1、Unit 27TEXT NEW WORDS AND PHRASES NOTES EXERCISES READING MATERIAL PROFESSIONAL WORDS AND PHRASES TEXT Flexible Manufacturing SystemsThe individual manufacturing system that were introduced here can be incorporated into a single large-scale system in which the production of part is controlled with t
2、he aid of a central computer.The advantage of such a production system is its high flexibility in terms of the small effort and short time required to manufacture a new product,and therefore it is denoted as a flexible manufacturing system(FMS).Existing FMS in the United States are typically made up
3、 of machining centers working in concert with the types of machines,all under the control of a central computer.The work pieces are on pallets which move throughout the system,transferred by towlines(or drag chains)located beneath the floor or by some other mechanism.These FMS limit handling by the
4、operators and can be more readily reprogrammed to handle new requirements.Future FMS will contain many manufacturing cells,each cell consisting of a robot serving several CNC machine tools or other stand-alone systems such as an inspection machine,a welder,an EDM machine,etc.The manufacturing cells
5、will be located along a central transfer system,such as a conveyor,on which a variety of different work pieces and parts are moving.The production of each part will require processing through a different combination of manufacturing cells.In many cases more than one cell can perform a given processi
6、ng step.When a specific work piece approaches the required cell on the conveyor,the corresponding robot will pick it up and lead it onto a CNC machine in the cell.After processing in the cell,the robot will return the semi-finished or finished part to the conveyor.A semi-finished part will move on t
7、he conveyor until it approaches a subsequent cell where its processing can be continued.The corresponding robot will pick it up and load it onto a machine tool.This sequence will be repeated along the conveyor,until,at the route,there will be only finished parts moving,then they could be routed to a
8、n automatic inspection station and subsequently unloaded from the FMS.The coordination among the manufacturing cells and the control of the parts flow on the conveyor will be accomplished under the supervision of the central computer.The advantages of FMS include the following:(1)Increased productiv
9、ity.(2)Shorter preparation time for new products.(3)Reduction of inventory of parts in the plant.(4)Saving of labor cost.(5)Improved product quality.(6)Attracting skilled people to manufacturing(since factory work is regarded as boring and dirty).(7)Improved operators safety.Additional economic savi
10、ngs may be from such things as the operators personal tools,gloves,etc.Other savings are in locker rooms,showers,and cafeteria facilities-all representing valuable plant space,which will not require enlarging if company growth is achieved with flexible automation systems.NEW WORDS AND PHRASES denote
11、 vt.指示，表示 pallet n.棘爪，货盘 supervision n.监督，管理 inventory n.存货，总量 flexible manufacturing system(FMS)柔性制造系统 labor cost 劳动力成本 product quality 产品质量 NOTES1The individual manufacturing system that were introduced here can be incorporated into a single large-scale system in which the production of part is co
12、ntrolled with the aid of a central computer.这里介绍的单个的制造系统可以结合起来成为一个单一的大规模的系统，在这个大系统中，零件的制造是借助于一台中心计算机来进行控制的。that were introduced here是主语the individual manufacturing system的后置定语，in which the production of part is controlled with the aid of a central computer是a single large-scale system的后置定语。2.To machi
13、ne a single unit with general-purpose machine tools may cost 100 times as much as to manufacture the same part by the most efficient mass production methods.使用通用机床加工单个零件的成本是利用高效的大批生产方式制造相同零件的100倍。times as much as 为形容词的比较级句型，意为“是的倍”。3These FMS limit handling by the operators and can be more readily r
14、eprogrammed to handle new requirements.这些FMS限制了操作者的人工处理并能够更容易地重新编程来满足新的加工需求。4In many cases more than one cell can perform a given processing step.在许多情况下，每个给定的加工步骤都可以在不同的加工单元上完成。5This sequence will be repeated along the conveyor,until,at the route,there will be only finished parts moving.这个过程沿传送带不断重复
15、进行，直到在整个传送路线上只有成品在移动。现在分词moving是parts的后置定语。EXERCISES1Answer the following questions:(1)What does the word flexibility means in manufacturing systems?(2)How do an FMS works?(3)What are the advantages of FMS?2Use English replace Chinese or use Chinese replace English.(1)FMS(2)mass production(3)batch p
16、roduction(4)special-purpose machine tool(5)general-purpose machine tool(6)CNC 3Place a“T”after sentences that are true and an“F”after those that are false:(1)In FMS the production of part is controlled with the aid of a central computer.()(2)The term batch production is applied to parts manufactured
17、 in lots ranging from 50 units to 10,000 units.()(3)To manufacture a single unit by the most efficient mass production methods may cost 100 times as much as to machine the same part with general-purpose machine tools.()(4)In future FMS a robot will serve a CNC machine tool or other stand-alone syste
18、m.()(5)In many cases every given processing step can be performed in more than one cell.()(6)FMS can reduce the inventory parts in the plant.()READING MATERIALMachining CenterThe flexibility and versatility of numerical control have led to the development of a new type of machine tool called the mac
19、hining center.Using simpler work holding fixtures and fewer cutting tools,this machine does the work formerly done on several machines.The machining center is provided with an automatic tool changer.On a command from the NC system,the tool change arm located above the spindle rotates clockwise,simul
20、taneously gripping the tool in the spindle and another tool in an interchange station located on the face of the machine which is used to store the tool temporarily.The arm then moves forward,removing the tools from the spindle and from the interchange station.After rotating clockwise 180 degrees,th
21、e arm retracts,inserts the new tool in the spindle,and places the used tool in the interchange system.The arm then returns to the original position.A mechanical hand inside the drum removes the tool from the interchange station and stores it in the tool drum.The mechanical hand removes the next tool
22、 to be used from the drum and places it in the interchange station in preparation for the next operation.The tool change operation may be completed in 5 seconds.The tool drum can hold a large number of different tools.Each tool holder being coded,the tools can be selected in a random order and in any sequence.Machining centers can also be available without NC;however,provided with numerical control,the potential of these machines can be fully realized.PROFESSIONAL WORDS AND PHRASES original adj.最初的，原始的 random adj.任意的，随便的 potential n.潜能，潜力 machining center 加工中心 holding fixture 夹具
