Quality Improvement: Problem Solving Seven QC Tools Problem Solving Quality Improvement: Problem Solving

Seven Quality Control Tools Pareto Chart Process flow diagram Cause and Effect Diagram Check sheet Histogram Control chart Scatter diagram Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Pareto Principle Vilfredo Pareto (1848-1923) Italian economist 20% of the population has 80% of the wealth Juran used the term “vital few, trivial many”. He noted that 20% of the quality problems caused 80% of the dollar loss. 7 Quality Tools Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Pareto chart 7 Quality Tools Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Grand total % 100 % How to Construct a Pareto Diagram 80 % Contributors 1. Total the data on effect of each contributor & sum these to determine grand total. 2. Re order the contributors from largest to the smallest 3. Determine the cumulative percent of total 4. Draw & label the left vertical axis. 5. Draw & label the horizontal axis. 6. Draw & label the right vertical axis. 7. Draw bars to represent the magnitude of each contributor’s effect. 8. Draw a line graph to represent the cumulative percent of total 9. Analyze the diagram 10. Title the chart, label the ‘ vital few’ and ‘useful many’ & show the cumulative percent contribution of the vital few. Quality Improvement: Problem Solving

Quality Improvement: Problem Solving

Seven Quality Control Tools Pareto Chart Process flow diagram Cause and Effect Diagram Check sheet Histogram Control chart Scatter diagram Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Flowcharts Flowcharts Graphical description of how work is done. Used to describe processes that are to be improved. 7 Quality Tools Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Flow Diagrams " Draw a flowchart for whatever you do. Until you do, you do not know what you are doing, you just have a job.” -- Dr. W. Edwards Deming. Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Flowchart Activity Decision Yes No 7 Quality Tools Quality Improvement: Problem Solving

Quality Improvement: Problem Solving 4/17/2018 Flowchart A flowchart diagrams the steps in a process. Flowcharts help problem solvers better understand the process so they can highlight quality problems. Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Flow Diagrams Quality Improvement: Problem Solving

Process Chart Symbols Operations Inspection Transportation Delay 4/17/2018 Process Chart Symbols Operations Inspection Transportation Delay Storage

Quality Improvement: Problem Solving Process Chart Operation Transport Inspect Step Delay Storage Distance (feet) Time (min) Description of process 1 2 3 4 5 6 7 8 9 10 11 Unload apples from truck Move to inspection station Weigh, inspect, sort Move to storage Wait until needed Move to peeler Apples peeled and cored Soak in water until needed Place in conveyor Move to mixing area Total Page 1 0f 3 480 30 20 15 360 190 ft 20 ft 50 ft 100 ft Date: 9-30-00 Analyst: TLR Location: Graves Mountain Process: Apple Sauce Quality Improvement: Problem Solving

Quality Improvement: Problem Solving

Seven Quality Control Tools Pareto Chart Process flow diagram Cause and Effect Diagram Check sheet Histogram Control chart Scatter diagram Quality Improvement: Problem Solving

Cause-and-Effect Diagrams Show the relationships between a problem and its possible causes. Developed by Kaoru Ishikawa (1953) Also known as … Fishbone diagrams Ishikawa diagrams 7 Quality Tools Quality Improvement: Problem Solving

Cause and Effect “Skeleton” Materials Procedures Quality Problem People Equipment 7 Quality Tools Quality Improvement: Problem Solving

Fishbone Diagram Quality Problem Machines Measurement Human Process 4/17/2018 Fishbone Diagram Quality Problem Machines Measurement Human Process Environment Materials Faulty testing equipment Incorrect specifications Improper methods Poor supervision Lack of concentration Inadequate training Out of adjustment Tooling problems Old / worn Defective from vendor Not to specifications Material- handling problems Deficiencies in product design Ineffective quality management Poor process design Inaccurate temperature control Dust and Dirt A cause-and-effect diagram, or fishbone diagram, is a chart showing the different categories of problem causes. Quality Improvement: Problem Solving

Cause and effect diagrams To construct the skeleton, remember: For manufacturing - the 4 M’s & E man, method, machine, material, environment. For service applications equipment, policies, procedures, people Quality Improvement: Problem Solving

Cause and effect diagrams Advantages Making the diagram is educational in itself Diagram demonstrates knowledge of problem solving team Diagram results in active searches for causes Diagram is a guide for data collection Quality Improvement: Problem Solving

Seven Quality Control Tools Pareto Chart Process flow diagram Cause and Effect Diagram Check sheet Histogram Control chart Scatter diagram Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Planning for Data collection What question do we need to answer How we will recognize & communicate the answers to the questions -Tells about required data What Data Analysis tools we need to use What type of data do we need in order to construct the tool Where in the process can we get this data Who in the process can give this data How we can collect data from those people with minimum efforts & chance of error. What additional information do we need to capture for future analysis, reference & traceability Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Check Sheet Shifts                 Defect Type           7 Quality Tools Quality Improvement: Problem Solving

Quality Improvement: Problem Solving 4/17/2018 Check Sheet COMPONENTS REPLACED BY LAB TIME PERIOD: 22 Feb to 27 Feb 1998 REPAIR TECHNICIAN: Bob TV SET MODEL 1013 Integrated Circuits |||| Capacitors |||| |||| |||| |||| |||| || Resistors || Transformers |||| Commands CRT | A check sheet is a fact-finding tool used to collect data about quality problems. A typical check sheet tallies the number of defects by previously identified categories. The next step is to graph the defects per category in a histogram. Quality Improvement: Problem Solving

