Capability Study for Leak Tester

#1
Hello All, I am trying to do a capability study for the leak tester machine we use for testing the blow moulded plastic vehicle fuel tanks. The test is only done to detect any leaks in fuel tank and there is no customer specification as for pressure. Now, shall i do a GAGe study or Capability study? the data type is attribute since its only pass or fail in leak test. I am doing this for the first time and would appreciate any kind of help.!!
Thank you
 
Elsmar Forum Sponsor

John C. Abnet

Teacher, sensei, kennari
Staff member
#2
Good day @shivam465 , and welcome to the site.
It sounds to me as if your measurement technique is objective (i.e detects LEAK or detects NO leaks and there is no subjectivity applied by the operator. Is this understanding correct?

I'm not sure how this test can only be attribute. In other words, how do we know if the equipment is detecting a loss of pressure (variable data) or not ?

Yes, the result of the measurement would be attribute i.e. PASS (no loss of pressure) vs FAIL (loss of pressure), but how is the gaging system verified to ensure it is detecting ANY loss of pressure over a set time?

Gage R&R for attributes is looking at "agreement". In other words does an operator(s) "agree" with themselves/each other over a particular set of data repeated?

Hope this helps.
 

bobdoering

Stop X-bar/R Madness!!
Trusted Information Resource
#4
You can buy standard orifices to test your machine. You can use them for calibration and sometimes gage r&r. But, capability requires checking parts - and they need some variability or you cannot detect the "difference" between them.
 
#5
Good day @shivam465 , and welcome to the site.
It sounds to me as if your measurement technique is objective (i.e detects LEAK or detects NO leaks and there is no subjectivity applied by the operator. Is this understanding correct?

I'm not sure how this test can only be attribute. In other words, how do we know if the equipment is detecting a loss of pressure (variable data) or not ?

Yes, the result of the measurement would be attribute i.e. PASS (no loss of pressure) vs FAIL (loss of pressure), but how is the gaging system verified to ensure it is detecting ANY loss of pressure over a set time?

Gage R&R for attributes is looking at "agreement". In other words does an operator(s) "agree" with themselves/each other over a particular set of data repeated?

Hope this helps.

Thank You so much sir for your help. As far as i know, there is no detection of pressure loss data, the machine runs the test at a specified pressure and if any leak of pressure is found, it shows red signal. I think I can only do capability and not gage study since there is no evidencial proof or base for operators to agree within themselves / different operator.

I really appreciate your answer sir.
 
#7
You can buy standard orifices to test your machine. You can use them for calibration and sometimes gage r&r. But, capability requires checking parts - and they need some variability or you cannot detect the "difference" between them.
I am not sure if I can use orifiices to test the machine since there is no variable output coming from machine as in Loss in pressure or any other data. Thank you for your recommendation sir.
 

optomist1

A Sea of Statistics
Super Moderator
#8
Hi Shivam465 welcome...a couple of questions:
1) how does one (your firm) define a "leak",
2) what is the duration of equipment looking for a "leak"?
3) 'Leak" test uses air as a leak gas?
 
#9
Hi Shivam465 welcome...a couple of questions:
1) how does one (your firm) define a "leak",
2) what is the duration of equipment looking for a "leak"?
3) 'Leak" test uses air as a leak gas?
A1) We are using Differential Pressure decay for testing the leak in fuel tanks.
A2) The cycle time for leak test is around 8.3 minutes. The leak tester looks for pressure leak in the test specimen by filling in air uptill the pressure that of the reference/ standard fuel tank already mounted onto the machine ( used as Standard condition). If the test specimen shows no sign of pressure decrease untill the pressure inside reaches similar to that of Reference tank, it shows green light for Pass, If there is any noticeable pressure drop it will stop creating pressure and will show Red. The exact location of leak operator has to manually find by using soap water.
A3) Air is used as Leak gas..


Adding on some photos to help understand better in the attachments.

Please help me suggesting how should I do the capability test for this machine.
ThaNk you very much for your reply.
 

Attachments

It Was I Who

Involved In Discussions
#10
Hi Shivam

I have just glanced through our question and let's see if i get it right.
You have a specified pressure that you pressurize the object with for a specified time. And after that time the light become green or red. (Is that right?)
If so you will probably have a reference volume somewhere. It could be a built in, in to the machine or it could be an equal reference as the volume you are testing. Never the less it will probably do the test similar.

Both volumes will get pressurized with the same pressure and then the valves will shut close. And in-between these two volumes ( The reference and the test object) there is an membrane in the machine that will detect the difference between the two. Ex. if the test object leaks the membrane will bend over to the reference side and will then registrat the deferens ( In Pascal most common.) there will be a Max pascal limit that will be triggering the red light to signal leak if it is exceeded.

So you have most probably a specified pressure for the object, a specified time and a max limit of pascal. ( The pascal will probably be recalculated into mm3/S Cubic mm per second. That is likely from the specifications for the tank
So if you need to make an R&R on this you need 5-10 pieces for the test that you will circulate one by one through the machine. ( you will need this due to that you need to ensure that the force in the test object is worn of between each test, so you don't have any left when you do the next test with that object) Now you need to get the reference Pascal that is set in the machine to be able to make the calculation.

I would say it is an variable gage and not an attribute. You will get an "Attribute answer" out from the variable test the machine is doing.

If not the test is conducted under water or with soap, to do a "Bubble test" then you have a attribute gage.
 
