Assignment 2
Operations Management I Indian Food Specialties Limited
Section No.
5
Group No.
AA1
Total Marks Marks Obtained
Sr No. 1 2 3 4 5
Name of Students
Roll No
1. Draw the R Chart and X bar for Mango Salt content AnsSample size
X bar chart
N
A2
D3
D4
7
0.419
0.076
1.924
R bar chart
R'
LCLr
UCLr
LCLx
UCLx
X''
0.865965
0.065813
1.666116
12.76445
13.49013
13.12729
R-Chart 2.50 2.25 2.00 1.75 1.50
R'
e g n 1.25 a R
LCLr
1.00
UCLr
0.75
R''
0.50 0.25 0.00 1 3 5 7 9 11 13 1 3 15 1 5 17 1 7 19 1 9 21 2 1 23 2 3 25 2 5 27 2 7 29 2 9 31 3 1 33 3 3 35 3 5 37 3 7 39 3 9 41 4 1 43 4 3 45 4 5 47 4 7 49 4 9 51 5 1 53 5 3 55 5 5 57 57 Sample number
X-bar Chart 14.00 13.75 13.50 e 13.25 g a r e v A13.00
X' LCL X UCL X
12.75
X''
12.50 12.25 1 3 5 7 9 11 13 13 15 1 5 17 1 7 19 1 9 21 2 1 23 2 3 25 2 5 27 2 7 29 29 31 3 1 33 33 35 3 5 37 3 7 39 3 9 41 4 1 43 43 45 4 5 47 4 7 49 49 51 5 1 53 5 3 55 5 5 57 57 Sample number
2. What are your interpretations about the process, from each of the above charts? Comment on the specific observations and probable causes, if you find that the process is not in control. Ans- Process variability& average are clearly not in control& show that there are some assignable causes which must be investigated to bring the process back in control. Above charts show that process is not generating output, output, on average, consistent with a target value set by the management management for the process. Probable causes are:
Poor mango crop may have led to process variability getting out of control
Workers may not be adhering to specific instructions given to them which may have led to above issues
Chemical hazards such as aflatoxins, microbial hazards such as bacteria & physical hazards such as flint stones, hair etc might have led to the above issues
As the process is out of control so as of now the company is having problem in meeting specifications specifications required by markets in UK & US
3. Draw the R Chart and X bar chart for Mango Acidity. Ans – Sample size
X bar chart
N
A2
D3
D4
7
0.419
0.076
1.924
R'
LCLr 0.140
R bar chart
UCLr 0.011
LCLx 0.269
UCLx 1.573
X'' 1.690
1.631
X Bar Chart 2.250
2.000
e g a r 1.750 e v A
x' LCL x" UCL
1.500
1.250 1 3 5 7 9 11 13 1 3 15 1 5 17 1 7 19 1 9 21 2 1 23 2 3 25 2 5 27 2 7 29 2 9 31 3 1 33 3 3 35 3 5 37 3 7 39 3 9 41 4 1 43 4 3 45 4 5 47 4 7 49 4 9 51 5 1 53 5 3 55 5 5 57 57 Sample Number
R - Chart 0.35 0.30 0.25 e 0.20 g n a R 0.15
R LCL R'
0.10
UCL
0.05 0.00 1 3 5 7 9 11 13 1 3 15 1 5 17 1 7 19 1 9 21 2 1 23 2 3 25 2 5 27 2 7 29 2 9 31 3 1 33 3 3 35 3 5 37 3 7 39 3 9 41 4 1 43 4 3 45 4 5 47 4 7 49 4 9 51 5 1 53 5 3 55 5 5 57 57 Sample number
4. What are your interpretations about the process, from each of the above charts? Comment on the specific observations and probable causes, if you find that the process is not in control. Ans – R Chart
The process went out of the upper control limit two times. The process also exhibits a run pattern i.e. it is sloping continuously downwards Though the process is within the control limits for all other values, it shows some variability across the LCL LCL and UCL UCL The company has been using the process from past when the quality specifications were not stringent.
