How to generate control limits in control chart

[Former Member]

I want to generate a X bar chart with control limits, sample size is Fix- 1.

SPC criterion I selected is 020 ie Task List characteristics/ Material.

1)Sampling Procedure I used- Fixed-1

2)Valuation mode I used- Attrib non conforming units/ manual.

3)Control chart I am using is 110- Shewart chart for X bar.

But when I click for control limits in chart it is saying control limits for track 1 could not be calculated.

Could anyone guide me, how to generate control limits for this graph. Sammple size will alwyas be 1.

Please let me know should I change control chart type in this case.

[Former Member]

Hi Jaison,

You should use valuation mode - SPC valuation in sampling procedure.

Also you have to use sampling procedure with inspection points.

as practically every hour or depending on the frequency decided we collect the measurements and calculate the SPC.

now after correction in the sampling procedure create new inspection lot and check SPC.

try out and revert.

Regards,

Anil

[Former Member]

I am not able to generate control limts.

I changed valuation mode into SPC and maintained control chART TYPE AS 110 shewart x bar chart. still its is not generating control limits.

My sample size is one and its not inspn point related chart. This is MFPR lot generation every day and spc criterion is for that material.

[Former Member]

I had this error message as well. But I was doing free inspection points with fix sample of 1 per material and used 111 chart. Turns out that 111 was using FM QRKT_MEAN_VALUE_SHEWHART which requires sample to be greater than one.

Now Shewhart 110 makes use of same FM QRKT_MEAN_VALUE_SHEWHART therefore if you are planning to use fix one sample best to use 112 chart instead.