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MORE_INFO_MENU
MORE INFORMATION
Select/Click-On a Subject of Interest
#m????;hypertext help#m - Click on the ???? or Press Enter to learn how
to operate the hypertext help system.
A. #mGeneral System Description;system1#m
B. #mRaw Data File Formats;format1#m
C. #mGraphs/Diagrams Overview;graph0#m
D. #mControl Charts Overview;charts0#m
E. #mSearch Chart Patterns Menu;find_pat_menu0#m
F. #mView Patterns Menu;view_pat_menu0#m
G. #mExpert Consultation Menu;consult_menu0#m
H. #mPrint Menu;print0#m
I. #mSPC Editor;edit1#m
J. #mOn line SPC User's Manual;users manual;cspc_man.pgh#m
K. #mDetailed Technical Description;paper;spcpaper.pgh#m
@
format1
STATISTICAL PROCESS CONTROL
CHART INTERPRETATION
RAW DATA FILE FORMATS
#mGeneral Information;format2#m #mU Charts;format15#m
#mRun Charts;format3#m #mBar Graphs;format17#m
#mXMR Charts;format5#m #mPareto Diagrams;format19#m
#mXBAR-R Charts;format6#m #mPie Charts;format21#m
#mXBAR-S Charts;format8#m #mHistograms;format22#m
#mPN Charts;format9#m #mFrequency Polygons;format24#m
#mP Charts;format11#m #mOgives;format25#m
#mC Charts;format13#m #mScatter Diagrams;format26#m
@
format2
RAW DATA FILE FORMATS
1. SPC will generate 8 different types of control charts
- RUN,XMR,XBAR-R,XBAR-S,PN,P,C,U.
2. SPC will generate 7 different types of diagrams/graphs
- BAR, PARETO, PIE, HISTOGRAM Frequency POLYGON, Ogive (CDF)
and SCATTER diagram.
3. Each type of chart/diagram requires a slightly different
format for the ASCII file which contains the raw process data.
4. The #mfirst 4 lines#m of every data file contain titles & axis labels
5. For all types of charts, entries in the raw data file must be
separated by SPACES or RETURNS.
* DO NOT SEPARATE ENTRIES WITH COMMAS, ETC. !!!
@
first 4 lines
RAW DATA FILE FORMATS
FIRST 4 LINES
The first 4 lines of every raw data file regardless of type
will always contain the same type of imformation:
LINE 1 : A TITLE for the graph/diagram
LINE 2 : A SUBTITLE for the graph/diagram
LINE 3 : The X-axis (horizontal axis) label
LINE 4 : The Y-axis (vertical axis) label
@
format3
RUN Chart Raw Data File Format
1. The #mfirst 4 lines#m contain titles & axis labels
è2. All entries in a RUN Chart must be numeric.
3. The length of the chart will be the number of entries.
SPC limits the number of entries in a RUN Chart to 100 or less.
4. A sample RUN Chart raw data file is located in the file
"#trun.gph#t" on your SPC System Disk.
#mSample File;format4#m
@
format4
SAMPLE RUN & XMR CHART RAW DATA FILE
Any Title
Any Subtitle
X Axis Label
Y Axis Label
0.2431
0.2117
0.2994
0.1864
0.3786
0.1103
0.7718
0.3627
0.2125
0.1766
@
format5
XMR (Moving Range) Chart Raw Data File Format
The format for an XMR (Moving Range) Control Chart is identical to
the required format for the RUN Chart.
A sample XMR Chart raw data file is located in the file
"#txmr.gph#t" on your SPC System Disk.
#mSample File;format4#m
@
format6
XBAR-R Chart
RAW DATA FILE FORMAT
1. The #mfirst 4 lines#m contain titles & axis labels
2. The first entry is an INTEGER between 1 and 5 inclusive.
This number represents the logical group size or sample size.
3. The remaining entries (REAL or INTEGER) represent the actual
process measurements.
4. The length of the chart(s) will be the number of process
measurments divided by the logical group size. For example,
if we have a group size of 3 and 69 process measurements, then
the length of the XBAR and R Charts will be 23.
5. Sample XBAR-R raw data files are located in files "#tinbox.gph#t" and
"#trand.gph#t" on your SPC System Disk.
#mSample File;format7#m
@
format7
SAMPLE XBAR_R CHART
RAW DATA FILE
Any Title
Any Subtitle
X Axis Label
Y Axis Label
4
0.2431
0.2117
0.2994
0.1864
0.3786
0.1103
0.1790
0.6853
0.7718
0.3627
0.2125
@
format8
XBAR-S Chart Raw Data File Format
The format for an XBAR-S Control Chart is identical to the required
format for the XBAR-R Control Chart.
