-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
1/15
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
2/15
CONCEPT OF STATISTICAL QUALITY
CONRTOL
f Statistical Quality Control ( SQC ) has been defined as,
monitoring of quality by application of statistical methods in
all stages of production.
f Functions of SQC
f 1. A basis for improved evaluation of materials through more
representative
sampling techniques.
f 2. As a means of achieving sharper control in certain
manufacturing processes.
f The use of SQC permits the evaluation of the magnitude of,
f 1. Chance variation
f 2. Assignable variation
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
3/15
TERMS WE NEED TO KNOW
f 1. Mean
f It is the arithmetic average of a series of values.
f Formula :
f 2. Standard Deviation
f It is an unbiased estimate of the standard deviation of the
population.
f Formula :
f 3. Range
f It is the difference between the maximum and the minimum
value.
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
4/15
TERMS WE NEED TO KNOW
f 4. Normal Frequency Distribution
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
5/15
TERMS WE NEED TO KNOWf Normal Frequency Distribution
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
6/15
QUALITY CONTROL CHARTS
f Used as aids in
f Controlling and analysing physical, chemical, analytic and
biologic parameters of a
product, such as,
f 1. Weight variation of tablets and capsules
f
2. Thickness of tabletsf 3. Volume of liquid filling in a
container
f 4. No. of defects in parenteral products
f Highlighting trends for intra- and inter- batch variation.
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
7/15
TYPES OF QUALITY CONTROL CHARTS
f 1. Charts based on variables
f They are based on continuous distribution of measurements that
can measure
degrees of un-acceptibility
f 2. Charts based on attributes
f They refer to go or no-go situations in which each sample
inspected is tested todetermine whether it conforms to the
requirements.
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
8/15
CONTROL CHARTS BY VARIABLESf Example
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
9/15
CONTROL CHARTS BY VARIABLE
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
10/15
CONTROL CHARTS BY VARIABLE
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
11/15
CONTROL CHARTS BY ATTRIBUTES
f The plan to employ these charts include following steps,
f 1. Sample should be chosen at random
f 2. For easier evaluation there should be a fix no. of sample (
n ) taken each time for
inspection
f 3. Each sample is evaluated so that the sample is accepted or
rejectedf 4. Each sample must be independent i.e., each tablet or
ampule has nothing to do
with another tablet or ampule
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
12/15
CONTROL CHARTS BY ATTRIBUTESf Different terms are used for
constructing these charts,
f 1. No. inspected , n
f 2. No. defective, d
f 3. Fraction defective, p
f Formula:
f 4. Average fraction defective,
f 5. Upper and lower control limits,
f Formula:
f 6. 3 Standard deviation,
f Formula:
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
13/15
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
14/15
CONTROL CHARTS BY ATTRIBUTES
-
8/8/2019 Statistical Evaluation of QC Charts During
Manufacturing
15/15
