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