Magazine article Management Today

Message in a Bottleneck

Magazine article Management Today

Message in a Bottleneck

Article excerpt

The pace of every operation in a production chain should be dictated by its weakest link, and that's where improvements should first be focused. It's not a new idea but it's one that a surprising number of manufacturers have yet to adopt.

Meet Herbie. He's a corpulent child reluctantly taking part in a route march with fitter, leaner boys than he, scouts who have the added advantage that their rucksacks are not weighed down with pots and pickles to stave off hunger. The trail is a single track and inevitably the group spreads out as most of the faster boys march on ahead. Everyone who has the misfortune to be walking behind a snail-like Herbie finds their route blocked.

The problem is that the whole group needs to be at the camp site before it gets dark, and while the boys up ahead will have no trouble, Herbie and those stuck at the back 'with him will be marching well into the night.

What to do? Inspiration strikes. Put Herbie up at the top of the file, forbid everyone to overtake him, and divvy up the contents of his backpack to the fitter boys. That way, Herbie, under pressure to walk swiftly, is freed up, while the more athletic bods with excess but unnecessary energy are slowed down slightly. Our telling tale ends with the entire group installed at the campsite comfortably before sundown, and the heroic organiser patting himself on the back for having worked out that it was the slowest not the fastest boy who set the pace for the assembled company.

The chances are that you've already met Herbie, since he is a crucial character in Eli Goldratt's runaway management bestseller The Goal, first published in 1984. Even if you haven't met him in the pages of a book, you've probably met him on a shop floor. For Herbie, read the one machine or process or operation which ultimately dictates the speed of throughput, a bottleneck by another name. For the group of boys spreading out in front of the bottleneck, read increased but ultimately useless inventory as each pulls his own way, trying to prove how fit he is.

Herbie's creator, following a fairly disastrous sortie into scheduling software known as Optimised Production Technology (OPT), now runs the Avraham Y Goldratt Institute and although his ideas on bottleneck management, which he now calls the Theory of Constraints (TOC), have moved on slightly, the basic message is remarkably similar. While Goldratt is keen to claim TOC is a useful approach to issues of project management and constraints in company policies, independent experts say production is where the true value still lies. 'A lot of work is being done to see how you can apply manufacturing theory outside of manufacturing,' explains Roy Westbrook, associate professor of operations management and chairman of the Sloan Masters Programme at the London Business School, 'but you always come up against the problem of environments that don't even have the stability offered by manufacturing, where at least if something takes an hour to make, it takes an hour to make. Outside of manufacturing, there is so much scope for informal systems.'

TOC boils down to the argument that the throughput (that is, output which is sold) of an entire plant is the measure of success for any company; that it is nonsensical for individual departments to work on improving their performance locally since this will only result in stockpiles of inventory or work-in-progress; and that there is always one weakest link in the chain, the point where improvement efforts should be focused first and whose limitations or constraints should inform all other steps. 'If you optimise already strong links without strengthening the weakest, all you do is heighten the imbalance - which translates into inventory,' says Goldratt.

The Word according to Goldratt is based on a user-friendly five-point action plan. Step one is to identify the constraints in the system and establish the weakest link; step two is to exploit the constraints (making sure the bottleneck machine works every hour of the day, for example); and step three is to subordinate everything else to the above (making sure the pace of every other operation is dictated by the bottleneck). …

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