Thread starter Similar threads Forum Replies Date
S Capability or Gage R&R Study for Leak Tester? Reliability Analysis - Predictions, Testing and Standards 15
O Capability or Gage R&R Study for Leak Tester Reliability Analysis - Predictions, Testing and Standards 11
B MSA (Gage R&R) vs. Capability Cpk Study - Helium Leak Check Station Statistical Analysis Tools, Techniques and SPC 2
A Capability Study - in the beginning of your career what should you have known about the tool Quality Tools, Improvement and Analysis 11
Q Capability study with a minimum spec Statistical Analysis Tools, Techniques and SPC 8
S Machine Setup for a CNC Machine Capability Study Capability, Accuracy and Stability - Processes, Machines, etc. 1
G Capability Study for Tapped Hole Reliability Analysis - Predictions, Testing and Standards 3
G Plotting capability study data - I have a bimodular data distribution Capability, Accuracy and Stability - Processes, Machines, etc. 4
V Generic requirements regarding capability study in automotive Capability, Accuracy and Stability - Processes, Machines, etc. 1
M IATF 16949 - Capability study on non critical dimensions? Statistical Analysis Tools, Techniques and SPC 4
L Excel Template for Cgk Study wanted (Capability Gauges Study) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 12
N Process Capability Study - Aggregate vs. Individual Processes Statistical Analysis Tools, Techniques and SPC 24
KyloDen Capability Study and Qualifying a Supplier Capability, Accuracy and Stability - Processes, Machines, etc. 5
B Capability Study => Check %Study Variance and NDC? Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 7
B Conflict between department of MSA and Capability Study Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 1
J How to determine a Capability Study for Low-Volume Suppliers Capability, Accuracy and Stability - Processes, Machines, etc. 3
S What is Cc? Capability Study on Key Critical Dimensions Capability, Accuracy and Stability - Processes, Machines, etc. 9
L Capability Study for a Honing Machine Statistical Analysis Tools, Techniques and SPC 3
A Inspection Capability Study (Kappa Analysis / Attribute R&R) as Certification Req't Training - Internal, External, Online and Distance Learning 7
C Subgroup Size in Minitab for Capability Study Statistical Analysis Tools, Techniques and SPC 4
O One Cavity Mold Prototype Capability Study and PPAP Approval APQP and PPAP 1
G How to calculate Subgroup Size for Machine Capability Study Statistical Analysis Tools, Techniques and SPC 4
V How to calculate Machine Capability Study using Minitab Using Minitab Software 4
V JCI standard numbers of pieces required for Capability Study? APQP and PPAP 2
T Industry Standards for # of parts for Capability Study and Layout FAI's? APQP and PPAP 4
D AIAG 4th Edition Capability Study and Gage R&R Requirements Document Control Systems, Procedures, Forms and Templates 8
P Capability Study for a Specific Thickness of Rubber Sheeting Capability, Accuracy and Stability - Processes, Machines, etc. 6
Q When to use Cpk or Ppk for a Process Capability Study? Capability, Accuracy and Stability - Processes, Machines, etc. 14
O Capability Study on Continual Arbitrary Dimension Capability, Accuracy and Stability - Processes, Machines, etc. 11
J Attribute Data and Capability Study of Holes in Parts Capability, Accuracy and Stability - Processes, Machines, etc. 11
D Process Capability Study which involves MMC (Maximum Material Condition) Capability, Accuracy and Stability - Processes, Machines, etc. 8
A Yearly MSA (Measurement System Analysis) & Capability Study - TS 16949 Requirements Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 2
J Process Capability - Interview Case Study Capability, Accuracy and Stability - Processes, Machines, etc. 1
A Process Capability Study using Variables Data (weight of the product) Statistical Analysis Tools, Techniques and SPC 9
M Capability Study on a New Machining Process - Issues Capability, Accuracy and Stability - Processes, Machines, etc. 40
S Does anyone know what is involved in a HiPot capability study? Capability, Accuracy and Stability - Processes, Machines, etc. 2
A Process Capability study of CNC Machining Process Capability, Accuracy and Stability - Processes, Machines, etc. 3
Q Machine Capability Study - Cpk (Cmk) of an R/F testing machine Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 5
T Machine GR&R (Gage R&R) - Capability Study Capability, Accuracy and Stability - Processes, Machines, etc. 5
M Cmk (Machine Capability) - Case study Capability, Accuracy and Stability - Processes, Machines, etc. 5
B Visual Inspection - Capability Study on Attribute Data Capability, Accuracy and Stability - Processes, Machines, etc. 13
M Capability Study on Extruded Alumin(i)um - How would one define a "batch"? Capability, Accuracy and Stability - Processes, Machines, etc. 4
A Capability Study Template Capability, Accuracy and Stability - Processes, Machines, etc. 1
C Capability Study Required as a Condition to Adopt a Sampling Plan? Inspection, Prints (Drawings), Testing, Sampling and Related Topics 6
S Process Capability Study for Electrostatic Powder Coating Statistical Analysis Tools, Techniques and SPC 6
J Process Capability Sheet for a short term 30 piece study needed Statistical Analysis Tools, Techniques and SPC 1
B Capability Study for Radii of laser cut pockets - 0.030" radius Capability, Accuracy and Stability - Processes, Machines, etc. 15
V Machine short term capability study with Cmk index in automotive industry Capability, Accuracy and Stability - Processes, Machines, etc. 3
A How do you identify your heat treat capability study samples? Capability, Accuracy and Stability - Processes, Machines, etc. 3
E Capability study on true position callout. What would be the upper and lower spec? Statistical Analysis Tools, Techniques and SPC 7

Similar threads

Top Bottom