28-06-2012, 06:08 PM
DESIGN AND FABRICATION OF LAPPING MACHINE
DESIGN AND FABRICATION OF LAPPING MACHINE.pdf (Size: 442.55 KB / Downloads: 219)
INTRODUCTION
In material science, fatigue is the progressive
and localized structural damage that occurs
when a material is subjected to cyclic loading.
The nominal maximum stress values are less
than the ultimate tensile stress limit, and may
be below the yield stress limit of the material.
THE PROPOSED SOLUTION
Fatigue strength can be increased by
increasing the surface smoothness. Even if
after machining of given surface whatever be
the smoothness may be microscopic
discontinuities is left in form of V-Shaped
which can be easily detected by the
microscope of higher resolution. So as to
minimise this surface discontinuity lapping is
carried out. In this model we’re going to lap a
cylindrical model of standard dimension. We
will then compare the fatigue strength of the
given cylindrical material with given unlapped
cylindrical model.
PHASES AND DURATION OF PROJECT
Project consists of following stages:
Design and fabrication of two
cylindrical components.
Design and fabrication of lapping
machine.
Finding and comparing the fatigue
strength of two cylindrical
components.
In first phase two cylindrical
component are designed and are turned in a
lathe machine to desired value of surface
smoothness. The expected duration of
completion of this phase is about one week.
CONCLUSION
The project aims to find out the extent to
which the surface roughness affects the fatigue
strength of the material. Fatigue strength found
to be more if the surface roughness is more. In
other word we can increase the fatigue
strength of the given specimen by polishing
the surface. Surface roughness plays an
important role in the fatigue strength.