# Cpk for 0 as Ideal Value

T

#### Technician3

I'm trying to figure out if it is possible to calculate Cpk for this type of proces:

Machine sticks label on product, according to spec this label can be shifted to the left or right by max. 1 mm. Ideally there is 0 mm shift.

So I set USL for 1 (shift to the right side) and LSL for -1 (shift to the left side) but I'm not sure if I can use negative numbers for LSL.

Can somebody point me in right direction...

#### Steve Prevette

##### Deming Disciple
Staff member
Super Moderator
Still works, even with negative numbers. If it does cause issues, you could always choose some positive number, say the label is 15 mm from the edge of the product. So, the LSL is 14, target is 15, and USL is 16 . . .

LTPD, AQL, Ppk and Cpk validation sampling plan table Inspection, Prints (Drawings), Testing, Sampling and Related Topics 0
Cp and Cpk for straightness and parallelism Capability, Accuracy and Stability - Processes, Machines, etc. 8
Capability - CPk comparison values Capability, Accuracy and Stability - Processes, Machines, etc. 12
Tolerance definition based on expected Cp/cpk Reliability Analysis - Predictions, Testing and Standards 14
Analysis variation among the lots during cpk calculation. Design and Development of Products and Processes 1
Recommendation for user friendly Gaga R&R and Cpk software Gage R&R (GR&R) and MSA (Measurement Systems Analysis) 10
How to set up Continuous CpK monitoring of an injection mold process Reliability Analysis - Predictions, Testing and Standards 7
Interpretation with regards to Ppk > Cpk Capability, Accuracy and Stability - Processes, Machines, etc. 14
Cpk Calculation - I analyse a double seam cans Manufacturing and Related Processes 15
Cp / Cpk on position using multiple MMC bonuses Capability, Accuracy and Stability - Processes, Machines, etc. 2
Can we use pin gauges to measure an accurate Cpk ? Capability, Accuracy and Stability - Processes, Machines, etc. 9
Final process capability results - What I am supposed to present? Cp and CpK? APQP and PPAP 11
CpK on a manufactured assembly? Reliability Analysis - Predictions, Testing and Standards 7
How is the Cmk and Cpk calculated? Statistical Analysis Tools, Techniques and SPC 0
Cpk for Unilateral Tolerance Capability, Accuracy and Stability - Processes, Machines, etc. 9
How to calculate CPK with n = 1 Manufacturing and Related Processes 2
CPK with a P value less than 0.005 Manufacturing and Related Processes 8
Short Term vs. Long Term SPC Study - Where is Cp and Cpk Defined Statistical Analysis Tools, Techniques and SPC 8
A Cpk Formula seems off, need help!? Capability, Accuracy and Stability - Processes, Machines, etc. 11
D Cp/Cpk on Gages for MSA (vs. Cg/Cgk) Capability, Accuracy and Stability - Processes, Machines, etc. 21
Questions regarding Cpk Calculation - Should we be using LSL/USL or LCL/UCL? Capability, Accuracy and Stability - Processes, Machines, etc. 5
Maximum Material Condition with Bonus - Determine Cpk for this one kpc Measurement Uncertainty (MU) 2
Cpk Setting Tolerance - Cart before the Horse? (Wifi Routers) Capability, Accuracy and Stability - Processes, Machines, etc. 3
Calculating LCL, UCL, Cp, and Cpk in an Excel Spreadsheet Statistical Analysis Tools, Techniques and SPC 3
Cpk on Position w/ MMC on Location and Size Capability, Accuracy and Stability - Processes, Machines, etc. 3
SPC Production - Getting Cpk and Ppk Statistical Analysis Tools, Techniques and SPC 8
S Track Cpk trend Statistical Analysis Tools, Techniques and SPC 5
M Cp & Cpk about a diameter measured with min.,max. and average values. Capability, Accuracy and Stability - Processes, Machines, etc. 13
P Non-normal Data Cpk Statistical Analysis Tools, Techniques and SPC 5
Cpk for Solder Paste Height Statistical Analysis Tools, Techniques and SPC 5
As a part of validation, should i include the acceptance criteria of CPk index >1.33? Qualification and Validation (including 21 CFR Part 11) 4
P Profile Tolerance and CPK Manufacturing and Related Processes 3
When to use Cp Cpk and Pp Ppk Capability, Accuracy and Stability - Processes, Machines, etc. 4
M Calculating Cpk when sample size equals to 1 Capability, Accuracy and Stability - Processes, Machines, etc. 12
CpK in Minitab when 0.0 is the lower spec limit Statistical Analysis Tools, Techniques and SPC 7
Best way to Chart an On-Going CPK Requirement Capability, Accuracy and Stability - Processes, Machines, etc. 4
U Cpk for Contaminant Mass - Washing Parts Capability, Accuracy and Stability - Processes, Machines, etc. 6
Help with Cpk procedure Capability, Accuracy and Stability - Processes, Machines, etc. 3
J Calculation of σ within subgroups for Cpk in Minitab Using Minitab Software 1
Value of Ppk or Cpk when targeting thinner material Statistical Analysis Tools, Techniques and SPC 4
How to validate Microsoft Excel Spreadsheet Calculations for the Cpk value Capability, Accuracy and Stability - Processes, Machines, etc. 9
Calculating Cpk on Non-Normal Data Distribution Capability, Accuracy and Stability - Processes, Machines, etc. 10
Cpk relation to Reliability Capability, Accuracy and Stability - Processes, Machines, etc. 4
B Process Capability - Changing Limits to Improve Cpk or find Root Causes? Capability, Accuracy and Stability - Processes, Machines, etc. 6
Cpk vs Ppk to look at the Capability by Fixture Capability, Accuracy and Stability - Processes, Machines, etc. 4
Convincing Management Cpk without Stability is Meaningless Capability, Accuracy and Stability - Processes, Machines, etc. 7
C Hardness Testing - Low Cpk's using Minitab Misc. Quality Assurance and Business Systems Related Topics 10
L Cpk after Data Transformation - How to Transform LCL /UCL to get Capability Report Capability, Accuracy and Stability - Processes, Machines, etc. 8
Customer requires CpK 2 and PpK 1.5 Capability, Accuracy and Stability - Processes, Machines, etc. 2
G Ongoing Cpk and Global/Historical Data Statistical Analysis Tools, Techniques and SPC 7