Skip to main content

7 QC Tools

 To do any work we require a set of tools, similarly to maintain quality in the product and process we require some tools and these tools are called as Seven Basics Quality Control Tools or 7 QC Tools. These tools not only maintain quality in the industry but also help to resolve the issues or defects, with the help of these tools we can easily solve the problem and find root cause of the problem. These tools are called basic tools as these tools can be used by operators also, these tools don't require any expertise in statistics. 

Before we learn about 7QC Tools, we should understand one important thing that we can't use all tools at the same time, each tools has its own uniqueness. For example to put nail on the wall we require hammer🔨  not axe.

7QC Tools are as follows:

  1. Check sheets
  2. Control charts
  3. Histogram
  4. Fish bone diagram
  5. Scattered diagram
  6. Pareto charts
  7. Stratification or flow chart



1. Check Sheets: Check sheets is online document which is used to check the quality or quantity of the machine/product as per the requirement. In check sheet we usually use tally marks which is easy to do by the operators and easy to read. It give us pictorial view.  

2. Control charts: Control chart is graphical representation of manufacturing process and determine that the product is manufactured in control torrance. In common control chart we have upper limit, lower limit and average limit of the process or product size, the work man have to maintain the quality at average line. 
Control chart is also called Shewhart Chart. As it shows the behaviour of the process it is also called process behaviour chart.
Subgroups of data points are collected and compiled together within a short interval of time. The average of the data points within a subgroup is represented as a single dot in the control chart. Control chart is represented short period like single shift or a day.

3. Histogram: Histogram is a type of Bar graph which is used to represent probability distribution or frequency distribution. Histogram make bell shaped diagram which shows that process lying in which area. It also define how precised process. In 
Histogram we put collected data into bins/cells/bucket/frequency interval. It's show which interval has maximum number of collected data. This is done after number of process is completed and we have to find the variation in process so that we can analyse where (which interval) the problem is. It is use to find area of problem or issue.

4. Fish bone diagram: Fish bone diagram is also called as Ishikawa diagram as it is designed by Kaoru Ishikawa. It commonly known as Cause and Effect diagram as in this we mention possible cause of the effect. It is  called as herringbone diagram and fish bone diagram as it look like fish skeleton 
This tool is used to find the root cause of the problem or some time use to develop new process or system. 
Fish bone diagram need lot of brainstorming by members of different functions. Potential causes found during brainstorming then separate in 6M, mainly known as Man, Machine, Material, Method, Mother Nature, Management/Money. After this fact varification of potential causes is done which finally reflect the main cause which is responsible for problem or effect.



5. Scattered diagram: Scatter diagram is known as scatter plots, scattered diagram is a graph which is used to visually represent the relationship between two variables in order to identify the correlation between them. The data are displayed as a collection of points, each having the value of one variable determining the position on the X-axis and the value of the other variable determining the position on Y-axis. For example, we can plot scattered diagram employees coming late on which day by this we can find on which day we have maximum number of points is the day when employee come late. A scatter plot can be used either when one continuous variable is under the control of the experimenter and the other depends on it or when both continuous variables are independent. 

6. Pareto charts: Pareto chart is a typical chart which is combination of two graphs i.e. bar graph and line graph. Pareto chart is name after famous Italian economist Vilfredo Pareto, he states that 80% of problem is due to 20% of causes. Pareto chart give us clear picture that where we have to focus to solve the problem, by solving main 20% of the causes we will 80% closer to our goal. In Pareto chart we have three axis, Left vertical axis where we define frequency of occurrence, Right vertical axis where we define cumulative percentage of occurrence, Horizontal axis where we define causes of occurrence. 
Pareto chart is important to prioritise the causes. As in Pareto chart bar graph, frequency of occurrence is arrange in decreasing order, which represent VITAL FEW, out of number of causes we can easily focus on 2 or 3 causes which is sufficient to solve 80% of our problem.

7. Stratification or flow chart: stratification is a technique to separate common data from the main data collected from different sources. Strata meaning is a group into which members of a population are divided in statified sampling. Stratification is used in combination with some other analysis tools like scattered diagram, etc. It is important to do stratification of the data as data collected from different sources can give different meaning. For example, different sources has different issues for sale loss.
In few areas stratification is replaced by Flow Chart, flow chart is diagrammatic represent of a process. Flow chart has sequential arrangment of process. Flow chart is used to understand the process, which step of the proces has problem, it gives view that which is the input step and output step of the step in which problem occurs.

Now we understand about 7QC Tools, but when should we use them.
7 QC tools can be used in any quantity improvement project or quantity process development. Basically we use PDCA CYCLE to approach any quality project. In initial planning phase we can use Flow chart, Fish bone diagram, control chart, Pareto chart. In the first phase of measuring and identifying, In DO step we can use Scatter Diagram, Histogram and Checklist. In CHECK step run chart, control chart can be used.