X Chart
The acidity content was above the upper control limit for the initial days after which it was under control for some time post which it went below the lower control limit As observed from the chart, the level of acidity is out of control for most part of the sampling process
This could be due to the fact that the company hasn’t been stringent on the quality specifications front in the past. Thus, as the quality specifications were implemented initially, the workers may not have been trained to handle such quality checks and the acidity levels went above the upper control limits With the intention to bring acidity levels below UCL, the workers might have tried to lower down the content which could have resulted in the incontrol acidity for a short period But again may be due to lack of training the process could have went below LCL as workers must have tried to control the acidity and might have ended up using low acids A method to control these variations would be to train the workers in terms of quality. Since, they must have been used to the original quality and composition standards from the past they need to be adequately trained. Another probable cause could be an improper mixing process. The process should be monitored so as to gauge the reason for any deviations from the recently set standards
5. Is the process capable of meeting the acidity and salt specifications? Ans - To check if the salt s alt and acidity is capable of meeting the process specification we have to calculate the process capability index and process capability ratio for both processes. Salt Specifications:
Sigma
(Ref:http://www.itl.nist.gov/div8 (Ref:http://www.itl.nist.gov/div898/handbook/pm 98/handbook/pmc/section3/pmc321.htm c/section3/pmc321.htm))
Where d2=3/(A2*sqrt(n)) d2=3/(A2*sqrt(n))
Where A2 is 0.419
Sigma is calculated as 0.321
Xmean of mean=Grand Mean =13.13
Lower specification=12.5 Upper specification=13.5 specification=13.5 Cpk=Min[(UpperSpecification-Gran Cpk=Min[(UpperSpecification-GrandMean)/(3sigm dMean)/(3sigma),(GrandMeana),(GrandMeanLowerSpecification)/(3sigma)] =Min[0.388,0.653] =.388 A check for Variability Cp=(13.5-12.5)/(6*.321)=.5192 The Value for Cpk is way below the critical limit 1(for a three sigma process and the critical values need to get higher as we move towards better quality control process like Five Sigma and Six Sigma). And going by the value of Cp we can say that process variability is the main cause for the systems not being able to meet any of the quality standards.
Acidity:-
Sigma =
(Ref:http://www.itl.nist.gov/div8 (Ref:http://www.itl.nist.gov/div898/handbook/pm 98/handbook/pmc/section3/pmc321.htm c/section3/pmc321.htm))
Where d2=3/(A2*sqrt(n)) d2=3/(A2*sqrt(n))
Where A2 is 0.419
Sigma is calculated as .05185
Xmean of mean=Grand Mean =1.63 Lower specification=1.50 Upper specification=1.70 specification=1.70 Cpk=Min[(UpperSpecification-Gran Cpk=Min[(UpperSpecification-GrandMean)/(3sigm dMean)/(3sigma),(GrandMeana),(GrandMeanLowerSpecification)/(3sigma)] =Min[0.84,0.45] =.45 A check for Variability Cp = (1.70 -1.50)/(6*.05185)=.643 -1.50)/(6*.05185)=.643 Even the acidity level shows s hows that the process variability is extremely high to meet any quality processes. Though the variability in acidity is lesser than in the salt level it’s still below acceptable limits. The management should take measures to reduce variability and run the test again to check for improvements.
6. Mr Hemant Patil, QC manager is convinced with the idea of implementing SPC on the shop floor immediately, immediately, to control the process. What control limits should he adopt? A qualitative discussion is sufficient. Ans - As none of the processes meet any quality standard, we can start by applying the control limit for salt level (12.76-13.49) and for acidity(1.57-1.69). So using this as the base we can reduce the causes of variability in this process. Once significant steps are taken to reduce the variability, take another set of observations and compute the value of CPk and Cp again.
SL NO
Sigma Process
CPk values
1
6
2
2
5
1.67
3
4
1.33
4
3
1.0
5
2
.67
6
1
.33
7. SPC is being followed, is it necesary to follow HACCP? Discuss. Ans The food industry cannot function completely based on statistics, s tatistics, apart from salt and acidity levels there are certain other factors that are of more importance, like bacterial level, microbe level, and potential causes of health issues like food poisoning. Here variability won’t help much, since even one rare case could lead to potential legal issues.
As IFS has expanded abroad it has to be more stringent with regards to the quality. HPCC would be essential since it would improve the overall hygiene, safety and quality of their products. HPCC will also enable the system to identify various risks and helps monitoring such activities. Managers should use HPCC to identify various systems risks and examine the cases of failure. SPC would give us how much these measures have helped reduce the variability and improve the overall consistency in the product.
