1) Superfinishing is a metalworking process that improves surface finish and geometry by removing a thin amorphous layer, usually about 1μm, left by previous processes using an abrasive stone or tape. 2) The process was developed by Chrysler in 1934 and involves oscillating or rotating an abrasive while the workpiece rotates in the opposite direction, creating a cross-hatch pattern. 3) A lubricant is used to minimize heat and carry away swarf; kerosene is common. The abrasive cuts the surface in three phases as its grains fracture and become dull.

1. Enrollment No. : - 126540319070 Date: - 07/July/2014
V.P.M.P POLYECHNIC
Mechanical Engineering Department
Seminar
Subject: - Manufacturing Engineering - 3 Semester: - 5th
Topic: - Super Finishing
Superfinishing, also known as micromachining, microfinishing, and short-
stroke honing, is a metal working process thatimproves surfacefinish and work
piece geometry. This is achieved by removing justthin amorphous surfacelayer
left by the last process with an abrasive stoneor tape; this layer is usually about
1µm in magnitude. Superfinishing, unlikepolishing which produces a mirror finish,
creates a cross-hatch pattern workpiece.
The superfinishing process was developed by the Chrysler Corporation in 1934.
Process
After a metal piece is ground to an initial finish, it is superfinished with a finer grit
solid abrasive. The abrasiveis oscillated or rotated while workpieceis rotated in
opposite direction; these motions are whatcause the cross-hatching. The

2. geometry of the abrasivedepends on the geometry of the workpiecesurface; a
stone is for cylindrical surfaces and cups and wheels are used for flat and
sphericalsurfaces.
A lubricant is used to minimize heat production, which can alter the metallurgical
properties, and to carry away the swarf; keroseneis a common lubricant.
The abrasivecuts the surfaceof the workpiecein three phases. The firstphase is
when the abrasivefirstcontacts the workpiecesurface: dull grains of the abrasive
fractureand fall away leaving a new sharp cutting surface. In second phasethe
abrasive“self dresses” whilemost of the stock is being removed. Finally, the
abrasive1grains becomedull as they work which improves the surfacegeometry.
 Types
There are three types of superfinising :
1) Through-feed,
2) Plunge,
3) Wheels
 Advantages and disadvantages

3. Advantages of superfinishing include: increasing part life, decreasing wear, closer
tolerance, higher load bearing surfaces, better sealing capabilities, and
elimination of break in period.
The main disadvantageis that superfinishing requires grinding oe a hard turning
operation beforehand, which increases cost. Superfinishing has a lower cutting
efficiency becausesmall chips and lower material removalrate.
 Specification Of Super finishing
Sr. No. Pressure Cutting
Speed
Grain
Size
Surface
Finish
Metal
Removal
1. 1-3
kg/cm^2
10-14
m/min
400-1000 0.05-
0.2µm
0.005-
0.025mm
 Merits and Demerits of Super finishingprocess.
 It increases part life, decreases wear, closer tolerances, higher load
bearing surfaces, better sealing capacities, and elimination of a break
in period.
 The main disadvantageis that superfinishing requires grinding or a
hard turning operation beforehand, which increases cost, it’s cutting
efficiency is low because of smaller chips and lower material removal
rate, tools used are softtherefore it wear more quickly.
 Applications.
Common applications include steering rack components, transmission
components, fuel injector components, camshaftlobe, hydraulic cylinder
rods, bearing races, needle rollers and sharpening stones and wheels
Itis proved that superfinishing certain parts makes them more durable. For
example if the teeth in a gear a superfinished then they last 4 times more.

4.  Machinable materials
The material used today are many and varied, it is not only steel in all its
many alloys and quantities that can be machined using superfinishing
machine. The superfinishing process is suitable for all thosematerial that
can be machined with geometrically undefined cutting edge.
This materials include ceramics, plastics, monocrystallinesilicon, castiron,
and non-ferrous metals.
But such coating as tungsten carbide, chromium, and copper, are also
processed in superfinishing machines to provide them with the perfect
surfacefinish.