OCTOBER 19-20, 2012 - YMCA University of Science & Technology

Proceedings of the National Conference on
Trends and Advances in Mechanical Engineering,
YMCA University of Science & Technology, Faridabad, Haryana, Oct 19-20, 2012
= × 1,000,000
= × 1,000,000
= 191253.6443
So, DPMO is 191253.
3.2.3 Schimdt and Launsby formula [4]
This formula is a basic formula for calculating the sigma level. It just needs the variable i.e. Defects per million
opportunities i.e. DPMO.
Sigma
= 0.8406 + Sqrt (29.37-2.221×ln(DPMO))
= 2.3767
3.3 Analyze Phase
Once all the measurements have been done it is the time to critically analyze the process, and to determine the key
variables and also to determine the next step for the purpose of improvement.
With the help of workers and engineers there and studies have determined the following factors that influence the
product quality:-
• Proportion in which the various raw materials are mixed viz clay, soil, water
• Method of Drying and the time required for drying also plays a vital role
• Rough Handling of the Raw Bricks can also produce defects
• Brick kiln Design
• Method of Firing
• Proper placements of Raw Bricks in the firing chamber during Hacking
• Most of the bricks break during packing and transportation i.e packing and transportation losses
Although the above factors were the key variables that effect the sigma value but it was practically impossible for us
to measure the %age effect that each factor has on the production quality. So it was decided to prepare charts and
analysis report on the no. of defects that are produced at each of the six stages mentioned before .Results are shown
in the following table.
Table 2. Average defects and their effect
Stage Average no. of defects on variation (per 1000) %age effect of each variable
Mining & Storage 0 0
Preparation 4 2.14
Forming the Brick 36 19.25
Drying 71 37.96
Firing & Cooling 47 25.14
De-hacking 29 15.51
Total 187 100
This shows that the no. of Defects in drying stage is maximum followed by firing and cooling, forming, de-hacking
and Preparation. We have almost zero defects in mining stage. So our improvements will be based on this analysis.
920