Lecture 4:
The General Problem Solving Process
6 March 2009

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Hanna Lestari, ST, M.Eng-FTI-UII

Pareto analysis
- Fishbone diagram
- Gantt chart
- PERT charting
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Product with low profit
Bottleneck operations
Workers complaints
Hanna Lestari, ST, M.Eng-FTI-UII

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Operation Process Chart (OPC)
Flow Process Chart
Flow Diagram
Gang Process Charts
Worker and Machine Process Charts
The Two-hand Process Chart
Hanna Lestari, ST, M.Eng-FTI-UII

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5 Why
◦ Why is this operation necessary?
◦ Why is this operation performed in this manner?
◦ …
4W + 1H
◦ How can the operation be performed better?
◦ Who can best perform the operation?
◦ Where could …
◦ When …
◦ Why …
Hanna Lestari, ST, M.Eng-FTI-UII

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Check sheets
Histograms
Pareto diagrams
Cause and effect diagrams
Stratification
Scatter diagrams
SPC
Hanna Lestari, ST, M.Eng-FTI-UII

5.
6.
7.
1.
2.
3.
4.
Waste from overproduction
Waste from waiting times
Waste from transportation and handling
Waste related to useless and excess inventories
Waste in production process
Useless motions
Waste from scrap and defects
Hanna Lestari, ST, M.Eng-FTI-UII

Function of
Organization
Plan
Do
Check
Action
Decision Making
Process
8 Steps of Problem Solving
1.
Problem
Identification
1. Determining the priority of problem
2. Finding causes of problem
3. Investigate the most important/main causes
4. Determining the steps of improvement
2. Developing Alternatives
Solution
3. Selecting Alternative
4. Implementation
5. Evaluation
5. Do the steps
6. Evaluating the result of improvement
7. Preventing the problem occur again
8. Solve the next problems
Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

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Problem-Solving Tools is called by seven quality control tools. They are:
◦ 1. Check sheet
◦ 2. Histogram
◦ 3. Pareto diagram
◦ 4. Fish diagram (the cause-effect diagram)
◦ 5. Stratification
◦ 6. Scatter diagram
◦ 7. Statistical Process Control (SPC)
Hanna Lestari, ST, M.Eng-FTI-UII

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Hanna Lestari, ST, M.Eng-FTI-UII

◦ Tool for collecting and organizing measured or counted data
◦ Data collected can be used as input data for other quality tools
◦ Collect data in a systematic and organized manner
◦ To determine source of problem
◦ To facilitate classification of data (stratification)
Hanna Lestari, ST, M.Eng-FTI-UII

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50
40
30
20
10
0
90
80
70
60
1st Qtr 2nd Qtr 3rd Qtr 4th Qtr
East
West
North
Hanna Lestari, ST, M.Eng-FTI-UII

Purpose:
To determine the spread or variation of a set of data points in a graphical form
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How is it done?:
Collect data, 50-100 data point
Determine the range of the data
Calculate the size of the class interval
Divide data points into classes
Determine the class boundary
Count # of data points in each class
Draw the histogram
Stable process, exhibiting bell shape
Hanna Lestari, ST, M.Eng-FTI-UII

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Problem areas can be defined by a technique developed by the economist Vilfredo Pareto to explain the concentration of wealth.
In Pareto analysis, items of interest are identified and measured on a common scale and are then ordered in ascending order, creating a cumulative distribution
Hanna Lestari, ST, M.Eng-FTI-UII

Prioritize problems.
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Create a preliminary list of problem classifications.
Tally the occurrences in each problem classification.
Arrange each classification in order from highest to lowest
Construct the bar chart
Hanna Lestari, ST, M.Eng-FTI-UII

 Pareto analysis helps graphically display results so the significant few problems emerge from the general background
 It tells you what to work on first
120
100
80
60
40
20
0
Defects
Dent
104
Scratch
42
Hole
20
Others
14
Crack
10
Stain
6
Gap
4
Hanna Lestari, ST, M.Eng-FTI-UII

Pareto Charts
 Weighted Pareto charts use the quantity of defects multiplied by their cost to determine the order.
900
800
Defect Total
Gap
Dent
Hole
Crack
Scratch
Others
Stain
4
104
20
10
42
14
6
Cost
200
2
Weighted cost
800
208
1
1
5
8
1
100
80
42
14
6
700
600
500
400
300
200
100
0
Weighted cost
Gap
800
Weighted Pareto
Dent
208
Hole
100
Crack
80
Scratch
42
Others
14
Stain
6
Hanna Lestari, ST, M.Eng-FTI-UII

