过程装备与控制工程专业英语.doc

#Manufacturing Engineering Processes1. Classification of Manufacturing ProcessesThe following table shows the classification of manufacturing engineering processes used in shaping materials. Note that only typical examples are mentioned in the table. Process typeState of materialCategory of basic processPrimary basic processProcess examplesMass-conserving processesSolidGranularFluidMechanicalMechanical MechanicalPlastic deformation Flow and plasticDeformationFlowForging &rollingPowder compactionCastingMass-reducing processesSolidMechanicalThermalChemicalDuctile fracture and brittle fractureMelting and EvaporationDissolutionCombustion Turning ,milling and drillingElectric discharge machining and cuttingElectrochemical machining CuttingJoining processes Atomic bondingAdhesionSolidFluid(vicinity of the joint)Solid(fluid filler material)MechanicalMechanicalMechanicalPlasticFlowFlowFriction weldingWelding(fusion)Brazing2. Examples of Manufacturing Processes Forging .Forging can be characterized as: mass conserving, solid state of work material (metal), mechanical primary basic process-plastic deformation. A wide variety of forging processes is used .The most common type of forging is drop forging .The metal is heated to a suitable working temperature and placed in the lower die cavity .The upper die is then lower so that the metal is forced to fill the cavity. Excess material is squeezed out between the die faces at the periphery as flash, which is removed in a later trimming process. When the term gorging is used, it usually means hot gorging. The material loss in forging processes is usually quite small. Normally, forged components require some subsequent machining, since the tolerances and surfaces obtainable are not usually satisfactory a finished product. Forging machines include drop hammers and forging presses with mechanical or hydraulic drives. Es involve simple .The machines involve simple translatory motions. Rolling Rolling can be characterized as: mass conserving, solid state of material, mechanical primary basic process-plastic deformation. Rolling is extensively used in the manufacturing of plates, sheets, structural beams, and so on. An ingot is produced in casting, and then, in several stages of rolling it is reduced in thickness, usually while hot. Since the width of the work material is kept constant, its length is increased according to the reduction. After the last hot-rolling stage, a final stage is carried out cold to improve surface quality and tolerances and to increase strength. In rolling, the profiles of the rolls designed to produce the desired geometry. Powder Compaction Powder compaction can be characterized as; mass conserving, granular state of material, mechanical primary basic process-flow and plastic deformation. In this context, only compaction of metal powder is mentioned, but generally compaction of molding sand, ceramic materials, and so on, also belong in this category. In the compaction of metal powders, the die cavity is filled with a measured volume of powder and compacted at pressures typically around 500N/mm2. During this pressing phase, the particles are packed together and plastically deformed. Typical densities after compaction are 80% of the density of the solid material. Because of the plastic deformation, the particles are” welded” together, giving sufficient strength to withstand handling. After compaction, the components are heat-treatedsinterednormally at 70%80% of the melting temperature of the material. The atmosphere for sintering must be controlled to prevent oxidation. The duration of the sintering process varies between 30 min and 2h. The strength of the components after sintering can, depend on the material and the process parameters closely approach the strength of corresponding solid material. The die cavity, in the closed position, corresponds to the desired geometry. Compaction machinery includes both mechanical and hydraulic presses. The production rates vary between 6 and 100 components per minute. 加工工艺过程1. 加工工艺过程的分类 加工工艺过程如下表所示，需注意的是在图中只列出了典型的。工艺类型材料状态基本工艺分类主要基本工艺工艺举例质量守恒过程固态粒状流体机械的机械的机械的塑性变形流动锻造和轧制粉末压塑铸造质量减少过程固态机械的热的化学的塑性断裂和融化和汽化分解氧化车，铣，钻放电机加工和切割电化学加工连接工艺原子焊固态流体连接处附近流体填充材料机械的机械的机械的塑性流动流动摩擦焊熔化剂铅焊2. 锻造工艺过程分类锻造 锻造过程的特性可表述如下，质量守恒，工作材料为固态，力学基本过程为塑性变形过程。金属被加工到合适温度，放到下槽中，多于金属被挤出来。在周围有毛坯，毛坯在后续加工中去掉。当我们说道锻造时，通常指锻造。在锻造中，材料损失很少。 现在，需要后续机加工，因为公差和表面粗糙度不令人满意。锻造机械包括锻造和锻压机，用机械或电压驱动，这些机械只进行简单的平移运动。轧制 轧制特性如下质量守恒，材料固态，大量应用于，板材，建材，型材。钢锭用铸造生产出来后，通常在他还是热的时候，就通过几个轧制阶段将其厚度减薄。因为工作材料金属不多，随厚度变薄，所以长度也增加了。经过最后一个热轧过程，逐渐冷却下来，做最后一个加工，提高表面质量。在轧制中，轧制的外形被设计成几何形状 粉末压塑 粉末压塑的特成为，质量守恒，材料为粉状。在这里我们仅仅介绍金属粉末压塑，但是我们这个模