An automated transfer line is to be designed. Based on previous experience, the average downtime per occurrence = 5.0 min, and the probability of a station failure that leads to a downtime occurrence is 0.01. The total work content time = 39.2 min and is to be divided evenly among the workstations, so the ideal cycle time for each station = 39.2/n, where n is the number of workstations.
Determine; (a) the optimum number of stations on the line that will maximize production rate and b) the production rate Rp and proportion uptime for answer to part (a).

Respuesta :

Answer:

a) 28 stations

b) Rp = 21.43

E = 0.5

Explanation:

Given:

Average downtime per occurrence = 5.0 min

Probability that leads to downtime, d= 0.01

Total work time, Tc = 39.2 min

a) For the optimum number of stations on the line that will maximize production rate.

Maximizing Rp =minimizing Tp

Tp = Tc + Ftd

[tex] = \frac{39.2}{n} + (n * 0.01 * 5.0)[/tex]

[tex] = \frac{39.2}{n} + (n * 0.05)[/tex]

At minimum pt. = 0, we have:

dTp/dn = 0

[tex] = \frac{-39.2}{n^2} + 0.05 = 0 [/tex]

Solving for n²:

[tex] n^2 = \frac{39.2}{0.05} = 784[/tex]

[tex] n = \sqrt{784} = 28[/tex]

The optimum number of stations on the line that will maximize production rate is 28 stations.

b) [tex] Tp = \frac{39.2}{28} + (28 * 0.01 * 5) [/tex]

Tp = 1.4 +1.4 = 2.8

The production rate, Rp =

[tex] \frac{60min}{2.8} = 21.43 [/tex]

The proportion uptime,

[tex] E = \frac{1.4}{2.8} = 0.5 [/tex]