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  • 1. Quality Er.Sartaj Singh Bajwa
  • 2. Quality
    • Quality
      • The extent to which a product or service is able to meet customer needs and expectations.
        • Customer’s needs are the basic standard for measuring quality
        • High quality does not have to mean high price.
    • ISO 9000
      • The quality standards of the International Standards Organization.
    Er.Sartaj Singh Bajwa
  • 3. Quality Control Process
    • 1-Prepration of policies regarding quality
    • 2-Fixation of quality standard relating to material & process
    • 3-Designing the production system
    • 4-Inspection and control of materials
    • 5-Inspection and control of process
    • 6-Production of goods and services
    • 7-Inspection of final product and service
    Er.Sartaj Singh Bajwa
  • 4. Objectives of Quality Control
    • Increased sales volume
    • Increased profits
    • Improving the company`s image
    • Improving the production system
    • Better procurement of material
    • To reduce the cost of inspection and losses
    Er.Sartaj Singh Bajwa
  • 5. Quality Circles
    • Small group of employees who meet regularly for solving problems related to cost , quality , efficiency , equipment ,tools etc.
    • In QC it is believed that each individual worker is responsible for quality and productivity
    Er.Sartaj Singh Bajwa
  • 6. Inspection
    • Process of examining an object for identification or checking it for verification of quality and quantity
    • Functions Of Inspection :
    • 1 – To maintain quality of RM , WIP , FG
    • 2 – To locate the defective items
    • 3 – To prevent losses
    • 4 – To detect sources of weakness
    Er.Sartaj Singh Bajwa
  • 7. Types Of Inspection
    • Vendor place inspection ( For raw material )
    • In process inspection
    • 1–Trial run inspection ( to check tool & M/C )
    • 2–First off inspection (items produced at first step are checked )
    • 3–Inspection by self control( checking the operations)
    • 4–Floor inspection(semi-finished goods are checked)
    • Final inspection
    • Post sales quality evaluation ( items rejected by customers should be analyzed)
    Er.Sartaj Singh Bajwa
  • 8. Control Charts
    • Whole production line is divided in sub groups such that variation in the quality , in each sub group is attributed to some change
    • Factors considered while making of the sub groups :
    • 1- Each sub group should be homogeneous
    • 2- Sample should not be taken at regular intervals
    Er.Sartaj Singh Bajwa
  • 9. Control Charts
    • Characteristics/Quality on Y axis
    • Quantity/number on X axis
    Er.Sartaj Singh Bajwa
  • 10. Interpretations of Control Chart
    • If all the points lie within UCL & LCL then the process is said to be in control
    • If one or more points lie beyond UCL & LCL then the process is said to be out of control
    • If points lie predominantly on one side of the central line then we cannot derive any conclusion
    Er.Sartaj Singh Bajwa
  • 11. Types Of Control Charts
    • Control chart for variables
    • 1 – M or Mean charts
    • 2 – R or Range charts
    • Control chart for attributes
    • 1-P chart (to calculate the number of defective items)
    • 2–C chart (to calculate the number of defects)
    Er.Sartaj Singh Bajwa
  • 12. Control Chart For Variables
    • When the quality characteristics is capable of direct quantitative measurement then the control chart is known as chart for variables.
    • Eg life of an item , diameter of a screw
    • Variables in these charts should be such that it can be measured and expressed in numbers.
    • It includes : Control chart for Mean
    • Control chart for Range
    Er.Sartaj Singh Bajwa
  • 13. Control Chart For Mean
    • Basic assumption here is that variability of the characteristic is under control
    • Mean(M) and standard deviation(sigma) of each sub group is calculated with size of the sample(n) to be known then Charts are given by :
    • UCL = M+3 (sigma/square root of n)
    • CL = M
    • LCL = M-3 (sigma/square root of n)
    Er.Sartaj Singh Bajwa
  • 14. Control Chart For Range
    • Basic assumption here is that variability of the characteristic is out of control
    • Value of d and standard deviation(sigma) of each sub group is calculated , with size of the sample(n) to be known then Charts are given by :
    • UCL = d2*sigma+3d3*sigma
    • CL = d2*sigma
    • LCL = d2*sigma-3d3*sigma
    Er.Sartaj Singh Bajwa
  • 15. Control Chart For Attributes
    • In this we cannot have direct quantitative measurement and the items can be classified only as good or bad , accepted or rejected
    • Eg quality of cloth
    Er.Sartaj Singh Bajwa
  • 16. Plotting the P Chart
    • Calculate p (fraction defective in the lot) in sample of size n
    • p = no. of defective items found , q=1-p
    • total no. of items
    • Control charts are given by :
    • UCL = p + 3*square root of(pq/n)
    • CL = p
    • LCL = p – 3*square root of(pq/n)
    Er.Sartaj Singh Bajwa
  • 17. Plotting the C chart
    • Calculate c ( average no. of defects per unit )
    • C= mean of the given frequency
    • Control charts are given by :
    • UCL = c + 3*square root of c
    • CL = c
    • LCL = c – 3*square root of c
    Er.Sartaj Singh Bajwa