Creating a Statistical Process Control Chart (SPC)..... X-Bar

Could I please have some hints and/or examples about how to create SPC
charts with LabVIEW? Specially for X-bar... how could I create it from
Scratch? Thanks in advance for the time and consideration regarding
this matter.

The thing to remember is that SPC was originally implemented during World War II so we are not talking high-tech here. In fact SPC was originally designed to be done using nothing more than graph paper and a pencil. Given that, it's vitally important that you know about how the process works. Therefore my recommendation is to find a book on SPC and read it. This book will tell you not just how to create the various plot types, but what they do and how. An excellent book I can recommend is:
Understanding Statistical Process Control, Wheeler and Chambers, SPC Press, 2nd edition, 1992, ISBN 0945320132
Mike...
Certified Professional Instructor
Certified LabVIEW Architect
LabVIEW Champion
"... after all, He's not a tame lion..."
Be thinking ahead and mark your dance card for NI Week 2015 now: TS 6139 - Object Oriented First Steps

Similar Messages

Statistical process control (spc)

Hello All,
I need some help in building SPC cycle. I succeded in a way to get (Shewhart chart for s) but result is not consistant like:
1) system shows values for control limits fields when I go for overview in QGC1/QGC2/QGC3 but didn't show any limits on chart
2) I am able to see chart only when inspection lot is in change mode and not display mode
3) even when I have chosen Valuation mode as SPC valuation in sampling procedure, system is not considering calculated control limits but considers specificaiton limits mentioned for Inspection Characteristics
I need some guidance on steps to be followed in setting up system, result recording, limit calculation and control chart display.
It would be great if any one can guide me with that or forward me some training/testing documents on SPC.
Thanks and regards,
Devang
Edited by: Devang Shah on Apr 4, 2011 3:06 PM

One correction.
I have a lot of inspection points for each inspection lot

QM Cpk,Cp control chart

Dear all gurus!
I need to check control chart where it is ? how to do configuration or transaction for control charts
and PPM level, and what is Cp & Cpk charts?
Thanks & regards
sudarshan

HI,
Cp stands for process capability.
Cpk stands for process capability index.
Cp and Cpk are measurements of process capabilities. They are used in studies such as process capability and can be used to monitor a process similar to how X-Bar and Range charts are used.
Cp - Inherent Process Capability
Note: in some industries this calculation is called pk.
This is the ratio of the Upper Specification Limit minus the Lower Specification Limit to six sigma. It is denoted by the symbol Cp.
Cp = (Upper Spec Limit - Lower Spec Limit)
6s Actual
Note: s = Sigma
You cannot calculate Cp if your specifications are one sided. In other words, if you specification only has an upper parameter specification limit or a lower specification limit. In these cases, Cp is ignored and only Cpk can be used.
There is some confusion about the difference between Cp and Pk along with Cpk and Ppk. The difference is in how you calculate the actual sigma, or standard deviation, either using an estimate, or the actual calculations. These terms are tossed around a lot and are sometimes used interchangeable, even though they are not. For details see the Sigma/Standard Deviation explanation.
We have made calls out for scientific proof that has been reviewed by peers as to the validity of the estimated way and have as of yet to seen the data. Statistics IS a science, and as such, all theory should be able to be validated by such peer reviews.
Cpk - Process Capability
Note: in some industries this calculation is called Ppk.
This is the capability of the process expressed in relation to a worse case scenario view of the data. It is denoted by the symbol Cpk.
Use it to determine if a process or service, is within the normal variation, and is capable of meeting specifications.
Cpk = the lesser of ...
Cpk = (Upper Spec Limit - Mean) (Mean - Lower Spec Limit )
or
3s Actual 3s Actual
Note: s = Sigma
For an example of a distribution, X Bar, and R Bar charts see our ZeroRejects features page. It makes doing statistical process control charts easy. And at only $150.00, (USD), our software can get you going quickly.
for control chart in sap please follow below link
http://help.sap.com/saphelp_erp60_sp/helpdata/en/4e/a8b43446a1c564e10000009b38f83b/frameset.htm
Regards
Bibhu

Implementing SPC/Control charts in Reporting Services/BI Solution

Hello All
I'm one of the BI specialists in our company - currently looking after our BI solution which incorporates SQL Server 2005, SSRS, SSIS, SSAS, Performance Point, Pro Clarity and various other bits and bobs etc.
What I'm aiming to do, is establish a suite of SPC/Control charts for our portal, based on the suite of cubes we already have. At the moment, I'm thinking of producing these in the SSRS environment, but I'm open to suggestions!
As a starting point, I've created the necessary charts in Excel (calculating averages, standard deviation, upper/lower control limit) etc, but now I'm looking at implementing it in our DWH.
Third party software may be an option (such as Dundas, which keeps cropping up in my crusades!) but I'd like to perhaps generate these myself - if I'm not asking too much that is!
Any advice greatly appreciated...
Cheers
Lee

