Advanced SPC · Western Electric & Nelson Rules

Automatic out-of-control detection across control charts

Active Rules
6
Rule Triggers 24h
7
Critical
2
Cp / Cpk avg
1.28 / 1.14

X-bar Chart — FRG-2048-A Diameter

Rule Book

  • Rule 1 · One point > 3σ from centerline2×
  • Rule 2 · Nine points on same side of centerline1×
  • Rule 3 · Six points steadily increasing/decreasing0×
  • Rule 4 · Fourteen points alternating up/down0×
  • Nelson · Two of three > 2σ same side1×
  • Nelson · Four of five > 1σ same side3×