Homework 4

Suppose you have a two-activity sequential process: Task 1 ---> Task 2. Task 1 has a throughput capacity of 10 units per hour; task 2 has a throughput capacity of 15 units per hour. What is the cycle time for task 1 (in hours)? Pick the closest answer.

.1

Refer to Scenario A. What is the actual throughput rate out of the Take Payment station, in customers per minute? Pick the closest answer.

.15

Following the previous question, what is the throughput capacity for housekeeping in rooms per minute? Pick the closest answer.

0.4

Refer to Scenario B. What would Task A's utilization be? Pick the closest answer.

100%

Consider a housekeeper at a hotel. The housekeeper cleans rooms in batches - it batches rooms by floor (10 rooms per floor). Each room take 20 minutes to clean. Before cleaning each floor, the housekeeper must setup their cleaning materials by restocking cleaning supplies & linens, emptying the vacuum, changing mop heads, etc.; this takes 30 minutes. Suppose for this example that a housekeeper blocks off the entire floor when setting up and cleaning the rooms on that floor. What is the throughput time for cleaning a floor, in minutes? Pick the closest answer.

230

A workstation or activity in a process is a bottleneck if

it has the smallest average capacity

Throughput time is defined as

the total elapsed time from the start to the finish of a job being processed at one or more workcenters, including the time a job waits for processing.

The maximum rate at which a resource or activity is capable of outputting units is called its

throughput capacity

Scenario A: Consider the following process flowchart for a hypothetical quick service restaurant. Throughput times are listed in parentheses after the name of each activity. For all questions, answer using customers and/or minutes as your units of measure. There are no inventory buffers between any stations; instead, blocking occurs for upstream activities. Take Order (6.1 minutes) ----> Prepare drinks (4.7 minutes) ----> Prepare food (7.9 minutes) -----> Assemble order (5.2 minutes) ----> Take payment (5.5 minutes). Each activity uses its own workers & equipment. The Prepare Food activity can handle 2 customers at once; each of the others can handle 1 customer at a time. What is the throughput time (in minutes) for the entire process (from the start of the take order activity through the end of the take payment activity)? Pick the closest answer.

30

Refer to Scenario A. What is the cycle time for the prepare food activity, in minutes? Pick the closest answer.

4

What would Task D's utilization be? Pick the closest answer.

60%

Suppose you have a two-activity sequential process: Task 1 ---> Task 2. Task 1 has a throughput capacity of 10 units per hour; task 2 has a throughput capacity of 15 units per hour. What is the utilization for task 2? Pick the closest answer.

66%

Refer to Scenario A. What is the utilization of the Assemble Order stage? Pick the closest answer.

85%

Scenario B: Consider the following generic manufacturing process. Throughput capacities are listed in parentheses after the name of each activity. Each task is performed by a separate piece of equipment. There is an inventory buffer between each station, and assume there is no limit on how big the inventory buffer can become. Suppose the process starts with all buffers being empty. Task A (8 units/hr) ----> (Inventory buffer) ---> Task B (12 units/hr) ----> (inventory buffer) ---> Task C (4 units/hr) -----> (inventory buffer) ----> Task D (7 units/hr) Which task(s) would be starved? Pick all that apply (2 pts)

B and D Task B (12 units/hr) ----> (inventory buffer) Task D (7 units/hr)

Which of the following tends to occur, which is often helpful in identifying bottlenecks?

Blocking occurs before the bottleneck; starvation occurs after the bottleneck

The average amount of time it takes for a resource or activity to output one unit is called the

Cycle time

There are three consecutive steps in a customer service process. The first two steps are each capable of serving 25 customers per hour while the third step can process only 20 customers per hour. Suppose that buffers (lines) can form anywhere within the process. Which of the following statements regarding this system is​ true?

If all steps are run at full​ capacity (100% utilization), a line of customers would form in front of the third step.

Refer to Scenario A. Which task(s) would be blocked? Pick all that apply. (2pts)

None of the above

Refer to Scenario B. Which task(s) would be blocked? Pick all that apply (2 pts)

None of the above

Refer to Scenario A. Which task(s) would be starved? Pick all that apply. (2pts)

Prepare food Prepare drinks Assemble order Take payment

Refer to Scenario A. Which task is the bottleneck?

Take order

Which of the following is NOT a characteristic of a "good" (well-managed) bottleneck in a process?

The bottleneck can be performed by relatively unskilled workers