A sample XBAR-S Chart raw data file is located in the file
"#txs.gph#t" on your SPC System Disk.
#mSample File;format7#m
@
format9
PN CHART
RAW DATA FILE FORMAT
1. The #mfirst 4 lines#m contain titles & axis labels
2. All entries in a PN Chart raw data file must be INTEGERS.
3. The first entry represents the fixed sample size.
4. The remaining entries represent the number of defectives
(rejects/failures) out of a fixed number of samples.
5. The length of the PN chart will be one less than the number
of entries in the raw data file.
6. A sample PN raw data file is located in the file "#tpntest.gph#t".
#mSample File;format10#m
@
format10
SAMPLE PN CHART
RAW DATA FILE
Any Title
Any Subtitle
X Axis Label
Y Axis Label
100
4
3
5
4
5
5
4
3
3
2
2
@
format11
P CHART
RAW DATA FILE FORMAT
1. The #mfirst 4 lines#m contain titles & axis labels
2. All entries in a P Chart must be PAIRS of INTEGERS!
3. The first integer in each pair represents the sample size.
4. The second integer represents the number of defectives or rejects.
5. The length of the P Chart will be the number of pairs of entries.
6. A sample P raw data file is located in the file "#tptest2.gph#t".
#mSample File;format12#m
@
format12
SAMPLE P CHART
RAW DATA FILE
Any Title
Any Subtitle
X Axis Label
Y Axis Label
115 15
220 18
210 23
220 22
220 18
255 15
440 44
365 47
255 13
300 33
320 38
225 29
@
format13
C CHART
RAW DATA FILE FORMAT
1. The #mfirst 4 lines#m contain titles & axis labels
2. All entries in a C Chart raw data file must be INTEGERS.
3. Each entry represents the number of defects (errors) in a
sample of fixed size/weight/length/etc.
4. The length of the C chart will be the number of entries
in the raw data file.
5. A sample C raw data file is located in the file "#tctest.gph#t".
#mSample File;format14#m
@
format14
SAMPLE C CHART
RAW DATA FILE
Any Title
Any Subtitle
X Axis Label
Y Axis Label
7
5
3
4
3
8
2
3
4
3
2
7
@
format15
U Chart
RAW DATA FILE FORMAT
1. The #mfirst 4 lines#m contain titles & axis labels
2. All entries in a U Chart must be PAIRS of entries!
3. The first entry in each pair can be either INTEGER or REAL
and represents the sample size/length/weight/etc.
4. The second entry must be an INTEGER and represents the number
of defects/errors/etc. in the sample.
5. The length of the U Chart will be the number of pairs of entries.
6. A sample U raw data file is located in the file "#tutest.gph#t".
#mSample File;format16#m
@
format16
SAMPLE U CHART
RAW DATA FILE
Any Title
Any Subtitle
X Axis Label
Y Axis Label
1.0 4
1.0 5
1.0 3
1.0 3
1.0 5
1.3 2
1.3 5
1.3 3
1.3 2
1.3 1
1.3 4
1.3 2
@
format17
BAR Graph
RAW DATA FILE FORMAT
1. The #mfirst 4 lines#m contain titles & axis labels
2. The numeric data for a BAR Graph MUST BEGIN ON THE FOURTH
LINE OF THE RAW DATA FILE.
3. The numeric data consists of PAIRS of entries.
4. The first entry can be any NON-NEGATIVE number.
5. The second entry can be anything - this will be the category
6. A sample BAR graph raw data file is located in the file
"#tdivision.bar#t" on your SPC System Disk.
#mSample File;format18#m
@
format18
SAMPLE BAR GRAPH
RAW DATA FILE
Any Title You Want
Any Subtitle you want
X AXIS LABEL
Y AXIS LABEL
25 Type A
15 Type B
2 Type C
55 Type D
@
format19
PARETO Diagram
RAW DATA FILE FORMAT
The raw data file format for a PARETO diagram is identical to
that for the BAR Graph.
A sample PARETO diagram raw data file is located in the file
"#tdivision.bar#t" on your SPC System Disk.
#mSample File;format20#m
@
format20
SAMPLE PARETO DIAGRAM
RAW DATA FILE
# Errors Per Division
By Division
Major Company Divisions
# Errors 3rd Quarter
55 Division #1
12 Division #2
24 Division #3
105 Division #4
6 Division #5
33 HQ
@
format21
Pie Chart Raw Data File Format
The format for a PIE Chart raw data file is identical to the
required format for the Bar Graph.
A sample PIE chart raw data file is located in the file
"#tdivision.bar#t" on your SPC System Disk.
