1、毕业设计（英文翻译） FMS: DEFINITION AND DESCRIPTION Summary： 1. Flexible manufacturing systems are regarded as one of the most efficient methods to employ in reducing or eliminating problems in manufacturing industries. 2. Definitions of FMS vary depending on industry type and the users point of view. 3. FMS
2、 enables manufacturers to machine a wide of workpieces on few machines with low staffing levels, productively, reliably, and predictably. 4. FMS is made up of hardware elements (machine tools, movable pallets, material-handling equipment, coordinate measuring machines, computer hardware equipment, a
3、nd the like)and software elements ( NC programs, inspection programs, work-order files, and FMS software ). The sophisticated FMS software is what actually drives the system. 5. A true FMS can handle a wide variety of different parts, producing them one at a time in random order. 6. FMS is not an en
4、d in itself, but a means to an end and the natural partner to integrate to existing CAD/CAM systems and progress toward CIM. Key words: FMS NC CAM CAD Definitions of FMS， or Flexible Manufacturing Systems ,are plentiful and in many respects are dependent on the ultimate users point of view as to wha
5、t the FMS consists of and how it will be used. However, the following represent a collection of FMS definitions, some traceable and some not traceable to their originating source. 1. United States Government: A series of automatic machine tool or items of fabrication equipment linked together with a
6、n automatic material handling system, a common hierarchical digital preprogrammed computer control, and provision for random fabrication of parts or assemblies that fall within predetermined families. 2. Kearney and Trecker： A FMS is a group of NC machine tools that can randomly process a group of p
7、arts, having automated material handling and central computer control to dynamically balance resource utilization so that the system can adapt automatically to changes in parts production, mixes, and levels of output. 3. FMS is a randomly loaded automated system based on group technology manufacturi
8、ng linking integrated computer control and a group of machines to automatically produce and handle(move) parts for continuous serial processing. 4. FMS combines microelectronics and mechanical engineering to bring the economics of scale to batch work. A central on-line computer controls the machine
9、tools， other workstations, and the transfer of components and tooling, The computer 毕业设计（英文翻译） also provides monitoring and information control. This combination of flexibility and overall control makes possible the production of a wide range of products in small numbers. 5. A process under control
10、to produce varieties of components or products within its stated capability and to a predetermined. 6. A technology which will help achieve leaner factories with better response times, lower unit costs, and higher quality under an improved level of management and capital control. Regardless of how b
11、roadly or narrowly FMS is defined, several key items emerge as critical to a general definition of FMS, and repeat themselves through a cross-section of standard definitions. Words like NC machine tools, automatic material handling system, central computer controlled, randomly loaded, linked togethe
12、r and flexible, all serve to help define a very general description and definition of FMS. Flexible manufacturing systems are based on modular part producing machinery machine tools, or injection molding machines, for example, and a wide variety of ancillary support equipment , linked and integrated
13、 together under central computer control to produce a variety of component in random order. Basically, a FMS is made up of hardware and software elements. Hardware elements are visible and tangible such as CNC machine tools, pallet queuing carousels (part parking lots), material handling equipment (
14、robots or automatic guided vehicles), central chip removal and coolant systems, tooling system, coordinate measuring machines(CMMs), part cleaning stations, and computer hardware equipment. Software elements are invisible and intangible such as NC programs, traffic management software, tooling infor
15、mation, CMM program work-order files .and sophisticated FMS software. A typical FMS layout and its major identifiable components can be seen in Fig-1. A true FMS can handle a wide variety of dissimilar parts, producing them one at a time, in any order ,as needed (very few so-called FMSs meet this st
16、rict definition ). To adapt efficiently in this mode, a FMS must have several types of flexibility. It needs the flexibility to adapt to varying volume requirements and changing part mixes, to accept new parts, and to accommodate design an engineering modifications. FMS also requires the flexibility
17、 to cope with unforeseen and unpredictable. FMS also requires the flexibility to cope with unforeseen and unpredictable such as machine downtime problems or last minute schedule changes； and the ability to grow with the times through system expansion and configuration, improvements, and alterations.
18、 These types of flexibility are made possible through computers and appropriate FMS software. In the long rage, FMS is the natural partner for CAM (Computer Aided Manufacturing) and CIM (Computer Integrated Manufacturing) which ultimately all server to bring a product from design from design to real
19、ity by the most efficient and cost-efficient means. In a FMS installation, the moment-by-moment functions, actions, and decisions are inherent within the system-operating completely without (or with very little) human 毕业设计（英文翻译） intervention. These moment-by-moment activities involve not only materi
20、al handling, but also inspection, part washing, tool storage, fixturing, and warehousing, in addition to downloading of NC programs and other normal machine functions. Depending on a companys specific manufacturing needs, a FMS may or may not be the answer. The graph in Fig-2 illustrates the range o
21、f application solutions available for a given set of workpiece volume and variety requirements. A FMS is set apart from any other kind of manufacturing system, such as a transfer line used in high volume automotive applications, because of its ability to accept parts or components in varying quantit
22、ies, in random order. Thus, a FMS can be designed to process any product, in an volume, in any order, within the family of components designed for the system./ By definition, a FMS can simultaneously process a variety of workpieces, using tooling and fixturing made available at the right machine, at
23、 the right time, and in the right sequence. The FMS computer functions to identify these needs and allocates resources in the from of tooling, fixtures, material movement, and NC and inspection programs in order to fulfill predetermined work order requirements. Is there an optimum size of FMS? At th
24、e present time the answer is no； size depends on users needs and resources. The number of NC machines in a system, for example, can be as low as one or two. This can provide a starting point for those who wish to take advantage of FMS in a step-by-step or phased-in approach. Generally, the number of
25、 processing machines or machine tools is three to ten. But what about the evolution of FMS. The concept of flexible manufacturing systems was born in London in the 1960s when David Williamson, a research and development engineer, came up with both the name and the concept. At the time he was thinkin
26、g in terms of a flexible machining system, and it was in a machine shop that the first FMS was installed. His concept was called System 24 because it was scheduled to operate for 24 hours a day under the control of a computer, but otherwise unmanned on the 16-hour night shift. This simple concept of
27、 decentralized computer control of machine tools, combined with the idea of using machine tools for 24 hours per day (16 unmanned on night shift ), was the beginning of FMSs. Williamson planned to use NC (numerically controlled) machines to work out a series of machining operations on a wide range o
28、f detail parts. Workpieces would be loaded manually on pallets, which would then be delivered to the machines and loaded automatically when needed. Each machine would be equipped with a magazine from which tools could be selected systematically to perform a variety of different operations. Included
29、in this overall process were systems for removing chips and cleaning workpieces. Included in this overall process were systems for removing chips and cleaning workpicecs. This system combined the versatility of computer-controlled machines with very low manning levels. With the growth in computer-controlled equipment and broader applications developing from metal forming to assembly, the concept of “flexible machining systems” was broadened to become what is known today as “flexible manufacturing systems,” or FMS.
