Cartas de Control Deber

 

DEBER DE HERRAMIENTAS ESTADÍSTICAS PARA LA CALIDAD CARTA DE CONTROL PARA VARIABLES Nombre: Joselyn Parra

7.4. A process that produces titanium forgings for automobile turbocharger wheels is to be controlled through use of a fraction nonconforming chart. Initially, one sample of size 150 is taken each day for twenty days, and the results shown in Table 7E.4 are observed. (a) Establish a control chart to monitor future production. (b) What is the smallest sample size that could be used for this process and still give a positive lower control limit on the chart? DATOS: n

Literal a.

Literal b.

150

 

 

7.10.  A control chart for the number of nonconforming piston rings is maintained on a forging process with np = 16.0. A sample of size 100 is taken each day and analyzed. (a) What is the probability that a shift in the process average averag e to np = 20.0 will be detected on the first day following the shift? What is the probability that the shift will be detected by at least the end of the third day? (b) Find the smallest sample size that will give a positive lower control limit.

DATOS np

Literal a.

Literal b.

16

n

100

p

0,16

 

7.27. A fraction nonconforming control chart with n = 400 has the following parameters: (a) Find the width of the control limits in standard deviation units. (b) What would be the corresponding parameters for an equivalent control chart based b ased on the number nonconforming? (c) What is the probability that a shift in the process fraction nonconforming to 0.0300 will be detected on the first sample following the shift? DATOS n UCL CL=p LCL

400 0,0809 0,0500 0,0191

Literal a.

Literal b.

Literal c.

7.40. The number of nonconformities found on final inspection of a tape deck is shown in Table 7E.12. Can you conclude that the process is in statistical control? What center line and control limits would you recommend for controlling future production?

 

 

7.44. An automobile manufacturer wishes to control the number of nonconformities in a subassembly área producing manual transmissions. The inspection unit is defined as four transmissions, and data from sixteensamples (each of size 4) are shown in Table 7E.14. (a) Set up a control chart for nonconformities per unit. (b) Do these data come from a controlled process? If not, assume that assignable causes can be found for all out-of-control points and calculate the revised control chart parameters. (c) Suppose the inspection unit is redefined as eight transmissions. Design an appropriate control chart for monitoring future production.

DATOS

Literal a y b.

n

4

g

16

 

  Literal c.