Capability Study on Continual Arbitrary Dimension

O

Ospif1

#1
Hi,

I am new to performing this kind of analysis so a little confused as to what my options are. We currently produce a heat shield and need to perform a capability study on the critical aspects of the shield, which are the diameters and locations of the fastening holes situation on the shield and the form of the shield.

The hole diameters and locations I have no issues with performing the capability however i am confused as to how i can perform one for the form since the form is not a set dimension, it's continual.

What we do have, is the ability to check whether or not the form is within a specified tolerance, but unless you measure the exact point of the form on ever shield tested, the co-ordinates of the form area tested will never be the same.

So I suppose my question is whether or not there is a method of performing a capability study for something which does not have an exact single dimension and location such as a hole does and all you have available to you is a CMM machine which can tell you if the form at any point on the shield is in or out of spec.

Appreciate any help, Cheers.
 
Elsmar Forum Sponsor

Bev D

Heretical Statistician
Staff member
Super Moderator
#2
depending on why you are performing a capability study, a simple approach is to use a categorical (aka attributes or pass/fail) data approach. Thsi gets you to how many bad parts you are making. If you are looking for margin to the limits or slow drifts towards the specification limits, you will need to fixture the parts and measure in specific locations...
 
O

Ospif1

#3
So does having a simple pass or fail option give you the requirement to perform a capability study? Would be great if that can be done because I can then perform a proper dimensional study on diameters and locations and then another for a pass/fail approach for the form and edge.

Thanks for your answer!
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#4
So does having a simple pass or fail option give you the requirement to perform a capability study?
Depends on where your requirement for a capability study comes from. If you are doing it because your customer requires it, then they may have specific requirements and constraints about what they want. (I always advocate for simply asking them) If the requirement comes from your organization, determine the true intent. Is it margin, trending, or yield prediction?
 
Last edited by a moderator:
O

Ospif1

#6
It will be very interesting to know how you do the capability study for hole locations.

Thanks.
We use a CMM machine to locate all the holes in relation to a single specific hole on the part.

So for example the x,y,z coordinates from hole A to hole B, A to C, A to D etc. We have columns for x,y and z, calculate the capability for each of those coordinates then determine an overall capability result from that.

It's bloody tiresome when you have to do 125 parts for a PPAP though :lol:

Thanks for the help guys, I will get back to the customer regarding their exact requirements for the special characteristics in question.
 

Stijloor

Staff member
Super Moderator
#7
We use a CMM machine to locate all the holes in relation to a single specific hole on the part.

So for example the x,y,z coordinates from hole A to hole B, A to C, A to D etc. We have columns for x,y and z, calculate the capability for each of those coordinates then determine an overall capability result from that.

It's bloody tiresome when you have to do 125 parts for a PPAP though :lol:

Thanks for the help guys, I will get back to the customer regarding their exact requirements for the special characteristics in question.
How are the hole locations toleranced? Any positional tolerances used; with or without modifiers? "M" for example?

Stijloor.
 
O

Ospif1

#8
How are the hole locations toleranced? Any positional tolerances used; with or without modifiers? "M" for example?

Stijloor.
Yeah the customer placed positional tolerances on the holes in all directions. I simply CMM the physical part to the CAD of the part and determine if the physical part follows the CAD within the supplied tolerances.
 

Stijloor

Staff member
Super Moderator
#9
Yeah the customer placed positional tolerances on the holes in all directions. I simply CMM the physical part to the CAD of the part and determine if the physical part follows the CAD within the supplied tolerances.
Did the customer accept this practice? If the MMC principle is specified, then it would possibly provide you with an additional (bonus) location tolerance. I am just guessing here because I have not seen the print.

Stijloor.
 
O

Ospif1

#10
Did the customer accept this practice? If the MMC principle is specified, then it would possibly provide you with an additional (bonus) location tolerance. I am just guessing here because I have not seen the print.

Stijloor.
To be completely honest with you, I am not sure how MMC works, the customer was also very vague as to their requirements with the capability, it was simply "we need it performed on 125 parts and for all special characteristics as shown on the FMEA" and the special characteristics were outlined as hole diameters and locations plus the form of the shield.

My own experience is also limited as this is the first time I have ever performed a PPAP and everything that goes with it (I didn't even know what a capability study was a month ago :p). So it's very much a learning experience for me.
 
Thread starter Similar threads Forum Replies Date
Q Capability study with a minimum spec Statistical Analysis Tools, Techniques and SPC 8
S Capability or Gage R&R Study for Leak Tester? Reliability Analysis - Predictions, Testing and Standards 15
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
O Capability or Gage R&R Study for Leak Tester Reliability Analysis - Predictions, Testing and Standards 11
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
ncwalker 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
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
B MSA (Gage R&R) vs. Capability Cpk Study - Helium Leak Check Station Statistical Analysis Tools, Techniques and SPC 2
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
Barahir 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
sridharafep 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
K Format for presenting capability study results? Statistical Analysis Tools, Techniques and SPC 7
Manix Initial Capability study on N50 parts - Subgroup Size? Statistical Analysis Tools, Techniques and SPC 5

Similar threads

Top Bottom