【机械类毕业论文中英文对照文献翻译】注塑成型机
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机械类毕业论文中英文对照文献翻译
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英文原文Injection molding machineInjection molding machine is plastic machine for short. It uses the thermal physical properties of plastics, the material from the hopper into the barrel, is barreled by heating coil heat, so the material will be melted, which is arranged by the external force under the action of the motor driving the rotation of the screw in the barrel. The material in the screw under the action of the screw groove, along the forward delivery and compaction, dual role the material in the heating and shear under gradually plasticizing, melted and homogenized, when the screw rotates, the material in the screw channel friction and shear force, the molten material is pushed to the screw head. At the same time, the screw with backward in the material, the screw head forming material storage space, completing the plasticizing process, then, screw in the injection cylinder piston thrust under the action of high speed, high pressure, in the material storage chamber, the melt through the nozzle to the mold cavity injection, cavity melt after pressing, cooling, solidification, mold in the mold closing mechanism of action next, open mold, and through the ejection device to finalize the design good products fall from the top die.Configuration according to the clamping member and the injection component type has horizontal, vertical, angle type three(1) Horizontal injection molding machine: horizontal injection molding machine is the most common type. Its characteristic is the center line injection assembly and clamping assembly center line of concentric or consistent, also with the parallel to the mounting surface. It has the advantages of low center of gravity, steady work, mold installation, operation and repair, which are convenient, the mold opening big, small occupied space height; but covers an area of large. (2) Vertical injection molding machine: its characteristic is clamping device and injection device of the axis line arrangement and perpendicular to the ground. It also has the advantages of small occupied area, convenient assembly and disassembly of insert mold, easy installation, since the bucket into the material plasticization is evenly, easy to realize automation and machine automation line management. The disadvantage of it is the top product is not easy to fall off automatically, it often needs manual or other method to take out, and is not easy to realize full automatic operation and large products injection; machine height, feeding, inconvenient repair.(3) Angle type injection molding machine: injection device and a molding device axis are arranged vertically. According to the injection assembly center lines are vertical, horizontal and relative position of the vertical and horizontal installation, recumbent points: horizontal vertical, injection assembly line and plane parallel, and mold assembly center line and the base of vertical and horizontal, vertical; injection assembly center line and the surface vertical, and die assembly center line and the reference surface. The advantages of angle type injection machine has the advantages of both horizontal and vertical injection molding machine, special apply to the mold opening side gate asymmetric geometry products.At present, the injection device are common cylinder form and double cylinder form, I plant the injection molding machine is double cylinder form, and is directly driven by a hydraulic motor of screw in injection molding. Because of different manufacturers, different types of machine components are not the same; the following will make a concrete analysis of our factory with machine.The working principle is: the plastic, screw in plastic parts in the drive the main shaft to rotate through the hydraulic motor, spindle end is connected with the screw, and the other end of the hydraulic motor key connection, screw rotation, plasticity and melt classified pushed to the storage chamber cylinder front, at the same time, screw back in the reaction material, and through the thrust bearing the thrust seat back, pulling the piston rod through the nut straight back. To