#mSample File;format18#m
@
format22
Histogram Raw Data File Format
1. The #mfirst 4 lines#m contain titles & axis labels
2. The numeric data for the Histogram must begin on the fourth
line of the raw data file. The numeric data consists of numeric
entries. Each entry can be any number, INTEGER or REAL.
3. A Histogram is limited to 500 numeric entries.
4. Sample Histogram Raw data file is located in file "#thist.dat#t".
#mSample File;format23#m
@
format23
SAMPLE HISTOGRAM RAW DATA FILE
Any Title You Want
Any Subtitle you want
X AXIS LABEL
Y AXIS LABEL
0.25
0.31
0.29
0.28
0.22
0.24
0.25
@
format24
Frequency Polygon Raw Data File Format
The format for a Frequency Polygon raw data file is identical to
the required format for the Histogram.
Sample Frequency Polygon Raw data file is located in file
"#thist.dat#t".
#mSample File;format23#m
@
format25
Ogive (CDF) Raw Data File Format
The format for a CDF raw data file is identical to the required
format for the Histogram.
Sample Ogive (CDF) Raw data file is located in file
"#thist.dat#t".
#mSample File;format23#m
@
format26
SCATTER DIAGRAM
RAW DATA FILE FORMAT
1. The #mfirst 4 lines#m contain titles & axis labels
2. The numeric data for a SCATTER Diagram MUST BEGIN ON THE FIFTH
LINE OF THE RAW DATA FILE.
3. The numeric data consists of PAIRS of entries. Both entries in
each pair can be any number, INTEGER or REAL.
4. The first number in each pair represents the x-coordinate for that
pair, and the second represents the y-coordinate.
5. Sample Scatter diagram Raw data files are located in files
"#tweight.sct#t", "#tnegative.sct#t" and "#tpositive.sct#t".
#mSample File;format27#m
@
format27
SAMPLE SCATTER DIAGRAM
RAW DATA FILE
Height vs Weight
A Hypothetical Sample
Weight (lbs)
Height (inches)
160 70
180 61
220 75
105 61
155 69
@
SPC MAIN MENU
SPC MAIN MENU
A. Select Raw Data File
B. Select Chart/Diagram Type
C. View Chart/Diagram
D. Search Control Chart Menu
E. View Chart Patterns Menu
F. Expert Consultation Menu
G. More Information
H. Print Menu
I. Options
J. SPC Editor
quit
@
system1
STATISTICAL PROCESS CONTROL SOFTWARE
SPC Ver 1.1 March 1992
#mBasic System Description;system2#m
#mDetailed System Description;system4#m
#mPoint of Contact;system3#m
@
system2
SPC is a software tool which automates the processes of
1. CONSTRUCTING and INTERPRETING control charts.
2. CONSTRUCTING BAR graphs, PIE charts, PARETO digrams,
HISTOGRAMS, Frequency POLYGONS, and Ogives (CDFs).
3. CONSTRUCTING and ANALYZING scatter diagrams.
@
system3
SPC was developed by
Mark Shewhart
Process Improvement Division
CSTI/PIAP
Wright-Patterson AFB, Ohio 45433
DSN : 785-7003 COM : (513) 255-7003
@
system4
SPC Version 1.1 Detailed Description
1. Raw PROCESS DATA is collected by the user and placed
into an ASCII file. This file can be created by any
word processing tool. SPC Version 1.1 includes a
built-in text editor for this purpose. The editor can
be used by selecting #mSPC MAIN MENU#m option J.
2. The user enters the name of the ASCII file which contains
the process data. This is done using #mSPC MAIN MENU#m option A.
3. The user then selects the appropriate control chart or
diagram type. This is done using #mSPC MAIN MENU#m option B.
4. While the user may directly select any chart/diagram type,
SPC provides an automated CONTROL CHART selection service.
The user will be asked 1 to 3 questions concerning the nature
of the process data. From these responses, the appropriate
control chart type will be selected. This is also done using
#mSPC MAIN MENU#m option B.
5. The user may at this point view the control chart or
diagram using #mSPC MAIN MENU#m option C.
6. The user may now search a control chart for unusual
patterns. Patterns can be found using 1 of 3 methods :
a. SHORT SEARCH - This is a quick search which only
finds the basic unusual patterns.
b. LONG SEARCH - This is a longer search which will
find all unusual patterns.
c. RETRIEVE - This option retrieves patterns which
resulted from a previous search that
was saved to a file.
This is done using #mSPC MAIN MENU#m option D.
AVAILABLE FOR CONTROL CHARTS ONLY.
