Take the Risk Out of Mechanical Maintenance

Know machine history and condition because there is more at stake than just downtime

Construction Equipment - February 1, 2004

Mike Vorster
Contributing Editor

It is strange that we don't have a name for the most important thing we do—repair machines before they break. We understand preventive maintenance and repairs, but what about the work we do before failure to prevent breakdowns? It is not a "repair" because nothing has "broken," but it is certainly more than normal, scheduled preventive maintenance.

What is it, why do we need to do it, and how can we proactively manage it with the philosophy of "If it ain't broke, keep it that way"?

Repairs are easy. The machine breaks down and needs to be fixed right now. All you can do is spend the required amount as effectively as possible under crisis conditions. It is a little like opening your parachute after jumping out of the plane: a necessary reaction to a current problem, and you hope for a safe landing.

The worst thing about a repair is the collateral damage caused by the breakdown. A $500 bearing can ruin a $7,000 transmission; a $100 hose can cause a $2,000 loss in production. Collateral costs are extremely difficult to measure, they do not appear in cost reports, and they are easily disregarded. Yet we simply cannot afford the collateral cost of equipment failures in the field if we want to complete construction on time and on budget. The impact that breakdowns have on operations and the frequency with which they occur are key factors in managing an individual machine or a fleet as a whole.

Preventive maintenance is also easy. Work is carefully defined in a maintenance check list, timing is set by the maintenance cycle, and work is performed in agreement with operations. Spending on preventive maintenance is an investment rather than a cost.

A manager can run a fleet based on a good preventive maintenance program, letting a machine run to failure before taking any additional action. Those that do this neglect the collateral cost of lost production, disrupted operations, increased repair costs, and crisis management. Instead, decisions are simple—the machine must be repaired and the money must be spent. The manager must only decide how to schedule the inevitable overtime, how to reduce the inevitable cost, and whether or not to use the downtime as an opportunity to replace a component or two that appear to be "tired."

The need to manage equipment costs without sacrificing reliability forces equipment managers to implement a Mechanical Maintenance program that focuses on repair before failure and bridges the gap between preventive maintenance and repair. It requires courage and a firm commitment to excellence in the management of the fleet. Here's how it works:

What must be done is determined by a knowledge of component lives, machine history, and the current condition of the machine. Nothing has broken down to reveal exactly what needs to be done.

When it must be done is your call. It can be done immediately or postponed depending on your assessment of the risk between the cost of taking action too early in the life of a component and the collateral cost of a failure in the field. Again, there's been no failure to indicate when to repair.

How much should be spent is dependant on which components you decide to replace and the work that must be done. Doing it this month would be good, but how about doing it next quarter when the budget situation should look a little better?

Mechanical maintenance is more than a no-option-necessary reaction to a current problem. It requires courage and a good understanding of what will happen if you let a machine run to failure.

Reliable machine information needed

The inspection and condition assessment work done as part of a preventive maintenance program together with a knowledge of component lives and machine history form the foundation for a mechanical maintenance program. There are three factors involved in a good mechanical maintenance program.

1. Know machine condition, component lives and history so you can make a reasonable prediction of component failure.
2. Understand the impact of failure and the collateral costs in terms of lost production, disrupted operations, increased repair costs and crisis management.
3. Determine your willingness to risk an on-shift failure and incur the associated collateral costs.

The accompanying flow chart (below) graphically illustrates the process.

Low-impact failures, predictable or not, are easy: Repair them. If there are no collateral impacts and it ain't broke, don't fix it.

High-impact failures are different and fall into two groups. The first are those that you can predict with reasonable accuracy with information provided by inspection and condition assessment programs. We can take preventive action knowing that we are not being overly conservative in our decision to repair before failure.

If we cannot predict failure with reasonable accuracy, then the picture changes drastically. We are forced to look at the risks involved and make a choice between two bad situations. On the one hand, we can run to failure and accept the impacts that unscheduled failures and unreliable machines have on operations in the shop and in the field. On the other hand, we can be conservative in our assessment, bring the machine in, fix it, and accept the costs of shortening component lives by taking early preventive action.

Our ability to implement an effective mechanical maintenance program therefore depends on our ability to predict failure and base high-impact decisions on good information rather than conservative guesses. This means we must use the best tools and techniques available for inspection and condition assessment.

The technicians performing preventive maintenance are the manager's eyes and ears. They visit the machines regularly and must have the time, training and tools needed to inspect and report not just check, change, adjust and lubricate. Armed with that information, we can make sure that "if it ain't broke, keep it that way."