7 QC Tools

What Is 7 QC Tools and How To Improve Quality


I would like to welcome you to this lecture on the 7 QC tools by the end of this course you will know what the 7 QC tools are and you will also have a general understanding of how and why each one of the 7 QC tools may be used.  

Okay, are you guys ready to learn some new knowledge? Well, let’s get things started by first providing a general usage definition of 7 quality tools.


What Is 7 QC Tools 

The 7 QC Tools of Quality (or seven QC Tools) may be a set of comparatively straightforward knowledge analysis tools accustomed to support quality improvement efforts. These Devices employed in understanding and up production processes. to resolve nearly all types of downside in a very plant or elsewhere, the seven basic tools of quality may be used are: 


1. Cause and Effect Diagram (it can be the Ishikawa Diagram / Fishbone Diagram)

2. Check Sheet

3. Control Chart

4. Flow Chart

5. Histogram

6. Pareto Chart

7. Scatter Diagram 

Okay guy, Let’s look at the 7 Basic Tools of Quality in more detail. 


1. Cause and Effect Diagram 


Cause and Effect Diagram 


First (7 QC tools)  is the Cause and Effect Diagram. (also called fishbone diagram (after its shape) or Ishikawa diagram (after its inventor): The cause and effect diagram gives a graphical arrangement to the potential causes of a problem(leading to an effect or symptom). This arrangement helps both with brainstorming and understanding areas of opportunity. In addition, it used to find the root cause for an effect. The application also commonly used to identify the problem and to Define the processor issue to be examined. 


2. Check Sheet 

Check Sheet 


The second 7 QC tools is a Check Sheet: Check sheets provide a way to collect and tally data. The individual collecting data simply makes a mark in the appropriate box as a data event is tallied. We do apply this tool When data can be observed and collected repeatedly by the same person or at the same location or When collecting data on the frequency or patterns of events, problems, defects, defect location, defect causes, or similar problems.


3. Control Chart


Control Chart


The third 7 QC tools is that the management Chart: these tools are accustomed to management method variations. management charts are fairly refined run charts that add in limits of applied mathematics variation. This helps groups separate traditional fluctuations engineered into a system from special causes that spike the output. Control chart visual representation of the comparison between actual performance and pre-determined control limits; helps in detecting assignable causes of variation, this tool is also called a chart. Application of this tool commonly used When controlling ongoing processes by finding and correcting problems as they occur and When predicting the expected range of outcomes from a process. 


4. Flow Chart


Flow Chart


Fourthly 7 QC tools are Flow Chart: Flowchart visual representation of the relationship between planned performance and actual performance over a period. A flow chart may be a visual illustration of the trail associate entity takes through a method. This ‘entity’ could be a person, product, or information. We do apply this tool whenever we want to clarify and visualize complex processes. Process flowchart enables you to: Now you already learned 4 of 7 basic quality tools in solving a problem.


5. Histogram




The fifth 7 QC tools which is Histogram: A histogram is a vertical bar chart that depicts the distribution of a set of data. Histogram graph of side-by-side vertical bars representing a frequency separation; it reveals patterns that remain hidden in tables of numbers, sometimes it is substituted or supplemented with a Gantt chart. This tool is used to Compare process results with specification limits. We apply this tool to Summarize large datasets graphically. Class intervals are taken on X-axis, while the frequencies are taken on Y-axis. 


6. Pareto Chart


Pareto Chart


The sixth 7 QC tools is Pareto Chart: Pareto chart based on the Pareto principle (a small percentage of the elements comprising a group accounts for the largest fraction of the value or the impact), it ranks causes from the most significant to the least significant. A Pareto Chart takes advantage of the 80/20rule to visually show the categories with the largest impact on a problem. So When should we use this tool? When there are many problems or causes and you want to focus on the most important. 


7. Scatter Diagram


Scatter Diagram


The seventh 7 QC tools, which is the Scatter Diagram: Scatter chart graph displays the relationship between two variables; which are the variable to be predicted, that is plotted on the vertical (‘Y’) axis, and the variable used to make the prediction (dependent variable)plotted on the horizontal (‘X’) axis. The application of this tool is usually used when we want to determine whether two effects occur relatively by the same cause. The tool confirms the relation between two variables like speed and mileage.  

Different patterns of scatter diagram. Are given hereunder. There are five types in total.i.Perfect positive correlation.Perfect negative correlation.High degree positive correlation.High degree negative correlations. Zero correlation you can see on the left figure, The chart which maintains the accuracy of the data is a mean chart. The mean chart is the presentation of the sample mean value between the control limit for instance the upper control limit (which is UCL) and the lower control limit (LCL). While the left one is a range chart that maintains the precision of data, the range chart is the presentation of the sample range with only control by the upper control limit ( the UCL) In conclusion, 

The 7 QC tools are great ways to visualize information relating to problem-solving.  

2- 7 QC tools be able to improve the quality of processes, products, and services. 

3. These 7 QC tools can be used throughout the midcycle. 

4. It provides evidence of how well the six sigma project has been executed according to its data-driven principles.  

This grouping of 7 QC tools is often credited to Kaoru Ishikawa. While it is clear that he used them, it is not certain that he specifically packaged them together in this grouping. It seems more likely that Lean historians put this bundle together after the fact. Regardless of the origin, though, this set of tools provide a good starting point for continuous improvement training efforts. With this set of tools, there are few problems that can’t be adequately analyzed. In business cases, I recommend that frontline leaders be well-versed in these tools—enough so that they can train and mentor their teams. Production team members, in addition to support staff,



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