Stastistical Techniques in Chemical Industry

Atul Khandekar

Quite Involved in Discussions
#1
Can someone provide any pointers to what statistical techniques are used in chemical / pharma industries for both batch and continuous processing? Is there anything different?

Thanx
 
Elsmar Forum Sponsor

Marc

Hunkered Down for the Duration
Staff member
Admin
#2
There is a difference but I admit I cannot explain details.

I remember back about 5 years ago this came up with a client. There was a difference in how they chose samples among othe things. Sorry I can't help personally. Maybe a CQE here can help.
 
V

venkat

#3
I was with pharma industry for a brief period.
In batch process each batch is identified bya separate tag and identified at the end in terms of yield, purity and overall quality of the product.
In case of continuous process the output of one step is the input for another and as such samples are withdrawn and checked and sampling technique is used based on the quantity of the material involved.
 

Darius

Quite Involved in Discussions
#5
Control Charting on Contiuos Process

In may experience, the problem with chemical continuos processing and control charts,:confused: is that some of the references recommend the use of individual and moving range, but something is left out, the autocorrelation between samples.
Some sites reccomend the use of other charts like EWMA or CUSUM, I tink they are excelent tools, but the objetive of them is to detect small changes in the mean (likely to be important in farmaceutical but not in chemical industries in general). :frust:
In Advanced topics on SPC from Donald Wheeler and some articles published on statistics say something about the autocorrelation coefficient, but there is not much information about, I used it and works fine for me.
There are some cases that even this coefficient does not work, when the quality is not affected by changes between specification limits, in that cases, some operators work at one setup, others on on a different ones, so in that cases precontrol charts work fine. :truce: I tink, the use of precontrol is against many SPC preformers, but it´s my belief, I hope this may help.
 

Atul Khandekar

Quite Involved in Discussions
#6
Re: Control Charting on Contiuos Process

Darius said:
In Advanced topics on SPC from Donald Wheeler and some articles published on statistics say something about the autocorrelation coefficient, but there is not much information about, I used it and works fine for me.

There are some cases that even this coefficient does not work, when the quality is not affected by changes between specification limits, in that cases, some operators work at one setup, others on on a different ones, so in that cases precontrol charts work fine. :truce: I tink, the use of precontrol is against many SPC preformers, but it´s my belief, I hope this may help.
Darius,
Could you please elaborate / provide some website links where I can read more about this. Any examples of use of pre-control?
Thanx,
_Atul.
 

Darius

Quite Involved in Discussions
#7
About autocorrelated process, there is just a few references

http://www.asq.org/pub/jqt/past/vol32_issue4/qtec-395.pdf

and a book

"Advanced topics in Statistical Process Control", the power of Shewhart's Charts by Donald J. Wheeler. SPC press, 1995
Chapter 12, Control Charts for Autocorrelated Data

It's a shame that Wheeler wrote many articles in quality magazine (that you can see on the net), but any about the subject.

In the book, he said that the autocorrelation coefficient does not affect when there is low autocorrelation, so, it's safe to use it anytime, and such is my experience.

:bigwave:

PreControl has it's uses, as Steiner said,

"in the final paragraph on control charts of Ishikawa ’s (1982)famous guide,where he wrote “Control charts are easy to construct so are widely used.But there are surprisingly few really useful charts ”

http://www.asq.org/pub/jqt/past/vol32_issue4/qtec-370.pdf

But one example that came into my mind is: when the process is drifting (going up or down) very slowly, of course SPC rules could detect it but as a run up or down, but in a chemical process the run up or down could not be a special cause, because most of the time is what is expected.

What, if you can not change anything (reduce variation of the variable), but you want to keep an eye upon the behaviur of the variable, to understand the relationship between variables, or to know what to expect of the process if a parameter is changing.

Darius

:smokin:
 
Last edited:

Darius

Quite Involved in Discussions
#9
About autocorrelated process, I like to explain a little more:

There are two ways is wich autocorrelation affects periodically collected data, excessive autocorrelation will have visible impact upon:

1. the running record (bu is something that most of the times happen in a continuos process without being a special cause condition)
2. the control limits calculated according to the usual formulas, the "contimated limits" will be narrower than they should be in order to properly characterize the process.

Calculation:

Autocorrelation_Coefficient=1/(1-r^2) ^0.5

being r the sample correlation coefficient, calculated using

v(1),v(2)...v(n)

x(1)=v(1), y(1)=v(2)
x(2)=v(2), y(2)=v(3), and so on


Sigma = Range_Average/d2*Autocorrelation_Coefficient

Darius.
 
