3 Coordinate Measuring Machine is use to inspect a specimen in order to produce a flatter
surfaces. This was done using the technique of design of experiments DOE.
1.2 Background of problems.
Grinding is an extensively used and important machining operation that has been stated to account for approximately 20 to 25 of all machining costs in the
industrialized world Malkin, 1989. Thus, achieving reductions in cycle time while increasing the resultant product quality are significant concerns for manufacturers as
global time while increasing the resultant product quality are significant concerns for manufacturers as global competition increases. To achieve high quality precisions
surfaces in a timely manner, it is important to control the grinding process to create smooth and contiguous surfaces, obtain a desired geometry with tolerances and limit or
mitigate both surfaces and sub surfaces damage to a ground part and to the grinding wheel.
To accomplish this results velocity, position and force must be controlled during grinding. Velocity control relates to the resulting surface finish, while positional controls
determine the geometric accuracy. To limit damage to parts and grinding wheel, current industrial grinding practices is to use slower feed rates reducing productivity. The
surface flatness is improved at the lowest material rate, in this case the flatness of workpiece is reduced when both feed rate and depth of cut is decreases.
4 Control of the grinding force not only reduces the possibility of damages to the parts, but
also affects the surface finish and geometry.
Hence, the author has investigated in detail the flatness produced in surface grinding machine on carbon steel and mild steel.
1.3 Statements of problem
This research study is aimed to find out the answers for the following questions:
i. What is the influence of machining parameters feed rate and depth of cut to
the mild steel and carbon steel in order to produce flatter surfaces?
The results of this study provide the opportunity to improve the obtainable tolerance achievable on a machine, or to improve the throughput on a machine by reducing the
need for spark out passes. Besides that, adjusting the depth of cut during grinding can be used to enhance the dimensional tolerance without the need of additional spark-out
passes. Keith A.H and Steven Y.L, 1998.
While the surface also contributed an importance factor in the industry, flatness is a form tolerances commonly attached to planar surfaces. For example, flatness is a critical
tolerance in the assembly of power train. When the engine cylinder heads is bolted to the engine block, the two mating surfaces must be flat to prevent the distortion of the
cylinder heads. Similarly, when the transmission valve body is bolted to the transmission cases, the two mating surfaces must be flat to ensure a tight seal and prevent
transmission fluid from leaking.
In the manufacture of precision parts and assemblies, especially where the parts will be required to be connected across a surface area in an air-tight or liquid-tight manner,
5 flatness is a critical quality of the manufactured surfaces; such surfaces are usually
machined or ground to achieve the required degree of flatness.
According to Beers and Tucker, Poor wringing contact of gage block can cause an erroneous flatness measurement. In manufacturing gage blocks, the gagging faces edges
are slightly beveled or rounded to eliminate damaging burrs and sharpness. Allowances should be made for this in flatness measurement by extracting the fringe tips where they
drop off sharply at the edges. Allowance varies but 0.002 inch is a reasonable bevel width to allow.
On the ease, efficiency and cost of finishing out tenant spaces, slab flatnesslevelness also has a major impact .The construction and installation of door frames, movable
partitions, pre-fabricated cabinetry and elevator landings are impacted by the flatness and levelness of the floor slabs. Therefore flatness is important in order to increased
inspection throughput, to reduced inspection cycle time, high-accuracy, large table dimensions, and to get a higher overall part quality.
Besides that, the flatness technology currently becomes importance in the engineering industry because of the several factors:-
i. A realization of the importance of the manufacturing process as the final
link in the design through manufacturing route. ii.
There is a desire by industry to reduce costs and improve quality in the face of international competition.
iii. There is a growing recognition of the legal implication of product
performance. iv.
Data hitherto assumed accurate have been found to be either unreliable or as insufficient explanation of surface phenomena.
6 v.
There are been several catastrophic failures which, when the evidence was analyzed, showed the danger of surface and sub surface material
transformation caused by exercise heat generation during manufacture. vi.
Major limitation of flatness vii.
The requirement for higher power to weight ratios and improved engine performances has lead to development of higher strength steels and the
use of thinner sections.
1.4 Objectives
