Question

There are 20 automatic turning machines in the lathe department. Batches of parts are machined in the department. Each batch consists of setup and run times. Batch size = 100 parts. The standard time to set up a machine for each batch is 5.0 hours. Four setup workers perform the setups. They each work 40 hours per week. Once a machine is set up, it runs automatically, with no worker attention until the batch is completed. Cycle time to machine each part = 9.0 min; thus, it takes 15 hours of run time to produce a batch. Assume all machines are perfectly reliable. What is the production output of the lathe department in 40 hours of operation per week?

Answer 1

Answer:

The capacity of the lathe department is 3200 parts/week. The workers capacity is the bottleneck.

Explanation:

In this case we have to compare the machine capacity and the worker capacity, and detecting shich one is limitating the capacity of the department.

Machine capacity

The time it takes for a machine to process a batch is

$Time_{batch}=T_{setup} + T_{machining}=5+(9/60)*100=5+15=20 h$

In 40-hour week, every machine can process 2 batches/week.

With 20 machines, the capacity of the department is 2*20=40 batch/week (4000 pcs/week).

Workers capacity

With 40-hour week and 5-hours setup, every worker can make (40/5)=8 setups a week.

If the department has 4 workers, the amount of setups that can be done is 4*8=32 setups/week. That means that only 32 batches can be processed per week (3200 pcs/week).

The workers resource is the limitating capacity, and therefore the capacity of the lathe department.