You may argue that what’s the big deal if my existing car doesn’t fit into the garage, I will rebuild the garage that can fit my bigger car.
You can always do it with garage but not with customer’s specifications as you can’t dictate it or simply customer won’t change his processes to fit your defective products. The only way is to improve your existing process or else lose your business to your competitors.
We can easily understand the concept of six-sigma using the analogy of parking a car into the garage and if you want to understand it more seriously, just imagine that you are entering a tunnel (instead of garage) at the speed of 150-200 Km/Hr!
When ever a car is bigger than the garage, it’s not possible to enter the garage. Take another car whose width is slightly less than the width of the car. This time it is possible to enter the garage but we will get frequent scratches unless you are an expert driver! Take a third car whose width is just half of the width of the garage , it’s is now possible for me to enter the garage even if I am drunk.
Car width represents the “current process capability“
Garage width represents the “Customer’s specifications“
We should remember that
“We need to buy a car according to the dimensions of the garage”
“We need to change our manufacturing processes to meet the customer’s specification”