Comments on: Introducing Control Charts (Run Charts)

By: Jon Peltier

Jon Peltier — Mon, 07 Dec 2009 13:26:24 +0000

Marilyn – What are you looking for?

By: Marilyn Sumonod

Marilyn Sumonod — Mon, 07 Dec 2009 09:10:54 +0000

can i ask some situation problem in how to make a control chart

please give me an example inside the organization..
thmxxxx………

By: darman

darman — Fri, 30 Jan 2009 06:23:36 +0000

does this Run CC build from runs test (non-par analysis)?

By: Validate Your Tables with Micro (Control) Charts | More Information per Pixel

Wed, 06 Aug 2008 08:34:19 +0000

[...] just by quickly scanning the shape. Let’s add a bit more science. In another post Jon showed that Control Charts can be used to identify [...]

By: Jon Peltier

Jon Peltier — Thu, 01 May 2008 18:48:43 +0000

Hi Damir -

The preferred approach is to calculate the mean and variation parameters (e.g., SD) at a point where the process has stabilized, that is, the process is in control. You then plot these values as the horizontal lines in the control chart, and don’t change them until the process is knowingly changed.

The dynamic control chart that this article links to calculates these parameters on all values in the chart, so if more observations are added, the parameters are recalculated. This is incorrect, as I designed that chart before I had been deeply involved in SPC-related activities.

By: Damir

Damir — Thu, 01 May 2008 18:13:28 +0000

How do you calculate sigma when creating a control chart with UCL, LCL and sigma zones (+/- 1 to 3)?
Is the sigma “locked”–meaning calculated on a batch of parts sometimes in past leading to constant LCL and UCL? Or, is it dynamically calculated which leads to LCL and UCL changing over time?
If dynamically, how did (would) you deal with a process with SLOWLY increasing sigma (something getting loose on a machine)?