Total Productive Maintenance

Part 4: Schedule Maintenance

by Roger A.P. Fielding, BENCHMARKS

In the last issue, we discussed the second step in implementing TPM––autonomous maintenance for operators––which involves training people to operate and maintain their machines. We emphasized the “Five S” Japanese management principles: organization, tidiness, purity, cleanliness and discipline. We stressed the importance of cleaning the equipment to make problems visible and to encourage operators to work on the equipment.

With the adoption of TPM, the initial machine cleaning activities enable operators to recognize where dirt and dust accumulate. And, because cleaning brings them into intimate contact with the machinery, they soon learn that cleaning and inspection can proceed at the same time.

Whereas new machines should obviously be designed for ease of maintenance from the outset, existing machines must often be re-designed and re-engineered for ease of maintenance. Through their cleaning activities, the operators of aluminum extrusion systems quickly identify where dirt, dust and saw chips can be reduced or eliminated, and where permanent covers, or simple modification are required, to make equipment easier to maintain.

“Bolting”––the tightening of nuts and bolts––goes hand-in-hand with cleaning and lubrication. If you see, or feel, something loose, tighten it! Or, conversely, if something should be loose––a roller or slide mechanism for instance––and it won’t rotate or slide, loosen it! If you don’t, you’re missing another possible source of scratches and dents. By making each group of operators responsible for their own work area, people who are familiar operating their machines soon take on the added responsibility for their maintenance.

Since the time available for cleaning, lubricating and bolting is limited, realistic methods and standards must be developed. But, when time standards cannot be met, practices and equipment must be improved to reduce the time required to do the work properly. During the early years of introducing TPM it’s not unusual for operators to identify problem areas where they can’t keep up with their added responsibilities for cleaning, inspection, bolting and lubrication. In these cases, emphasis must be placed on supporting the workforce, developing more efficient methods, and, in the short-term, using engineering and maintenance resources to provide additional help.

The Impact of Scheduled Maintenance

The initial impact of TPM will be to increase the workload placed on maintenance personnel. The equipment inspections undertaken by the operators will identify maintenance and repair work that would otherwise have been overlooked or “put off” for another day. And, there will be demands for additional engineering and maintenance support from operators who are gaining new insights into the operation of their equipment. The frequency of equipment breakdowns will not immediately decline, and there will be a new urgency to get things fixed. The activities of the maintenance department will have to be coordinated with the autonomous maintenance activities of the operators.

Scheduled maintenance is used to minimize breakdowns while meeting a company’s objectives for increased equipment availability and reduced maintenance costs. In order to minimize disruption during the introduction of TPM, scheduled maintenance, with features to allow for co-ordination of maintenance activities with the autonomous maintenance by operators, should be introduced first. The results of planned maintenance activities are then audited, compared with the objectives, and corrected accordingly.

The TPM improvement process is continuous, and the actions of the workforce continuously change to meet the challenges of improving operations. Improvement activities are planned, the plan is executed, the results evaluated, and a new list of actions identified.

Total Productive Maintenance - Part 5