Capability Calculation on 1 Population Multiple Tolerances

F

frantz

#1
Hi,
Does anyone knows how to calculate process capability for a population with multiple tolerances?
Can we consider using deviation from Aim and then calculate capabilities with a tolerance of +/- 1.0 and How?
Example temperature.
Below is a data sample:
Temp Aim LSL USL
889.0 904 854 954
883.4 882 832 932
887.6 882 832 932
890.5 904 854 954
887.2 904 854 954
888.4 882 832 932
883.9 882 832 932
892.3 882 832 932
891.0 882 832 932
891.2 882 832 932
888.8 904 854 954
899.1 904 854 954
891.6 904 854 954
902.7 910 860 960
908.5 910 860 960
906.9 910 860 960

Thanks
 
Elsmar Forum Sponsor

howste

Thaumaturge
Super Moderator
#2
Are you mixing data from multiple process streams, or are you changing the settings with different batches?
 
Q

qualitytrec

#3
I do not really understand your question. Are you asking how to track capability on an oven at various settings or how to track capability on a process with multiple settings or...???

It sounds like you are asking capability on ovens set at different temps. Perhaps heat treat ovens.

Mark
 
F

frantz

#4
Are you mixing data from multiple process streams, or are you changing the settings with different batches?
Howste,
Here is the problem, we have a continuous process and the temperature tolerances is dependent of the product, therefore when the product is going to the furnace the temperature and the tolerances change. In my opinion there is no way to calculate capability on the whole population. I used to do a deviation from aim (Delta) and calculate the capability for the process base on the deviation. Someone told me that calculating capability from deviation from the aim is wrong.
Hope that answer your question.

Thanks
Frantz
 
F

frantz

#5
I do not really understand your question. Are you asking how to track capability on an oven at various settings or how to track capability on a process with multiple settings or...???

It sounds like you are asking capability on ovens set at different temps. Perhaps heat treat ovens.

Mark
Mark,
I am sending you the answer I send to Howste.
Here is the problem, we have a continuous process and the temperature tolerances is dependent of the product, therefore when the product is going to the furnace the temperature and the tolerances change. In my opinion there is no way to calculate capability on the whole population. I used to do a deviation from aim (Delta) and calculate the capability for the process base on the deviation. Someone told me that calculating capability from deviation from the aim is wrong.
Hope that answer your question.

Thanks
Frantz
 

Bev D

Heretical Statistician
Staff member
Super Moderator
#6
'someone' is mis-informed. there is no reason that a capability analysis can't be performed based on delta to target. There are special considerations when calculating a Capability index, but these are useless anyway.

Basically plot your data first and see what it tells you. dont' automatically combine the different temperature levels but look to see if you have difficulty with any particular setting.
 