Hi Lee,
Based on your descriptions, you want to implement Statistical Process Control(SPC) chart in SQL Server Reporting Services. If I have misunderstood, please do not hesitate to let me know.
By default, we only have Column, Line, Shape, Bar, Area, Range, Scatter, Polar charts in SQL Server Reporting Services. As a workaround, we can anaylze the data using SQL Server Analysis Services, and then use these chart to display the data in SQL Server Reporting Services. We can use parameters to filter data.
Third party software may be an option. However, if you want to implement these charts by yourself, we can implement a custom report item in SQL Server Reporting Services. We can start it from here: http://msdn.microsoft.com/en-us/library/ms345231.aspx
If you have any more questions, please feel free to ask.
Thanks,
Jin Chen
Jin Chen - MSFT

The control chart in the sampling method does not match the insp. char. Mes

The control chart in the sampling method does not match the insp. char.
Message no. QD240
how solve?????

You need to compare 'requirement for control chart' and 'control indicator of insp. characteristic'.
1. Requirement for control chart
QCC0 > Quality Planning > Basic Data > Sample, SPC > Statistical Process Control > Define Control Chart Type
See detail for your control chart and check 'requirement' in characteristic type screen area.
2. Control indicator of insp. characteristic
QS24
Check 'control indicator' is suitable for requirement.
Regards, Do Wook KIM

Define control chart tape - SHEWHART X-R

Hi SAP Gurus,
exists any way how to implement SHEWHART X-R chart for statistical process control in SAP? I found some information about it here: How to implement X-R chart in Inspection.
Could anybody give me more detailed informations?
Regards
Lukas

Hello,
For Control limits your chart needs to closed. and offcourse for calculation u need to have more than one inspection lot. then system will calculate the same. UD is also required against lots.
Regards

Regarding SPC control chart

Hi all & Happy frienship Day
Can anybody tell me how to create SPC control chart in QM module .
Thanks & Regards
AMIT

You need to do two things
1. Define char as SPC relevant and it should be of fixed scope.
2. Sampling procedure : Define a sampling procedure of fixed sample size and assign a chart type in sampling procedure.
Now you should be able get control chart for the char when inspection lot created

Spc control chart not showing UCL CL or LCL

Hi people,
I have an spc control chart within my app. However for some reason the UCL, CL and LCL aren't showing on my graph.
A brief background:
This is an app for people entering measurement data into several numberboxes the average of which goes onto the graph. These numbers generally vary from 32.0 to 28.0
The UCL is at 30.6 the CL at 30 and LCL 29.4 However none of these values are showing on the graph.
Has anyone used this control and know why I am having a problem here?
Rik
That glass?
Thats glass is neither half full or half empty....
Its twice the size it needs to be
Solved!
Go to Solution.

Hi Henrik,
Thanks for the contribution however this didn't seem to work. It may be worth noting that I am not using a waveform chart and instead am using a "control chart" which is included in the SPC package.
If I could work out how I would include a picture of my current code however print screen seems to have stopped working (odd eh?)
Basically I have an array going into X and another array going into Y
There is a control which is generated by the control chart called control chart lines. I have hooked up my limits to this.
I can find very little documentation on this control and so have hit a bit of a wall
Vielen Dank für Ihre Zeit
Rik
That glass?
Thats glass is neither half full or half empty....
Its twice the size it needs to be

Issue with displaying QM control chart for specific date range

Dear All
In our chemical mfg organisation, we just implemented SAP QM solution and things are working fine. I have implemented control chart functionalities as below:
SPC Criteria in Inspection Plan: Task List Charateristics / Material (0020)
Sampling Procedure: Fixed Sample / SPC Inspection (without inspection point)
We use process orders to get the inspection lots for products (material) and record results for the MICs and UD the inspection lots.
Currently all our Control Chart have status 1 (created) and we have not moved any of those charts to status 3 and 5 yet.
Using QGC1 when user trying to run control chart for any particular material in the plant and for a specific date range, report showing all the charts for that material with different MICs as expected. Though the result is NOT restricted to the selection dates either against "Lot Created On" or " Insp. Start Date" ( may be due to SPC criteria????) , its always showing all the result for any particular MIC for that material starting from go live till today.
How to restrict the dispaly of result on the chart for any particular MIC against the Material / Plant within a specific date range ?
Looking forward for your response.
Best Regards
SK

Hi,
1. Even though when i give the Created on, and to date the system is displaying the report which is prior to the created on date.
2. Similarly the report data is different when the field is maximum no of Hits is given. for example when i giving this field as 10, 20, 30, etc the report is showing only 10 line items. if i enter 50, 60 etc it is showing the list for half i given.
Note that system is having more than 1000 line items to display..
Regards,
R. Loganathan

How to generate control limits in control chart

I want to generate a X bar chart with control limits, sample size is Fix- 1.
SPC criterion I selected is 020 ie Task List characteristics/ Material.
1)Sampling Procedure I used- Fixed-1
2)Valuation mode I used- Attrib non conforming units/ manual.
3)Control chart I am using is 110- Shewart chart for X bar.
But when I click for control limits in chart it is saying control limits for track 1 could not be calculated.
Could anyone guide me, how to generate control limits for this graph. Sammple size will alwyas be 1.
Please let me know should I change control chart type in this case.

