Apr-Jun.12 - the Nitie

pouring. This will eliminate pin holes appearing at
the manufacturer’s logo on the casting.
After every 50 castings produced there should be
a material composition check to avoid defects.
For proper material handling mechanical roller
conveyer should be used. Presently tractor is used
for transportation and castings are dumped very
roughly.
Proper technical training should be imparted
to the workers in respective areas especially in
moulding. They should be provided with good
incentive schemes to stay motivated.
For Hammer:
be maintained around 130 0 c at time of quenching
instead of 80 0 c.
Gating system should be revised.
Insulating sleeves could be used for riser
design.
Ceramic gating system could be used
Some stirring mechanism should be used at the
time of quenching to allow uniform cooling
gradually resulting in uniform hardness
For Nose-ring segment:
Welding with CO 2
instead of simple Arc welding.
Pre heating of welding electrodes and product
itself to remove moisture content.
Proper technical training should be imparted to the
workers in respective areas especially in welding.
3.7 Control phase
The basic objectives of this phase are to ensure that
our processes stay in control after the improvement
solution has been implemented and to quickly detect
out of control state and determine the associated causes
so that actions can be taken to control the problem
before non-conformances are produced. Success in
this phase depends upon how we did in the previous
phases. In control phase, tools are put in place to ensure
that the key variables remain within acceptable ranges
over time so that process improvement is maintained.
Depending up on type of the problem and operating
system of the concern, the following control measures
were recommended:
Periodic review of the various measures suggested
in Improve phase.
Application Statistical Quality Control (SQC)
charts, such as p-charts to check the quality
of the castings and keep it under control, thus
maintaining targeted sigma level.
4 Concluding remarks
The objective to introduce Six Sigma quality
achieved. Quality of three critical products was
improved by reducing their rejection rates by
application of DMAIC methodology of Six Sigma.
The implementation of it resulted in understanding
the problems from all aspects, qualitatively as well as
quantitatively, and laying out the improvements through
of Six Sigma are well reported in large organizations
worldwide. But small industries, especially foundries
are inherently capable of adopting Six Sigma as
breakthrough strategy. They need to show the roadmap.
achieved by the foundry in question by this initial effort
of Six Sigma are attractive enough for them to deploy
Six Sigma company-wide. Following text summarizes
the overall conclusion of the study.
By applying DMAIC methodology of Six Sigma
improvement strategy, the foundry could improve
quality by lowering the rejection rates in three critical
castings. This resulted in to savings in rework time and
of Six Sigma are indicated in table 4.
Vol. 36, No. 2, April-June, 2012
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