what is 7 QC Tools : definitions, Diagram and it's usages:

7 QC Tools :

The 7 QC (Quality Control) tools are a set of techniques used for process improvement and problem-solving. They were first introduced by Dr. Kaoru Ishikawa, a Japanese quality control expert, in the 1950s. The 7 QC tools are:

1. Pareto Chart.

2. Cause-and-Effect (Ishikawa) Diagram.

3. Check Sheet.

4. Control Chart.

5. Histogram.

6. Scatter Diagram.

7. Flowchart.

1. Pareto Chart: 

A Pareto Chart is a bar graph that displays the relative frequency or size of problems in descending order of importance. It is a useful tool for identifying the vital few causes of defects or problems that contribute to most of the issues in a process.

The chart is named after Vilfredo Pareto, an Italian economist who observed that 80% of the land in Italy was owned by 20% of the population. This principle is known as the Pareto principle or the 80/20 rule, and it is often applied in quality control and process improvement.

To create a Pareto Chart, follow these steps:

• Identify the problem or issue you want to analyze.
• Collect data and categorize the causes of the problem.
• Determine the frequency or percentage of each cause.
• Order the causes from the most frequent or important to the least frequent or important.
• Create a bar graph with the causes on the x-axis and the frequency or percentage on the y-axis.
• Draw a cumulative percentage line by adding up the percentages of each cause from left to right.
• Interpret the chart to identify the most significant causes and prioritize improvement efforts accordingly.

The Pareto Chart is a simple but powerful tool for identifying the most significant causes of problems and focusing improvement efforts where they will have the greatest impact.

usage of Pareto Chart:

Pareto Charts are useful tools in many different industries and contexts. Here are some common usages of Pareto Charts:

Quality Control: Pareto Charts are often used in quality control to identify the most common defects or issues that are causing problems in a production process. By focusing on these issues, improvements can be made to increase efficiency and reduce costs.

Customer Service: Pareto Charts can be used to identify the most common complaints or issues that customers are experiencing. This information can be used to prioritize improvements that will improve customer satisfaction.

Safety: Pareto Charts can be used in safety analysis to identify the most common accidents or incidents that are occurring in a workplace. By focusing on these issues, improvements can be made to reduce the risk of injury or harm.

Sales and Marketing: Pareto Charts can be used in sales and marketing to identify the most common reasons why customers are not purchasing a product or service. This information can be used to prioritize improvements that will increase sales and customer satisfaction.

Inventory Management: Pareto Charts can be used in inventory management to identify the most common items that are in high demand. This information can be used to prioritize the ordering and stocking of inventory items to ensure that the most important items are always available.

2. Cause-and-Effect (Ishikawa) Diagram: 

A Cause-and-Effect Diagram, also known as an Ishikawa diagram or fishbone diagram, is a visual tool used to identify the potential causes of a problem or defect. It was developed by Dr. Kaoru Ishikawa, a Japanese quality control expert, and is commonly used in quality control and process improvement.

The diagram is called a fishbone diagram because it resembles the skeleton of a fish. The head of the fish represents the problem or effect being analyzed, and the bones of the fish represent the potential causes.

To create a Cause-and-Effect Diagram, follow these steps:

• Identify the problem or effect that you want to analyze and write it at the head of the fishbone diagram.
• Draw a horizontal line across the page to represent the backbone of the fish.
• Draw angled lines off the backbone to represent the major categories of potential causes. These categories will vary depending on the problem being analyzed, but common categories include people, process, equipment, materials, and environment.

• Brainstorm potential causes within each category and write them on the appropriate angled lines.
• Analyze the diagram to identify the most likely causes of the problem and prioritize improvement efforts accordingly.

The Cause-and-Effect Diagram is a powerful tool for identifying the potential causes of a problem and can be used to guide improvement efforts. By analyzing the diagram, teams can identify the root causes of a problem and implement targeted solutions to address them.

3. Check Sheet: 

A Check Sheet is a simple and effective tool used to collect data in a structured manner. It is a form designed for recording and organizing data in a way that makes it easy to analyze and understand. Check Sheets are often used in quality control and process improvement to collect data on defects or other issues.

To create a Check Sheet, follow these steps:

• Determine what data you want to collect and organize it into categories.
• Create a form with categories and space to record data. The form can be in paper or digital format.
• Collect data by recording each occurrence of the event or issue in the appropriate category on the Check Sheet.
• Analyze the data to identify patterns or trends and determine the root cause of the issue.

The Check Sheet is a valuable tool for data collection and analysis. It provides a simple and structured way to collect data and organize it for analysis, allowing teams to quickly identify trends and patterns. The tool can be used in a variety of contexts, such as tracking equipment downtime, recording defects in a manufacturing process, or monitoring customer complaints. By using Check Sheets, teams can improve their processes and reduce errors and defects.

