ISHIKAWA DIAGRAM / CAUSE EFFECT DIAGRAM / FISHBONE DIAGRAM

A cause effect diagram is a graphical tool to explore and display the possible causes of a certain effect. The cause effect diagram using the natural categories ( man, method, equipment, environment and people) is called classic cause effect diagram and the diagram made to show causes of problems at each step is called process-type cause effect diagram.
Benefits of making a cause effect diagram may be

•  It helps people to understand that there are many problems that contribute to an specific effect.
•  It diagrammatically displays the relationship that causes to the effect and to each other.
•  It helps to understand areas of improvement.

STEPS FOR MAKING A CAUSE-EFFECT DIAGRAM:

STEP 1:- Write the effect in a box on the right hand side of a page, draw a horizontal line to the left of effect.

STEP 2:- List the major categories of factors of effect that are to be studied and draw diagonal lines above and below the horizontal line and label them with categories you have choosen.

STEP 3:- Generate list of causes in each category.

STEP 4:- List the causes on each diagonal respectively and draw branches on them to show relationship among causes.

STEP 5:-  Develop the causes by asking "why?" until you have reached a useful level of detail i.e., when the cause is specific enough to be able to test a change and measure its effect.

HELPFUL HINT.:-

Consider using a positive effect (an objective, for example) instead of a negative effect (a problem, for example) as the effect to be discussed. Focusing on problems can produce “finger pointing,” while focusing on desired outcomes fosters pride and ownership over productive areas. The resulting positive atmosphere will enhance the group’s creativity.

EXAMPLE:-

THANK YOU...

YOUR FEEDBACK AND QUERIES ARE MOST WELCOME.

PARETO CHARTS

It is a technique for prioritizing possible changes by identifying the problems that will be solved by making this approach in other words it is used to graphically summarize and display the relative importance of the difference between groups of data.

Pareto Charts are based on 80-20 rule i.e. it divides the causes for a problem into vital few and trivial many i.e. 20% of causes generate 80% of the results. With this tool we try to find that 20% of work which will generate 80% of positive results.

STEPS TO USE THE TOOL.

STEP 1:- IDENTIFY AND LIST PROBLEMS
Find out all the existing problems, it may be the defects or customer problems and make a list of them.

STEP 2:- IDENTIFY ROOT CAUSE FOR EACH PROBLEM
Find out the fundamental cause for each problem, use techniques such as BRAINSTORMING, WHY-WHY ANALYSIS, ROOT CAUSE ANALYSIS etc to direct you to exact causes.

STEP 3:- GIVE A SCORE TO PROBLEMS
Now you need to score your problems, scoring depends upon the results you are trying to achieve. If you are looking for cost reduction then you must look for things that cost you extra money.

STEP 4:-GROUP PROBLEMS CAUSED BY SAME CAUSE
Now you need to group the problems that are caused by same root cause. For example:- you can group the problems caused by lack of staff together.

STEP 5:-ADD UP SCORED FOR EACH GROUP
Now add up the scores for each group, the group with top score is your top priority and the one with lowest score is least priority.

STEP 6:-TAKE ACTION
Now you need to take action on your top priority problem.

SOLVED EXAMPLE :-

Now when we see the above chart carefully we will realize that 80% of our problems are caused due to the first two problems i.e. traffic tie-up and woke up late, hence most of our problems are solved by solving these problems.

OVERALL EQUIPMENT EFFECTIVENESS (O.E.E.)

The effectiveness of an equipment is the actual output over the reference output, it shows how effectively an equipment is utilized when compared to an ideal equipment.
In other words, it is used to evaluate how well an manufacturing machinery is utilized in an organization. However it is not the absolute measure rather it is used to identify scope for process improvement and how to get the improvement.

O.E.E. divides the overall performance of an manufacturing machinery into three measurable factors, namely :-

• Availability
• Performance
• Quality

AVAILABILITY:-

This metric represents the percentage of scheduled time the machine is available to operate i.e. total planned production time subtracting the unplanned downtime.

AVAILABILITY= RUN TIME / PLANNED PRODUCTION TIME

 PERFORMANCE:-
This metric represents the speed at which the machine works as the percentage of its designed speed i.e. how well a machine is running when it is running.

PERFORMANCE = (PARTS PRODUCED*IDEAL CYCLE TIME)/RUN TIME

QUALITY:-
This metric represents the percentage of good units produced as the percentage of total units produced i.e. good parts produced vs bad parts produced.

QUALITY = NO. OF GOOD PARTS / TOTAL PARTS PRODUCED 

 OVERALL EQIPMENT EFFECTIVENESS

MAJOR LOSSES IN O.E.E.:-

O.E.E. CALCULATION EXAMPLE:-

7 TOOLS OF QUALITY CONTROL.

The SEVEN TOOLS OF QUALITY is a name given to the basic 7 tools used by quality personnel around the world to counteract on quality related issues. They are also called basic tools of quality assurance because they are easy to implement and understand.

