AQL ANSI z1.4 & z1.9 - What are the differences between these 2 standards?

[Leoismyname]

Hi,

I am getting confused with the AQL standard for z1.4 and 1.9.

what's the difference between this 2 standard?

where can i find the sampling table for z1.9?

 

[Bev D]

Z1.4 uses categorical or ""Attributes" data (count of defects)
Z1.9 uses continuous or "Variables"" data (measurement data, such as length, width, hardness, etc.)

There are many sites that sell the standards including the ANSI site and ASQ. (www.ASQ.org)

 

[Statistical Steven]

Hi,

I am getting confused with the AQL standard for z1.4 and 1.9.

what's the difference between this 2 standard?

where can i find the sampling table for z1.9?

The term AQL is identical for the two standards. As Bev points out, the difference between the standards is the type of data collected.

 

[Mike S.]

MIL-STD-414 is essentially identical to Z1.9, but free.

 

[Chitchat]

Can z1.9 be used for continuous data?

My customer has provided me with a sampling procedure and the corresponding k-values that they will use at incoming inspection for tensile testing. This works fine for them, as they will be selecting the entire sample at one time which represents the lot. My issue is, I want to sample the lot on a continuous basis and test the individual samples to ensure that my process is still in control.

How do I apply the k-value? There is a risk that my individual measurements will be within spec but the calculated k-valve would out, resulting in rejection of the lot, at which point it's too late from a process control perspective.

Can the k-value be used for process control applications?

Thank you.

 

[Bev D]

No. It is NOT intended for process control. use a control chart. You could probably start with a I, MR chart.