1) A. You are recently promoted as the Director of Operations for the PC Manufacturing unit. You are examining a particular workstation (“Keyboard Assembly”) that has a mean time between
arrivals of 50 hours and a standard deviation of 25 hours. The effective process times at this portion of the line are 5 hours with a standard deviation of 10 hours. Identify the following metrics:
ta = 50 σa = 25 ca2 = 0.25 ra = 1/50
te = 5 σe = 10 ce2 = 4 re = 1/5
Suppose the workstation is composed of a single machine. Find the following metrics:
u = ra *te = te / ta =5/50=0.1
cd2 = =0.1*0.1*4+(1-0.1*0.1)0.25=0.04+0.2475=0.2875
CTq = [(0.25+4)/2]* [0.1/(1-0.1)] *5= 1.18
CT = CTq + te =6.18

B. If the utilization were 90% (instead of what you calculated above), what impact would you observe in terms of the queueing time i.e. CTq & CT? Calculations needed.

C. The accounts department just allocated funds for you to buy an additional machine at the “Keyboard Assembly” workstation. How would having an additional machine at “Keyboard Assembly” affect the
following? Use the times and standard deviations from Part A.
u =
cd2 =
CTq =
CT =

D. The workstation immediately following “Keyboard Assembly” is “Software Setup”. What is the arrival variability (i.e. ca2) at “Software Setup” workstation?