Many confuse availability with equipment reliability. In reality, it is only one part of the calculation. Availability is the actual time that the machine or system is capable of production as a percent of total planned production time. Availability rate should not be confused with overall availability. The latter is calculated using total calendar time as the divisor, not planned production time.
Most plants do not have a formal reliability engineering function nor do they have programs that directly address reliability problems. In a few instances, product quality and maintenance management programs acknowledge equipment reliability as an issue. However, these programs do not include specific programs that will improve reliability. In part, this omission is created by our inability to assign responsibility for equipment reliability. Maintenance has an important role; but so do production, plant engineering, purchasing, sales and training. Each of these plant functions has a direct impact on performance.
Poor maintenance practices are perceived as the dominant factor that limits production capacity, product quality and profitability. In some cases, this perception is valid; but most of the reliability problems that adversely affect plant performance are not attributable to poor maintenance. Many of the perceived maintenance problems are really outside of the maintenance function. Improper operating procedures, poor design or improper scheduling of production is the real sources of many plant reliability problems. These plant functions must also assume an active role in equipment reliability.
Asset dependability begins with the specification and selection process. The plant engineering and purchasing functions must actively pursue reliability as part of the process. Life cycle cost, maintainability and employee skill requirements must be key factors in the decision-making process. The purchase price of new and replacement systems are not a true measure of equipment cost or its impact on overall plant performance.
Purchasing must also use good judgment when selecting replacement components for both maintenance and production. Too many plants select vendors and components solely on costs. Little or no consideration is given to a component’s life cycle cost or its impact on reliability. As an example, one client elected to purchase a light duty bearing for critical foundry exhaust fans. The decision was based on a purchase price that was $5.00 less for each bearing. Because of this decision, the mean-time-between-failure of these fans dropped from six years to six months. Purchasing must assume an active role in equipment reliability. Without their support and active participation, acceptable plant performance levels are not achievable.
Production has the greatest role to play. For every maintenance-related problem, there are 50 problems generated by poor operating procedures or methods. Operator error is an obvious cause of equipment downtime and product quality problems. However, production's contribution to poor performance is much greater. According to an evaluation of a 4-High Tandem Mill , Eighty percent of the problems that restricted the system's capacity, product quality and costs were directly attributable to poor operating procedures and practices. Most of the problems were easy to correct and none required a financial investment.
Sales and marketing directly affect equipment reliability. The sales function determines how most plants operate. In some discrete manufacturing plants, this does not present a serious problem. However, in continuous process plants, such as steel, paper, chemical, , oil & gas poor sales strategy can have a serious, negative impact on plant performance. If the sales function loads a plant with short-run, low quantity orders, the number and frequency of machine set-ups will increase. This constant stopping, set-up change and re-start have a direct impact on reliability, product quality and capacity.
Employee skills are also a critical part of equipment reliability. Operators and maintenance personnel must have adequate knowledge and proper procedures to follow before an acceptable level of performance is achievable. The training function must accept its role in supporting equipment reliability. Without the training function’s support, acceptable skill levels will not be achieved. Inadequate standard procedures for both operation and maintenance also contribute to poor reliability. In most cases, standard operating and standard maintenance procedures do not provide enough data to properly operate or maintain plant equipment. These shortcomings are too often viewed as employee failures. Management assumes that the workforce lacks the skills or motivation to perform their duties. In many cases, the failure is in the procedures and not the employees.
Who is responsible for asset reliability? The answer is both simple and complex. Everyone must take an active role. A viable reliability improvement program must start with corporate management. They must establish and support policies that create an environment that is conducive to maximum utilization of manufacturing and process systems. Without their active support, improvement is difficult to achieve. Unfortunately, lack of corporate leadership and support is the norm, and often contributes to poor equipment reliability.
Plant engineering, purchasing, Sales and marketing, production, maintenance and training are the critical functions. Life cycle cost, ease of maintenance, and reliability must become their primary focus. They must work together with a common objective ─ to achieve the best performance from all plant equipment and systems. If you can improve the reliability of your equipment, product quality, increased capacity and profitability will follow.
Statistical analyses conducted by a number of industrial, trade and professional organizations conclusively point to the fact that maintenance is the primary source of less than 20% of availability losses. The majority, as much as 85%, is the result of deficiencies in other functional groups or functions within the plant or corporation. Therefore, the solution to availability problems should be clear—a holistic approach to standardized, value-added business and work practices that assure availability, best quality and lowest total cost of ownership. Single-focused approaches, such as maintenance improvements, simply will not generate enough benefits to warrant the effort—it cannot affect the majority of the factors that limit availability.
If you want to improve the availability of your premiss, contact KTT for advice and support.