Manufacturing is easily the most challenging and complex system in any organization. MyNAP members SAVE 10% off online. Improving the design in this direction is very important. Factor of safety is a ratio of maximum stress withstand by an object to applied stress. Reliability Leads to Profitability:This highlights that consistent reliability exhibited by product or system leads to increase in … Ready to take your reading offline? 6.4.4 Reliability Factor (K rel) Endurance limit obtained experimentally is the mean value and it varies even for same material and conditions. Some specific needs in these areas are addressed below. The panel considers ERM to be a significant factor in the competitiveness of manufacturing firms, an assessment supported by the case studies in the section on present practice (pp. The way users operate the system 1. Click here to buy this book in print or download it as a free PDF, if available. This vision for ERM is rooted in the evolution of product and process design and intelligent. Operational changes that will enhance ERM must be identified. A complementary focus is needed on using technology. The ratio of a structure's absolute strength (structural capability) to actual applied load; this is a measure of the reliability of a particular design. The origins of the field of reliability engineering, at least the demand for it, can be traced back to the point at which man began to depend upon machines for his livelihood. The on-line system included hardware, software, and diagnostic engineering services. All rights reserved. manufacturing control. It is seldom possible to predict how a system will fail when something somewhere in the plant breaks down. Reliability Factor k e From Fig. Manufacturing engineering and software training programs are badly needed. Such continuous improvements will be required to keep direct cost per unit and factory overhead competitive in the global marketplace. The Japanese have done it by adhering to the basic principles of motivation, commitment and understanding, and training and discipline. In many companies, career paths for these employees are deemphasized, and responsibility for their training and development is specifically assigned to no one. The design, construction, maintenance, adjustment, calibration, and use of measuring and of manufacturing equipment are factors which impact on the reliability of the product. The term equipment reliability and maintenance (ERM) encompasses not only equipment, such as machines, tools, and fixtures, but also the technical, operational, and management activities, ranging from equipment specifications to daily operation and maintenance, required to sustain the performance of manufacturing equipment throughout its useful life. The hard data needed to make a convincing argument to management are hard to find. Few U.S. manufacturers have programs that provide white collar staff with exposure and experience in the actual manufacturing process. Technology management is becoming an accepted discipline in a growing number of U.S. academic institutions. 6 6 6. Veteran engineers in one Japanese company with fewer than 50 employees, for example, developed all of the firm's equipment, tools, and dies. Who is, and is not, walking the floors of today's plants is also of concern. Partnerships with key equipment suppliers were critical to the success of both parts of the program. HVAC: Heating, Ventilation & Air-Conditioning, Factors to be considered while Designing Machine, This post is part of the series: Machine Design or Mechanical Design. Similar results are being achieved in old as well as new factories throughout Japan. Reliability is a measure of the probability that an item will perform its intended function for a specified interval under stated conditions. Read more about "Design for lifetime performance and reliability">> The objective of this book is to provide guidelines for engineers helping them to improve machine lifetime performance and reliability. In U.S. manufacturing, equipment availability is generally ensured by the existence of standby equipment, i.e., buying two machines when one will produce the desired throughput. Executive management awareness of present ERM practice in the United States and abroad, and its importance for competitiveness. The charter of a U.S. plant maintenance institute might include: competitive assessment of ERM (United States versus other countries), research to improve ERM competitiveness and spread best practice, assistance to companies attempting to improve ERM, ERM training assistance, a forum for technology transfer, and recognition of companies that meet predefined ERM thresholds. Their technology exchange programs today include concurrent engineering of next-generation equipment for new product and process requirements and replacement of Intel factory equipment engineering and maintenance staff with supplier personnel. Do you want to take a quick tour of the OpenBook's features? Rather, it is the result of a strategy for achieving zero defects and zero breakdowns through common-sense engineering, attention to basics, and hard work and team effort guided by a top-management vision. Copyright © 2020 Bright Hub PM. In the preparatory stage, management (1) decides to employ the strategy, (2) mounts an educational campaign to reduce or eliminate resistance to it, (3) creates a hospitable organization and establishes basic policies and goals, and (4) formulates a master plan. 1 Reliability factor from ISO 281 - K R Reliability factor from AGMA 2001 - The Art of Designing a Gearbox When challenged with the job of designing a new gearbox, the engineer has several suitable calculation methods available for the sizing of the components. 