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.