complete the measurement, injection, the injection cylinder rod chamber oil inlet through the bearing to push the piston rod to complete the action, the rod chamber piston oil inlet to push the piston rod and screw and finish the injection.The work principle of screw plasticizing components: performs, screw rotation, from the material inlet into the screw groove material advancing continuously forward, heating ring through the barrel wall of the heat transfer to the spiral groove material, solid material in the dual role of external heating and screw rotational shear, and through the thermal process functional section of screw, achieving the plasticizing and melting, melting away the check ring around the screw head, front end through the channel into the screw, and generates backpressure, push the screw after the shift measurement complete melt, at the time of injection screw up, piston effect, with rapid advancement, in the cylinder, will melt reservoir material in the chamber through the nozzle into the mold.Screw plasticizing components generally have the following characteristics:The screw has two functions of plasticizing and injection;The screw in plastic, only for the plasticThe plastics in plasticizing process, thermal process through than extrusion;The screw on the plasticizing and injection were to occur, axial displacement, and screw in working state of intermittent when to stop, thus forming a non - stability of screw plasticizing process.(1) ScrewScrew is a key component of plastic parts, direct contact with plastic, plastic through the effective length of the screw channel, after the heat for a long time, must go through 3 states (glass, behavior, viscous state) transformation, geometric parameters, geometry, length of functional section of screw will directly affect the transmission efficiency and the plasticizing quality of plastic, will ultimately affect the quality of injection molding cycle and product.Compared with the extrusion screw, plastic screw has the following characteristics:The injection screw length-diameter ratio and compression ratio is small;Screw groove of injection screw is section of the deep;The injection screws feeding sections is longer, and are short;The injection screw work, plasticizing capacity and melt temperature will vary with the axial displacement screw and change.(I) classification, screwInjection screw according to the plastic adaptability, can be divided into general and special screw, general also called conventional screw, can be processed with low viscosity, most of the thermoplastic, civil plastic crystalline and amorphous and engineering plastics, is the most basic form of the screw, and the corresponding and special screw, is used to process with ordinary screw processing hard plastic; according to the screw structure and geometry characteristics, can be divided into conventional screw and screw, the conventional screw is also known as the three section screw, is the basic form of the screw, screw form has many kinds, such as separation screw, screw, wavy shunt screw, no metering section of screw.The conventional screw thread effective length is usually divided into feeding sections (conveying), the compression section (Plastics segment), and metering section (averaging period), according to the plastic properties of different, can be divided into gradual, mutation type and general type screw.The tapered screw: compression long, plasticizing energy transfer for PVC relaxation, poor thermal stability of plastic.The mutant compression screw: short, plasticizing energy conversion is more acuteness, used for polyolefin, PA crystalline plastics.The general purpose screw: adaptability is strong, and can be suitable for processing a variety of plastic, avoid frequent replacement of the screw, increase production efficiency.DS screw diameter, screw diameter directly affect the plasticizing capacity, will directly affect the injection volume, therefore, injection volume of injection molding machine the screw diameter is large.L/ds - screw length to diameter ratio. L is the effective length of screw thread part of the screw, the ratio of length to diameter is larger, the length of that thread, directly affect the thermal process of