AQL and Sampling Plan as they relate to Functional In-Process Inspections

P

Pudge 72

#1
OK Cove.

Throughout my career I have always been weak in the area of Sampling Plans and AQL levels as they relate to functional In-Process inspections whether it is the operator checking the part or as a QC function.
So, here goes the question. Has anyone created or does anyone have a good plan in Excel or Word for determining the amount of pieces to be inspected on an hourly basis as would be required per a Control Plan for production parts? Or, a document that explains a good methodology for the selection of # of pieces and time that would be acceptable to a customer?

IE - I check a feature on a part that is a length let's say. This Length is listed as a Feature that is Inspected on the Control Plan, but, it is not a customer critical. I inspect 5 pcs. per hour. I do not do CPK on this feature as it is more of a "preventive" inspection so that I can see a drift during the run to assist with an adjustment if necessary.
On this part, I have let's say 5 or 6 of these types of features to inspect and I am measuring 5 pcs. per hour.

I do 5 pcs. per hour because that is what I have always done and it seems to be economical whether it is the operator or QC - seems to be effective. But, what is the real or better way to arrive at the amount of pieces or time frame in the beginning of the project? I can't change the IP based on rolling data because it is submitted with my Control Plan - it needs to be developed on the Front end.
Any Ideas guys?? I hate the norm and never thought that this method was quite right.
 
Elsmar Forum Sponsor

Jim Wynne

Staff member
Admin
#2
Re: AQL, Sampling Plan

OK Cove.

Throughout my career I have always been weak in the area of Sampling Plans and AQL levels as they relate to functional In-Process inspections whether it is the operator checking the part or as a QC function.
So, here goes the question. Has anyone created or does anyone have a good plan in Excel or Word for determining the amount of pieces to be inspected on an hourly basis as would be required per a Control Plan for production parts? Or, a document that explains a good methodology for the selection of # of pieces and time that would be acceptable to a customer?

IE - I check a feature on a part that is a length let's say. This Length is listed as a Feature that is Inspected on the Control Plan, but, it is not a customer critical. I inspect 5 pcs. per hour. I do not do CPK on this feature as it is more of a "preventive" inspection so that I can see a drift during the run to assist with an adjustment if necessary.
On this part, I have let's say 5 or 6 of these types of features to inspect and I am measuring 5 pcs. per hour.

I do 5 pcs. per hour because that is what I have always done and it seems to be economical whether it is the operator or QC - seems to be effective. But, what is the real or better way to arrive at the amount of pieces or time frame in the beginning of the project? I can't change the IP based on rolling data because it is submitted with my Control Plan - it needs to be developed on the Front end.
Any Ideas guys?? I hate the norm and never thought that this method was quite right.
Use of a sampling plan with an associated AQL or OPerating Characteristic Curve is usually done with finished lots of material, as in the case of final or incoming inspection. Determining sampling quantities and intervals for in-process checks is a little like setting calibration intervals. You do it based on experience and history. You should monitor closely in the beginning (what "closely" means will vary with the processes involved) and then gradually expand the interval until you're reasonably sure nothing bad is happening between inspections. The goal of these checks should be process control--knowing how to control the variables that can affect product quality.
 
P

Pudge 72

#3
Excellent.
This is exactly the type of feedback I am looking for.
I agree with you completely Jim. The philosophy you suggest is along my lines of thinking - but, based on my expierience, it will be hard to implement as it almost falls into QE territory whereas you base the inspection interval on historical data - the problem falls in where someone has to analyze all of that not to mention that it has to run for a while to gather this data.
So, while it could be said that in the end you will have a cost savings based on eliminating unecessary inspection, you will spend a lot to get to that point.
That is kind of my ultimate dilemma, in this day and age of listening to how much QC (by the operator or direct QC) is a non-value added activity, we don't seem to have good definitions in place for analyzing In-Process data to arrive at these points and eliminate the waste during production which is where the rubber meets the road - not Final inspection.
 

Jim Wynne

Staff member
Admin
#4
That is kind of my ultimate dilemma, in this day and age of listening to how much QC (by the operator or direct QC) is a non-value added activity, we don't seem to have good definitions in place for analyzing In-Process data to arrive at these points and eliminate the waste during production which is where the rubber meets the road - not Final inspection.
That's exactly what statistics is for. :D
 
P

Pudge 72

#5
I know, but I am sure that you feel my pain when I try and explain and justify someone analyzing data - even if it is for improvement. Just wondering if you or anyone else had a better method right out of development - IE - CPK of 1.75 = 3 pcs. per hour for In-Process Inspection instead of 5 based on a certain lot size or something. I am not sure, I know how to apply the statistics on the historical data, but to change all of the paperwork for sampling sizes is a pain - probably trying to take a lazy way out that is really not there.:bonk:
 
