Quotes About Constraints

What are the "ifs" and "buts" that limit my enjoyment of life?

The linear-programming was - and is - perhaps the single most important real-life problem.

The claim that the only constraints on our success are the limits of our imagination, although generally false, has lifted hearts for millennia. Grand visions take precedence over prosaic numbers.

Every human being experiences limitation. Everyone's body is limited: limited within a certain span of years, limited in having to live and work with other people who also have their desires and plans.

The new orders have changed the balance. We took more orders, which by themselves didn't turn any resource into a new bottleneck, but they did drastically reduce the amount of spare capacity on the non-bottlenecks, and we didn't compensate with increased inventory in front of the bottleneck.

We need a process," he says. "That's obvious. It's too bad that the five-step process that we developed turned out to be false. No . . . Wait a minute Alex, that's not the case. At the end, the problem was not wandering bottlenecks. It was insufficient protection for the existing bottlenecks. Maybe we can use that five-step process?

What aspect of operation did we change?" Mimicking his voice I answer, "The measurements, the policies, the procedures. Many of them were cast into behavioral patterns. Lou, don't you see? The real constraints, even in our plant, were not the machines, they were the policies.

We had physical constraints that helped us to focus our attention, to zoom in on the real policy constraint. That isn't the case in the division. Over there we have excess capacity going through our ears. We have excess engineering resources that we succeed so brilliantly in wasting. I'm sure that there is no lack of markets. We simply don't know how to put our act together to capitalize on what we have.

Flow means that inventories in the operation are moving. When inventory is not moving, inventory accumulates. Accumulation of inventory takes up space. Therefore, an intuitive way to achieve better flow is to limit the space allowed for inventory to accumulate. To achieve better flow, Ford limited the space allotted for work-in-process between each two work centers.

The daring nature of Ford's method is revealed when one realizes that a direct consequence of limiting the space is that when the allotted space is full, the workers feeding it must stop producing. Therefore, in order to achieve flow, Ford had to abolish local efficiencies. In other words, flow lines are flying in the face of conventional wisdom; the convention that, to be effective, every worker and every work center have to be busy 100% of the time.

Bottlenecks temporarily limit throughput. Maybe your plant is proof of that. But they have little impact upon inventory." "It's completely the opposite, Hilton," I say. "Bottlenecks govern both throughput and inventory. And I'll tell you what my plant really has shown: it's proved our performance measurements are wrong.

You mean make them into non-bottlenecks," says Stacey. "No," he says. "Absolutely not. The bottlenecks stay bottlenecks. What we must do is find enough capacity for the bottlenecks to become more equal to demand.

What's happening isn't an averaging out of the fluctuations in our various speeds, but an accumulation of the fluctuations. And mostly it's an accumulation of slowness—because dependency limits the opportunities for higher fluctuations.

What my people and I have done is to examine daily the queues in front of the assembly and in front of the bottlenecks— we call them 'buffers.' We check just to be sure that everything that's scheduled to be worked on is there—that there are no 'holes.' We thought that if a new bottleneck pops up it would immediately show up as a hole in at least one of these buffers.

You see, whenever there's a hole in a buffer—and I'm not talking about just the work that's supposed to be done on a given day, but the work for two or three days down the road—we go and check in which work center the materials are stuck.

First, make sure the bottlenecks' time is not wasted," he says. "How is the time of a bottleneck wasted? One way is for it to be sitting idle during a lunch break. Another is for it to be processing parts which are already defective—or which will become defective through a careless worker or poor process control. A third way to waste a bottleneck's time is to make it work on parts you don't need.

By running non-bottlenecks for "efficiency," we've built inventories far in excess of demand.

Eighty percent of your products require at least one part from a bottleneck. What are you going to substitute for the bottleneck part that hasn't shown up yet?" Bob scratches his head and says, "Oh, yeah . . . I forgot." "So if we can't assemble," says Stacey, "we get piles of inventory again. Only this time the excess inventory doesn't accumulate in front of a bottleneck; it stacks up in front of final assembly.

With the bottlenecks more productive now, our throughput has gone up and our backlog is declining. But making the bottlenecks more productive has put more demand on the other work centers. If the demand on another work center has gone above one hundred percent, then we've created a new bottleneck.

The bottlenecks have spread." "What do you mean 'the bottlenecks have spread'?" I ask. "Is there a disease out there or something?" "No, what I mean is we have a new bottleneck—or maybe even more than one; I'm not sure yet.

What we know now," I tell him, "is that we shouldn't be looking at each local area and trying to trim it. We should be trying to optimize the whole system. Some resources have to have more capacity than others. The ones at the end of the line should have more than the ones at the beginning—sometimes a lot more. Am I right?

It's kind of horrifying to think of an era when people were so constrained to and by gender, in which the externals you were born with were something you would be stuck with your whole life, could never alter, and it would determine your entire social role and your potential for emotional fulfilment and intellectual achievement.

You know, even grown-up people cannot do what they want most" "Then why grow up?

While writing The Summer Queen, I was constantly told that Alienor was a "woman ahead of her time." But my own take is that she was a woman of her time doing her best within the boundaries of what society would permit. Any attempt to go outside those boundaries was immediately and sometimes brutally quashed, but she was nothing if not resilient. I