Thread starter Similar threads Forum Replies Date
bobdoering Unilateral Tolerance Capability Calculation Imported Legacy Blogs 0
B Calculation of c4 unbiasing constant - Capability results from Minitab in MS Excel Statistical Analysis Tools, Techniques and SPC 25
C Sample Size Calculation Formula for Process Capability Statistical Analysis Tools, Techniques and SPC 25
P Sample Size for Capability Calculation Inspection, Prints (Drawings), Testing, Sampling and Related Topics 33
L Capability Calculation/Error associated to faulty normality distribution assumption Statistical Analysis Tools, Techniques and SPC 2
L Capability calculation on unequal bilateral tolerances? Capability, Accuracy and Stability - Processes, Machines, etc. 5
T Upper and Lower Limit Calculation with Capability Formula - Product Weight Capability, Accuracy and Stability - Processes, Machines, etc. 12
Howard Atkins Calculation of capability of a minimum requirement with no found maximum Statistical Analysis Tools, Techniques and SPC 1
D Ppk - Capability calculation using the estimated sigma calculated from the Rbar/d2 Capability, Accuracy and Stability - Processes, Machines, etc. 16
K Machine Capability Capability, Accuracy and Stability - Processes, Machines, etc. 2
C How to Establish the Calibration & Measurement Capability (CMC)? ISO 17025 related Discussions 1
lanley liao How to keep the manufacturing capability under the API monogram Oil and Gas Industry Standards and Regulations 6
M Minitab Capability of the Population (no sampling) Using Minitab Software 11
A Capability Study - in the beginning of your career what should you have known about the tool Quality Tools, Improvement and Analysis 11
B Two excellent examples of process capability analysis from Quality Magazine Capability, Accuracy and Stability - Processes, Machines, etc. 5
Q Capability study with a minimum spec Statistical Analysis Tools, Techniques and SPC 8
Q Capability - CPk comparison values Capability, Accuracy and Stability - Processes, Machines, etc. 12
R Capability analysis - What is going on this chart? Manufacturing and Related Processes 15
H Capability Data for Paint Thickness on Painted Parts Statistical Analysis Tools, Techniques and SPC 10
N Is capability applicable for a destructive test? Capability, Accuracy and Stability - Processes, Machines, etc. 9
S Capability or Gage R&R Study for Leak Tester? Reliability Analysis - Predictions, Testing and Standards 15
D Pre-Production Capability Assesment Reliability Analysis - Predictions, Testing and Standards 5
T Iec 60601 Impedance and current-carrying capability IEC 60601 - Medical Electrical Equipment Safety Standards Series 1
S Machine Setup for a CNC Machine Capability Study Capability, Accuracy and Stability - Processes, Machines, etc. 1
D O Ring capability and measurement - What is the automotive 'norm' for capability studies on O Rings? General Measurement Device and Calibration Topics 3
M Measuring Capability of Process with Multiple Specifications Capability, Accuracy and Stability - Processes, Machines, etc. 6
G Capability Study for Tapped Hole Reliability Analysis - Predictions, Testing and Standards 3
E Sampling for capability studies for variables and attributes Capability, Accuracy and Stability - Processes, Machines, etc. 4
L How to evaluate the process capability of a data set that is non-normal (cannot be transformed and does not fit any known distribution)? Capability, Accuracy and Stability - Processes, Machines, etc. 12
T Final process capability results - What I am supposed to present? Cp and CpK? APQP and PPAP 11
G Plotting capability study data - I have a bimodular data distribution Capability, Accuracy and Stability - Processes, Machines, etc. 4
A Statistic Tools to Know Capability of Sealing Machine for Seal Width Capability, Accuracy and Stability - Processes, Machines, etc. 3
Q How to perform Process Capability for true position Statistical Analysis Tools, Techniques and SPC 11
V Generic requirements regarding capability study in automotive Capability, Accuracy and Stability - Processes, Machines, etc. 1
A Capability Analysis for Packaging Seal Strength with spec. >0.1 Kgf using Minitab Using Minitab Software 6
J Initial capability for injection molding part Capability, Accuracy and Stability - Processes, Machines, etc. 6
Ron Rompen Ford Method - Position Capability with MMC Modifier Capability, Accuracy and Stability - Processes, Machines, etc. 14
O Capability or Gage R&R Study for Leak Tester Reliability Analysis - Predictions, Testing and Standards 11
S Understanding control chart and measurement capability Statistical Analysis Tools, Techniques and SPC 2
L IATF 16949 Cl. 8.3.3.2 Manufacturing process design input - Process capability IATF 16949 - Automotive Quality Systems Standard 1
B Short term vs Long term Capability - We ship millions of parts in a year Capability, Accuracy and Stability - Processes, Machines, etc. 7
M IATF 16949 - Capability study on non critical dimensions? Statistical Analysis Tools, Techniques and SPC 4
J Are Capability Requirement(s) Valid for All Characteristics? Capability, Accuracy and Stability - Processes, Machines, etc. 6
Y Process Capability for Non-Normal Data - Philosophical Questions Capability, Accuracy and Stability - Processes, Machines, etc. 6
M Process Capability in a High Precision Environment Capability, Accuracy and Stability - Processes, Machines, etc. 7
M CAAC-145 Manuals - Looking for examples of MOM's, MMM's Capability Lists, etc. Federal Aviation Administration (FAA) Standards and Requirements 13
J Powdercoating Capability Employing a Robotic Arm Manufacturing and Related Processes 1
L Excel Template for Cgk Study wanted (Capability Gauges Study) Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 12
V Product Development - When to start calculating Process Capability Capability, Accuracy and Stability - Processes, Machines, etc. 3
V Capability for Correlated Charteristics Capability, Accuracy and Stability - Processes, Machines, etc. 2

Similar threads

Top Bottom