Compression Spring Force MSA

Dave Cx

Involved In Discussions
#1
I have a PPAP from a supplier where the compression spring force MSA is not for the actual spring, the supplier said they used a 'stable spring' as this validates the force measuring system rather than the variation in using the actual part number being PPAP'd.

I have requested the MSA on the actual spring, but can anyone testify to the suppliers argument that 'some' spring designs are not initially repeatable / stable. I'm told a spring is set by compressing to close the coils then released, initially when compressed it returns to 95% of its original free length. When compressed a 2nd time 97% of free length, then after being compressed 5 or more times it recovers to the same length, more compressions = more consistent free length becomes. As the spring length stabilises so does force measurement.

The actual production process only requires 1 set (that's what we are paying for), so to stabilise (compress x10) the spring before the GR&R is not production representative. What would you do, I expect the new MSA on the actual spring will show the variation initially but then improve throughout the study?
 
Elsmar Forum Sponsor

Golfman25

Trusted Information Resource
#2
I would treat it like "destructive testing." So you get one crack at the spring. Not sure how to do MSA in that situation.
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#3
The intent of MSA is to separate part variation from measurement variation. this situation requires a conversion of science, logic and data. It’s not ‘cookbook’. First we have to realize that an initial measurement of an unconditioned spring is in essence a ‘proxy’ measurement. So the first step is to prove out the basic repeatability of the measurement system adn doing this with a set of stable springs is appropriate. Then teh supplier should measure several (30) springs from initial compression to stability. A correlation can then be made to the initial acceptable range of results to the stable period. At this point you know that if the system measures the first compression to be in the range proven by the study, then the final range that you will experience is also acceptable...this is waht MSA is about as opposed to a standard “Guage R&R”. It’s not about checking a box...
 

GRP

Involved In Discussions
#4
Agree with above. I would not treat it as destructive initially, but would opt to assess if the dynamic property can be stabilized. If it can be stabilized, then I´d proceed with a GRR as normal.

If it cannot be stabilized, I would have done what you supplier did and use stabilized samples, arguing the same logic: the intention is to evaluate the measurement system, with some supporting description of the measurement setup, stabilized samples, and so on.

Am I your supplier? Just kidding, not in the spring business. But I have had to deal with forces in vehicle interior components.

The phenomenon of reaching stability and the principle of correlation described by Bev D is also what I would apply in an injection molding shop floor to allow measuring parts before they have fully contracted, say 10 mins after leaving the tool, to validate the start of production.
 

Dave Cx

Involved In Discussions
#5
Thanks for the replies, this illustrates that (me) being so conditioned that you cannot deviate from the rules that you miss the point of what the study sets out to achieve. Just when you think you have seen it all........
 

hngrad1977

Starting to get Involved
#6
I was a Quality Manager in the spring industry for 20 years and gauge r&r studies were a nightmare. You have to take the material used into consideration. For example SST 613 it did not matter if you pressed it solid 20 times you would not get all the set out of it. Whereas if use chrome silicon and heat set it at a set height, those will work for a gauge study. Music wire will not get you there either. And it may be your pressing to solid height only one time may not be enough. If you want stability and the study used on your part, there are a lot of variables, and as you know only two things change load, and that the O/D of the spring and the length. We were tier one and actually packed up a load tester and went to the customer with virgin springs and had to put on a show, measuring springs after pressing one time, two, three............ and on and on. The finally realized their spring did not have the ability to pass a study so it decided we would press every spring 3 times before shipping and the customer would press them once because springs will relax sitting on a shelf.
Your spring supplier is telling you the truth. You may have to belly up to the bar and either change material or get a print change. If you are using any SST, music, chrome silicon (without heat set), vanadium, you will never get there. I will glad to offer help but it would be to much to type here. You can message me.


