Hello everyone, does anyone have any visual aids for interpreting Control Charts ? I would like to have visual examples that would show the following :
• One point outside the 3 sigma limits
• Two out of three consecutive points more than 2 sigma away from the mean on one side.
• Four out of five consecutive points more than 1 sigma away from the mean on one side
• Seven consecutive points on one side of the mean
• Six consecutive points trending up or down
• Fourteen consecutive points alternating up or down

I would like all the examples to fit on one sheet that I could print out, I could then put them at the work cells so the operators would have visual aids to help them determine if their process needs to be adjusted. SPC has not been used in our facility in a number of years so the majority of the operators are a little rusty. We currently do not have any purchased SPC softwrae we will be using Rbar & R charts that are made in Excel.

If someone has something already made up I would appreciate it.
Thanks, Trae

This is the Nelson Rules, used by JMP sofware, you can also download it from thier Prodcut documentaion at thier website.

Hi Reynald,

You talk about Nelson rules, are they included in a standard? Could you tell me more about these rules?

Thanks for your reply.
:bigwave:

Star18.

Check out this page. If you scroll down a little bit there are the "special cause" rules you are looking for (I think). This is an Infinity QS (SPC software company) website. I happened to have a mouse pad I got from a class from them that has a lot of the data from this page on it. Pretty handy.

http://www.infinityqs.com/content.asp?contentid=687

Doesn't have the 14 points alternating on it but everything else.

..You talk about Nelson rules, are they included in a standard?
Star18.

Not sure what standard you are referring to but Nelson rules are one (if not the most) of the most widely used rules in interpreting control charts.
The other 2 that i know are the Western Electric Rules and the Boeing rules.
There are not much differences though.
Nelson rules are developed by Dr. Nelson (forgot the first name) based on the probability of each scenario (test 1: 1 pt beyond 3 sigma, test 2...) to happen
if the process is still within control.

Check out this thread for great posts:
http://elsmar.com/Forums/showthread.php?t=13866&highlight=interpreting+control+charts

Hi,

attached (i hope) is a quick reference i use for training our setters,

hope it helps

geoff

Thanks alot for the posts, this will help out alot.