Hi Jaison,
You should use valuation mode - SPC valuation in sampling procedure.
Also you have to use sampling procedure with inspection points.
as practically every hour or depending on the frequency decided we collect the measurements and calculate the SPC.
now after correction in the sampling procedure create new inspection lot and check SPC.
try out and revert.
Regards,
Anil

How to see Control chart for a specific date range in QGC3

Hi
I am developing SPC for my client.I am facing one problem.
I am using one control chart for all inspection lot for a particular MIC.Free inspection point is used in inspection plan.
Control chart is used 516.(XMR chart)
Now when i am calling control chart for MIC executing QGC3,chart is showing results since creation chart date to todays date.
Now if i want to see chart for a particular period or date range,what is the procedure.
Thanks in advance
Nilanjan

Hi,
1. Even though when i give the Created on, and to date the system is displaying the report which is prior to the created on date.
2. Similarly the report data is different when the field is maximum no of Hits is given. for example when i giving this field as 10, 20, 30, etc the report is showing only 10 line items. if i enter 50, 60 etc it is showing the list for half i given.
Note that system is having more than 1000 line items to display..
Regards,
R. Loganathan

Control Chart capabilities

While we were reviewing requirments for our dashboard one element
that was requierd is show Delivery performance in a form of a control
chart. Currently we use minitab to produce this control charts. Minitab
is capable to produce this control chart calculating average,UCL,LSL and
show "error types" when a point is out of UCL LCL limits. Question is that
if oracle tools will be able to produce such control charts or something
similar and determine if we will have to reproduce calculations that
minitab does using custom processes that will be part of the Dashboard.

Hi,
It is the date on which the SPC characteristic is first assigned to the lot. It gives the reference of the lot for which it was assigned first.
Hope this is helpful.

QM-Control charts

Dear all
i have checked all the parameters required to maintain control charts. but when i enter data for in process insp. lot and display control chart an error message occur
"track 1 of the control chart does not contain any data"
so please guide me how can i see the control chart and explain me to rectify that fault.

Hi Shoaib,
Check the following.
Condition 1:
In sampling valuation mode should be SPC Inspection and Control choose any control chart type.
Condition 2:
In result recording your MIC should be single result entry as well as you have to enter more than one result.
Check and revert.
Regards,
Babu

Control chart limit calculation not being done

Hi
I have maintained MIC, sampling procedure and Insp plan for a char and have made two lots with them. Though charts are being displayed correctly, control limit calculation is not being possible. Msg is "Control limits for track 1 could not be calculated".
What customization should be made for this?
And in QGC1/2/3, only one insp lot is there, what went wrong?

Dear Gajesh,
I tried with status 3. When i remove lot created start date, it shows me the fist lot with which we statred SPC in SAP. But If i put any specified start date, it returns no value. Does that mean with status 3 it will show the very 1st lot with which SPC usage started? Then what are the cases for status 1 and 5?
My sampling procedure setting is:
sampling type: Fixed sample
Valuation mode: SPC inspection
W/O inspection point
Sample size: 1
Chart type:115 Shewhart chart for X bar/USA
Inspection plan setting is:
SPC criterion : 020 task list char/materia
Base qty : 1KG
Thanks!

Control chart tolerance limits lines not shown

As Run chart displays values of Single result, SPC Control charts also Displays these reults with tolerance limit with Showing lines of uper and lower limit Tolerence. I have an issue while showing these lines .when i am doing result recording control charts Some times shows tolerance limit lines and some times not ? Kindly clarify me the SPC control chart process too?but my main question is that why SAP some times shows Results and sometimes not .
More over I already did all settings as below
Sapmling procedure with Fixed samples ,and SPC inspection crieteria,
Inspection plan -Inspection task list cahracterstics
MIC
      Sampling proceudre -active
      SPC - Active
      Required Chrac.-Active
      Single result -Active
      Fixed scope -Active
All settings of number ranges is set
Control chart 115 -Shewchart X bar is using .

Hi Vineeth,
We are using SPC inspection chars, in results recordin it is not calulating the control limits automatically. When i click to calculate the control limits, getting the message Control limits for track 1 could not be calculated.
Can you please let me know
1) The process flow for SPC inspection results recording
2) How to get the control limits automatically for SPC inspection chars.
3) System will require some results to calculate control limts, right? So, till system calculates those control limits, how system will valuate results (will it be with specificaiton limits specified at inspection characteristics level), do we have any option of entering preliminary results so that system can control limits on bases of those results and so from very first inspection lot we have control limits for valuation?
Thanks in advance
Bob

Creating a Statistical Process Control Chart (SPC)..... X-Bar

Similar Messages

Maybe you are looking for