Design of Experiments (DOE) is a structured approach for varying process and/or product factors (x’s) and quantifying their effects on process outputs (y’s), so that those outputs can be controlled to optimal levels. DOE deals with identification of critical factors and their response variables, and the magnitude of the response for each level of the critical factors. DoE is also used to understand the interaction…

## Sixth principle of SPC – causes for Variation

According to the sixth principle of SPC a frequency distribution will be deviating from normal distribution, only in the presence of any assignable cause. A frequency distribution is a tally of measurements that shows the number of times the measurement is included int he tally. From this frequency distribution we can see if there are only chance causes present in the process of any assignable…

## Basic Principles of Statistical Process Control

The six principles below are the Basic Principles of Statistical Process Control (SPC). These can be clearly understood using Frequency Distributions. The principles are listed below. The explanation is linked to each sentence No two things are exactly alike Variation in a product or process can be measured Things Vary according to a definite pattern Whenever things of the same kind are measured, a large group of…