Back in March I wrote a post about the importance of Lean Six Sigma (LSS) for aftermarket service and support. I took the somewhat controversial position that, in the maintenance world, consistency should be a higher priority than efficiency and while companies usually focus on helping mechanics fix stuff faster, they would see more benefit by getting mechanics to fix stuff in the same amount of time. In other words, reducing the variability of maintenance execution provides more value than streamlining maintenance procedures. This doesn’t mean that reducing mean-time-to-repair (MTTR) is irrelevant, nor does it mean that improving work flows should be ignored; but it does mean that companies should control the maintenance process before they try to streamline it.

To understand why this is true we need to unpack the LSS acronym within the context of aftermarket service and support. Lean focuses on accelerating the overall repair process by modifying (or eliminating) non-value added maintenance tasks – to increase efficiency. Six Sigma focuses on reducing the variation in the time required to complete each task – to increase consistency. The big “aha” moment comes when companies realize that servicing equipment consists of multiple maintenance tasks and that no matter how streamlined the process, any variation between the fastest and slowest workers to complete each task has a compounding effect that can wreck the repair schedule and increase downtime. Any delays in maintenance execution trickle-down to the next task, destroying the ability to predict when equipment can be returned to service. This is why companies place a high premium on experienced mechanics. If a company can staff up with experts, they will have less variability in service execution and a more predictable and more flexible support organization.

At this point it makes sense to offer a word of warning about MTTR. Companies often overuse MTTR because it’s easy to understand and easy to measure. This makes it a very convenient number to track and report. However, MTTR is deceptive because it replaces the total range of repair times (as performed by each mechanic) with a single number (that represents the group). MTTR thereby masks the real source of blown schedules which is not the maintenance process but the variability of the workforce. Measuring the variability in repair times (for each task) is the critical first step for truly optimizing equipment maintenance.

In fact, reducing maintenance variability usually results in multiple options for the service organization to increase revenue and profits. One major OEM demonstrated that by reducing the variability of field service calls they could: 1) maintain the existing customer base with 12% fewer mechanics; 2) provide higher-margin service options (like a gold-level service plan); 3) increase the customer base up to 13% (by expanding the service territory). When comparing the impact of variability to cycle time (MTTR) this OEM realized that reducing variability provided much greater benefit.

So what’s more important for a maintenance organization: efficiency or consistency? As I said in the first blog post, the best answer is probably both. (Sometimes they go hand-in-hand.) But in terms of priority, companies should tackle consistency before efficiency. Once maintenance variation is under control, tasks that add no value become obvious. Enigma solutions help companies improve both aspects of Lean Six Sigma – efficiency and consistency.

For more information on Lean Six Sigma visit these sites:
http://www.army.mil/ArmyBTKC/focus/cpi/tools3.htm
http://www.amazon.com/Lean-Six-Sigma-Service-Transactions/dp/0071418210
http://jobfunctions.bnet.com/abstract.aspx?docid=236972

Do you have ideas about optimizing aftermarket service and support? We welcome your input! Feel free to submit questions or comments to continue the dialog.