1. The U.S. view is that “the equipment is now performing at its best and over time performance will degrade.” The Japanese view is that “the equipment is now performing at its worst and work needs to be done to improve its performance dramatically.”, Emphasis on short-term profitability at the expense of preventive maintenance programs, personnel, and spare parts actually decreases long-term profitability by increasing the frequency of catastrophic events (i.e., breakdowns that demand emergency repair). To this end, research in the area of ERM should be directed at finding ways to: inculcate the attitude that equipment should improve through use;use; identify and analyze operational changes that might enhance ERM and inform equipment suppliers of these changes; communicate ERM requirements in clear, operational terms; support industrywide collection and analysis of standardized ERM data; foster an understanding of enterprise optimization; and. To. Though generally accepted accounting principles are inadequate for manufacturing decision making, no substitutes have gained wide acceptance. Finance-driven managers who do not understand manufactur-. Given the opportunity cost of shutdown, such a system could calculate the benefit of reducing or eliminating each category of downtime. While this does not mean that U.S. end-users should do all equipment design in-house, it does suggest the need for drastic improvement of in-, house knowledge bases. FIGURE 3-2 Expected trend in cost of state-of-the-art semiconductor manufacturing facilities. Journal of Machinery Manufacture and Reliability is devoted to advances in machine design; CAD/CAM; experimental mechanics of machines, machine life expectancy, and reliability studies; machine dynamics and kinematics; vibration, acoustics, and stress/strain; wear resistance engineering; real-time machine operation diagnostics; robotic systems; new materials and manufacturing … Cost: Cost has always been the major factor of consideration while designing the machine elements or machine and in this age of competition it has become more important. To this end, the training of finance and accounting people to guide and support the concurrent engineering process is critical. In addition to a broader professional Master of Science degree, greater emphasis is needed on the production of master technicians. The research agenda should reflect the present perspective on ERM. Needed is a production monitoring system capable of providing information about all machine shutdowns, classifying discrete events, and aggregating these events within categories. A clear link must be established between equipment requirements and reliability. Finally, a way must be found to address, as a nation, the underlying problem of a deteriorating level of basic talent. The Japanese are succeeding at this because they have an integrated view of manufacturing as a system. Only adjusts Fig. maximum applied pure bending stress. Durability: The longer the life of the machine more it develops the reputation of being the dependable machine and more will be its sale. Reliability is extremely design-sensitive. For example, meeting process parameters more reliably via FMECA increases factory yields and reduces work-in-process inventory. Obtain the load factor for the case of bending. Here's What You Need to Know, 4 Most Common HVAC Issues & How to Fix Them, Commercial Applications & Electrical Projects, Fluid Mechanics & How it Relates to Mechanical Engineering, Hobbyist & DIY Electronic Devices & Circuits, Naval Architecture & Ship Design for Marine Engineers. FIGURES 3-3 and 3-4 Results in trial fabrication plants for both implanter equipment (1987-8) and wafer etch equipment (1988), with and without service contract, show a substantial increase in average monthly uptime and increased predictability by reducing the range of monthly uptime. Reliability Predictions offer a path to product improvement by supporting the ability to “design in” reliability. 2. The problem needs to be viewed in its totality, with a balanced emphasis on human and technological issues and barriers. uptime (Figure 3-3 and Figure 3-4). This apparently sensible procedure, however, creates an incentive for managers to propose small projects that fall just below the cut-off point where higher level approval would be needed. Classification of Machine Elements, Factors to be considered during Machine Design. Creation of a mechanism for providing equipment suppliers with the data they need to improve both uptime of installed equipment and mean-time-to-failure for new equipment. The company developed a two-part strategy that focused on reducing the operations and support costs of installed equipment while simultaneously influencing the design of a new generation of equipment using life cycle cost data from the factory floor. Many books are written about machine design. and vertically to supervisory controllers above or slaves below. Because management needs both knowledge and data to know what to do and how to do it, a concurrent effort must be mounted to identify and supply the hard data without which even an enlightened management will be unable to identify the areas that need improvement. Small investments (under $100,000, say) may need only the approval of the plant manager; expenditures in excess of several million dollars may require the board of directors' approval. U.S. manufacturing will want to jump to this futuristic plane from its present plateau. Results of these performance comparisons are published in the trade press. These bridges outside the engineering school will help recast the industrial engineer of yesterday as the systems engineer of today. 6–17 While judgment is required to ensure that manufacturing equipment is efficiently utilized, sensor technologies and self-diagnostics may be sufficient to ensure that it is reliably maintained. Rather, research should follow the model that takes the long-term view while working hard on short-term activities. Historically, the evolution of ERM can be traced from breakdown maintenance and repair to preventive maintenance to predictive maintenance. 