Inspection plan

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Inspection plan

Postby Tumbleweed Tim » 06 May 2008, 20:39

Anyone know if after you establish a sample size, would an inspection plan, describing what to inspect and how be a requirement for a sound system?

At places I have worked in the past usual plan was a folder with characteristics listed, sometimes by the QC person sometimes by the ME, QE, or manager.

Seems to me if I was an auditor after asking how to get a sample size, I might want to know what you are going to inspect and how.

Right now I see a hole in our system because it does address critical characteristics and designating them on drawings, but no mention how to proceed with minor things.

Is this flawed??

PS: Thanks in advance for you opinion.
Tim
Tumbleweed Tim
 
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Location: San Diego

Re: Inspection plan

Postby Stan Hilliard » 07 May 2008, 13:15

Tumbleweed Tim wrote:Anyone know if after you establish a sample size, would an inspection plan, describing what to inspect and how be a requirement for a sound system?

At places I have worked in the past usual plan was a folder with characteristics listed, sometimes by the QC person sometimes by the ME, QE, or manager.

I think the documentation should include everything necessary to disposition the inspected material. In my opinion it should describe (off the top of my head):
  • the product,
  • the procedure and/or test method,
  • the personnel requirements,
  • the quality characteristics and their classifications,
  • sample size, frequency, acceptance number or decision limits.
  • the definition of a lot,
  • what to do with a lot when accepted and if rejected (rework, scrap, etc.),
  • and what records are kept of the inspection.
I also think the decision properties of the sampling plan should be documented:
  • Acceptable Quality Level (AQL)
  • Rejectable Quality Level (RQL)
  • Producer's Risk (Alpha)
  • Consumer's Risk (Beta)
  • the Operating Characteristic Curve (OC Curve)
  • the within-lot standard deviation for variables plans
  • the source of the sampling plan.
Seems to me if I was an auditor after asking how to get a sample size, I might want to know what you are going to inspect and how.
If I were the auditor I would be suspicious that the plan might not be a reality if I did not see that documented.
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Stan Hilliard
 
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Postby Tumbleweed Tim » 07 May 2008, 23:40

Thanks Stan,
I just don't think the current documentation that instructs you to select a sample from a lot is near enough to achieve any high level of certification within our corporation.
Example: Lot of turbine blades come in. Inspector selects sample based on the C=0 plan we use. Probably always 6 parts. Then they do what? Inspect what is convenient? Inspect what you feel like? Inspect per direction of wind blowing.
???
All Characteristics would be the class 4 minor, but I still think you need some documented criteria selected from the drawing based on something other than ones personal experience.
We have a ways to go to get there, but I am sure we will arrive eventually. :D
Tim
Tim
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Joined: 06 May 2008, 20:26
Location: San Diego


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