SPC on Attributive data?

8 Replies

SPC on Attributive data?

Posted by Emanuel Alexandru Orzan on Feb 12, 2020 7:17 am

Hello everyone! 
My name is Emanuel, and I currently work as Production Engineer (the job profile is more supplier quality engineer).  I have always worked in Quality, Product Quality, Quality Engineer, Customer Quality Engineer, Supplier Quality.  


I my current assignment the RE (requirement engineer) recently defined CTQ (Critical to Quality) dimensions on drawing, but also marked as CTQ the thread of a screw for example, we are checking this by a GoNoGo gauge so we have ok/nok. Also tensile test is marked as CTQ but for this we only define min value ex. 3000N 

The management wants to us to implement SPC for all CTQ, my question is how would you handle this attributive data in this situation? Any experience with this?

Any feedback is really appreciated.
Regards,
Emanuel
 

Re: SPC on Attributive data?

Posted by Duke Okes on Feb 12, 2020 10:58 am

Attribute SPC charts include c, p, np and u charts.  Whether or not they will work well will depend partially on sample size, which you can control somewhat by frequency of plotting the data, although this may also impact the ability to respond in a timely manner.

Re: SPC on Attributive data?

Posted by Emanuel Alexandru Orzan on Feb 12, 2020 12:20 pm

Thanks Duke! I will look in to those charts and frequency of plotting the data. 

Re: SPC on Attributive data?

Posted by Trish Borzon on Feb 12, 2020 12:51 pm

Hi Emanuel - Welcome to myASQ & thanks for posting a questions right away.  This is a great community & I'm glad Duke Okes‍ helped - Thanks Duke! 
Hope you enjoy the community 
Trish 

Re: SPC on Attributive data?

Posted by Duke Okes on Feb 12, 2020 1:05 pm

Trish, ASQ probably has some online resources that might help.  I didn't take time to look them up.

Re: SPC on Attributive data?

Posted by Trish Borzon on Feb 12, 2020 2:23 pm

Gretchen Peterson‍ - can you help? 
thanks :D 
Trish 

Re: SPC on Attributive data?

Posted by Gretchen Peterson on Feb 12, 2020 3:11 pm

Thanks for the tag, Trish Borzon‍.

Emanuel Alexandru Orzan‍, a good starting point is the Statistical Process Control Learn About Quality page: https://asq.org/quality-resources/statistical-process-control

Of most use to you may the additional references listed at the bottom of the page.  I'd also encourage you to look at what is available in the Resources tab, especially the articles related to this topic. 

I hope that this is helpful to you!

Gretchen
Gretchen Peterson MLIS Research Librarian gpeterson@asq.org

Re: SPC on Attributive data?

Posted by Emanuel Alexandru Orzan on Feb 13, 2020 12:13 am

Hello all, 

Thank you very much for your help. 

Thank you very much Gretchen Peterson, this page is really helpful! 

Regards, 
Emanuel 

Re: SPC on Attributive data?

Posted by Alexander Kholodov on Feb 20, 2020 7:47 am

Hi Emanuel - I would recommend you to consider, in addition to many other fantastic resources available through ASQ, the following handbook -  Introduction to Statistical Quality Control by Douglas Montgomery (any edition), which I was lucky to come across in the beginning of my Quality journey.

Regards,
Alexander Kholodov
ASQ CQE