4. Indirect benefits often outweigh direct savings. SUBSTANTIAL CAPITAL investments, in the form of facilities and equipment, are required for manufacturing almost all goods of economic significance. Given customer preoccupation with initial cost and technical features, equipment is frequently designed to perform specific tasks within the constraints of an acquisition budget, with little regard for optimizing economic performance over its lifetime. Several tests are required at each load level to account for the statistical nature of the failure mechanism. In photolithography, attempts to increase mean time between failures have yielded a 30-percent increase in availability and an approximately 30-percent decrease in area throughput time while achieving a 10-percent reduction in total fabrication throughput time (Figure 3-5). Appearance of the machine: While designing the machine the aesthetics and ergonomics of the machine should be given due consideration without affecting its functionality. Equipment-related needs can be grouped under the categories of performance measurement (identifying what we need to know and how to measure it), tools and techniques (what we can do for. Capital authorization processes3 provide only an appearance of effectively managing some of the crucial bases of competition, including ERM (on which production capacity is clearly dependent). The key technology in stamping is the transfer press, which incorporates a mechanism for moving parts between five or six dies. Reliability testing will be performed at several levels. Without a measurement system that can quantify relationships between engineering work and profit/asset benefits, assess the costs of equipment waiting (e.g., load, unload, operator, material) and downtime, and allocate maintenance costs to reflect reality, results will be anecdotal and perception of the basis for changing the incentive structure will remain shaky. FIGURE 3-1 Improvements in equipment reliability with increasing computerization. ERM issues will not be addressed unless management chooses to address them. As the shafts transmitting power are subjected to fatigue loading, therefore higher factor of safety of 3 to 4 is used on the basis of yield strength for static load analysis. The Japanese stamping lines, for example, are specified to run at a lower, more reliable rate than equivalent U.S. lines. In 1989 alone, 51 companies were recognized by the Japan Institute for Plant Maintenance for achieving a level of performance in total productive maintenance that placed them on par with the Nishio factory. These figures are often given on a yield basis (e.g., output per unit of time or material input). A standard methodology for measuring the performance of ERM is needed, as is a way to quantify the benefits of ERM for top management. The unavailability of internship programs is a serious deficit in U.S. manufacturing. Intelligent manufacturing control for improved reliability and greater precision. For example, the mouse on your computer might have a reliability of 0.990 (or 99%) over the next 1000 hours. This factor is called the safety factor. This will help reduce the cost of the machine and ensure easy availability of the parts. Inquiries into ERM in the next generation of equipment should be based on practical investigations into improving it in the present generation. Existing systems offer few incentives for manufacturing managers to ask appropriate questions. High acquisition and operating costs (stamping dies and presses constitute a substantial part of the capital investment in automobile manufacture) lead automakers to run multiple sets of dies on a given line. Research needs in this area are amplified in Chapter 2, Intelligent Manufacturing Control. The strategy was implemented in four stages. Many of the managers who cannot improve their plants arrived in manufacturing with finance/MBA training and had never set foot in a factory. Development of standards for design and test, measurement and evaluation of ERM, and operator–equipment interfaces. In short, plant managers are given short-term cost-reduction targets that only can be achieved by deemphasizing maintenance staffs and equipment repair, the true costs of which will appear only over the long term. Light weight and minimum dimensions: The machine elements and machine should be strong, rigid and wear resistant with minimum weight and least dimensions. These outside suppliers of engineering services hesitate to experiment at the expense of their customers and so are unlikely to foster significant improvements. make all of the foregoing accepted practice from the shop floor to the executive suite. Quantifiable reasons must be found for employing technologists in the manufacturing sector of an enterprise. Needed in equipment design is a design-for-reliability approach that takes into account all life-cycle costs (acquisition, installation, operation, maintenance, repair, and salvage). comparable, if not superior, to those produced by manufacturers of low volume, luxury cars. Development of standards for design and test, for measuring and evaluating ERM, and for operator–equipment interfaces, would be a great facilitator in each of the areas discussed above. Systematic methodologies that will enable manufacturers to communicate equipment requirements in clear, operational terms need to be developed. Scheduled output is the output expected from an operation for a given allocation of time, material, and labor; it is usually based on a published output rate. Compliance with state standards: Following the standards makes designing easier and availability of various parts faster and easier. In Japan, for instance, many firms are engaged in a 10-year program to upgrade predictive maintenance to the point where ERM becomes the responsibility entirely of operators. Making progress with people-related issues will be much harder than solving technological problems. Factor of safety (FoS), also known as safety factor (SF), is a term describing the structural capacity of a system beyond the expected loads or actual loads. Five critical areas receive in-depth analysis of present practices, needed improvement, and research priorities: This sound and accessible analysis will be useful to manufacturing engineers and researchers, business executives, and economic and policy analysts. This situation is reflected in the radically different perceptions of the performance of newly installed equipment in the United States and Japan. In many companies, the capital approval process specifies different levels of authorization depending on the size of the request. FIGURE 3-5 For photolithography, attempts to increase mean time between failures have yielded a 30% increase in availability and an approximately 30% decrease in area throughout, while achieving a 10% reduction in total fabrication throughput time. ERM practices contribute significantly to this achievement. By increasing uptime and yields of good parts, ERM can reduce capital requirements, thereby cutting total production costs. Reliability Testing is one of the key to better software