7. After the pattern search, the user may then view the unusal
patterns highlighted on the control chart. Each pattern may
be view separately or all together. This is done using
#mSPC MAIN MENU#m option E.
8. After the pattern search, the user may also obtain expert
advice concerning the unusal patterns highlighted on the
control chart. Information about each pattern may
be viewed separately or all together. This is done using
#mSPC MAIN MENU#m option F.
AVAILABLE FOR CONTROL CHARTS ONLY.
9. The user may print out a paper copy of any chart or diagram
by selection #mSPC MAIN MENU#m option H. Several differnt printers,
print densities, and paper orientations are available.
10. At any time, the user may edit the current raw data file (or
any other ASCII text file) by using the SPC integrated
editor. The SPC Integrated Text Editor is availble by
selecting #mSPC MAIN MENU#m option J.
@
in_control1
IN CONTROL!
Your chart is in control! This means that there are
no unusual patterns within the chart which suggest
the presence of #massignable causes of variation;in_control3#m.
Only #mnatural variation;in_control2#m is present.
@
in_control2
NATURAL VARIATION
The random fluctuation of points within the limits results from
variation built into the process. Such random variation is
natural, results from common causes within the system (e.g. design,
choice of machine, preventative maintenance, etc.), and can only
be affected by changing the system itself.
@
in_control3
UNNATURAL VARIATION
However, points which fall outside of the control limits or which
form "unnatural" patterns indicate that some of the variation
within the process may be due to assignable causes. Assignable
causes of variation (e.g.measurement errors, unplanned events,
freak occurrences, etc.) can be identified and result from
occurrences that are not part of the process.
@
maybe_in_control1
IN CONTROL?
Your chart MAY BE in control. This means that the
SHORT or ABORTED SEARCH found no unusual patterns
within the chart which suggest the presence of
#massignable causes of variation;in_control3#m.
Only #mnatural variation;in_control2#m is present.
SUGGEST LONG SEARCH
The SHORT or ABORTED SEARCH could find no unusual patterns
within the control chart. To ensure that there are absolutely
no unnatural patterns, use a LONG SEARCH of the control chart.
@
find_pat_menu0
MORE INFORMATION
SEARCH CHART PATTERNS MENU
1. #mShort Search;find_pat_menu1#m
2. #mLong Search;find_pat_menu2#m
3. #mRetrieve Patterns From File;find_pat_menu3#m
4. #mSave Current Patterns To File;find_pat_menu4#m
5. #mView List of Current Patterns;find_pat_menu5#m
6. #mReturn to SPC MAIN MENU;find_pat_menu6#m
Select an option to provide a
brief summary of the functionality
of each item in the SEARCH CHART
PATTERNS MENU.
@
find_pat_menu1
MORE INFORMATION
SEARCH CHART PATTERNS MENU
Option 1 : Short Search
1. Short Search - This option allows you to quickly search your
control chart for unnatural patterns. This
option only searches for runs, freak points,
freak patterns, and stratification. Trends,
shifts, and cycles will not be identified in
a short search.
This search will be fast on all computers.
@
find_pat_menu2
MORE INFORMATION
SEARCH CHART PATTERNS MENU
Option 2 : Long Search
2. Long Search - This option allows you to search your control
chart for all possible unnatural patterns. A
Long search should be completed before your
chart can be considered "under control".
This search will take up to 15 minutes on computers without
math co-processors. For this reason, options 3 and 4 were
added to allow you to run this lengthy search only once and
then save your results for later use.
@
find_pat_menu3
MORE INFORMATION
SEARCH CHART PATTERNS MENU
Option 3 : Retrieve Patterns From File
3. Retrieve Patterns From File - This option allows you to retrieve
previous pattern search results which
were saved earlier using option 4.
@
find_pat_menu4
MORE INFORMATION
SEARCH CHART PATTERNS MENU
Option 4 : Save Current Patterns To File
4. Save Current Patterns to File - This option allows you to save the
results of your most recent search
to a file for later reference using
option 3.
@
find_pat_menu5
MORE INFORMATION
SEARCH CHART PATTERNS MENU
Option 5 : View List of Current Patterns
5. View List of Current Patterns - This options allows you to view a
list of the results of the most
recent pattern search.
@
find_pat_menu6
MORE INFORMATION
SEARCH CHART PATTERNS MENU
Option 6 : Return to SPC MAIN MENU
6. Return to SPC MAIN MENU - This option returns you to the opening
menu.
