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SPC (Statistical Process Control)

We want to make "same" products. But "same" is difficult. With statistics , we build quality control system.

SQC stands for Statistical Quality Control. SPC stands for Statistical Process Control. SPC put heavier weight on control charts. But contents of SQC and SPC are same.

The name "SPC" includes "statistical". SPC uses Statistics . The idea of Sampling , Average and Process Capacity is the method of statistics.

SPC also uses graphs . It is the method of visualization.

Seven QC Tools are the tools of stasistics and graphs.

Quality control with data science was done without computers. But today, we can do efficiently do it in large scale.

Decrese the Troubles of Quality

SPC is the method to decrease the troubles of quality.

The methods in SQC are "KAIZEN", "Watching Y and X" and "Quality Engineering". When we use these methods, we use statistics to analyze data.


The PDCA of KAIZEN will make the strong process.

Normalization is the last step of KAIZEN. All workers can do the improved work by normalization.

Quality Engineering

The idea, "design the product not to recieve the changes of the process" and "study the touble-less process before production" are called Robust Design in Quality Engineering .

Quality Engineering also uses statistics . It is a kind of SPC.


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