VELOCITY - DEE JACOB [116]
“That’s why we have takt time!” Wayne said. “We calculate takt and balance the line so that everyone has sufficient time to complete whatever tasks have to be done.”
“But, Wayne, you’re loading every workstation to run at ninety-three or ninety-four percent of its capacity,” said Murphy. “What happens when somebody isn’t ready at the end of the takt cycle? When somebody drops the ball? Something just doesn’t show up when the clock strikes?”
“Then we’re late!” Wayne admitted. “And if it happens consistently, we make adjustments.”
“The problem,” said Murphy, “is that you never know who’s going to have a bad day. And if you constantly keep making adjustments based on temporary bottlenecks, then the workforce doesn’t know which end is up.”
Wayne tried not to scowl, but he knew there was truth in this because he had seen the confusion at Oakton when Kurt had been forced to scramble employees from one area of the plant to another for exactly that reason.
“Well, I don’t know that much about production,” said Sarah, “but if a balanced line is problematic, what’s the alternative? An unbalanced line?”
“Yes, an unbalanced line,” said Tom. “And the way you unbalance the line is through the use of a constraint.”
“Now I know where you’re going – to the Theory of Constraints,” said Wayne. “I’ve been reading about it, but … I don’t know. I’m just not convinced.”
“All right, I hear you,” said Tom. “But let’s just give it a try.”
And they did. The setup was the same as in the round before, with four pennies in queue in front of everyone except Amy, who had the penny jar. But this time everyone would use two dice – except for Murphy, who would only have one. Murph would represent the constraint.
After the twenty turns, simulating a month’s output, they had moved an impressive eighty-six pennies through the system. This was obviously well above the sixty-five-cent target.
“Excess finished goods!” Wayne carped at the end.
“All right, Mr. Wise Guy,” said Amy. “We are assuming plenty of demand and a profitable market for everything we process. The point is that we not only met the low target, but we beat the expectation handily. With a constraint in place.”
“And with doubled capacity everywhere else!” Wayne countered. “Seriously, look at how you got there! Twice the capability for four out of the five of us doing the processing. In the real world that would be very expensive.”
“On the other hand, look at your throughput,” said Murphy. “Output has nearly doubled. We’re selling everything we make. Customers are happy because they’re getting their products. I say that higher throughput – the rate of making money, I’m talking about here – more than offsets the higher inventory and expense!”
“Does it?” asked Wayne. “I’m not so sure. Look at all that inventory still on the table, especially in front of you, Murph. That’s got to be forty to fifty pennies stuck in front you.”
“But remember,” said Amy, “that buffer is in place so that the constraint always has enough to work on, and keeps chugging along. Everywhere else, inventory levels are fairly low.”
“He does have a point, though,” said Tom. “The overall inventory number is high – sixty-one pennies.”
“Yes! You see! This would be a very expensive system to run!” said Wayne.
“I have to take Wayne’s side on this one,” said Elaine. “From an accounting point of view, I’d be wondering about costs and investment.”
“That’s why in Round Three, we’re going to improve it,” said Tom. “We’re going to run things the same way, with a constraint in place, but we’re going to make a couple of changes. First, we’re going to take away Amy’s dice. Whatever Murphy rolls with his one die, he will call out that number to Amy – and Amy will feed that same number of new pennies to Wayne and into the system.
“Second, we’re going to set up Murphy with a large buffer of pennies so that even with high rolls of his one die, he should have a large