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Also known as ishikawa or cause-effect diagram.
Fish diagrams were developed by Ishikawa in the early 1950s
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No statistics involved
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Maps out a process/problem
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Makes improvement easier
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Looks like a “Fish Skeleton”
Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

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Step 1 - Identify the Problem
Step 2 - Draw “spine” and “bones”
Example: High Inventory Shrinkage at local Drug Stor
Hanna Lestari, ST, M.Eng-FTI-UII

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Step 3 - Identify different areas where problems may arise from
Ex. : High Inventory Shrinkage at local Drug Store employees

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Step 4 - Identify what these specific causes could be
Ex. : High Inventory Shrinkage at local Drug Store
Expensive merchandise out in the open
No security/ surveillance
Anti-theft tags poorly designed

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Ex. : High Inventory Shrinkage at local Drug Store employees attitude new trainee benefits
Shrinkage
Expensive merchandise out in the open
No security/ surveillance
Antitheft tags poorly designed training practices

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Step 5 – Use the finished diagram to brainstorm solutions to the main problems.
Hanna Lestari, ST, M.Eng-FTI-UII

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Stratification is a effort for grouping data into several groups that have the similar characteristics
Use in combo with other tools
Separates data to view patterns
Use before collecting data
Improves estimation
Analyze subsets
Hanna Lestari, ST, M.Eng-FTI-UII

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Purpose:
To identify the correlations that might exist between a quality characteristic and a factor that might be driving it
A scatter diagram shows the correlation between two variables in a process.
◦ These variables could be a Critical
To Quality (CTQ) characteristic and a factor affecting it two factors affecting a CTQ or two related quality characteristics.
Dots representing data points are scattered on the diagram.
◦ The extent to which the dots cluster together in a line across the diagram shows the strength with which the two factors are related.
Hanna Lestari, ST, M.Eng-FTI-UII

How is it done?:
• Decide which paired factors you want to examine.
Both factors must be measurable on some incremental linear scale.
• Collect 30 to 100 paired data points.
• Find the highest and lowest value for both variables.
• Draw the vertical (y) and horizontal (x) axes of a graph.
• Plot the data
• Title the diagram
The shape that the cluster of dots takes will tell you something about the relationship between the two variables that you tested.
Hanna Lestari, ST, M.Eng-FTI-UII

• If the variables are correlated, when one changes the other probably also changes.
• Dots that look like they are trying to form a line are strongly correlated.
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Sometimes the scatter plot may show little correlation when all the data are considered at once.
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Stratifying the data, that is, breaking it into two or more groups based on some difference such as the equipment used, the time of day, some variation in materials or differences in the people involved, may show surprising results
Hanna Lestari, ST, M.Eng-FTI-UII

• You may occasionally get scatter diagrams that look boomerang - or banana-shaped .
 To analyze the strength of the correlation, divide the scatter plot into two sections.
 Treat each half separately in your analysis
Benefits:
• Helps identify and test probable causes.
• By knowing which elements of your process are related and how they are related, you will know what to control or what to vary to affect a quality characteristic.
Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

Hanna Lestari, ST, M.Eng-FTI-UII

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In fact, the five steps described here are useful in the logical and systematic approach to solving almost any problem.
1. Problem Definition.
◦ The definition or formulation of the problem is the first step in the problem-solving procedure, this is often preceded by the need to recognize that a problem exists such as,
 "Costs are too high,"
 "Output must be increased," or
 "There is a bottleneck in order filling in the warehouse.
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2. Analysis of the Problem.
◦ The formulation of the problem may have resulted in a broad statement or definition. Now it becomes necessary to obtain data to sort out the facts and determine how they apply to the problem
3. Search for Possible Solutions.
◦ The basic objective of course is to find the preferred solution that will meet the criteria and the specifications that have been establish. This suggests that several alternative solutions be found and then the preferred solution can be selected from these.

4. Evaluation of Alternatives.
◦ We have now arrived at several solutions or partial solutions to the problem under consideration. In fact, we may have accumulated a large number of ideas bearing on the problem. Some of these can be eliminated rather quickly and the remaining solutions can be considered more carefully. An examination can be made to determine to what extent each solution meets the criteria and conforms to the original specifications
5. Recommendation for Action.
◦ In many cases, the person who solves the problem is not the one who will either use the recommended solution or give final approval for its adoption. Therefore, after the preferred solution has been found, it must be communicated to other persons. The most common form of communication of course is the written or oral report. The written report or the oral presentation then becomes the final step in the problem-solving procedure

Hanna Lestari, ST, M.Eng-FTI-UII