PPT include SUPERFINISHING processes ( honing, lapping and superfinish), their type, specs. and applications.

1. SUPERFINISHING PROCESSES

2. SLIDE PLAN :-
1) HONNING:-
• HONNIG PROCESS
• HONNING STONES
• ABRASSIVE USED IN HONNING PROCESS
• ABRASSIVE GRIT SIZE
• APPLICATION
2) LAPPING:-
• LAPPING PROCESS
• TYPES OF LAPPING PROCESS
• APPLICATION
3) SUPERFINISHING:-
• SUPERFINISHING PROCESS
• RADIAL AND PLUNGE MODE IN SUPERFINISHING PROCESS
• APPLICATION

3. • Honing is a low velocity abrading process in which
stock is removed from metallic or non metallic
surfaces by bonded abrasive sticks.
• Honing improves the accuracy and finish of
automobile cylinder bores, hydraulic cylinders, and
similar parts. The honing machine consists of four
fine-grain abrasive stones attached to an expandable
tool that is then slowly revolved and oscillated inside
the cylinder until the desired finish and diameter are
obtained.
HONING

5. HONING STONES
• Honing stones are made from common abrasive
and bonding materials, often impregnated with
sulphur, resin, or wax to improve cutting action
and tool life.
• Abrasive particles must withstand the cutting
pressure for metal removal.

6. • Bond must be strong
enough to hold the
grit.
• Not so hard as to rub
the bore and retard
cutting.

7. ABRASIVE
• Selection of abrasive depends on
– Composition
– Hardness of metal being honed.
– Finish required
– Cost.

8. GRIT SIZE OF ABRASIVE
• Size ranges from 36-600
• Most widely used size : 120-320
• Selection depends on
– Material removal rate
– Required finish

9. APPLICATION
• Produce high finish
• To correct
• Out of orderness
• Taper
• Axial distortion
• Employed very frequently for finishing of
– Bores
– Gear teeth
– Roller bearings

10. LAPPING
• Lapping is a machining operation, in which two
surfaces are rubbed together with an abrasive
between them, by hand movement or by way of a
machine.
• This can take two forms. The first type of lapping
(traditionally called grinding), typically involves rubbing
a brittle material such as glass against a surface such as
iron or glass itself (also known as the "lap" or grinding
tool) with an abrasive such as aluminum oxide,
jeweller's rouge, optician's rouge, emery, silicon
carbide, diamond, etc., in between them. This
produces microscopic conchoidal fractures as the
abrasive rolls about between the two surfaces and
removes material from both.

11. TYPES OF LAPPING PROCESS
1) RING LAPPING
2) MACHINE LAPPING

12. RING LAPPING
• Laps in the form of ring made of closed grain cast iron are used for manual
lapping of external cylindrical surface.
• Workpiece held in lathe chuck and rotated. Ring lap is reciprocated over
workpiece. Lap should be short than workpiece and should have adjustable slots
• Bore of ring lap and work size are very close and can be adjusted by screws.
• Ring lapping is recommended for finishing plug gauges and machine spindles
requiring great roundness accuracy.
• For External threads lapping , Special laps having interchangeable threaded
bush corresponding to the external thread to be lapped , with provision for
precise adjustment are used.

14. MACHINE LAPPING
• In this method a rotating table is used
in place of the plate.
• Again the work piece to be lapped is
given rotary by a cage and rotated on
the surface of the table. Rotating lap is
used above & below the work piece to
produce parallel surfaces
• Used for economic lapping with high
accuracy of batch qualities.
• Metal laps and abrasive powder held in
suitable vehicles are used.

15. • Bonded abrasives in the form wheel
are chosen for commercial lapping.
• Machine lapping can also employ
abrasive paper or abrasive cloth as the
lapping medium.
Production lapping of flat surfaces

16. APPLICATION
• Tractor's lift pump and control valve
• Hydraulic and Pneumatic valves and pistons
• Sewing machine needle bar and shafts
• Two-three wheeler gudgun pins
• Sintered products tools
• Tool room
• Gauges and pins for measuring
• Automobile components
• Lubrication system

17. SUPERFINISHING
• Similar to honing, but uses a single abrasive stick.
• The reciprocating motion of the stick is performed at higher frequency and
smaller amplitudes.
• Also, the grit size and pressures applied on the abrasive stick are smaller.
• A cutting fluid is used to cool the work surface and wash away chips.
• Cutting action terminates by itself when a lubricant film is built up between
the tool
and work surface. Thus, superfinishing is capable only of improving the
surface finish
but not dimensional accuracy.
• Mirror like finishes with surface roughness values around 0.01 μm.
• Superfinishing can be used to finish flat and external cylindrical surfaces.

19. Radial & Plunge Mode in Superfinishing
RADIAL MODE
• In Radial Mode both feeding and
oscillation of the superfinishing
stone is given in the radial direction.

20. PLUNGE MODE
• In Plunge Mode the abrasive stone
covers the section of the workpiece
requiring super finish. The abrasive
stone is slowly fed in radial direction
while its oscillation is imparted in the
axial direction

21. APPLICATION
• steering rack components
• transmission components
• camshaft lobes
• hydraulic cylinder rods

22. REFERENCES :-
1)- https://www.slideshare.net/Mechbytes/unit-4a-
grinding?qid=b2dba98b-0f77-4f71-a4c7-
ea34bc0b89d0&v=&b=&from_search=1
2)- https://www.slideshare.net/karanprajapati3/specifications-
of-lapping-honing-and-broaching-machine
3)- https://en.m.wikipedia.org/wiki/Honing_(metalworking)