7 TOOLS OF QUALITY CONTROL PRESENTED BY: RASHMI VAISH MBA- HAHC
DEFINITIONThe Seven Basic Tools of Quality is adesignation given to a fixed set ofgraphical techniques identified asbeing most helpful introubleshooting issues relatedto quality.
SEVEN TOOLS ARE:• Cause and effect diagram.• Flowchart• Checklist• Control chart• Pareto chart• Histogram• Scatter diagram
CAUSE AND EFFECT DIAGRAM• Identifies potential causes for particular quality problem.• Also known as FISHBONE DIAGRAM.• Head of fish is quality problem.• Head is connect with spine which are various aspects of production process.• Commonly used by quality control team.
FLOW CHART• Schematic diagram of sequence of steps involved in a operation or process.• Provide visual tool that is easy to use and understand.• Give clear idea about how operation works and where problem could rise.
CHECKLIST• List of common defects and number of observed occurrence of these defect.• Simple and effective fact finding tool.• Used to focus on other dimensions like location or time.
CONTROL CHART• Used to evaluate whether a process is operating within expectation relative to measured value.• Chart has two lines above and below central line : upper control line and lower control line.
PARETO CHART• Used to identify quality problem based on degree of importance.• We grade on defect on their occurrence time.
SCATTER DIAGRAM• Show how two variables are related to one another .• Useful in detecting amount of correlation and degree of linear relationship between two variable.• More scatter diagram less correlation between variable and vice versa.
ADVANCE TOOLS OF QUALITY• SQC(Statistical Quality Control)• Control chart for variables and attributes
STATISTICAL QUALITY CONTROL• Used to describe the set of statistical tools used by quality professtional.• Broadly catagorised by: descriptive statistical:-used to describe quality characterstic and relationship.
CONTD…. Statistical process control:-involves inspecting a random sample of the output from a process.Acceptance sampling :- determines whether a batch of goods should be accepted or rejected.
TYPE OF CONTROL CHART• Control charts are one of the most commonly used tools in statistical process control.• The different characteristics that can be measured by control charts can be divided into two groups: variables attributes
CONTROL CHART FOR VARIABLES• A control chart for variables is used to monitor characteristics that can be measured and have a continuum of values, such as height, weight, or volume.
CONTD….• x-bar chart:-A control chart used to monitor changes in the mean value of a process.• Range (R) chart:- A control chart that monitors changes in the dispersion or variability of process.
CONTROL CHART FOR ATTRIBUTES• Control charts for attributes are used to measure quality characteristics that are counted rather than measured.• Attributes are discrete in nature and entail simple yes-or-no decisions.
CONTD….• P-charts:- are used to measure the proportion of items in a sample that are defective.• C-charts:- count the actual number of defects.