material in the screw, the ability to influence the absorption of energy, while the energy source has two parts: one part is the external heating coil to the barrel, and another part is friction thermal and shear heat generated by the rotation of the screw, the external mechanical energy conversion, therefore, L/ds directly affect the melting effect of material and melt, but if L/ds is too large, the transmission torque increase, increased energy consumption.L1 - feeding length. The feeding section is also called conveying or feed section, in order to improve the transport capacity, screw groove surface must be smooth, the length of the L1 shall ensure that the material conveying length too short enough, because L1 will lead to premature melting material, thus it is difficult to guarantee the transportation conditions of stabilizing pressure, will be difficult to ensure the screw later. Plastic under their own gravity from the hopper to slip into the screw, screw rotation, the thrust surface friction in the barrel and screw groove under the action of the material is compressed into a solid, nut intensive, the relative motion along the direction of the thread, this section, plastic solid state, namely the glass state.The depth of screw channel H1 - feed section. H1 deep, is receiving materials, improving the feeding quantity and plasticizing capacity, but will affect the shear strength of material plasticization and screw root, general H1 (0.12 0.16) ds.L3 - melting length. Melting section called homogeneous section or the measuring section, melt further homogenization, uniform temperature in the channel of L3 segment, uniform composition, the formation of good quality of melt, the length of L3 is helpful to melt in the screw groove fluctuations, stable pressure, causes the material to feed evenly extruded from the screw head, so it is also called the metering section. L3 short time, help to improve the general screw plasticizing capacity, L3= (4 5)ds.H3 - melting section of spiral groove depth, H3 small, shallow groove, improves the plasticizing effect of plastic melt, to melt homogenization, but H3 is too small will lead to higher shear rate, and shear heat is too large, causing degradation of the molecular chain, the effect of melt quality,; conversely, if the H3 is too large, the perform, enhanced flow screw back pressure generated, will reduce the plasticizing capacity.L2 - plasticizing period (compression) length of thread. The tapered space material continuously under compression, shear and mixing effect, material from the L2 point, molten pool increased, to the point of weld pool has been occupying the entire screw groove, the material from the glass state through viscoelastic state transition to a viscous state, namely this segment, the plastic is state of coexistence in the particles with a molten body. The length of L2 will affect the transformation of the material from the glassy to viscous flow state, is too short will not change, plugging in the terminal segment of the L2 formation of high pressure, torque or axial force of solid material; too long will increase the screw torque and unnecessary consumption, general L2= (6 8) ds. For the crystalline plastics, material melting point, melting a narrow range, L2 can be shorter, generally (3 4) ds, for heat-sensitive plastic, this section Kvetching.S - Pitch, the size effect of helix angle, thus affecting the transport efficiency of screw, general S ds.E - Compression ratio. =h1/h3, namely the feeding section of spiral groove depth H1 and the melting section of spiral groove depth ratio of h3. E, will enhance the shear effect, but will weaken the plasticizing capacity, generally speaking, slightly smaller as well, to help improve the plasticizing capacity and increase the adaptability to raw materials, for crystalline plastics, the compression ratio is 2.63.0. For low viscosity and thermal stability of plastic, can choose the high compression ratio and high viscosity; thermal sensitivity plastic, should choose low compression rate.