Usage of check sheet:

Check Sheets are a versatile tool that can be used in a variety of contexts to collect and analyze data. Here are some common usages of Check Sheets:

Quality Control: Check Sheets are often used in quality control to collect data on defects or issues in a production process. By tracking these issues, improvements can be made to increase efficiency and reduce costs.

Process Improvement: Check Sheets can be used to collect data on any process and identify potential issues or inefficiencies. This information can be used to streamline processes and improve productivity.

Customer Service: Check Sheets can be used in customer service to track customer complaints or issues. This information can be used to improve customer service and increase customer satisfaction.

Safety: Check Sheets can be used in safety analysis to collect data on accidents or incidents in a workplace. This information can be used to reduce the risk of injury or harm.

4. Control Chart:

A Control Chart is a statistical tool used to monitor and control a process over time. It is a graphical representation of process data over time, with upper and lower control limits that indicate the range of variation that is considered acceptable for the process.

The main purpose of a Control Chart is to identify when a process is out of control, meaning that the variation in the data is beyond the acceptable range. When a process is out of control, it is an indication that there is a problem that needs to be addressed. Control Charts can be used to identify the source of the problem and implement targeted solutions to improve the process.

To create a Control Chart, follow these steps:

• Collect data on the process you want to monitor over time.
• Calculate the mean and standard deviation of the data.
• Calculate the upper and lower control limits based on the mean and standard deviation.
• Plot the data on a graph over time, with the upper and lower control limits clearly marked.
• Monitor the data over time and look for any patterns or trends that indicate the process is out of control.
• If the process is out of control, identify the source of the problem and implement targeted solutions to address it.

A graphical tool used to monitor and control a process over time. It displays the variation in a process and helps identify if the process is stable or if there is any special cause of variation.

5. Histogram: 

A Histogram is a graphical representation of data that shows the distribution of values in a dataset. It is a bar chart where the x-axis represents the range of values in the dataset and the y-axis represents the frequency of occurrence of those values.

Histograms are commonly used in statistical analysis to visualize the shape of a dataset and to identify patterns and trends in the data. They can be used to answer questions such as:

1. What is the range of values in the dataset?
2. What is the central tendency of the dataset (i.e., the mean, median, or mode)?
3. How is the data distributed (i.e., is it skewed to one side or does it have a normal distribution)?

A graph that shows the distribution of data. It is used to identify if a process is operating within acceptable limits.

Usage of Histogram:

Data Analysis: Histograms are used to visualize the distribution of data and to identify patterns and trends in the data. They are particularly useful when working with large datasets.

Quality Control: Histograms are used in quality control to identify patterns in the data that may indicate issues with the manufacturing process. They can be used to track defects, monitor product quality, and identify opportunities for improvement.

Finance: Histograms are used in finance to analyze stock prices, interest rates, and other financial data. They can be used to identify trends, track performance, and make informed investment decisions.

6. Scatter Diagram:

A Scatter Diagram, also known as a scatter plot, is a graphical representation of a dataset that shows the relationship between two variables. Each point on the plot represents a single observation in the dataset, with one variable plotted on the x-axis and the other variable plotted on the y-axis.

Scatter diagrams are used to analyze the relationship between two variables, such as:

Whether there is a correlation between two variables.
The strength and direction of a correlation.
Whether there are any outliers or other patterns in the data.

To create a Scatter Diagram, follow these steps:

• Identify the two variables that you want to analyze.
• Plot the values of the first variable on the x-axis and the values of the second variable on the y-axis.
• Plot each observation in the dataset as a single point on the graph.
• Analyze the pattern of the points to identify any trends, correlations, or outliers.

7. Flowchart: 

A Flowchart is a diagrammatic representation of a process, workflow or system, using standardized symbols and arrows to show the sequence of steps and decisions involved. It is a visual representation of a process that shows the flow of information or materials from one step to another.

Flowcharts are used to:

Analyze and improve processes: Flowcharts are commonly used to identify inefficiencies and bottlenecks in a process, and to develop solutions to improve the process.

Communicate and document processes: Flowcharts are used to document and communicate complex processes or workflows to stakeholders, employees or customers.

Standardize procedures: Flowcharts can be used to establish standardized procedures for tasks or processes, ensuring consistency and quality.

Plan and organize projects: Flowcharts can be used to plan and organize projects, identifying dependencies and critical paths, and ensuring that all necessary steps are included.

To create a flowchart, follow these steps:

• Identify the process or system to be documented or analyzed.
• Identify the key steps in the process or system and the sequence in which they occur.
• Use flowchart symbols to represent the steps and decisions in the process, and connect them with arrows to show the flow of information or materials.
• Test the flowchart to ensure that it accurately represents the process or system.

Flowcharts are used in a wide range of industries, including manufacturing, healthcare, finance, and education. They can be used to analyze and improve processes, document procedures, standardize tasks, and plan projects.