@
charts0
CONTROL CHARTS OVERVIEW
TABLE OF CONTENTS
#mThe Need for Control Charts;charts1#m
#mInterpretation of Control Charts;charts3#m
#mControl Limits;charts5#m
#mTypes of Control Charts;charts6#m
#mChart Type Selection Summary Table;charts11#m
#mRUN Charts;charts12#m
#mMoving Range (XMR) Charts;charts14#m
#mXBAR-R Charts;charts13#m
#mXBAR-S Charts;charts16#m
#mP & PN Charts;charts18#m
#mC & U Charts;charts21#m
@
charts1
THE NEED FOR CONTROL CHARTS
Histograms and check sheets consolidate process data to show the
overall picture, while Pareto diagrams are used to indicate problem
areas. These methods group the data for a specified period and
express them in static form. However, in our processes we also
want to know more about the nature of the changes that take place
over a specified period of time, that is, the dynamic form.
This means that we not only have to see what changes in data occur
over time; we must also study the impact of the various factors in
the process that change over time. Thus, if the materials, the
workers, or the working methods or equipment were to change during
this time, we would have to note the effect of such changes on our
process.
One way of following these changes is by using control charts.
@
charts3
INTERPRETATION OF CONTROL CHARTS
Now the problem is to find out whether the points on the graph are
abnormal or not. Such a determination cannot be made unless
standards of evaluation are set. Without such standards, one is
liable to make an arbitrary judgement or one favorable to oneself
and the graph will not be meaningful. When irrational evaluations
are made, necessary action may be missed or unsuitable action may
be taken in haste, thus causing confusion. This will result in
inappropriate conclusions being drawn, thus lowering quality and
efficiency.
STANDARDS FOR EVALUATION
Limit lines can be drawn on graphs to indicate standards for
evaluation. These lines will indicate the dispersion of the data
on a statistical basis and indicate if an abnormal situation occurs
in your process.
@
charts5
CONTROL LIMITS
A graph or a chart with limit lines is called a CONTROL CHART, and
the lines are called control lines. There are three kinds of
control lines :
(1) Upper Control Limit (UCL)
(2) Central Line (or Average)
(3) Lower Control Limit (LCL)
@
charts6
TYPES OF CHARTS
A control chart's form varies widely according to the kind of data
it contains. Certain data are based on measurements, such as the
measurement of length of a product (in mm) or the measurement of
the time required to sort a batch of mail (in minutes). These are
known as indiscrete values or continuous data. Other data are
based upon counting, such as the number of defective articles or
the number of defects in a product. They are known as discrete
values or enumerated data. Control charts based upon these two
categories of data will differ. Click #mX;charts11#m for a summary table.
Three major factors affect the choice of chart type :
1. #mIndiscrete vs Discrete Data;charts8#m
2. #mConstant vs Variable Sample Size;charts9#m
3. #mCounting Defectives vs Counting Defects;charts10#m
@
charts8
Indiscrete vs Discrete Data
1. Discrete (Attribute Data)
Examples include : number of errors
number of rejects
number of reworks
2. Indiscrete (Measurement) Data
Examples include : length
weight
time
@
charts9
Constant vs Variable Sample Size
1. Constant - Examples include :
(a) # pin holes in a fixed area of sheet metal
(b) # rejects out of a fixed batch size
2. Variable - Examples include :
(a) # pin holes in pieces of sheet metal differing
in area
(b) # rejects out of batches differing in size
(c) # typographic errors in letters (of differing
length)
@
charts10
Counting Defectives vs Counting Defects
1. Defectives - This is the number of parts/units/etc that
are rejected or un-usable. Examples include :
(a) # letters returned for rework.
(b) # sheets of metal rejected.
2. Defects - This is the number of flaws in a part/unit/etc.
Example include :
(a) # typographic errors in a letter.
(b) # pin holes in a sheet of metal.
@
charts11
CHART TYPE SELECTION SUMMARY TABLE
Chart-type Measurement-type Sample-size Defects/Defectives
---------- ---------------- ----------- ----------------
Run Continuous 1 N/A
XMR Continuous 1 N/A
XBAR-R Continuous Constant > 1 N/A
XBAR-S Continuous Constant > 10 N/A
PN Discrete Constant Defectives
P Discrete Variable Defectives
C Discrete Constant Defects
U Discrete Variable Defects
@
charts12
RUN CHART
Run charts are employed to visually represent data. They are
used to monitor a process to see whether or not the long range
average is changing.
Run charts are the simplest tool to construct and use. Points
are plotted on the graph in the order in which they become
available. It is common to graph the results of a process
such as machine downtime, yield, scrap, typographical errors or
productivity as they vary over time.