(2) The screw headIn the injection screw, screw head is: the plastic, can be good plastic melt and releasing to the storage chamber, and in high pressure injection, and can effectively close the melt front screw head, prevent backflow.The screw head is divided into two categories, with check ring and not the inverse ring with the check, the check ring, a plastic screw, melt homogenizing section will check ring away, through the gap formation and the screw head, into the storage chamber, injection pressure, melt screw the head of the formation of thrust, the non-return valve return channel plugging, prevent backflow.For some high viscosity materials such as PMMA, PC, AC or poor thermal stability of PVC material, in order to reduce the retention time of shearing and material, can not check ring, but this injection will produce reflux, prolonging holding time.On the screw head requirements:The screw head to be flexible smooth;The check ring and the cylinder to be suitable with the gap, to prevent melt flow, and flexible;The existing flow section is enough, but also to ensure the check ring face a return force, making fast closed at the time of injection;The structure should be easy disassembly, convenient cleaning;The direction of the screw thread screw and screw in screw head instead, prevent a plastic screw head loose.(3) Cylinder(I), the barrel structureCylinder is an important part of plastic parts; interior screw is arranged outside the heating coil, under complex stress and thermal stress.(II), the feeding portStructure feeding port directly affects feed effect and plastic parts of the feeding ability, injection molding machine most by gravity feed material in hopper, simple manufacture, but feed the negative; the feed material and the screw contact angle, contact area is large, can improve the feed efficiency, is not easy in the hopper into bridge hole.(III), cylinder wall thicknessCylinder wall thickness is of sufficient strength and stiffness, because the barrel to melt and gas pressure, and the barrel length to diameter ratio, cylinder requires enough heat capacity, so the cylinder walls have a certain thickness, otherwise it is difficult to ensure that the temperature stability; but if it is too thick, barrel bulky, waste material, the thermal inertia of large, slow temperature rise, temperature regulation of delay larger.(IV), cylinder clearanceCylinder gap refers to the single gap barrel wall and screw diameter, the gap is too large, plasticizing capacity is reduced, injected back into the discharge increases, injection time, causing material degradation in the process; if it is too small, the thermal expansion effect on the screw and barrel friction, energy consumption increased, even death card, this gap delta = (0.0020.005) ds.(V), the material heating and cooling tubeInjection molding machine barrel heating with electric resistance, ceramic heating, cast aluminum heating, should be reasonably arranged according to the application and processing of materials, commonly used has the resistance heating and ceramic heating, to comply with the requirements of injection molding process, the barrel to subsection control, small 3, large machine 5.Cooling refers to the feeding mouth is cooling, because the feeding mouth if the temperature is too high, the solid in the feeding mouth bridge, blocking the outlet, thus affecting the transport efficiency of feed section, so the cooling water jacket is arranged in the cooling it. Our factory is through the cooling circulating water cooling of the feed inlet.(4) Nozzle(I) function of spray nozzleThe nozzle is an important part of connecting plasticizing device and mold flow; nozzle has a variety of functions:The perform, establishment of backpressure, degassed, prevent melt salivation, improve plasticizing capability and measurement precision;The injection mold, forming the contact pressure and the main cast, keep good contact with pouring nozzle sleeve, forming a closed channel, to prevent the plastic melt under high pressure overflow;injection, establish the melt pressure, shear stress, and the pressure head into the velocity head, the increase of shear rate and temperature, enhance mixing and homogenizing;Changing the nozzle structure to match the mold and plasticizing device, a new type of flow channel or injection system;The nozzle also bears the thermostat, thermal insulation and cutting function;The reducing melts in the import and export of the viscoelastic effect and the eddy loss, in order to stabilize its flow;The holding pressure, easy to mold products of feeding, and the cooling shaping increased reflow resistance, reduce or prevent the melt in the cavity to return.