VELOCITY - DEE JACOB [117]
The Third Round began – and when the little die left Murphy’s big hand, a measly single dot was the result. So Amy removed one penny from the jar, and with a look worthy of Ebenezer Scrooge, slid it across the table to Wayne Reese. For his part, Wayne rolled a four with his two dice, and so emptied his entire stock to Sarah, leaving him at the end of the turn with that one penny in queue from Amy.
On the second turn, Murphy rolled a boxcar – six – and Amy drew six from the jar to pass to Wayne. At the same time, Wayne rolled a four, but could only pass that single penny in queue on to Sarah.
And so it went, turn after turn. By the end of the twenty-turn month, the results were clear: inventory had fallen dramatically – choked by the rolls of the constraint – yet output was still quite high. The pennies moved across the finish line by the sweep of Elaine’s hand numbered seventy-four. Yet work-in-process inventory was nearly the same as at the start: thirty-one at the concluding turn, as opposed to twenty-eight at the beginning.
“Look at what happened,” said Tom. “You exceeded the expectation of sixty-five by nine cents. That’s what? More than ten percent.”
“About fourteen percent,” said Elaine.
“And you kept inventory at quite manageable levels,” Tom said. “Ending inventory was about the same as the starting inventory, and was way below the ending levels of the two previous rounds. Everything flowed quickly to the constraint, and quickly away from the constraint toward the finish line. If you think about it, Wayne, you’re actually abiding by Lean principles better with a constrained system than you are with a balanced line.”
Wayne nodded, but kept quiet. The lightbulb had not quite been switched on in his mind, but he was beginning to see the light.
“What you have at this point,” Tom went on, “is a system that is stable and robust. You have enough processing speed that if one of the workstations goes down for a day – goes to zero output – that station, once it’s restored, could catch up again quickly, and your month wouldn’t be ruined.”
“Unless I am the one who goes down,” said Murphy.
“Yes, that’s right. In this configuration, if Murphy gets knocked out for a turn or more, you’ve lost whatever he would have rolled in those turns from your month. So you want to protect the constraint above all. But actually there is a way that Murph could take a day off or go off-line for maintenance or whatever, and yet it wouldn’t ruin you. Or more important, you can increase your output, yet keep the system stable. I’ll show you that, and then I have to go. I’m off to the Florida Keys.”
Amy looked at him. This was news to her.
“Now we have a stable and robust system,” Tom continued. “What do we want to do next?”
No one answered.
“The market its growing,” Amy prompted. “The minimum demand is now in excess of seventy-five cents, not sixty-five. Or the market is asking for new offerings or more flexibility in options in what we currently offer.”
“They don’t just want pennies anymore,” said Garth. “They want nickels and dimes, too.”
“Something like that,” said Amy.
“So think,” said Tom. “We have a good system, but we need more from it. What do we do?”
“Improve it,” said Wayne.
“Yes, but how? And where?” asked Tom. “Do we improve Sarah? Do we give her three dice instead of two? If we did, what would we gain from that? Nothing. She already does everything as fast and as perfectly as we could want.”
“That’s what I’ve always thought,” said Sarah.
“Or do we give everybody three dice – everybody except Murphy, who stays with one die?”
“No, that doesn’t make any sense,” said Elaine. “What would be the point? And now you really are talking about excess capacity.”
“You have to improve the constraint,” said Wayne. “Logically, that would be the thing to do.”
“Right!” said Tom. “To improve the system, you improve performance with respect to the constraint. You do what they call ‘elevate’ the