MSA clause 7.1.5.1.1 - Statistical studies on counting weight scale

#1
How do others do statistical studies on a weight counting scale? We have our scales calibrated annually and confirm counts throughout the packaging process. Is a statistical study required? Any insight is appreciated.
 
Elsmar Forum Sponsor

leftoverture

Involved In Discussions
#2
Our company is not yet IATF, but we have never done any MSA activity on our counting scales. We have invested a lot of effort to train people to use them properly and to set sample sizes that yield the best accuracy (since our part weights vary so much). None of my customers has ever asked for any further MSA activity, but I have one customer who wishes we would do more frequent (daily) calibration checks. But based on my outside lab calibration results, the data doesn't suggest a need for further calibration effort.
 

Johnny Quality

Quite Involved in Discussions
#3
Why would you do a statistical study on a weight scale used only to count parts?

If you are using the weighing scales for inspection/SPC to customer requirements then yes, you should do an MSA if you haven't already.
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#5
I certainly agree that a repeatability study is probably not warranted for most scales used to count parts by weight. However, a MSA is a measurement system analysis which is more than a ‘simple’ Gauge R&R study. The purpose of any control is to ensure the quality of whatever it is assessing. The MSA is intended to establish this ability. If the system can’t achieve it’s goal of assuring quality then you need a different system.

For counting scales the analysis is to see if we can reliably differentiate between 4 parts and 5 parts, or 100 parts and 101 parts,etc. essentially, the weight of the parts themselves has to be consistent enough that you actually can count them using the weight. If you can’t then you need a different system. Perhaps a ‘counting’ sensor can be used or packaging like an egg carton that specifically holds the correct number of individual parts.
 
#6
We reference weight counting scales and visual inspections on our Control Plan so our auditor is requiring that we do MSA studies for both. We already do it for all measurement equipment.
 

leftoverture

Involved In Discussions
#7
Remove weigh counting from your control plan. I see no need to have it on there. At my company, weigh counting is covered by the process work instructions and is not on the control plan and I have never had this questioned.
 

Matt's Quality Handle

Involved In Discussions
#8
Remove weigh counting from your control plan. I see no need to have it on there. At my company, weigh counting is covered by the process work instructions and is not on the control plan and I have never had this questioned.
I've been raked over the coals over parts counting by an Automotive OEM customer that rhymes with "Rhonda". So this may be relevant. It was a big deal for our customer, so it made it to the control plans.
 

leftoverture

Involved In Discussions
#9
I've been raked over the coals over parts counting by an Automotive OEM customer that rhymes with "Rhonda". So this may be relevant. It was a big deal for our customer, so it made it to the control plans.
That's interesting. I have a customer where we have experienced quite a few counting errors, mainly because they "kit" the parts on their end so they always find even the smallest counting error. We have found the biggest reasons for counting errors are: 1) operators who don't properly set the scales; 2) using too small of a sample size for the part (light parts need larger sample); and 3) using too large a scale for the box count/part size. A traditional "gage R&R" study would not resolve those issues, though I think if we'd have documented the studies we've done on counting it would certainly qualify as an MSA, just not in the traditional sense. How did you handle the MSA with "rhymes with Rhonda"?
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#10
Having worked for Rhonda and being a Customer of 'weigh counted' parts where the count is critical and supplying 'kits' that must have the correct count of parts in them (medical imperative) I can state that there are times when the correct count is absolutely necessary and not just because of regulatory 'accountability'.
Rhonda and us: a line stoppage if the count is too low is very expensive.
Medical: if the disease is somewhat rare and the test can expire the Vet may only buy one kit. the disease can be not only fatal but highly contagious. ensuring that a critical part of the test is in the kit box is essential.
Regulatory: some materials are highly regulated and every part or drop must be accounted for as they cannot "fall into the wrong hands".
these are just the times off the top of my head when there should (really must) be a validated control mechanism. Not all counting belongs in this category but some do. As quality professionals we need to recognize this and more importantly understand it and ensure that it's done correctly.

