As you have learned from your reading, knowing when a part or system will fail is important for a company.
Mean time between failures (MTBF) is the expected time between failures of a part, process, or system and is
a common matrix for a firm to use to understand how often a failure will occur.
Assume that you are the manager of a production line and are responsible for keeping the machines running
24 hours per day, 365 days per year. When a machine breaks, it must be repaired and put back onto operation
as soon as possible. The problem is that your machines are always breaking down, and you really do not have
a good understanding of how often a machine breaks down.
Hint: For this assignment, you will NOT be using the OM software but should use Excel to work the problem.
You decide to run a test to determine the mean time between failures. During the test, you start with 20
operational machines on your production line producing widgets. You record breakdowns during an 80-hour
observation period in which three of the machines broke down. One at 35 hours into the test, one at 50 hours
into the test, and the 3rd failure comes at 75 hours.
Use Excel and the data you collected to calculate the MTBF of your machines. Analyze your results and place
them on the spreadsheet.
Continue to Step 2: Calculate the Expected Breakdown Maintenance Costs . . .
After collecting and analyzing the MTBF data, you were surprised at how often your machines really broke
down. At your last company, you remember that they had a service firm that would come in and perform
preventive maintenance (PM) on your machines and you wonder if this would be an option to reduce
breakdowns. However, before you go to your boss to pitch the idea, you want to see if using an outside PM
firm would reduce your cost.
So you do some research on the cost and run another study on the number of breakdowns of your machines.
Over the last 12 months, the machines have broken down at the rate indicated in the following table:
Number of Breakdowns Number of Months that Breakdowns Occurred
0 0
1 7
2 3
3 2
You also do some research on breakdown cost and find that the average cost of a breakdown to your firm is
$350. You find a service firm and request a price quote from them. The PM service firm costs $200 per month,
but they tell you that you can still expect on average of 2 breakdowns per month even with the PM service.
Use Excel and the data to calculate the expected breakdown maintenance cost versus hiring the PM firm to
service your machines.
Analyze your results and indicate which of the options you will recommend to your boss – hire the firm or
continue dealing with the breakdowns at the current rate?
Sample Solution
I Love You Like Crazy Cakes is the story of a mother who goes to China to adopt a baby girl based on the authors own experiences. It celebrates the love and joy the baby brought into the authors home. The authorâs journey to motherhood began with a letter to Chinese officials asking if she can adopt a baby from the âbig room with lots of other babiesâ. The babies in that room are all looked after by nannies but are missing a mother. The mother is missing something also â a baby. She travels to China to meet her new little girl and is in love immediately. Taking her baby home to America she introduces her to her family and friends for them to begin their life together. The book shows both the difficulties and happy moments as they settle into their life together. The book is set out like a love letter to her child and it shows how important to them it is that their child is adopted and how being adopted doesnât make you any less loved than any other kid. In the end of the book, the mother reflects and thinks about the birth mother and her losses. Two Homes Picture Book/Realistic Fiction Masurel, C., & Denton, K. (2003). Two Homes. Candlewick. Two Homes is the story of a young boy called Alex whose parents are now together living in separate homes, which means Alex has two homes. It never discusses why Alexâs parents are not together, whether they divorced or never married. At Mommyâs house Alex has a soft chair but at Daddyâs house Alex has a rocking chair. In each house Alex has a special bedroom with lots of toys and friends to play with. It gives a tour of both homes, two kitchens, two bedrooms, two favorite chairs. Alex lives in the two homes, but the two homes are very similar, and he is happy in both. No matter which home Alex is in: Mommy or Daddy â Alex knows that he is loved more than anything. It is written from the perspective of Alex who travels between the two homes and provides a realistic yet positive view of having two single parents. The book is a great window which can be used to reassure children going through divorce to focus not on what is lost but what is gained. It does not focus on the reason for the separation or the two hou>
I Love You Like Crazy Cakes is the story of a mother who goes to China to adopt a baby girl based on the authors own experiences. It celebrates the love and joy the baby brought into the authors home. The authorâs journey to motherhood began with a letter to Chinese officials asking if she can adopt a baby from the âbig room with lots of other babiesâ. The babies in that room are all looked after by nannies but are missing a mother. The mother is missing something also â a baby. She travels to China to meet her new little girl and is in love immediately. Taking her baby home to America she introduces her to her family and friends for them to begin their life together. The book shows both the difficulties and happy moments as they settle into their life together. The book is set out like a love letter to her child and it shows how important to them it is that their child is adopted and how being adopted doesnât make you any less loved than any other kid. In the end of the book, the mother reflects and thinks about the birth mother and her losses. Two Homes Picture Book/Realistic Fiction Masurel, C., & Denton, K. (2003). Two Homes. Candlewick. Two Homes is the story of a young boy called Alex whose parents are now together living in separate homes, which means Alex has two homes. It never discusses why Alexâs parents are not together, whether they divorced or never married. At Mommyâs house Alex has a soft chair but at Daddyâs house Alex has a rocking chair. In each house Alex has a special bedroom with lots of toys and friends to play with. It gives a tour of both homes, two kitchens, two bedrooms, two favorite chairs. Alex lives in the two homes, but the two homes are very similar, and he is happy in both. No matter which home Alex is in: Mommy or Daddy â Alex knows that he is loved more than anything. It is written from the perspective of Alex who travels between the two homes and provides a realistic yet positive view of having two single parents. The book is a great window which can be used to reassure children going through divorce to focus not on what is lost but what is gained. It does not focus on the reason for the separation or the two hou>
