How to determine Process Capability using Minitab 17

M

Marc L

Hi,
I am a new with Minitab and this is my first post. Can any one let me know how to determine the process capability study using minitab 17?
Mill produces thin plates with a nominal thickness of 2 mm and width of 1200 mm. One hundred sheet, the average thickness of the coil 2,01mm is calculated, a standard deviation of 40 ?m. Product quality, the thickness tolerance of +/- 0.14 mm.

a) Determine the process capability.
b) the thickness of the thin plate set tolerance limits, so that a 95% probability that the boundaries of the tolerance as many as 99% of the population.

Thanks
Marc
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reynald

Quite Involved in Discussions
I don't have Minitab in my PC now, but if I remember correct go to STAT-->CAPABILITY-->Normal?
 

v9991

Trusted Information Resource
process capability - minitab lit ref.

not sure if you were looking for minitab-steps for calculating capability...here's few references to supplement the help files itself...
(also from minitab)
]
I Think I Can, I Know I Can: A High-Level Overview of Process Capability Analysis

Process Capability Statistics: Cp and Cpk, Working Together

Lightsaber Capability Analysis: The Results

Process Capability Analysis Using MINITAB -1

Process Capability Analysis Using MINITAB -1I

just in case if you havent referred them...
 
M

Mary - QA Manager

Hello all! Have a question, I now have Minitab 17 (Ugh). I have been using the Assistant-Capability Analysis for all my Ppk graphs. Now I need the same graph but with only on tolerance value...True position, Max Variance and Perpendicularity. I am not sure I am using the correct data analysis for one sided dimensions.
Can someone let me know if Minitab has a option for this?

Thanks
Mary
 

Miner

Forum Moderator
Leader
Admin
Minitab 17 Assistant can handle one sided tolerances such as a maximum. However, if you need to enter a Boundary condition such as zero, you will need to use Stat > Quality Tools > Capability Analysis ...
 
M

Mary - QA Manager

Please see the options. Any advice?

thanks!

Mary
 

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Miner

Forum Moderator
Leader
Admin
Depends on your data. Since you have continuous data you would use one of the following: Normal, Between/Within, or Nonnormal.

  1. Start by plotting your data in a control chart to verify stability.
  2. If stable, plot it on a normality plot to verify normality. GDT characteristics tend to become nonnormal as they approach the boundary condition of zero, but may well be normal if they are far from zero.
  3. If normal use Normal or Between/Within. If nonnormal, use Nonnormal (duh).
Regarding Normal versus Between/Within, Normal provides the plain, simple answer that you need. Between/Within is slightly more advanced and provides a breakdown of Between subgroup and Within subgroup variation.

For nonnormal you should fit the distribution before using this option. I do not recommend using the Box-Cox transformation.
 
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