You are correct that a 'traditional' gauge R&R will not help. but a measurement systems analysis will help. see my post above for that and other ideas about ensuring counts. no one can count so we need to move on from that and error proof the process when counts are necessary.
 
Thread starter Similar threads Forum Replies Date
Ashland78 MSA clause or wording needed. Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
K MSA - Is Measurement Systems Analysis required in R&D? TS 16949 Clause 7.6.1 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 14
V MSA - Using a R&R study for a Tape Measure Reliability Analysis - Predictions, Testing and Standards 19
M Options when MSA acc. to VDA 5 is NOK (Qms > 30%) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
F MSA for non-contact CMM - ISO10360 Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
T Thermometers and Thermocouple or Transducer's require MSA? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
R MSA Studies for chemical analytical instruments in QC Lab Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
A IATF MSA study Type 1 General Measurement Device and Calibration Topics 7
Nihls MSA after the device move Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
M MSA angle issue - Nylon parts using Aberlink 3D Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
Nihls MSA Study Type 2 (special conditions ) IEC 60601 - Medical Electrical Equipment Safety Standards Series 0
Nihls When the MSA results show no operator influence Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
S MSA for attribute relation gage Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
Nihls MSA Study Type 1 (CMM) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
M MSA Study Type 1 not capable. We are at the limit. And manufacturing wants to continue producing. Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
I Overwhelmed with attribute MSA requirement for visual inspection IATF 16949 - Automotive Quality Systems Standard 10
H Need MSA 4th ed. compliant attribute MSA template General Measurement Device and Calibration Topics 4
P MSA for titration Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
P MSA - what exactly mean "system" and master sample Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
P MSA study for visual system with artifical inteligence Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
D MSA strategy Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
K Updated MSA with the Annual PPAP validations APQP and PPAP 8
E MSA for Push and Pull test Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
6 MSA for Calculated Clearance Dimension Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
Ron Rompen MSA on automated measurement system - Multiple Step Vision System Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 3
G MSA check list to audit IATF 16949 - Automotive Quality Systems Standard 10
R MSA for ATE (Automatic Test Equipment Embedded Software) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 9
Bev D MSA Tools Misc. Quality Assurance and Business Systems Related Topics 3
R MSA studies for Heat Treatment Equipment Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
C Industrial scales and MSA (IATF 16949 requirement 7.1.5.1.1) IATF 16949 - Automotive Quality Systems Standard 30
M Difference between MSA and MSE? General Measurement Device and Calibration Topics 1
M Test method validation - Is MSA (MSA1, MSA2, MSA3 and linearity) a good solution? Medical Device and FDA Regulations and Standards News 2
A MSA results differences - Supplier results vs. My results Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
R Preliminary MSA and Sockets' correlation Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
I MSA requirement for 5 Micrometers + CP changes need customer approval? IATF 16949 - Automotive Quality Systems Standard 2
T Correct MSA study for an automated camera system which makes attribute inspection Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
Bev D MSA Misc. Quality Assurance and Business Systems Related Topics 46
Emran.mi Measurement system analysis - Can you help me about implementation MSA for CMM device Manufacturing and Related Processes 2
N MSA Study for a Leak Testing Device Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
N Justifications for not performing MSA (Measurement System Analysis) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 6
D Do I need part variation while doing Destructive Variable Gage R&R MSA study Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 19
Prashant G MSA Study - AS 9100 and and our customer want us to do MSA study for their parts dimension Reliability Analysis - Predictions, Testing and Standards 4
D Compression Spring Force MSA Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
E MSA Study on MTS dynamic rate measurements Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
A The FILE recommended by AIAG MSA 4ed for LINEARITY Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 0
S IATF 16949 Audit MSA IATF 16949 - Automotive Quality Systems Standard 10
C Do Calibration Reference Standards require an MSA study? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
A MSA When an Instrument Measures More than One Parameter Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
G MSA Type 1 - Cg and Cgk ranges Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
O MSA Study for a steel ruler Manufacturing and Related Processes 6

Similar threads

Top Bottom