#1 - Operations Management - 72 60 points total (56 pts/question) NOTE: For the following exercises, in order to make your calculations as straightforward as possible; please assume unless stated otherwise that: 1. There are sufficient parts or raw materials so initial operations are never starved. 2. Except as noted, processing times have negligible variability, and over time, workers neither speed up nor slow down, but work always at the processing rates given. 3. There are no machine breakdowns or maintenance. 4. When there are buffers shown, they are large enough to accommodate any amount of WIP that would reside in those buffers under normal operations, but they are not infinite in size. 5. Travel time and time to transport parts from one operation to another is negligible. 6. All operations run with 100% yield, i.e., the operations produce no defective units. 7. All processes are in steady state; thus, you may ignore any start-up effects. 8. Assume strict batch flow discipline. That is, batches cannot be split among two or more different workstations (even if the workstations do the same thing). Each batch is processed through one step completely before advancing to the next step. A Consider the following process. All Steps (A, B, C, D, and E) are necessary to create each finished unit. Each step employs a single worker. Task times are shown for each step. 1a. What is the fastest a rush order for one unit can go through the process? 2a. Working eight hours a day, what is the daily capacity of the process? 3a. During the day, what is the average labor utilization of the five workers? ! ! ! B Consider the following three-step worker-paced line: ! Each step employs a single worker who is not cross-trained for any other step. The set-up represents the amount of time the worker spends setting up the machine for each order. No units can be processed on a machine while it is being set up. The run time represents the amount of time it takes the worker to process a single unit. When a worker completes an order, he or she hands it off to the next stage. ! 1b. If only 10-unit orders are produced, what is the average capacity of the process per 8-hour day? 2b. At what order size does the bottleneck move? That is, at what order size are there two steps that are both bottlenecks? C Consider a five-workstation, worker-paced line, with five manual tasks to be performed before the product is completed, as diagrammed below: ! ! The times shown are the times, in minutes, that it takes one worker to perform that task for one unit of product. This line is staffed with six workers, two of whom are assigned to Workstation D. For the next three questions, assume that each of the Tasks A through E are never split among multiple workers. Thus, the two workers doing Task D work on every other unit, each doing all of Task D on the particular unit on which he or she is working. (Assume there is ample equipment so that all workers can perform their tasks). 1c. What is this line's capacity in an eight-hour day? 2c. What is the direct labor content per unit (in minutes)? 3c. Assume that there are only two costs: each worker receives wages of $10 per hour, and material cost is $15 per unit. Every unit produced generates $36 in revenue; assume that every unit produced can be sold. In steady state, what is the average contribution (revenue - costs) per unit? ! ! D At a local business school, there is a toasted submarine sandwich process that uses a conveyor-fed oven. Zeynep is the sole operator of the sub making process. In the first step of the process, she spends 2 minutes putting various ingredients in the sub. Then, she puts the sub on a conveyor belt and, over a period of 12 minutes, the conveyor moves the sub from the beginning of the oven to the end of the oven, fully toasting it. After the sub comes out of the oven, Zeynep spends 1 minute slicing the sandwich and putting it in a box. At most, 5 subs can fit in the oven at once. The toasting time in the oven does not depend on the number of subs in the oven. ! ! !load! !ingredients! ! ! 2!min/sub! (Zeynep)! ! ! slice!and! box! 12!min!! (oven)! 1!min/sub!!!!!!!! (Zeynep)! 1d. What is the hourly capacity of this sub making process? 2d. What is the labor utilization? Suppose another employee is hired to do the slicing and boxing, and Zeynep now only loads the subs with the right ingredients: 3d. What is the hourly capacity of this process with the additional employee? 4d. What is the labor utilization of the two employees