-> Select for an #mExample Run Chart Process Measurement;charts17#m
@
charts13
XBAR-R Chart
The XBAR-R control chart is one that shows both the mean value,
XBAR, and the range, R of a sample. This is the most common type
of control chart using indiscrete or continuous values. The XBAR
portion of the chart mainly shows any changes in the mean value of
the process, while the R portion shows any changes in the
dispersion of the process. This chart is particularly useful
because it shows changes in mean value and dispersion of the
process at the same time, making it a very effective method for
checking abnormalities in the process.
-> Select for an #mExample XBAR-R Chart Process Measurement;charts17#m
@
charts14
MOVING RANGE (XMR) Chart
Sometimes collecting enough data to produce a XBAR-R chart is
inpossible or at least impractical. Sometimes the natural subgroup
size should be one (1) like when a measurement represents a lot
or batch. In this case we need to be able to look at just a single
measurement as a subgroup, hence and individuals chart. But what
about the fact that the range is based on the variation between
subgroup members? In this case, we use a range chart made of the
range of the last two individuals or a moving range chart.
The XMR chart does not detect changes in the process as fast as
an XBAR-R chart. So we should only use them when it is not
practical to use the XBAR-R chart because of limits in data
availability or if the rational subgroup is one (1).
-> Select for an #mExample XMR Chart Process Measurement;charts17#m
@
charts16
XBAR-S Chart
The XBAR-S chart is identical to the XBAR-R chart except that the
R (range) chart is replaced by an S (standard deviation) chart.
XBAR-S charts should be used when the logical group size is
larger than ten (10).
-> Select for an #mExample XBAR-S Chart Process Measurement;charts17#m
@
charts17
SAMPLE PROCESS MEASUREMENTS
RUN, XMR, XBAR-R, & XBAR-S Chart
(a) The length of time a document sits in an "in-box"
(b) The number of hours required to sort a bundle of mail
(c) The diameter of a bore hole in a machining process
@
charts18
P and PN CHARTS
A P chart is one that shows the fraction defective (p), whereas a
PN chart shows the number of defectives (pn). Basically, they are
the same except that a PN chart is used when the size of the
subgroup (sample size) (n) is constant and a P chart is used when
it is not constant. Obviously, when the size of the subgroup (n)
varies, the defective measurement can only be meaningful in
fractional or proportional terms. The P and PN charts are not used
together as are the XBAR and R charts. This is because P and PN
charts show the characteristics of both mean and dispersion of the
process.
-> Select for an #mExample PN Chart Process Measurement;charts19#m
-> Select for an #mExample P Chart Process Measurement;charts20#m
@
charts19
SAMPLE PROCESS MEASUREMENTS
PN Chart
(a) The number of bytes of a 1 Megabyte file incorrectly
transferred via modem.
(b) The number of broken eggs in a carton of eggs.
@
charts20
SAMPLE PROCESS MEASUREMENTS
P Chart
(a) The number of letters returned for rework each day
(This assumes that the number of letters worked each
day may be different.)
(b) The number of customers who leave each day before getting
service due to long delays.
(c) The number of documents which spent more than a total of 4
hours that day sitting in in-baskets.
(d) The number of defective components in batches of varying size.
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charts21
C and U CHARTS
A U chart is used in dealing with the number of defectives when the
material being inspected is not constant in area and length such
as the unevenness of woven materials or pin holes in enamel wire.
A C control chart is used in dealing with the number of defects
which appear in fixed unit samples, such as the number of
imperfectly soldered connections in radios, etc.
-> Select for an #mExample C Chart Process Measurement;charts22#m
-> Select for an #mExample U Chart Process Measurement;charts23#m
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charts22
SAMPLE PROCESS MEASUREMENTS
C Chart
(a) The number of incorrectly soldered connections on a particular
circuit board.
(b) The number of surface flaws in identical pieces of sheet metal.
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charts23
SAMPLE PROCESS MEASUREMENTS
U Chart
(a) The number of misspellings in documents of varying length.
(b) The number of surface flaws in pieces of sheet metal of varying
area.
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view_pat_menu0
MORE INFORMATION
VIEW CHART PATTERNS MENU
1 #mView Graphic of All Patterns;view_pat_menu1#m
2 #m <pattern-type1> <start-point1> to <end-point1> in <chart-type>;view_pat_menu3#m
3 <pattern-type2> <start-point2> to <end-point2> in <chart-type>
4 <pattern-type3> <start-point3> to <end-point3> in <chart-type>
5 <pattern-type4> <start-point4> to <end-point4> in <chart-type>
6 #mReturn to SPC MAIN MENU;view_pat_menu3#m
The following screens provide a brief summary of the functionality
of each item in the VIEW CHART PATTERNS MENU. The particular menu
used in this example would be displayed if 4 patterns were found
in your control chart.
