Engineering reference

Engineering guides

Practical explanations, formulas, and worked examples for engineering decisions. Start with the question your measurements need to answer, then check the assumptions before applying a method.

Explore the guides

Process statistics

Cpk vs Ppk

Compare within and overall variability using a complete thickness example, and learn why a high index does not prove stability.

Process monitoring

I-MR control charts

Calculate Individuals and Moving Range limits from ordered data. Separate control signals from specification failures.

Electroplating

Copper electroplating and Faraday’s law

Connect deposited geometry to copper mass, charge and conditional plating time, with explicit units and efficiency.

Split-lot analysis

Semiconductor split-lot analysis

Work through Welch, ANOVA and unequal-sample Tukey–Kramer comparisons. Distinguish significance from an engineering threshold.

DOE interaction

DOE interaction effects

Use a replicated two-factor example to understand interactions and the limits of observed-condition screening.

Choose a method for your question

Process capability compares a distribution with specification limits; control charts examine ordered measurements. Experimental comparisons ask whether observed conditions differ. Electroplating calculations connect geometry, charge and current under explicit physical assumptions.

These are different questions. A calculation alone does not establish stability, causation or production qualification.