Quality and Productivity
The Quality and Productivity work group focused on requirements to maintain and improve the quality of forged parts and decrease dimensional variation among parts, while increasing all-around productivity. Group members included representatives from forging companies, forging equipment suppliers, steel manufacturers/suppliers, a forging industry consulting engineering firm, a DOE national laboratory, a collaborative manufacturing research and development consortium, a non-profit research organization, the Forging Industry Association, and a DOE research program. This broad mix of participants provided a good range of perspectives on the challenges and opportunities facing the forging industry in quality and productivity.
The ability of forgers to handle small orders, ensure on-time delivery, and maintain parts-per-million quality levels at low selling prices will be increasingly important in successfully competing with alternative domestic processes and off-shore competitors. The forging industry of the future will need to develop and implement a variety of advanced technologies to stay ahead of competitors on quality and productivity.
The industry's vision, Forging Industry Vision of the Future, relays a number of strategic targets for the industry to work towards over the next twenty years. The vision's targets for quality and productivity, shown in Exhibit 5-1, were the work group's initial subject of discussion. During the course of the discussion, the group agreed to a number of revisions that modify or expand the targets as outlined in the vision.
The first quality goal should be clarified by noting that the objective is to reduce to 25 ppm the rejected or returned work from the end-user (rather than during the entire manufacturing process). With this clarification, the 25 ppm target is a realistic long-term goal.
The ability of the industry to achieve a ±8 sigma process control level was the subject of extended discussion. There was some concern that setting this level as an industry-wide standard might be asking for higher levels of quality (which comes at a cost) than the customer really needs or wants. Cost-benefit analyses could help to determine the appropriate level of quality to strive for in different applications. Parts that will be used in very demanding applications, such as in airplanes, will require zero defects. Other parts used in less critical applications may compete more on the basis of cost than premium quality. A couple of participants noted that from the perspective of the metal suppliers, it would be very helpful to know what the end-use of the metal work piece will be so that they can properly process and test the work piece before it is shipped to the forgers.
Finally, the group added a third strategic target for quality improvements: No in-service failures. This target is needed to emphasize the fact that the ultimate goal of quality control is to assure that all parts perform without failure for the duration of their expected lifetime. Initially, the target was limited to eliminating in-service failures due only to problems originating from the forging process. However, since the forging company will be liable for the problem no matter where the defect originated (design, metal workpiece, etc.), the target was revised to read as above.
The group also modified the strategic targets for productivity that were elaborated in the forging vision. In order to make the first productivity target more clear, it was recommended that it include tons of product produced per employee. A baseline level is needed in order to measure progress, and this baseline will be particular to the forging company and product line. The second target was rewritten as "reduce per-piece manufacturing costs by 60%" to reflect the fact that labor costs are only one component of the total manufacturing cost. Lastly, the group felt that a clear definition of "up-time" was required to clarify the third productivity target. Using a definition of "scheduled" up-time (which excludes scheduled down-time for routine, preventative maintenance), the group agreed that a target of greater than 95% is necessary and achievable. Thus, the third target should be revised to read "achieve forging facility scheduled up-times of greater than 95%." This means that the forging facilities must be available and ready for work greater than 95% of the time they are scheduled to be available.
There are a number of technical problems that prevent the forging industry from achieving these quality and productivity targets today. As shown in Exhibit 5-2, these barriers are related to equipment limitations, lack of integration/communication among the different members of the manufacturing supply chain, availability of process modeling/simulation and process monitoring/control technologies, and infrastructural issues. The most critical problem area is the lack of robust, reliable, cost-effective process monitoring and control technologies for the forging industry. Without these technologies, it will be impossible to achieve the manufacturing efficiencies required to meet the industry's productivity goals and reduce the process variations that create defective or off-quality parts. One of the key problems highlighted in this category is the lack of cost-effective, robust, self-tuning sensors. Going on the premise that you cannot control what you cannot sense, a variety of sensors are needed to monitor and regulate all stages of the forging operation. Existing sensors, when available, often cannot withstand the high temperatures and force of the forging environments for extended periods. Those that can are often rendered unreliable before long because they are not capable of periodically re-calibrating themselves. Cost is also an issue, since sensors are needed for virtually all processes.
