大型轴齿轮专用机床设计(摘要+英文文献翻译+CAD图纸)
Integrated Computer Aided Manufacturing
1.INTRODUCTION
Today’s industry competes in a truly international marketplace. Efficient transportation networks have created a “world market” in which we participate on a daily basis. For any industrial country to compete in this market, it must have companies that provide economic high-quality products to their customers in a timely manner. The importance of integrating product design and process design to achieve a design for production system cannot be overemphasized. However, even once a design is finalized, manufacturing industries must be willing to accommodate their customers by allowing last-minute engineering-design changes without affecting shipping schedules or altering product quality.
Most U.S.-based manufacturing companies look toward CAD/CAM and CIM to provide this flexibility in their manufacturing system . Today ,the use of computers in manufacturing is common . Manufacturing system are being designed that not only process parts automatically ,but also move the parts from machine to machine and sequence the ordering of operations in the system.（ Figure 1） contains a plot of the economic regions of manufacturing. It should be noted that manual handcrafted goods will always have a market in the United States as well as abroad. This is also true of industrial products—there will continue to be a need for special one-of-a-kind items. The spectrum of one-of-a-kind goods through high-volume goods dictates that a variety of manufacturing methods be used to meet our various industrial needs. Some of these systems will look like the factories that our grandparents labored in, whereas others will take on a futuristic look. In the following sections, a discussion of flexible manufacturing systems is presented.
Figure 1 Volume versus variety regions for economic manufacturing
2.FLEXIBLE MANUFACTURING SYSTEMS
A flexible manufacturing system, or FMS as they are more commonly known, is a reprogram-able manufacturing system capable of producing a variety of products automatically. Since Henry Ford first introduced and modernized the transfer line, we have been able to perform a variety of manufacturing operations automatically. However, altering these systems to accommodate even minor changes in the product has been quite taxing. Whole machines might have to be introduced to the system while other machines or components are modified or retired to accommodate small changes in a product. In today’s competitive marketplace ,it is necessary to accommodate customer changes or the customer will find someone else who will accommodate the changes. Conventional manufacturing system s have been marked by one of two distinct features:
1. Job shop type systems were capable of producing a variety of product ,but at a high cost.
2. Transfer lines could produce large volumes of a product at a reasonable cost, but were limited to the production of one ,two, or very few different parts.
The advent of numerical control (NC) and robotics has provided us with reprogramming capabilities at the machine level with minimum setup time. NC machines and robots provide the basic physical building blocks for re-programmable manufacturing systems.
2.1.FMS Equipment
2.1.1Machines
In order to meet the requirements of the definition of an FMS, the basic processing in the system must be automated. Because automation must be programmable in order to accommodate a variety of product-processing requirements, easily alterable as well as versatile machines must perform the basic processing.
For this reason, CNC turning centers, CNC machining centers, and robotic workstations comprise the majority of equipment in these systems. These machines are not only capable of being easily reprogrammed, but are also capable of accommodating a variety of tooling via a tool changer and tool-storage system. It is not unusual for a CNC machining center to contain to 12 or more tools (right-hand turning tools, left-hand turning tools ,boring bars, drills ,and so on ) . The automatic tool changer and storage capabilities of NC machines make them natural choices for material-processing equipment.
Parts must also be moved between processing stations automatically. Several different types of material-handling systems are employed to move these parts from station to station. The selection of the type of material-handling system is a function of several system features. The material-handling system, first, must be able to accommodate the load and bulk of the part and perhaps the part fixture. Large, heavy 923