Statistical Process Control (SPC) in Quality Improvement

Statistical Calculators - Calculator Icon for confidence intervals

Stage I and II SPC

BISNet Team BIS.Net Team

Shewhart, the recognized founder of statistical process control specified two stages for SPC. The first stage is about the initial establishment of the process.

Continue Reading
Statistical Calculators - Calculator Icon for confidence intervals

Taguchi's loss function

Dr Juergen Ude Dr Juergen Ude

Taguchi’s loss function has no sound mathematical basis, it was derived by simply arbitrarily truncating Taylor’s theorem at a mathematically convenient point.

Continue Reading
Statistical Calculators - Calculator Icon for confidence intervals

Short Run SPC

Dr Juergen Ude Dr Juergen Ude

If we really wish to make competitive improvements, we will need to go beyond slavish adherence to methodologies developed in the 1920s. Many statistical methodologies of the ‘twenties’ were based on assumptions no longer appropriate in an age of readily available computer power.

Continue Reading
Statistical Calculators - Calculator Icon for confidence intervals

The effectiveness of SPC

Dr Juergen Ude Dr Juergen Ude

If the sample size is small a popular option is to calculate a confidence interval using sample information. If the confidence interval covers the reference value, then the null hypothesis is accepted.

Continue Reading
Statistical Calculators - Calculator Icon for confidence intervals

Control Limits That Are Too Wide

Dr Juergen Ude Dr Juergen Ude

This article discusses how the use of sub-groups can lead to exceedingly wide control limits, reducing the effectiveness of control charts, leading to loss of credibility. The x-bar chart will be used to demonstrate the problem.

Continue Reading
Statistical Calculators - Calculator Icon for confidence intervals

In Process Control

Dr Juergen Ude Dr Juergen Ude

The quality movement seems to agree that it is wastefully to inspect quality into the product, after it is manufactured, instead of getting-it-right-first. As we are advancing towards the twenty first century it is appropriate to ask whether we really have advanced from the old way of doing things.

Continue Reading
Statistical Calculators - Calculator Icon for confidence intervals

Statistical Applications

Dr Juergen Ude Dr Juergen Ude

For effective process control we need a control chart which is sufficiently sensitive to rapidly detect a change in the process average, whilst rarely giving false alarm signals. A measure of sensitivity is the average run length (ARL).

Continue Reading
Statistical Calculators - Calculator Icon for confidence intervals

Problems with statistical process control theory

Dr Juergen Ude Dr Juergen Ude

This article discusses the various problems that may occur through direct text-book application of statistical process control chart theory. SPC is currently receiving considerable attention by industry to improve quality and productivity.

Continue Reading
WHO WE ARE

Qtech International has specialized in the development of quality information systems and analytic technologies for leading manufacturing corporations for 30 years in 40 countries. Our research into machine-powered algorithms has spanned over 10 years, with foundation research being university supervised prior. Research has involved many sectors, including manufacturing, health, political campaigning, retail, finance and more.

www.qtechinternational.com