SQCPack SPC Software Subgroup Size to Small

Brad Gover

Involved In Discussions
Hi all, my company uses SQCPack version 6.0 software made by PQ Systems. I need to have a subgroup size of 216; however, the program only allows for a maximum of 40. I need n = 216 because we have 54 blind holes in a disk. Each disk has 4 tabs in it thus 216. My variation is not within a blind hole; but, across the entire disk (holes 1 thru 54). Any luck overcomming the limit of n = 40 max?

Thanks for any help
Brad
 

Miner

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Admin
It is highly unlikely that you need a subgroup that large. First, you need to determine the rational subgroups. You have at least two choices:
  1. Within hole variation forms the subgroup. Subgroup size = 4.
  2. Within disc variation forms the subgroup. Subgroup size <= 54. You do not need to measure all 54 holes to have a good representation of across disc variation. 5 would check 4 quadrants and the center. 7 would check every 60 degrees and the center, etc. Are specific hole sizes repeatable from disc to disc? You may have 54 process streams.
You apparently are not concerned about within hole variation. Are you concerned about hole to hole variation within a disc? From disc to disc? Your answers to these questions should be used to establish your subgroups.
 
M

Matt33

Brad,
I am sure you meant to do the following: Create the characteristic with a Sample size (Subgroup size) should be entered = 1.
The number of subgroups or samples (not the subgroup size), can be 216 or any other number. There are no known limits on the number of samples that SQCpack allows you to enter and/or chart.
Or, as the other poster, Miner, indicated, the Sample size might be 4 with 54 rows or 54 samples of data.
 
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