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view_pat_menu1
MORE INFORMATION
VIEW CHART PATTERNS MENU
Option 1 : View Graphic of All Patterns
Use this option to view each unusual pattern highlighted on the
control chart.
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view_pat_menu2
MORE INFORMATION
VIEW CHART PATTERNS MENU
Options 2 - # : View Graphic of a Particular Pattern
Use these options to view specific patterns highlighted on the chart.
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view_pat_menu3
MORE INFORMATION
VIEW CHART PATTERNS MENU
Last Option : Return to SPC MAIN MENU
Use this option to return to the SPC MAIN MENU.
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consult_menu0
MORE INFORMATION
CONSULTATION MENU
1 #mConsult on All Patterns;consult_menu1#m
2 #m <pattern-type1> <start-point1> to <end-point1> in <chart-type>;consult_menu2#m
3 <pattern-type2> <start-point2> to <end-point2> in <chart-type>
4 <pattern-type3> <start-point3> to <end-point3> in <chart-type>
5 <pattern-type4> <start-point4> to <end-point4> in <chart-type>
6 #mReturn to SPC MAIN MENU;consult_menu3#m
The following screens provide a brief summary of the functionality
of each item in the CONSULTATION MENU. The particular menu
used in this example would be displayed if 4 patterns were found
in your control chart.
@
consult_menu1
MORE INFORMATION
CONSULTATION MENU
Option 1 : Consult on All Patterns
Use this option for an expert consultation on each unusual pattern
found in the control chart.
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consult_menu2
MORE INFORMATION
CONSULTATION MENU
Options 2 - # : Expert Consultation for a Particular Pattern
Use these options to for an expert consultation on specific patterns
found in the control chart.
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consult_menu3
MORE INFORMATION
CONSULTATION MENU
Last Option : Return to SPC MAIN MENU
Use this option to return to the SPC MAIN MENU.
@
graph0
GRAPHS/DIAGRAMS OVERVIEW
Select/Click-On An Item of Interest
#mBar Graphs;graph1#m
#mPareto Diagrams;graph3#m
#mPie Charts;graph5#m
#mScatter Diagrams;graph6#m
#mHistograms;graph9#m
#mFrequency Polygons;graph10#m
#mOgives (CDFs);graph11#m
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graph1
Bar Graphs
Bar Graphs are a very simple way of illustrating the nature of your
process data. A bar graph simply illustrates the relative
frequencies or magnitude of data which can be broken down into
distinct categories.
#m * ;graph2#m Sample Bar Graph Data
@
graph2
SAMPLE BAR GRAPH DATA
Frequency Category
----------- --------------
20 Type A
15 Type B
55 Type C
22 Type D
5 Type E
7 Type F
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graph3
The Need For Pareto Charts
There are many aspects of any process that could be improved :
defectives, time allocation, cost savings, rework, etc. In fact,
each problem consists of so many smaller problems that it is
difficult to know just where to begin solving them. In order to
be efficient, a definite basis is needed for any action.
A Pareto chart is the tool to use when you need to display the
relative importance of all of the problems or conditions in order
to : choose the starting point for problem solving, monitor
success, or identify the basic cause of a problem.
#mWHAT IS A PARETO CHART?;graph4#m
@
graph4
WHAT IS A PARETO CHART?
A Pareto Chart is a special form of a vertical bar graph which
helps us determine which problems to solve in what order. Doing
a Pareto Chart based upon either Check Sheets or other forms of
data collection helps us direct our attention and efforts to the
truly important problems. We will generally gain more by working
on the tallest bar than tackling the smaller bars. More information
concerning the use of Pareto Charts is available through SPC's
MORE INFORMATION MENU.
@
graph5
Pie Charts
Pie Charts are simply graphs in which the entire circle represents
100% (not 360 degrees) of the data to be displayed. The circle
(pie) is divided into percentage slices that clearly show the
largest shares of data. This is useful in the same was a a Pareto
Chart. The Pie Chart is sometimes even more useful since it is
widely used to display data on T.V. or in the newspapers. More
information concerning the use of Pareto Charts is available
through SPC's MORE INFORMATION MENU.
@
graph6
Scatter Diagrams
A Scatter Diagram is the tool to use when you need to display what
happens to one variable when another variable changes in order to
test a theory that the two variables are related.
A Scatter Diagram is used to study the possible relationship
between one variable and another. The Scatter Diagram is used to
test for possible cause and effect relationships. It cannot prove
that one variable causes the other, but it does make it clear
whether a relationship exists and the strength of that
relationship. Select for #mSAMPLE SCATTER DIAGRAM DATA;graph8#m.
