Case Study Part I

The average number of strokes for a tool is 45,000.

The standard deviation is 2,500 strokes.

A punch has a total of 25 mm that can be ground off before it is no longer useful.

Each regrind to sharpen a punch removes 1 mm of punch life.

The cost to regrind is:

2 hours of press downtime to remove and reinsert tool, at $300 per hour

5 hours of tool maintenance time, at $65 per hour

5 hours of downtime while press is not being used, at $300 per hour

The average wait time for unplanned tool regrind is 15 hours at $300 per hour.

Because of the large number of strokes per tool regrind, this is considered to be a continuous distribution. The normal curve probability distribution is applicable.

Case Study Part II

Using the data provided in Case Study Part I above, perform calculations to answer the following questions:

Question:

What is the mean and standard deviation of the "production over life of tool"?