7 QC Tools
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Transcript of 7 QC Tools
BASIC PROBLEM SOLVING TOOLS
INTRODUCTION
● Problem Solving Tools - A Systematic, Structured and Organised way to solve a problem.
● Elementary Statistical Methods are used to solve the Problem.
● 80% of all problems within an organisation can be solved by these tools
THE PDCA APPROACH (Deming Cycle)
PLAN
CHECK DO
ACT
1. PlanIdentify problemDevelop plan for
improvement
2. DoImplement plan
on test basis
3. Study / CheckIs the plan working
4. ActInstitutionalize improvement
Continue cycle
THE PDCA APPROACH (Contd…)
TOOL FOR DATA ANALYSIS
● CAUSE AND EFFECT DIAGRAM● PARETO DIAGRAM● GRAPHS● SCATTER DIAGRAM● HISTOGRAM● CONTROL CHARTS● BRAINSTORMING
1.CAUSE AND EFFECT DIAGRAM
Effect
ManMachine
MaterialMethod
Environment
Possible causes: The results or effect.
CAUSE AND EFFECT DIAGRAM (Example)
Why did the Milk Get Sour
Not Fresh Unclean Storage
No hygiene Hands Unclean
Hot weather Process not clear No Training
Sour Milk
Method
Man
Environment
Materials
2. PARETO DIAGRAM
● Helps us prioritize problems● Segregate “Vital Few” and “Trivial Many”
PARETO DIAGRAM (Example)
Factor(Menu)
Freq.(Number Sold)
Cum.Freq. Percent Cum.
Hamburger
Noodles
Fried Fish
Pizza
206
180
70
16
206
386
456
472
44%
81%
97%
100%
Total 472
Effective Space Utilization in Cold Room
PARETO DIAGRAM (Example)
Freq
uenc
y100
80
60
40
20
0
500
400
300
200
100
0 Cum
ulat
ive
perc
enta
ge
Hamberger Noodles Fried Fish Pizza
3. GRAPHS
● The purpose of graph is is to show data in an easy-to-understand manner.
● Use for Analysis and Presentation.● Very good tool for visual display & trend analysis .
Types of Graphs:● Bar Graph● Line Graph● Pie chart
20
15
10
5
0
Num
ber o
f def
ects
First Second ThirdShift
BAR GRAPH (Example)Shift wise Number of Defects.
LINE GRAPH (Example)
8:00 8:30 9:00 9:30 10:00 10:30 11:00 11:30 12:00 12:30
Num
ber o
f pat
ient
s
Time
16141210 8 6 4 2 0
Number of Patients at a clinic at Different Times
PIE CHART (Example)
PROPORTION OF INWARD TELEPHONE CALLS IN A COMPANY
SCATTER DIAGRAM
● Show whether there is a relationship between the main cause and the problem.
● Verify suspected causes identified during Cause & Effect Diagram .
● Identify Problems.● Make predictions
SCATTER DIAGRAM (Example)
Employee A B C D E F G H I J K L M
Years Employed 4 10 8 1 5 2 12 7 9 5 7 9 3
Average monthly Errors 28 12 14 35 20 27 2 23 8 29 13 17 34
RELATIONSHIP BETWEEN THE NUMBER OF ERRORS MADE BY THE TYPIST & EXPERIENCE IN THE COMPANY
SCATTER DIAGRAM (Example) contd…
No. of years employed1 2 3 4 5 6 7 8 9 10 11 12 13
40353025201510 5A
vg. m
onth
ly e
rror
sAVG. MONTHLY ERRORS Vs NUMBER OF YEARS EMPLOYED
HISTOGRAM (Example)
Class Boundary values(wt./bottle) gm
Centre Value(wt./bottle) gm
Frequency
12345678
7.5 – 8.08.1 – 8.58.6 – 9.09.1 – 9.59.6– 10.0
10.1 – 10.510.6 – 11.011.1 – 11.5
7.758.258.759.259.75
10.2510.7511.25
41122312017105
DATA SHEET
HISTOGRAM (Example) Contd…
Content wt./bottle gm 7.75 8.25 8.75 9.25 9.75 10.25 10.75 11.25
30
25
20
15
10
5
0
Freq
uenc
y
STRATIFICATION
● It is a way of sorting out or arranging the data to be collected .
● Purpose of Stratification is to breaking down the causes of the problem into parts to examine each cause better.
STRATIFICATION (example)
Raw Material
Mat
eria
l Str
engt
h
Supplier A
Supplier B