A Scatter Diagram is set up whereby the horizontal axis (x-axis)
represents the measurement values of one variable, and the vertical
axis (y-axis) represents the measurement values of the second
variable. More information concerning the use of Scatter Diagrams
is available through SPC's MORE INFORMATION MENU.
@
graph8
SAMPLE SCATTER DIAGRAM DATA
Person Weight Height
1 160 70
2 180 61
3 220 75
. . .
. . .
50 105 61
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graph9
Histograms
As we have already seen with the Pareto Chart, it is very helpful
to display in bar graph form the frequency with which certain
events occur (frequency distribution). The Pareto Chart, however,
only deals with characteristics of a product or service, e.g., type
of defect, problem, saftey hazards, etc. (attribute data). A
Histogram takes measurement data, e.g., temperature, dimensions,
etc., and displays it's distribution. This is critical since we
know that all repeated events will produce results that vary over
time. A Histogram reveals the amount of variation that any process
has within it.
@
graph10
Frequency Polygons
Another kind of graphical display of a frequency distribution
(Histogram) is the Frequency Polygon. Here the cell (data range)
frequencies are plotted at the midpoint of each cell and the
midpoints are joined by straight lines.
@
graph11
Ogives (Cummulative Distribution Function)
If the same technique in the Frequency Polygon is applied to the
cummulative distribution function, we obtain what is called an
Ogive (rhymes with alive) or CDF. The only difference is that in
constructing the Ogive (CDF), the cell boundary is used as the plot
point rather than the middle of the cell.
@
print0
SPC Version 1.1 Printer Options
#mBasic Overview;print1#m
#mPrint Status Box;print2#m
#mPRINT MENU;print3#m
#mPrinters/Ports Supported;print4#m
#mPrint Modes/Orientations Supported;print5#m
@
print1
SPC MAIN MENU Option 8 : Print Menu
Option 8 allows you to make a paper print-out of the current chart
or diagram. More detailed help is available by pressing <F1> at
any of the printer option menus.
@
print2
PRINTER STATUS BOX
CURRENT PRINTER SETTINGS
-------------------------------------
Printer Type Epson FX/IBM ProPrinter
Graphics Mode Half Page 75 dpi
I/O Port LPT1
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print3
PRINT MENU
1. Print Graph/Display
2. View Graph/Display
3. Select Printer Type
4. Select Graphics Mode
5. Select I/o Port
6. Save Printer Settings
7. Return to SPC MAIN MENU
@
print4
SPC Version 1.1 supports the following printers :
A. Epson FX/IBM Pro Printer
B. Epson LQ
C. IBM Proprinter X24
D. IBM Quietwriter
E. Toshiba P321
F. HP Laserjet/Desk Jet
G. Post Script
SPC Version 1.1 supports the following printer ports :
A. LPT1 (Parallel Port #1)
B. LPT2 (Parallel Port #2)
C. COM1 (Serial Port #1)
D. COM2 (Serial Port #2)
@
print5
SPC Version 1.1 supports the following print-out orientations :
A. Half-Page
B. Land-Scape
C. Full-Page
SPC Version 1.1 supports the following print densities :
A. 75 dpi (Draft)
B. 150 dpi (Medium)
C. 300 dpi (High)
@
edit1
SPC MAIN MENU Option 9 : SPC Editor
Option 9 allows you to edit any ASCII text file that is in the SPC
directory on your computer. You may directly edit the current raw
data file by selecting Option 1 from the SPC EDITOR MENU. If you
would like to edit any other ASCII text file, select option 2 from
the SPC EDIT MENU. You will then be prompted for the name of the
file you wish to edit. Detailed help on using the SPC Editor is
available from within the editor by pressing <F1>.
SPC EDIT MENU
1. Edit Current Raw Data File
2. Create/Edit Any File
3. Return to SPC MAIN MENU
@
hypertext help
HYPERTEXT INFORMATION SYSTEM
1. You are currently using the hypertext information system.
2. Text which is highlighted in light green or light blue are
referred to as hot links.
3. This is a #mSample Text Hot Link#m Click on this with the
left mouse button or by pressing <ENTER>.
4. "#tdivision.bar#t" is a sample Text File Hot Link. Click
on it with the left mouse button or move the highlight
over it using TAB or CTRL-DOWN_ARROW and then press
<ENTER>.
5. HYPERTEXT window help is availble by pressing <F1>
@
Sample Text Hot Link
After you click on a Text Hot Link, additional text will come
up in a window. #mOther hot links#m may also be in this window.
To go back to the previous window, press ESC or click the
right mouse button.
@
Other hot links
Again, a text box appears. This
may repeat for several levels.
To go back to the previous window,
press ESC or click the right mouse
button.
@