Control plan - Multiple batches

#1
Hi All,

As part of a problem in our manufacturing site, we need to recontrol 10 batches of product. After calculation, I have found that we need to control more than 10000 units (zero tolerance).

Below are the informations about each batch:
  • Each pack has 10 grouped units.
  • 20 packs per box.
  • 30 box per pallet
Suppose that I have 5 big batches (with 100K units) and 5 smalls batches (with 50K units). It would be complicated if I come up with a plan that require to take 1 unit per pack. How should I define the sampling plan (number of units to be controlled per batch, per pallet, etc?) that makes sense and is not too challenging for the production team?

Thank you very much.
 
Elsmar Forum Sponsor
#2
When we need to take random samples from boxes either post production or at incoming, we first figure out how many samples in total we need then use the formula
n=√(number of boxes) [rounded up]
Then divide the number of samples to be taken from each box.

In your instance, you need 10,000 units to measure. If I did the math correctly, you have 75,000 packs in total, so 3,750 boxes in total. Using the above equation, the sqrt of 3,750 is 61.23, so rounded up is 62.

So you need to inspect 62 random boxes. So 10,000/62 = 161.29 or just 161. In this case, you would find 62 random boxes across your batches and take 161 parts from each. Since I rounded down, 62 boxes at 161 parts each ends up being 9,982 parts. So you'd need to make sure for 18 of the boxes, they take 162 samples.

I would suggest the number of boxes taken from each batch correlate with how big the batch is (the bigger batches have more boxes taken for inspection than the smaller batches).
 

Bev D

Heretical Statistician
Leader
Super Moderator
#3
Do you believe the defect is randomly distributed or is their a time relationship?
A random distribution will require a random sample while a time based distribution is more directed and potentially easier.
do you know the expected defect rate per lot/batch?

of course the easiest method for manufacturing is to scrap everything
 
Thread starter Similar threads Forum Replies Date
leftoverture Control Plan - Multiple Process Steps FMEA and Control Plans 8
apestate Multiple Attachments: FMEA and Control Plan Forms Document Control Systems, Procedures, Forms and Templates 14
K ISO 2859-5 (single run production) control plan issues FMEA and Control Plans 2
Q Control Plan and the frequency of sampling FMEA and Control Plans 11
C Control Plan APQP and PPAP 7
S Control plan for "highly automated processes" FMEA and Control Plans 3
B 8.5.1.1 Control Plan - question audit NC IATF 16949 - Automotive Quality Systems Standard 5
B QM Plan vs Control Plan IATF 16949 - Automotive Quality Systems Standard 3
N AS 13004 Control Plan and AQL FMEA and Control Plans 1
J PFMEA/control plan question- PLEASE HELP ! IATF 16949 - Automotive Quality Systems Standard 8
Y FMEA link to Control Plan frequency and sample size FMEA and Control Plans 19
S Linking control chart with control plan Statistical Analysis Tools, Techniques and SPC 5
S Operation of possible rework in control plan FMEA and Control Plans 8
M Process & Product Characteristic in Control Plan FMEA and Control Plans 17
Sonja D AIAG VDA PFMEA and Control Plan training FMEA and Control Plans 9
A Control plan for IATF - example? FMEA and Control Plans 1
S Maintenence related action in Control plan FMEA and Control Plans 3
R Control Methods in Control Plan FMEA and Control Plans 5
L Looking for Control Plan and FMEA Stamping process FMEA and Control Plans 2
Jimmy123 IATF16949 Control Plan FMEA and Control Plans 1
A Prototype control plan FMEA and Control Plans 2
S Which department should prepare the control plan? could you show me a standard regarding to this matter. FMEA and Control Plans 17
G Control Plan & PFMEA Review Procedure? FMEA and Control Plans 10
P IATF 16949 requirement - error-proofing in control plan IATF 16949 - Automotive Quality Systems Standard 3
earl62 What is the best way to control special characteristics in Control plan? Is it Mandatory to have SPC for IATF 16949? IATF 16949 - Automotive Quality Systems Standard 12
I Control Plan (Product/Process specification/ Tolerance) acceptance FMEA and Control Plans 27
J Control Plan use on the manufacturing floor FMEA and Control Plans 4
E Change in control plan - Do I have to do sampling? IATF 16949 - Automotive Quality Systems Standard 1
D All Dimensions listed on control plan FMEA and Control Plans 10
DuncanGibbons Manufacturing Plan vs Material Specification vs Control Plan Manufacturing and Related Processes 5
S Should safety checks be included in the Control Plan? IATF 16949 - Automotive Quality Systems Standard 5
D Supplied Product on Control Plan - Lot ranging in 40,000 pcs per product FMEA and Control Plans 3
M Is there any pre-defined Control plan format/template acc. VDA? VDA Standards - Germany's Automotive Standards 1
G Control Plan - Include the processes for each sub component? APQP and PPAP 2
A Redesigning our process flow chart, PFMEA and Control Plan Process Maps, Process Mapping and Turtle Diagrams 4
D Link between FMEA, flow chart and control plan FMEA and Control Plans 10
M Dynamic Control Plan Draft - need review FMEA and Control Plans 2
Ashland78 IATF 16949 Control Plan Authorizations IATF 16949 - Automotive Quality Systems Standard 2
N Control plan evaluation methods - Which methods should be carried over from the PFMEA? FMEA and Control Plans 6
Rameshwar25 What is a Control Plan at "Material Level"? IATF 16949 - Automotive Quality Systems Standard 4
O Difference Between PFMEA & Control Plan FMEA and Control Plans 3
W Purchased Part Control Plan (IATF 16949) FMEA and Control Plans 7
J VDA audit, control plan - My hair is almost gone now VDA Standards - Germany's Automotive Standards 5
Howard Atkins MSAs are now required on every feature of the control plan - IATF 16949 IATF 16949 - Automotive Quality Systems Standard 13
Jeff Putman EQI Prelaunch Control Plan - Definition Customer and Company Specific Requirements 0
V How to Add Annual Revalidation requirements to Control Plan? FMEA and Control Plans 5
N Control plan references FMEA and Control Plans 6
L Simple Example for PFMEA / Control Plan Training Training - Internal, External, Online and Distance Learning 1
J Functional group / area responsible on a Control Plan IATF 16949 - Automotive Quality Systems Standard 1
T Should Testing be a separate operation in the Control Plan? FMEA and Control Plans 5

Similar threads

Top Bottom