Thread starter Similar threads Forum Replies Date
W LTPD, AQL, Ppk and Cpk validation sampling plan table Inspection, Prints (Drawings), Testing, Sampling and Related Topics 0
T Defining sampling plan for different AQL AQL - Acceptable Quality Level 3
Nicole Desouza Sampling plan for a customer who wants AQL 1.0 (per ANSI Z1.4) AQL - Acceptable Quality Level 5
A AQL Sampling Plan SOP / WI - Medical Device Industry Inspection, Prints (Drawings), Testing, Sampling and Related Topics 14
B Designing a Sampling Plan - AQL AQL - Acceptable Quality Level 19
S Class III Sampling Plan - Explain AQL vs. 95%C & 90%R Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
F AQL - ISO 3951-4:2011 Sampling Plan Requirements AQL - Acceptable Quality Level 2
P Why sample size for c=0 sampling plan reduces across the increases of AQL AQL - Acceptable Quality Level 2
N AQL (Acceptable Quality Level) Sampling Plan for Small Lots AQL - Acceptable Quality Level 8
0 AQL Sampling Plan based upon ISO 2859 AQL - Acceptable Quality Level 1
N AQL - Sampling plan (variable, inspection level ii, normal inspection S-method) AQL - Acceptable Quality Level 2
B Sampling Plan - AQL effect on Sample Size AQL - Acceptable Quality Level 9
Y What is the confidence level for a given AQL in zero sampling plan AQL - Acceptable Quality Level 4
W AQL and RQL Calculation for Variables Sampling Plan AQL - Acceptable Quality Level 8
V How to interpret AQL sampling tables AQL - Acceptable Quality Level 5
A AQL sampling bags of parts Inspection, Prints (Drawings), Testing, Sampling and Related Topics 5
I Sampling processes - Who must define the AQL level? AQL - Acceptable Quality Level 9
J AQL for Effectiveness Check - What AQL tiers to use on this type of sampling? Nonconformance and Corrective Action 9
N The question asks about sampling plans and AQL Reliability Analysis - Predictions, Testing and Standards 5
alonFAI AQL and Sampling Size for Components Solderability Test Statistical Analysis Tools, Techniques and SPC 3
U AQL, Lot Size vs Sampling Plans AQL - Acceptable Quality Level 8
P Which Sampling Tables for AQL? Statistical Analysis Tools, Techniques and SPC 6
K Verification Sampling vs. AQL - Sampl Sizes Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
B AQL Sampling Tables Question Inspection, Prints (Drawings), Testing, Sampling and Related Topics 4
R Is AQL sampling plans applicable for Bulk Pharmaceutical Manufacturing (API)? Pharmaceuticals (21 CFR Part 210, 21 CFR Part 211 and related Regulations) 1
A What is the purpose of using AQL (Acceptable Quality Level) for Sampling? AQL - Acceptable Quality Level 3
J Sampling Plans - AQL Table Application AQL - Acceptable Quality Level 2
C C=0 vs. AQL MIL Standard 105 E - Sampling Plans Inspection, Prints (Drawings), Testing, Sampling and Related Topics 6
A AQL Tables or Binomial/Poisson Method? Attribute Sampling Inspection, Prints (Drawings), Testing, Sampling and Related Topics 7
J Incoming Inspection AQL Sampling of Bulk Textiles AQL - Acceptable Quality Level 3
H How to decide AQL value? Sampling Plans AQL - Acceptable Quality Level 5
A What is a good lot size? We use the C=0 Sampling plans at AQL %1.0 AQL - Acceptable Quality Level 9
A Use of sampling plans like MIL-STD-105 E or ANSI Z1.4 for setting AQL's? AQL - Acceptable Quality Level 13
M Sampling AQL - Am I understanding it correctly? AQL - Acceptable Quality Level 2
S Using AQL to get true random sampling using General Inspection Level II AQL - Acceptable Quality Level 4
M Sampling a continuous process - How to use AQL with a continuous process AQL - Acceptable Quality Level 6
R AQL, Consumer Risk and MA Statistical Analysis Tools, Techniques and SPC 2
A AQL - How to count samples with defects for each defect class AQL - Acceptable Quality Level 17
S ARMY AQL - Requirements which don't have an AQL associated with them Manufacturing and Related Processes 2
M AQL table - I need to sample 1250pcs AQL - Acceptable Quality Level 3
S AQL Inspector's Rule - bring into CQE Exam? Professional Certifications and Degrees 5
K Defining Acceptance Quality Level, I need clarity on AQL 1.5, 2.5, 4.0 AQL - Acceptable Quality Level 5
V Receiving Inspection AQL - Am I allowed to just pick a AQL? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 10
L Established a c=0 "AQL" or "RQL" table AQL - Acceptable Quality Level 5
C Example Work Instruction/Procedure for AQL (Acceptable Quality Level) AQL - Acceptable Quality Level 4
L How to calculate the Probability of Deficiency of the AQL of an Inspection AQL - Acceptable Quality Level 16
P Setting Acceptance Quality Limits (AQL) for New Medical Devices ISO 13485:2016 - Medical Device Quality Management Systems 4
K AQL for Sterile Product - Laminate Tubes 21 CFR Part 820 - US FDA Quality System Regulations (QSR) 5
M How to Mathemetically Derive the AQL Tables given Lot Sizes AQL - Acceptable Quality Level 5
L AQL ANSI z1.4 & z1.9 - What are the differences between these 2 standards? AQL - Acceptable Quality Level 5

Similar threads

Top Bottom