Another key problem is the lack of computer-controlled forging equipment with feedback loops to detect/prevent production problems. Too often, problems are not detected until later in the process, when the cost of scrapping the product is higher. Another problem is that metal suppliers to the forging industry lack the technology required to properly, and cost-effectively, test the quality of the raw materials supplied to forgers as work pieces. A related supply chain problem is that there is a lack of communication on testing requirements and protocols among materials suppliers, forgers, and customers. Unless the metal supplier knows what the end-product will be used for and the environment that that product will be placed in, it is impossible to determine what tests should be specified. In general, a key barrier to quality and productivity goals is the lack of integration of the needs and expectations of materials suppliers, designers, forgers, and original equipment manufacturers.
In the category of process modeling and simulation, the biggest problem is that there is too much trial and error involved in developing the dies and processes for producing forged parts, which results in significant inefficiencies. The industry lacks validated, widely-available, pc-based simulation tools. Easy-to-use, reliable, predictive simulation tools are especially needed on the shop floor. The lack of good simulation tools leads to other problems, like the inability to manufacture the part correctly the first time it is tried. An underlying problem is the lack of good data and databases on materials properties, especially new materials, that feed into the simulation tools.
Much of the forging equipment available today has not been optimized for use by the forging industry, so equipment limitation problems are not surprising. The current technology is simply not capable of producing forgings that meet the long-term quality and productivity targets. Hammer technologies are a particular problem, with significant operational variations. Improvements are also needed in heating methods and equipment.
The final area of technology barriers, infrastructure issues, focuses mainly on problems related to education and capital. Currently, there are far too few students interested in pursuing careers in metallurgy or forging. The image of the forging industry, and most of the other "smokestack industries," is negative or non-existent among students. Without a technically skilled and educated workforce in the future, the forging industry will not be able to achieve its quality and productivity goals. The lack of capital is another main problem. The forging industry is primarily made up of small and medium-sized firms that lack the capital to invest in new technologies, test or demonstrate emerging technologies, and perform or fund research and development.
A wide range of research is required to overcome the technical barriers to achieving quality and productivity goals in the forging industry, as pictured in Exhibit 5-3. If started today, some of the research would be able to yield commercial results fairly quickly, within 3 years. Other research needs tackle more complex problems and would take longer to produce commercial results -- in the mid-term (3- to 10-year) time frame. A few long-term research needs to develop radically new forging equipment and processes would not be expected to yield commercially-applicable results for 10 years or more.
Many of the research needs are ongoing, and would be expected to produce commercial results in all time periods. The majority of these research needs require funding support from the government in order to be accomplished in the time frames described here. Since the forging industry lacks the resources to perform much R&D on its own, some of the research needs would probably be left undone and most would be substantially delayed if the government or outside support is not available. Research needs were identified for each of the categories of barriers described above and for an additional materials category. The priority research needs in each of the categories are described below.
Process Monitoring and Control
Not surprisingly, the largest number of research needs fell into this area, which was identified as the most critical problem area. Many of the research needs described here and in the category of process modeling and simulation are ultimately directed towards the development of "smart presses" that produce net- and near-net-shape forgings using advanced instrumentation, automation, and robotics. In this regard, a high-priority research need that can be accomplished in the near term is the development of hot dimensional measuring capabilities for taking real-time measurements of forgings during the deformation process. Another near-term need is for the development of vibratory signature analysis equipment that is especially designed for use by the forging industry. More sophisticated machine controls and process simulation software that can be run on a personal computer platform and are easy to use are likely be developed in the near term by individual companies for use with their particular array of equipment and product lines.
In the mid-term, the development of robust, high-temperature sensors that can accurately measure process parameters such as vibration, acoustics and strain would be essential components of smart forging presses. Improved sensors will also enable the development of closed loop process control systems for hot forging. While there are a number of sensors currently on the market, many of these are not cost-effective and have unacceptably short life times. A key goal of smart press technology is to optimize the forging process to achieve the desired product properties with a minimum amount of wasted time and materials. Research directed at producing forging processes that can achieve this goal is a high priority for the industry in the long term.
Process Modeling and Simulation
An important research need in process modeling and simulation is the development of three-dimensional simulation technology. Two-dimensional models currently available do not accurately portray actual operating conditions, and thus have limited potential to improve operating efficiency. It will also be important to improve the reliability and predictive power of process design, modeling, and simulation software by better linking design and process modules and by incorporating into the software relevant and validated data on materials and equipment characteristics and behaviors. More sophisticated modeling and simulation will not be possible unless validated, baseline materials and equipment data are made available.
