Question

"A production line is currently organized so that all parts go through an initial tuning" process. Each part that exits the tuning process goes to either inspector A or inspector B. Currently 50 parts per hour goes into the tuning station, 40% of which will later be sent to inspector A and 60% will be sent to inspector B. Each inspected part exits the inspection process either with a "pass" or "fail" result. Both inspectors reject about 30% of all units inspected.
On average there are 30 units at the tuning station, 20 units at inspector A’s station, and 25 units at inspector B’ station. Assume that we have a stable process throughout.

a. What is the process flow time?
b. What is the average flow time of parts that go through inspector B?
c. What is the average flow time of parts that will pass the inspection?
d. Assume that the company above competes in an industry where high volume is an order qualifier. Use little’s law to explain specifically what the firm should focus on if it wants to have better flow time performance.

Answer 1

Answer:

a.  The process flow time is 1.50 hours

b. The average flow time of parts that go through inspector B is 1.433 hours

c. The average flow time of parts that will pass the inspection=1.5 hours

d. To have a better flow time performance the ideal thing would be to have more quantity produced

Explanation:

a. In order to calculate the process flow time we would have to calculate the following formula:

process flow time=percentage of parts which will later be sent to inspector A*(tunning flow time+1)+percentage of parts which will later be sent to inspector B*(tunning flow time+B flow time)

process flow time=40%*(0.6+1) + 60%*(0.6+0.833)

process flow time= 1.50 hours

The process flow time is 1.50 hours

b. In order to calculate the average flow time of parts that go through inspector B we would have to calculate the following formula:

average flow time of parts that go through inspector B=flow time tunning+flow time B

average flow time of parts that go through inspector B=0.60+0.833

average flow time of parts that go through inspector B= 1.433 hours

c. In order to calculate the average flow time of parts that will pass the inspection we would have to calculate the following formula:

average flow time of parts that will pass the inspection=number will pass of A*(tunning flow time+1)+number will pass of B*(tunning flow time+ flow time B)

average flow time of parts that will pass the inspection=(14/35)*(0.6+1) + (21/35)*(0.6+0.833)

average flow time of parts that will pass the inspection=1.5 hours

d. To have a better flow time performance the ideal thing would be to have more quantity produced