(II) The basic form, nozzleNozzle can be divided into straight-through nozzle, locking type nozzle, hot runner nozzle and the flow nozzle, the present stage our factory are straight-through nozzle.Straight-through nozzle is the nozzle is widely applied, its characteristic is the direct and main casting mold nozzle spherical contact, the nozzle radius and the channel than the mold to be small, injection pressure, melt directly through the mold runner system is filled into the cavity, fast speed, low pressure loss, manufacturing and installation are all relatively convenient.Locking type nozzle is mainly to solve the problem through the nozzle salivation, suitable for low viscosity polymer (such as PA) processing. In the closing the nozzle plastic, prevent melt salivation phenomenon, and when the injection and injection pressure to open, so that melt into the mold cavity.2 injection cylinderIts working principle is: the injection cylinder into the oil, the piston drives the piston rod and the bearing is arranged on the thrust seat, drive screwPush the screw forward or backward. Through the nut piston rod head, can adjust the timing of two parallel to the axial position of the piston rod and the injection screw axial position.3 thrust bearingInjection, thrust bearing thrust shaft driven by screw injection; while the plastic, the oil motor drive screw rotation to achieve thrust shaft drives the perform.4 cylindersWhen a moving oil cylinder into the oil, forward seat injection or the back action, and to ensure the injection nozzle and mould the main cast set of circular arc closely contact, the injection pressure can seal the melt.The 5 part accuracy requirements for injectionAfter the assembly, the components are arranged on the machine frame, must ensure that the nozzle and mold water sleeve is tightly bonding, in order to prevent overflow, the center line of injection parts requirements and the clamping parts of the center line of concentric; in order to ensure the accuracy of injection screw and barrel inner hole, must ensure that the two injection cylinder bore and the center cylinder hole is parallel with the center line of symmetry; in the horizontal plane, parallelism and symmetry for the center of a moving oil cylinder two guide holes also must ensure that the vertical machine, it must ensure that the two seat moving oil cylinder hole and a cylinder positioning the center hole is parallel with the center line of symmetry. Factors affecting the location accuracy of hole and shaft are associated parts size precision, geometric accuracy, precision and assembly precision.Each kind of plastic, has an ideal plastic processing temperature range, should control the processing temperature of barrel, which is close to the temperature range. Granular plastic from the hopper into the barrel, the first will arrive at a feeding section, in the feeding section will appear dry friction, when the plastic is heated, melting is not uniform, very easy to cause the barrel wall and screw wear surface. Similarly, the compression section and the entire segment, if the molten state disorder plastic uneven will result in increased wear.Speed should be adjusted properly. The friction force of these substances on the metal material is often much larger than the molten plastic. In the plastic injection molding, if using high speed in the shear stress on the plastic at the same time, it will also strengthen correspondingly more torn fibers, the torn fibers containing sharp end, to wear a large force to increase. Inorganic minerals on the surface of metal high-speed taxiing, the scraping is not a small role. So the speed should not be too high.In addition to check in plastic debris, the original purchase fresh plastic and no debris, but after weighing, transport, drying, mixing, especially to add recycling back material, there may be mixed with debris. Small as metal filings, as big as a heating ring nut clip, or clusters of warehouse key, mixed into the barrel had