Seven Quality Control Tools Pareto Chart Process flow diagram Check sheet Histogram Cause and Effect Diagram Control chart Scatter diagram Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Histograms A Histogram is a Graphic summary of variation in a set of data. The pictorial nature of the Histogram enables us to see patterns that are difficult to see in a simple table of numbers. This is a good tool to analyze data that contain variation. It tells us about pattern of variation of the process. The tool is most useful to work out Process Capability Index. Hence this tool is used to compare before project & after project process variation spread, pattern, improvement in Cp. Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Steps for Constructing a Histogram 1. Collect the measurements / data. 2. Arrange / Group the data column wise in Table form 3. Find & mark the largest and smallest number / value in each group. 4. Find the largest(Max) and smallest value(Min.) in whole set. 5. Calculate the range of measurements, i.e. Range = Max. - Min. 6. Determine the number of class intervals for the Frequency diagram Guidelines :- No of Readings No of Class intervals < 50 5 to 7 50 to 100 6 to 10 > 100 7 to 12 7. Determine Intervals and Boundaries Interval = Range / Class Interval 8. Determine the frequencies of each class interval with tallies. 9. Prepare the frequency Histogram - mark & label the vertical scale (Frequency) - Mark & label the horizontal scale ( Measurement value) - Draw the columns according to the frequency tallies. - Label the Histogram. Quality Improvement: Problem Solving

Quality Improvement: Problem Solving

“Stem and leaf” displays Data Integrated Circuit Response Time (ps) Quality Improvement: Problem Solving

“Stem and leaf” displays Integrated Circuit Response Time (ps) 3 7 4 4 7 7 4 3 7 9 4 6 0 1 5 6 2 6 7 1 1 5 6 4 8 3 4 5 6 1 6 0 0 Quality Improvement: Problem Solving

Dot diagrams 3 4 5 6 Integrated Circuit Response Time (ps) Plant A Plant B Quality Improvement: Problem Solving

Quality Improvement: Problem Solving What is Graph ? Graph is a diagram which explains connections or inter relations amongst 2 or more things. These connections are represented by a number of distinctive dots, lines, bars, columns. Common type of graphs - Line Graph Column / Bar Graph Pie Graph Quality Improvement: Problem Solving

Seven Quality Control Tools Pareto Chart Process flow diagram Cause and Effect Diagram Check sheet Histogram Control chart Scatter diagram Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Definition of Control Chart A Control Chart is a special type of trend chart used to detect the special causes of variation in the process. Types of Control Charts - For Variables , i.e. For the characteristics that can be measured - X - R Chart For Attributes - For characteristics that can be judges as pass or fail, go or no-go, defective or non-defective etc. - np chart, p chart, c chart, u chart Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Advantages of using control charts - It is a effective tool to control the process statistically (SPC) It helps to detect changes in the process over a period of time and take corrective action. It differentiates chance cause variation & assignable cause variation in the process. It is an effective tool which helps to reduce variations in the process It provides information about process capability. Quality Improvement: Problem Solving

Quality Improvement: Problem Solving Control Charts Quality Improvement: Problem Solving 7 Quality Tools

Quality Improvement: Problem Solving 4/17/2018 Control Chart 27 24 UCL = 23.35 21 c = 12.67 18 15 Number of defects 12 9 Process control involves monitoring a production process and charting the results on a control chart. If any of the points plotted falls outside the control limits, the process is out-of-control. 6 LCL = 1.99 3 2 4 6 8 10 12 14 16 Sample number Quality Improvement: Problem Solving

Seven Quality Control Tools Pareto Chart Process flow diagram Cause and Effect Diagram Check sheet Histogram Control chart Scatter diagram Quality Improvement: Problem Solving

4/17/2018 Scatter Diagram . Scatter diagrams and tightness of points plotted on the graph gives an indication of the strength of the relationship. A cluster of points resembling a straight line indicates the strongest correlation between the variables. In this graph, there is a strong positive correlation between x and y.

Scatter Diagram A Scatter diagram is a graphic presentation of the relationship between two variables. In quality improvement, scatter diagrams are usually used to explore cause - effect relationships in the diagnostic journey. It establishes correlation A example - A Hydraulic system was tripping for indication of overload. The tripping mechanism is provided as safety. The electronic control circuitry was executing safety shut down of the hydraulic system, with Voltage as a signal. The complaint was more in Summer months from areas that were close to large bodies of Water.

Quality Improvement: Problem Solving One of the Probable cause was “ The higher Relative Humidity causes stickiness in the system, leading to increased load and subsequent tripping.” The diagram clearly shows that as Relative Humidity increases the sensor reads higher voltage. This causes circuitry to believe that the hydraulic system had exceeded it limits & trips. Effect Voltage Cause Relative Humidity Quality Improvement: Problem Solving

Quality Improvement: Problem Solving The graphic nature of the scatter diagram helps a team to see the relationship between the variables. The patterns of Correlation - It can be statistically described as Pearson’s Correlation Coefficient A) Linear ( It can be strong or Weak correlation) Negative correlation Positive Correlation B) Non Linear C) No Correlation Quality Improvement: Problem Solving

Quality Improvement: Problem Solving 4/17/2018 Thank You Quality Improvement: Problem Solving