• CAUSE AND EFFECT DIAGRAM:- (also called fishbone diagram or Ishikawa diagram) It is used to identify as many possible causes for a for a problem and divides them into useful categories.
• CHECK SHEET:- It is a format used to collect required data and analyzing it, it can be adopted for a variety of purposes in an production organization.
• CONTROL CHART:- It is a graph used to study process variations over time or with changing conditions, it is used to assure that the effect of changing causes stays within restricted limits.
• HISTOGRAMS:- It is a graph used for spotting frequency distributions i.e. it is used to highlight the different values in a collection of data.
• PARETO CHARTS:- They are used to distinguish the significant causes from less significant one, it helps in dividing the causes into vital few and trivial many.
• SCATTER DIAGRAM:- They are used to plot a paired data, one on each axis so that a relationship can be established between them.
• STRATIFICATION:- It is used to differentiate between data collected from variety of resources and visualizes the data variation trend observed from different sources and establishing a relationship between them, if any. 

WORK DISTRIBUTION / PRODUCTION LINE BALANCING

In an organization each part or product is to be manufactured to a deadline and with high degree of quality and accuracy. To successfully run an production organization the work in assembly or production lines is needed to be balanced to be produced in desired time.

LINE BALANCING

Line balancing means to distribute the work content to balance the cycle time to the rate of customer demand.

There are some line balancing parameters required to aid in line balancing.

• Takt Time Equation
• Line balance ratio (L.B.R)
• Line arrangement efficiency (L.A.E.)
• Optimum manpower equation.

Once the takt time is calculated by using the customer demand, time study of various process is needed to be done and the time required for various processes is needed to be noted down.

When you have the details of time required for various processes and the takt time then a graph can be made to visually represent the findings.

Consider the following time operation graph:-

Once the graph is plotted you can calculate the following parameters:-

LINE BALANCE RATIO:

LINE ARRANGEMENT EFFICIENCY:

OPTIMUM MANPOWER:

*Note:- For LINE BALANCE RATIO & LINE ARRANGEMENT EFFICIENCY the ideal case value is 100%.

Now, from the results obtained we can balance the works so as to keep the cycle time of each process under the takt time .

Once the adjustments are made the Line balance ratio and Line arrangement efficiency can be recalculated to measure the benefits of the adjustments made.

*Note:- It may take multiple attempts to balance a line practically so don't get dishearten if you did't achieve optimum results in one or two times.

CONSIDERING THE FOLLOWING EXAMPLE WILL RE-CLEAR YOUR CONCEPTS:-

*Notes:-

• L.A.E. depends on manpower i.e. it will only change if number of operators are altered during adjustments.
• L.A.E. will reach 100 % when sum of times of all process is equal to the product of takt time and number of operators. 

LEAD TIME AND CYCLE TIME..

LEAD TIME and CYCLE TIME

LEAD TIME is the delay between initiation and execution of process. In simple words LEAD TIME is defined as time taken between receiving and order and delivering the product.

CYCLE TIME on the other hand is described as the total time required from beginning to end of process, it includes process time during which a unit is acted upon to bring closer to output and the waste and non value added times.

For a line assembly process cycle time is the time required for the most time taking process to complete. The most time taking process is also called the bottleneck process.

Consider the following example:

In the above time-operation distribution chart process four is the "bottleneck process" and hence determines the cycle time of the process. 

TAKT TIME

TAKT TIME:-

Takt Time is the time available for producing one unit so as to meet the customer demand exactly on time. 

For Example:- If a customer demands 5000 pieces of a certain product "x" every day. Then the takt time for product "x" can be calculated by dividing the required customer quantity by the planned production time for that day.

It should be kept in mind that Takt Time is calculated by taking into consideration the net available time for production excluding the planned breaks and changeover time.

The wholesome use of Takt Time calculation is to match the production with customer demand. It facilitates organizations to manage their production planning schedules to be up to date with their customer's requirements. Takt Time is also the standared for production line balancing. The bottlenecks are balanced so as to be under the Takt Time so that production is not delayed.

MOTION ECONOMY CHARTS

Motion Economy Charts are used to provide suggestions regarding reduction of fatigue and unnecessary movement by the worker, which can lead to reduction of work related trauma. A motion economy charts provides score to various categories of requirements in a workplace so that areas of prime concern can be focused upon.

A example of Motion Economy Chart is shown below.:-

                                                                                                                                                The score of 1 means that it is the area of our prime concern and major unnecessary motion takes place due to this cause. So, now we get the prime waste motions occuring in our production procedure and we can easily work on to eliminate those.

Scores are based upon time wasted in that particular category .

For Example:

The worker takes 180 seconds in finding the right fixture for his job, so we will provide it a score of 1 and plot it on the representation.

Then we can reduce the motion by conducting KAIZEN's .