- Speaker washers
- Shock Absorber Piston rod Fan shafts
- Rotor shaft/cooler shaft
- Speedometer shaft
- Mixie shaftDental drill
- Are adaptable for use on lathes, screw machines, VTL Machines, NC& CNC machines,
- Produce high quality finishes (0.13-0.20um) and saves machine time and set- up cost through single machining operations.
- The ideal operations for the carbide roller burnishers are shafts and cylinders of non- uniform cross section.shafts with radii, fillets and grooves, and cylinders with undercuts, tapers and contours are perfect application. Another successful application is the burnishing of axles and shafts requiring high- quality finishes.
- Reduce cost by eliminating finishing operation on secondary work centers.
- Suitable for most CNC turning centers.
- Produce high quality finishes (0.13-0.20um)
- This tool design employs a long life 45mm diameter carbide roller with a heavy- duty bearing rotating on a hardened axle. The carbide roller is a spring loaded in two axial directions to provide the correct pressure for the burnishing operation. The carbide roller can be reground several times as required.
- The tool can burnish ferrous and non- ferrous metals and achieve good surface hardness and high abrasion resistance. This self feed tool provided with helix angle of rollers is available from a tool range of 8mm to 300mm.
- These special tool for bearing sizes 6201,6202 etc.has an adjustment range for bearing sizes from-0.05 to 0.15mm. the tool range from 12mm to400mm. A surface finish of 0.4 to 0.05uRa value is obtainable.
- Bunishes two different bore diameters separately or simultaneously. Practical for thru- hole and blind- end application. Recommended for high- column use only.