Vibez by Lifelong Smartwatch for women Metal Strap & 1.28" HD Display, Bluetooth Calling, Multiple Watch Faces, Health Tracker, Sports Modes & free silicone strap (Emerald, Gold)

Comments

Post a Comment

Popular Articles

What is FMEA

 FMEA is stand for Failure Mode and Effects Analysis. FMEA is a process analysis tool. FMEA is used to identify all the failures or potential failures that may occur in a process, before any physical error occur in the process and analysis consequences due to failures. It is one of the core tool of IATF16949 . Other core tool of IATF16949 are: APQP: Advance Product Quality Planning PPAP: Production Part Approval Planning MSA: Measurement System Analysis SPC : Statistical Process Control Type of FMEA: There are two type of FMEA: DFMEA (Design Failure Mode and Effects Analysis) PFMEA (Process Failure Mode and Effects Analysis) 1. DFMEA (Design Failure Mode and Effects Analysis): DFMEA is a methodology which is used to analyse the risk or failure during new product or process development, it also used during any change or modification in product or process. 2. PFMEA (Process Failure Mode and Effects Analysis) PFMEA is a methodology which is used to analyse risk or failure during manufact
1 comment
Read more

What is PPAP?

  PPAP is stand for Production Part Approval Proces . PPAP is standard process in automotive and aerospace industries. It is basically written contact between supplier and customer about a product or process through which product will manufacture. It is output of APQP. Intresting thing about pronunciation of PPAP is that is not pronounced as P P A P, where as it is pronounce as P-PAP .   It is one of the core tool of IATF16949 . Other core tool of IATF16949 are: APQP: Advance Product Quality Planning FMEA: Failure Mode and Effects Analysis SPC : Statistical Process Control MSA : Measurement Systems Analysis You can read about above topic by clicking on them. PPAP is very important for supplier and manufacturer, to understand the requirement of customer and also helpful to the customer to know, that, how well product will produce through it's lifetime by manufacturer. PPAP is a risk identification and mitigation process used to provide evident to the customer that there is a relia
2 comments
Read more

What is SPC?

SPC is stand for S tatistical Process Control.   SPC is a tool used for continuous improvement. SPC used to maintain quality by monitoring the process and well detect the possible occurrence of the error before it actually happened and we'll detective. It is one of the core tool of IATF16949 . Other core tool of IATF16949 are: APQP: Advance Product Quality Planning PPAP: Production Part Approval Planning MSA: Measurement System Analysis FMEA : Failure Mode and Effective Analysis   The SPC process is better than other quality tools because it is based on detection and prevention rather than the correction of problems after they have occurred, it means it help us to detect the fault or give indication before error actually occur, which means we can correct the process or the job size before any error occur in our job. It is real time process, so machine operator can easily identify the trend of the job and take corrective action before generation of any NG product. SPC is not only u
1 comment
Read more

What is APQP ?

 APQP is stand for Advance product Quality planning. APQP is a process that is used satisfy product quantity as per customer requirements. APQP is not just a process but it is set of process or framework of process that are used while developing new product or new process. By APQP we ensure that new product or process should well established before product reach to the customer. APQP (Advance Product Quality Planning) is one of the five basic core tool of IATF 16959 . Other four core tools of IATF16949 are: PPAP : Production Part Approval Proces FMEA: Failure Mode and Effects Analysis SPC : Statistical Process Control MSA: Measurement Systems Analysis  Soon we will be writing about these four core tools. In this article we will concentrate on APQP only. There two aims of APQP   Firstly , To increase communication between different departments of the company specially R&D, production, logistics, sales, etc. Most of the work what R&D is doing, is not aware to other departments,
2 comments
Read more

What is LPA?

  LPA is a stand for Layer Process Audit . LPA is Quality technique that focus on how well the process is working or following by the manufacturing Industry at the shop floor. LPA is not just an fault finding audit but it is a process improvement audit as it is audit where changes (Observation Closure) can be done during audit only. By LPA, rejection and other waste is reduced and  work towards continual improvement.  It is one of the important part of IATF16949 (Clause no. 9.2.2.3) and OEM customers (CSR) requirement.  LPA is not only confined with Quality department, rather it include all departments and all level of management and supervisor. Supervisor do LPA at their own function and frequency of doing may be weekly. Middle management do LPA at their function and other functions also but for them frequency of doing audit may be monthly. Senior management do LPA to any one function and frequency is quarterly.  LPA in one of the Audit where supervisor and operator learn about proce
Post a Comment
Read more