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 that are involuntary and unavoidable in the process.
Laksmi: ¿Can be represented as the varibility?
Dany: The variability can be represented numerically. With the variance calculation and graphically with a histogram.
Laksmi: The rules attempt to distinguish unnatural patterns from natural patterns based on several criteria:
Dany: The absence of points near the centerline
Laksmi: The absence of points near the control limits
Dany: The presence of points outside the control limits.
Laksmi: Other unnatural patterns
Dany: What are the rules nelson?
Laksmi: Nelson Rule 1One point is more than 3 standard deviations from the mean.
Dany: Nelson Rule 2Nine (or more) points in a row are on the same side of the mean.
Laksmi: Nelson Rule 3Six (or more) points in a row are continually increasing (or decreasing).
Dany: Nelson Rule 4Fourteen (or more) points in a row alternate in direction, increasing then decreasing.
Laksmi: Nelson Rule 5Two (or three) out of three points in a row are more than 2 standard deviations from the mean in the same direction.
Dany: Rule 6Four (or five) out of five points in a row are more than 1 standard deviation from the mean in the same direction.
Laksmi: Nelson Rule 7Fifteen points in a row are all within 1 standard deviation of the mean on either side of the mean.
Dany: Rule 8
Eight points in a row exist with none within 1 standard deviation of the mean and the points are in both directions from the mean.
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