Workcell

A workcell is an arrangement of resources in a manufacturing environment to improve the quality, speed and cost of the process. Workcells are designed to improve these by improving process flow and eliminating waste. They are based on the principles of Lean Manufacturing as described in The Machine That Changed the World by Womack, Jones and Roos.

Classical manufacturing thinking suggests that we lower costs by having each step of the process be as low-cost and efficient as possible. This tends to have machines be placed apart from each other to maximize the efficiency and throughput of each machine. The thought is, "we can lower the cost of each machine by having them produce as many parts as possible." This makes sense since our normal accounting for the capitalization of the machine is based on the number of parts produced (the larger the number the lower cost per part).

Unfortunately, it adds waste in many areas:

 * Inventory
 * Transportation
 * Overspecialization of labor

Inventory tends to pile up after each machine. Plus, one now has to transport the parts from one machine to the next. Also, workers tend to become proficient on only particular machines which make division of labor difficult (for example, you may need 3 workers 60% of the time on each machine - but that's still 3 workers).

Lean Manufacturing has us see things differently. Lean's primary concern is to eliminate waste. In the case above, the waste is primarily inventory and the transportation costs. Lean tells us to optimize the whole. In other words, focus on the process of getting a finished product out at the lowest cost instead of lowering the cost of each step.

Thus is born the workcell. In the workcell, the machines involved in building a product are placed next to each other (possibly in a circular fashion so an operator can be in the middle operating all of them). The starting machine begins the process with raw materials, its output is immediately given to the next machine and so forth down the line.

Although this process seems somewhat counter-intuitive and even almost going back to when we manufactured things in a craftwise manner, costs can drop by an order of magnitude (90%). Workcells is one technique that gives Toyota and other lean manufacturers a great cost advantage.

Of course, other factors (good team, good process) must be present for workcells to work.

In software development, the core of the workcell is the cross-functional team. The cross-functional team works together to do (a little) analysis-design-code-test (not necessarily in that order). Let's contrast agile, cross-functional teams with the more traditional waterfall teams:

                   WATERFALL              AGILE, CROSS-FUNCTIONAL
                   _______________        _______________________
 Team composition  Separate roles         Cross-functional
 Steps are         One at a time          Integrated
 Size of steps     Large                  Small
 Focus is on       Completing step        Quality
 Team work         Present only at        Present all the time
                     boundaries of tasks
 Results are       Historically poor      Fast, high-quality
                     slow, buggy        

The cross-functional team allows developers to build in small increments, and to build code quickly.