Material de apoyo para el video control estadístico del proceso
PROCESOS INDUSTRIALES EN EL ÁREA DE MANUFACTURA SPC CONTROL ESTADÍSTICO DEL PROCESO LIC. EDGAR GERARDO MATA ORTIZ LAKSMI RODRIGUEZ CORTEZ DANIEL AGUILERA MUÑOZ 3°C
Laksmi: What is the variability in processes?Dany: Variability is a kinf of small changes thatare involuntary and unavoidable in the process.Laksmi: ¿Can be represented as the varibility?Dany: The variability can be representednumerically. With the variance calculation andgraphically with a histogram.Laksmi: The rules attempt to distinguish unnaturalpatterns from natural patterns based on severalcriteria:Dany: The absence of points near the centerlineLaksmi: The absence of points near the controllimits
Dany: The presence of points outside the controllimits.Laksmi: Other unnatural patternsDany: What are the rules nelson?Laksmi: Nelson Rule 1One point is more than 3 standard deviationsfrom the mean.
Dany: Nelson Rule 2Nine (or more) points in a row are on the sameside of the mean.Laksmi: Nelson Rule 3Six (or more) points in a row are continuallyincreasing (or decreasing).
Dany: Nelson Rule 4Fourteen (or more) points in a row alternate indirection, increasing then decreasing.Laksmi: Nelson Rule 5Two (or three) out of three points in a row aremore than 2 standard deviations from the mean inthe same direction.
Dany: Rule 6Four (or five) out of five points in a row are morethan 1 standard deviation from the mean in thesame direction.Laksmi: Nelson Rule 7Fifteen points in a row are all within 1 standarddeviation of the mean on either side of the mean.
Dany: Rule 8Eight points in a row exist with none within 1standard deviation of the mean and the points arein both directions from the mean.