quality. Here, is the load factor, is the size factor, is the surface factor, is the temperature factor, is the reliability factor and is the unmodified endurance limit. If U.S. machine tool utilization, for example, were to go from 50 percent to 100 percent, investment could be cut in half. Ease and simplicity of servicing and control: The machine and its element should be simple enough so that very little maintenance and servicing is required. National Advisory Committee on Semiconductors. tomer demands or regulatory influences, are forced overseas in their search for suppliers who are willing to quantify machine reliability and to work to meet ERM goals. Initial emphasis was on detecting problems before they became serious enough to force outages. Industrywide collections of such information will facilitate sharing of technical data—both ERM statistics and qualitative information about the relative effectiveness of different techniques—and help pinpoint areas where improvement is essential to global competitiveness. The system was later expanded to incorporate preoutage maintenance plan-. Results in trial fabrication plants for both wafer etch and implanter equipment show a substantial increase in average monthly uptime and increased predictability by reducing the range of monthly. Such a model should address matching of capabilities, design issues and rules, maintenance, installed base, culture, and organization. While they are generally effective, these practices have been considerably enhanced by state-of-the-art maintenance planning, management, and implementation technologies that incorporate information on equipment design, application, and operation. This approach to maintenance is in marked contrast to that taken in other countries. Current emphasis should shift from graduating applied scientists and specialists to producing engineers and interdisciplinarians. The definition of the safety factor is simple. One need is a checklist of procurement practices that will ensure that reliability, or lack of it, is recognized in specific equipment. Just-in-time (JIT) is a method of manufacturing by which parts and assemblies are made or delivered as needed, thereby greatly reducing inventory. Does not imply overall reliability. Between 1979 and 1982, the Japanese Nishio pump factory of Aishin Seiki reduced equipment breakdowns from 700 per month to effectively zero, while achieving an extraordinary level of quality— 11 defects per 1 million pumps produced. Aishin Seiki's success reflects neither high technology nor large investments in new facilities. It cannot. A better job of debugging these systems via simulation, analysis, and rapid development needs to be done. Die change time, which necessarily represents scheduled machine downtime, is a critical element of overall operating performance, and rapid, efficient die changing is a key basis of competition in stamping operations. In theory, a reliable product is totally free of technical errors; in practice, however, vendors frequently express a product's reliability quotient as a percentage. Technology alone will not yield significant improvements in ERM —it is only an enabler. ning, the cost of generator outages, prevention of in-service failure, and the increasing percentage of older units in service. Attainment of set performance levels by equipment is celebrated with the sipping of sake. This adds up to important savings because the base cost of many types of equipment exceeds $1 million per unit. Software and sensors have the potential to enhance ERM and so mitigate the added complexity associated with these technologies (see Figure 3-1). In the introduction stage, the ERM program is kicked off. Events that slow or interrupt the manufacturing process or degrade the product impair the competitiveness of a manufacturing enterprise. Benefits of Intel's ERM program have included reduced cost per unit at each process step, as factory operations and support costs associated with downtime or slower area throughput time have been reduced. Some two-year colleges are already cooperating with manufacturers to teach technical skills to shop floor personnel. Japanese companies that have excelled in this area characteristically have the ability to develop and produce their own equipment. Restoration of apprenticeship programs and manufacturing laboratories. Needed in equipment design is a design-for-reliability approach that takes into account all life-cycle costs (acquisition, installation, operation, maintenance, repair, and salvage). Obtain the coefficients for Surface-Factor Equation from Table 6-3 from the … Software maintenance and lack of skills have emerged as major contributors to the perception that mechatronic equipment is less reliable than electromechanical equipment. A strawman model that would support analysis of the impacts of various methodologies on the manufacturing environment would be useful. This is true even of smaller companies. The very terminology of ERM can impede its adoption and practice. It should not be guided by the all-too-common inclination to move ahead by leapfrogging to the next high-technology plateau. Emphasis on sensor technologies and self-diagnosis. Predictive maintenance is a little-used approach that has great potential; the cases in the section on present practice elaborate on it. While total abandonment of tradition, or complete cultural change, is neither possible nor desirable, U.S. manufacturers may need to import, adapt, and fine-tune techniques from other countries such as Japan. Lacking strength in manufacturing systems engineering, many plants rely on system integrators distinct from the equipment builders to configure their manufacturing systems. How is the safety factor calculated. divided by the factor of safety. Preventive maintenance is the systematic servicing of equipment to reduce the possibility of failure. Workshops sponsored by the National Research Council could serve to acquaint manufacturing executives with present practice in the United States and Japan. © 2020 National Academy of Sciences. In contrast to design engineers who, because they are charged in most cases directly to a product, are viewed as contributors, manufacturing engineers and skilled workers are considered manufacturing overhead and, hence, as opportunities for cost reduction.