Forging operations are highly interdependent with their suppliers. To achieve its goals for quality and productivity, the forging industry will need to work cooperatively with vendors supplying raw materials, coatings and lubricants, forming and processing equipment, and other essential products. A high priority in this regard is improving the channels for communication among forging companies and supplier companies. In the near term, the industry needs to make better use of the Internet for exchanging data, and must develop a standard format (e.g., STEP) for recording and transferring data among all data users and providers (forgers, suppliers, and forging customers). Two ongoing research needs in the supply chain are to develop next-generation die manufacturing technology and to improve the understanding of the roles and characteristics of lubricants in order to improve their properties. Better lubricants will increase die life, improve product quality, boost process efficiency, and reduce environmental impacts. The elimination of graphite in warm forging operations is also a goal, and may be achievable through the use of new lubricants or die materials.
Existing forging equipment is not capable of meeting the strategic targets established for productivity and quality by the industry. The development of smart forging presses will improve existing technology to make it better integrated and significantly more efficient. However, research on radically new, breakthrough types of forging equipment is also needed to stay ahead of international competitors in forging and alternative metal processing industries. For example, long-term research on technologies such as hydro-forming and zero-gravity forging could yield promising innovations. Baseline information on forging equipment capabilities, limitations, and desired specifications will need to be collected and communicated on an ongoing basis in order to properly target equipment improvements.
A high priority need in the materials category is to develop technology that can internally inspect the ingot for defects prior to forging. This technology must be coupled with communication throughout the supply chain about the ultimate end-use of the product(s) to be forged from the ingot. Ideally, the metal supplier will know what tests to run and have the technical capability to cost-effectively perform these tests before the ingot is shipped, forged, and delivered to the customer. This research could produce commercial results in the near term because the technology (e.g., infrared, ultrasound, etc.) is available, but needs some modification for it to be cost-effective in the forging supply chain.
Again, it is important to generate data on materials properties, and how they perform and react in operating conditions. A better understanding of the materials used in forging will be necessary for modeling, simulation, and process optimization.
Industry-specific fatigue analysis is identified as an activity that would help to convey the benefits of forged parts and products to customers. A key competitive strength of forging is the high strength, reliability, and tolerance that it imparts. Industry-specific fatigue analysis, which could be completed in the mid term, would help to emphasize these benefits to customers and better illustrate the relatively low life-cycle costs of forgings.
Two of the highest priority research needs for improving quality fall under the infrastructure category. The most pressing need is to establish a dedicated research and development center that can address the various technology needs of the industry in an integrated, coordinated, sustained fashion. It is important that industry be a full partner in directing the operation of the center so that the center's research is relevant to industry's needs. Industry must also participate in research conducted by the center in order to assume a portion of the cost and risk, and to ensure that the data and technologies produced by and located in the center are made available to all forging companies. An industry-directed R&D center would enable the industry to gain access to the expertise and facilities necessary to tackle these complex research problems. It would also establish a mechanism and infrastructure for establishing the contracts and collaborations required to form and operate research partnerships.
The center could be centrally located at one location or it could be a "virtual center," linking together the specialized facilities, capabilities, and expertise that are located throughout the country. Currently, a number of research and technical support institutions have the capability to conduct and/or facilitate partnerships for forging research, including Oak Ridge National Laboratory (ORNL), Sandia National Laboratories, Concurrent Technologies, Inc., and the National Center for Manufacturing Sciences (NCMS). Other government research centers are also likely to have capabilities in forgings, arising from defense- and aerospace-related research activities. Currently, NCMS is working on establishing a forging demonstration center at Wright-Patterson Air Force Base. The center would make use of the facilities and equipment located at the base, but activities there would not be funded or directed by the Air Force. The Metals-Processing Laboratory User Center (MPLUS) at ORNL is a Department of Energy user facility designed to provide industry with access to the specialized technical expertise and equipment needed to solve technology-related metals processing problems. MPLUS includes four primary user centers: Metals Processing, Metals Joining, Metals Characterization, and Metals Process Modeling.(2)
In conjunction with or as a near-term alternative to the R&D center, an industry-directed consortium is needed to serve as a legal, representative body that can issue calls for proposals on behalf of the industry. Similar to the Cast Metal Coalition founded in 1988 by metalcasting technical societies, a forging consortium would serve to promote R&D needed by the industry. As such, the consortium would define and communicate areas of technical interest to the forging industry, issue requests for proposals, and manage the proposal review and selection process. Funding for awards would be provided by members of the consortium, including government agencies.
Education is another high priority research need within the infrastructure category. Forging must become better represented in the science and engineering curricula of high schools, colleges, and universities. One way to do this would be to develop training modules for use in educational institutions as well as in forging companies for on-the-job training and continuing education.