occurred, the screw damage is self-evident. (barrel of course also damage), therefore must install the magnetic iron material, strict management and monitoring.Moisture in plastics has a certain effect on the wear surface of the screw. If the plastic in injection unprecedented will eliminate all residual moisture, moisture into the screw compression section, they formed before melt blend in molten plastic with high temperature and high pressure steam particles, with the injection process screw propulsion, from homogeneous section until the screw head, these steam particle, pressure drop and expansion in the injection process, the impurities such as a fine grain, rubbing on the wall damage. In addition, for some types of plastic, under high temperature and high pressure, the water may become a catalyst for cracking of plastic, harmful impurities can corrode the metal surface. Therefore, the drying work plastic injection before, not only has a direct relationship to the product quality, but also affects the service life of the screw.中文译文注塑成型机注塑成型机简称注塑机。注塑成型是利用塑料的热物理性质，把物料从料斗加入料筒中，料筒外由加热圈加热，使物料熔融，在料筒内装有在外动力马达作用下驱动旋转的螺杆，物料在螺杆的作用下，沿着螺槽向前输送并压实，物料在外加热和螺杆剪切的双重作用下逐渐地塑化，熔融和均化，当螺杆旋转时，物料在螺槽摩擦力及剪切力的作用下，把已熔融的物料推到螺杆的头部，与此同时，螺杆在物料的反作用下后退，使螺杆头部形成储料空间，完成塑化过程，然后，螺杆在注射油缸的活塞推力的作用下，以高速、高压，将储料室内的熔融料通过喷嘴注射到模具的型腔中，型腔中的熔料经过保压、冷却、固化定型后，模具在合模机构的作用下，开启模具，并通过顶出装置把定型好的制品从模具顶出落下。按合模部件与注射部件配置的型式有卧式、立式、角式三种（1）卧式注塑机：卧式注塑机是最常用的类型。其特点是注射总成的中心线与合模总成的中心线同心或一致，并平行于安装地面。它的优点是重心低、工作平稳、模具安装、操作及维修均较方便，模具开档大，占用空间高度小；但占地面积大，大、中、小型机均有广泛应用。（2）立式注塑机：其特点是合模装置与注射装置的轴线呈一线排列而且与地面垂直。具有占地面积小，模具装拆方便，嵌件安装容易，自料斗落入物料能较均匀地进行塑化，易实现自动化及多台机自动线管理等优点。缺点是顶出制品不易自动脱落，常需人工或其它方法取出，不易实现全自动化操作和大型制品注射；机身高，加料、维修不便。（3）角式注塑机：注射装置和合模装置的轴线互成垂直排列。根据注射总成中心线与安装基面的相对位置有卧立式、立卧式、平卧式之分：卧立式，注射总成线与基面平行，而合模总成中心线与基面垂直；立卧式，注射总成中心线与基面垂直，而合模总成中心线与基面平行。角式注射机的优点是兼备有卧式与立式注射机的优点，特别适用于开设侧浇口非对称几何形状制品的模具。目前，常见的注塑装置有单缸形式和双缸形式，我厂注塑机都是双缸形式的，并且都是通过液压马达直接驱动螺杆注塑。因不同的厂家、不同型号的机台其组成也不完全相同，下面就对我厂用的机台作具体分析。工作原理是：预塑时，在塑化部件中的螺杆通过液压马达驱动主轴旋转，主轴一端与螺杆键连接，另一端与液压马达键连接，螺杆旋转时，物料塑化并将塑化好的熔料推到料筒前端的储料室中，与此同时，螺杆在物料的反作用下后退，并通过推力轴承使推力座后退，通过螺母拉动活塞杆直线后退，完成计量，注射时，注射油缸的杆腔进油通过轴承推动活塞杆完成动作，活塞的杆腔进油推动活塞杆及螺杆完成注射动作。螺杆式塑化部件的工作原理：预塑时，螺杆旋转，将从料口落入螺槽中的物料连续地向前推进，加热圈通过料筒壁把热量传递给螺槽中的物料，固体物料在外加热和螺杆旋转剪切双重作用下，并经过螺杆各功能段的热历程，达到塑化和熔融，熔料推开止逆环，经过螺杆头的周围通道流入螺杆的前端，并产生背压，推动螺杆后移完成熔料的计量，在注射时，螺杆起柱塞的作用，在油缸作用下，迅速前移，将储料室中的熔体通过喷嘴注入模具。螺杆式塑化部件一般具有如下特点： 螺杆具有塑化和注射两种功能； 螺杆在塑化时，仅作预塑用 塑料在塑化过程中，所经过的热历程要比挤出长； 螺杆在塑化和注射时，均要发生轴向位移，同时螺杆又处于时转时停的间歇式工作状态，因此形成了螺杆塑化过程的非稳定性。（1） 螺杆螺杆是塑化部件中的关键部件，和塑料直接接触，塑料通过螺槽的有效长度，经过很长的热历程，要经过3态（玻璃态、黏弹态、黏流态）的转变，螺杆各功能段的长度、几何形状、几何参数将直接影响塑料的输送效率和塑化质量，将最终影响注射成型周期和制品质量。与挤出螺杆相比，注塑螺杆具有以下特点： 注射螺杆的长径比和压缩比比较小； 注射螺杆均化段的螺槽较深； 注射螺杆的加料段较长，而均化段较短； 注射螺杆的头部结构，具有特殊形式。 注射螺杆工作时，塑化能力和熔体温度将随螺杆的轴向位移而改变。（）、螺杆的分类注塑螺杆按其对塑料的适应性，可分为通用螺杆和特殊螺杆，通用螺杆又称常规螺杆，可加工大部分具有低、中黏度的热塑性塑料，结晶型和非结晶型的民用塑料和工程塑料，是螺杆最基本的形式，与其相应的还有特殊螺杆，是用来加工用普通螺杆难以加工的塑料；按螺杆结构及其几何形状特征，可分为常规螺杆和新型螺杆，常规螺杆又称为三段式螺杆，是螺杆的基本形式，新型螺杆形式则有很多种，如分离型螺杆、分流型螺杆、波状螺杆、无计量段螺杆等。常规螺杆其螺纹有效长度通常分为加料段（输送段）、压缩段（塑化段）、计量段（均化段），根据塑料性质不同，可分为渐变型、突变型和通用型螺杆。 渐变型螺杆：压缩段较长，塑化时能量转换缓和，多用于PVC等热稳定性差的塑料。 突变型螺杆：压缩段较短，塑化时能量转换较剧烈，多用于聚烯烃、PA等结晶型塑料。 通用型螺杆：适应性比较强的通用型螺杆，可适应多种塑料的加工，避免更换螺杆频繁，有利于提高生产效率。ds 螺杆外径，螺杆直径直接影响塑化能力的大小，也就直接影响到理论注射容积的大小，因此，理论注射容积大的注塑机其螺杆直径也大。L/ds 螺杆长径比。L是螺杆螺纹部分的有效长度，螺杆长径比越大，说明螺纹长度越长，直接影响到物料在螺杆中的热历程，影响吸收能量的能力，而能量来源有两部分：一部分是料筒外部加热圈传给的，另一部分是螺杆转动时产生的摩擦热和剪切热，由外部机械能转化的，因此，L/ds直接影响到物料的熔化效果和熔体质量，但是如果L/ds太大，则传递扭矩加大，能量消耗增加。L1加料段长度。加料段又称输送段或进料段，为提高输送能力，螺槽表面一定要光洁，L1的长度应保证物料有足够的输送长度，因为过短的L1会导致物料过早的熔融，从而难以保证稳定压力的输送条件，也就难以保证螺杆以后各段的塑化质量和塑化能力。塑料在其自身重力作用下从料斗中滑进螺槽，螺杆旋转时，在料筒与螺槽组成的各推力面摩擦力的作用下，物料被压缩成密集的固体塞螺母，沿着螺纹方向做相对运动，在此段，塑料为固体状态，即玻璃态。h1 加料段的螺槽深度。h1深，则容纳物料多，提高了供料量和塑化能力，但会影响物料塑化效果及螺杆根部的剪切强度，一般h1（0.120.16）ds。L3 熔融段长度。熔融段又称均化段或计量段，熔体在L3段的螺槽中得到进一步的均化，温度均匀，组分均匀，形成较好的熔体质量，L3长度有助于熔体在螺槽中的波动，有稳定压力的作用，使物料以均匀的料量从螺杆头部挤出，所以又称计量段。L3短时，有助于提高螺杆的塑化能力，一般L3=（45）ds。h3 熔融段螺槽深度，h3小，螺槽浅，提高了塑料熔体的塑化效果，有利于熔体的均化，但h3过小会导致剪切速率过高，以及剪切热过大，引起分子链的降解，影响熔体质量，；反之，如果h3过大，由于预塑时，螺杆背压产生的回流作用增强，会降低塑化能力。L2 塑化段（压缩段）螺纹长度。物料在此锥形空间内不断地受到压缩、剪切和混炼作用，物料从L2段入点开始，熔池不断地加大，到出点处熔池已占满全螺槽，物料完成从玻璃态经过黏弹态向黏流态的转变，即此段，塑料是处于颗粒与熔融体的共存状态。L2的长度会影响物料从玻璃态到黏流态的转化历程，太短会来不及转化，固料堵在L2段的末端形成很高的压力、扭矩或轴向力；太长则会增加螺杆的扭矩和不必要的消耗，一般L2=（68）ds。对于结晶型的塑料，物料熔点明显，熔融范围窄，L2可短些，一般为（34）ds，对于热敏性塑料，此段可长些。S 螺距，其大小影响螺旋角，从而影响螺槽的输送效率，一般Sds。 压缩比。=h1/h3，即加料段螺槽深度h1与熔融段螺槽深度h3之比。大，会增强剪切效果，但会减弱塑化能力，
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