Thread starter Similar threads Forum Replies Date
J Mechanical inspection techniques of close tolerance parts Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
H Statistical Techniques Procedure - What should be included Document Control Systems, Procedures, Forms and Templates 4
M Acceptance of remote auditing techniques - Can you help me with my research? General Auditing Discussions 0
V Acceptance Criteria Gage R&R - Simple vs Complex Techniques Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 8
L When are Statistical techniques not applicable? Service Industry Specific Topics 16
Q Problem Solving Techniques - 5 why or Fishbone diagram ? Problem Solving, Root Cause Fault and Failure Analysis 8
J Defining Martial Arts and Gymnastics Statistical Techniques Statistical Analysis Tools, Techniques and SPC 4
G Examples of Quality Management Techniques Quality Manager and Management Related Issues 6
Q Production Planning Templates, Tools & Techniques Document Control Systems, Procedures, Forms and Templates 1
M Autocorrelation Techniques (Student Question) Statistical Analysis Tools, Techniques and SPC 6
P What are FMEA Risk assessment techniques? FMEA and Control Plans 4
gunnyshore Corrective Action Filing and Traceability Techniques ISO 13485:2016 - Medical Device Quality Management Systems 2
J Print (Drawing) Bubble Techniques Document Control Systems, Procedures, Forms and Templates 45
W Pro-active Quality Culture Improvements - Suggestions, Tools and Techniques Quality Tools, Improvement and Analysis 3
D Surgical Techniques - What are the requirements? EU Medical Device Regulations 4
B CI (Continuous Improvement) Tools and Techniques - What is the state of the art? Lean in Manufacturing and Service Industries 4
P DFX & DFLSS (DFSS) Techniques & Processes - Real world example of the usage Six Sigma 1
D Effective Thread Length, Top Lock Nut - Inspection Techniques Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
M Potable Water Distribution Process and Audit Techniques Food Safety - ISO 22000, HACCP (21 CFR 120) 1
B Writing Techniques for Audit Findings, Reports, etc. Internal Auditing 15
C Techniques for Measuring Flatness General Measurement Device and Calibration Topics 37
I Critical success factors for efficient use of statistical techniques Other Medical Device and Orthopedic Related Topics 14
V Team feasibility commitment : meaning of efficient material handling techniques ? APQP and PPAP 1
P Deming - Management of Statistical Techniques for Quality and Productivity Philosophy, Gurus, Innovation and Evolution 9
D Problem Solving Techniques Training Materials Training - Internal, External, Online and Distance Learning 4
V What type of SQC or SPC Techniques can be implemented in Machine Shops Statistical Analysis Tools, Techniques and SPC 8
ScottK Using Lean techniques to speed First Article Inspection Lean in Manufacturing and Service Industries 13
D Software Code Review - Inspection Techniques Used Software Quality Assurance 2
K Variations in Tool Use Techniques and How to Improve Consistency? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
T Comparing two different Ultrasonic Tester Calibration Techniques General Measurement Device and Calibration Topics 2
N Statistically Comparing Technician Techniques Reliability Analysis - Predictions, Testing and Standards 16
C Improving Small Diameter Cable Length Measuring Techniques - Process Improvement Preventive Action and Continuous Improvement 3
B How 8D is different from DMAIC or other Problem solving techniques Nonconformance and Corrective Action 3
kedarg6500 How to write clear & concise Problem Statement when using problem solving techniques? Quality Tools, Improvement and Analysis 7
Y How to handle difficult customer - Improving my communication skill and techniques Service Industry Specific Topics 5
S List of QA (Quality Assurance) Tools and Techniques Quality Tools, Improvement and Analysis 13
apestate What tools and techniques are used in paper gaging? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 8
M Statistical techniques for determining which factors are affecting the yield? Statistical Analysis Tools, Techniques and SPC 2
G ISO/TS 16949:2002 - 6.2.2.1 Product Design Skills - Tools and techniques needed Design and Development of Products and Processes 4
S Medical Device Industry Corrective Action Techniques - Is 8D valid method? Nonconformance and Corrective Action 4
G Statistical Techniques Measureables for Application Development Company Statistical Analysis Tools, Techniques and SPC 3
A Statistical techniques in ISO 9001:2000 ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 8
K CQE Exam preparation - Help requested - Planning and Control Techniques Professional Certifications and Degrees 2
D Statistical Techniques in Research - Application of 820.250 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 4
B Sampling Questions - Theory behind the use of sampling techniques Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
C SPC Techniques - Low volume environment - What can be applied? Statistical Analysis Tools, Techniques and SPC 6
N Problem Solving Techniques - Seeking Information Quality Tools, Improvement and Analysis 8
S 21 CFR 820 QSR 820.25 Statistical Techniques Procedures Requirements ISO 13485:2016 - Medical Device Quality Management Systems 5
S TS 16949 Implementation Kick Off Promotional Techniques?? IATF 16949 - Automotive Quality Systems Standard 5
ccochran Customer Satisfaction Book - Techniques, and Formulas for Success Book, Video, Blog and Web Site Reviews and Recommendations 6

Similar threads

Top Bottom