lean maintenance and repair

Time zero maintenance for production systems
A lean management made by the Aachen Institute for German company survey shows that manufacturing companies make considerable potential in the field of maintenance of its facilities. For 81% of respondents indicate it Lean Maintenance Methods of the way to more and better value.



Gallery: 2 photos
Figure 2: In the area of ​​plant maintenance are considerable optimization potential. Images: Lean Management Institute

The integration of the maintenance services in the daily operations but now prepares in many cases are still difficulties and costs productivity, because the plants during the maintenance period can produce.

Maintenance time zero maximizes productive time



This is where the process-oriented Lean Maintenance system: The maximization of productive time due to the concept of "time zero maintenance" as well as a useful cut of the maintenance effort will be the focus. Value-added, time is not productive anymore due to maintenance "wasted" are.

This is the maintenance organization, starting from the production system, developed tailor-made. Goal of Lean Maintenance is to minimize downtime and maximize the value creation process with full stability. To achieve this, does the Lean Maintenance System back on methods and tools that are in the areas of lean production and lean administration known and tested: The approaches of Lean management, but the customer support processes as effective as for production processes.

Four stages of Lean Maintenance System

While many in business in the maintenance of the highest priority of the plants is awarded, which have the highest level of complexity or even the most investment value, the lean-maintenance system is another way: Here, get the plants the most attention, which is actually crucial to maintaining the current value is. For it is not necessary to repair equipment at great expense to maintain, for example, if there are redundancies and you could be so used in an incident the next plant and the current value would not be disturbed.

1st Prioritization system: the application of lean concrete begins Maintenance Systems to analyze the individual facilities to evaluate, prioritize based on their importance and then to a divide by eight classes of pollutants. Influencing the production system: the criteria for the prioritization system are. Occurs in a system failure a failure of the production system or not? Position in the value stream: Is failure to classify a plant for the value stream as critical or uncritical? Influencing the customers: If a system failure, the affected customers low or high? In this way it is ensured that the facility, which represents, for example, the bottleneck in the system, as well as the associated systems give the highest priority. At the same time avoiding unnecessary costs on installations for the entire system has a minor role or be easily replaced in their function.
2nd Schad Classification: To provide a sound basis for the selection of maintenance strategy will be judged at Lean Maintenance System in the next step, the possible damage to the individual system components and the components are then assigned to one of eight classes of pollutants. Even so recommendations for the maintenance and stocking of spare parts are connected. Basis for the evaluation of the components are the following three criteria. Impact on the operating system: Does the failure of the process components of the function or safety of the plant? Predictability of failure: If the damage is foreseeable or occurs suddenly, as a rule? Claims frequency: How often does a mistake?
3rd Concept Development: After the first two steps will determine the prioritization of equipment and components, there are also recommendations for the various maintenance strategies. In the development of plant-specific maintenance concepts will now distinguish between critical and noncritical systems. Depending on the priority level is for systems that are critical for the production company, created a well-coordinated action plan that addresses the priority system, the damage and the priority class Deglitch. To minimize the effects of disturbances on the current value as low as possible, maximum fault clearance can be defined. By an 8-point program where appropriate, the Deglitch be reduced to the point that the maximum repair time is not exceeded. For the non-critical systems, the autonomous maintenance is introduced in which the operating staff in down times that occur due to set-up and reconstruction work in case of incidents or carrying out any necessary maintenance work.
What changes can arise in this new concept of development shows an example of a wire manufacturer, in which after the prioritization system and the repair of the damaged Classification stop ungskonzept was adapted to the analysis results. This Störcharakteristik described the errors that occurred at the various plants, their frequency and duration. It turned out that for example the roll stand, a number of damages occurred that were judged very differently. Thus the failure of the tachometer generator was damaged in the uncritical Class 2, however, belonged to an overheating of the framework in Class 3 pests In the most harmful effects of class 8 was one of the most critical defect of the inlet guides, which occurred about 20 times per year and had a fault duration of around five hours. The consequences were plant downtime and quality problems as well as the overloading of the engines. So far the damage has been repaired after the onset of the disorder. This maintenance strategy changed. To avoid the error with this significant impact on the production system, a weekly change of the bearings was introduced.
4th Organizational development: If the fixed measures and concepts for each installation, can be derived from the organization. These are the necessary activities at the individual facilities and calculates the structure capacity. From the individual results for the different systems can then be calculated at divisional level, the necessary staff for centralized and decentralized maintenance teams and a pool specialist.
Noticeable effects on plant operation

Through the approaches of Lean Maintenance System, the following positive effects:

Reduction of maintenance time: Maintenance is largely organized so that at least no longer a bottleneck facilities due to maintenance activities must be turned off. Downtimes are thus used more effectively and minimize repair times.
Increasing OEE: By reducing downtime and the use of compliant concepts increases the overall production time. In addition, further enhanced by the relocation of maintenance time in rebuilding and other downtime, the OEE.
Higher Process Stability: Standardization and elimination of waste in maintenance activities increases process stability and hence the product quality.
Reduce costs: With the help of a targeted employee utilization and improved management processes reduces the resource requirements. MM
Dr. Bodo Wiegand is director of the Lean Management Institute, 52 074