Let's assume your customers requirements are 25 PPM. That means that you would be allowed 25 pieces for every 1,000,000 pieces or 250 defective parts per year. Or to put it another way, one bad part per day! Notice I did not say one bad part per day per person or job, or shift or machine.
The dynamic inheritance allows you to follow open-closed principle by extending classes without modifying existing classes and allows you to choose features that you need at runtime. Of course, dynamic languages such as Ruby make this a lot easier as you can extend classes or objects with modules at runtime, e.g.
Inheritance is the ability to define a new class that is a modified version of an existing class. It is called âinheritanceâ because the new class inherits the methods of the existing class. Extending this metaphor, the existing class is called the parent and the new class is called the child. As an example, letâs say we want a class to represent a âhand,â that is, the set of cards held by one player.