Dave
 
Thread starter Similar threads Forum Replies Date
R Compression Spring Force measurement correlation with Supplier Capability, Accuracy and Stability - Processes, Machines, etc. 7
shrutisancheti Exact Classification for Trans Radial Compression Device per EU directive 93/42/EEC EU Medical Device Regulations 2
T Test Standards for Compression Springs Manufacturing and Related Processes 14
S Calibration of Load Cell using Compression Machine as Comparator General Measurement Device and Calibration Topics 5
B Measuring Uncertainty on a Compression Testing Machine Measurement Uncertainty (MU) 5
N Check Valve and Pumps for Gas Compression Systems - Ped 97/23/ec? CE Marking (Conformité Européene) / CB Scheme 1
SteveK Adiabatic Compression Testing ISO 10524-1 (? 6.6)? Other Medical Device Related Standards 2
R Process Control - Force in compression moulding of rubber keypads Capability, Accuracy and Stability - Processes, Machines, etc. 5
Q Ford's for material test methods for tensile strength, compression deflection, etc. Customer and Company Specific Requirements 4
L R&R study on a compression tester - Looking for an example and instructions Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 4
T Loaded spring device - Active medical device? EU Medical Device Regulations 1
P RAC-US Spring 2020 Study group_Discussions Professional Certifications and Degrees 17
Marc Daylight Savings time (US) - Spring (ahead) - Sunday March 10, 2019 Coffee Break and Water Cooler Discussions 1
T RAC US Spring 2019 certification - Study group Professional Certifications and Degrees 5
R Canada classification of spring-driven autoinjector Canada Medical Device Regulations 2
W RAC EU/Global focus certification - Study Group for Spring 2015 Professional Certifications and Degrees 4
S Spring Steel Hydrogen Embrittlement Manufacturing and Related Processes 19
C Suggestions for the RAC Regulatory Affairs Spring 2014 - US exam Professional Certifications and Degrees 1
D RAC Regulatory Affairs Spring 2014 EU or Global Exam Study Group Professional Certifications and Degrees 15
R RAPS Certification Exam Prep Study Group for Spring 2014 Professional Certifications and Degrees 2
P RAC (Regulatory Affairs Certification) US Spring 2013 Preparation Study Group Professional Certifications and Degrees 3
K Poka Yoke for Leaf Spring placement by Operator Misc. Quality Assurance and Business Systems Related Topics 2
Jim Wynne Baseball Opening Day--A Sure Sign Of Spring Coffee Break and Water Cooler Discussions 3
N Preparation time for the 'spring' RAC Exam - sufficient time? Professional Certifications and Degrees 1
Marc Holi (होली ) - The Festival of Colours - Hindu spring festival - 2010 Coffee Break and Water Cooler Discussions 2
F Spring Steel Wires - JIS 3560, DIN 17223 & SAE 9254 (JIS G 3561) Manufacturing and Related Processes 2
M AS9100 - Easier Than TS16949? Spring & Pressing company AS9100, IAQG, NADCAP and Aerospace related Standards and Requirements 3
Scott Catron Disneyland for Spring Break Coffee Break and Water Cooler Discussions 24
Q Early Spring Cleaning - Finding Old Documents and Specifications ISO 9000, ISO 9001, and ISO 9004 Quality Management Systems Standards 2
ScottK Is anyone here from North Jersey going to the Spring ASQ Conference (4/19)? Training - Internal, External, Online and Distance Learning 1
L Spring measurement device - Measuring the torque of the spings at diferent angles General Measurement Device and Calibration Topics 1
GStough 2007 Spring Conference in St. Louis (ASQ) General Auditing Discussions 4
R SPC in Spring Brakes - Measuring Angles - What do I need to do? Statistical Analysis Tools, Techniques and SPC 14
N Requirements for the identification and traceability of demo product for sales force US Food and Drug Administration (FDA) 1
J Calculating impact force, expressed in lbs, of a 5 lb weight dropped 48 inches Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
K Measurement Force on Kickdown Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
J GHTF (Global Harmonization Task Force) SG2 Guidance Documents EU Medical Device Regulations 3
B Kanban - What is the pulling force which triggers replenishment? Lean in Manufacturing and Service Industries 7
V How to Calibrate Ring Force Gauges Service Industry Specific Topics 1
kedarg6500 How much test force to be applied for Vickers hardness Inspection, Prints (Drawings), Testing, Sampling and Related Topics 1
S IATF (International Automotive Task Force) Rules 4th edition changes IATF 16949 - Automotive Quality Systems Standard 1
Z Force & Strain Calibration Uncertainty for ISO/IEC 17025 ISO 17025 related Discussions 2
W Force Calibration - In-House Load Cell Calibration General Measurement Device and Calibration Topics 7
D Force Testing Round Pieces that are Twisted Together Manufacturing and Related Processes 9
Jen Kirley My son leaves for the Air Force today Coffee Break and Water Cooler Discussions 30
V Medical Device Definitions outside GHTF (Global Harmonization Task Force) Other Medical Device Regulations World-Wide 2
P GHTF's (Global Harmonization Task Force) Latest ASQ, ANAB, UKAS, IAF, IRCA, Exemplar Global and Related Organizations 5
M Rules for achieving IATF (International Automotive Task Force) recognition IATF 16949 - Automotive Quality Systems Standard 1
S Customers an Extension of the Sales Force? Customer Specific Marketing Material Quality Manager and Management Related Issues 3
D Effect of Puncture Orientation on Force Value Other Medical Device Related Standards 1

Similar threads

Top Bottom