注塑工艺手册

1、注塑工艺手册工艺注塑手册Injectionprocesshandbook1. 基本理念：Basicopinion:1 .什么是最佳的流动状态：Whatisthebestflowstate:流体流动状态应该是喷泉状的，最佳的流动状态是流体前端的流动速度在型腔内处处相等。由于流动方向上截面积的不同，在其变化的位置应进行注射速度的调节（注意：机床上所能设定的注射速度是指螺杆的前进速度）。Theflowstateshouldbelikefountain,andthebestisthatthespeedofthefrontmeltisthesameeverywhereinthecavities.Ford

2、ifferentareasinthedirectionthatisverticalwiththeflowway,wemustadjusttheinjectionspeed.2 .什么是最佳的压力，温度分布状态：Whatisthebestpressureandtemperaturestate最佳的压力和温度分布状态是压力和温度分布在型腔内部处处相等，并且随着熔体地逐步冷却而下降并使最终产品的内应力为零。Thebestpressureandtemperaturestateshouldbelikethisthatthepressureandtemperatureeverywhereincavitie

3、sarethesame,andmaketheforceofthepartinsidebezerofinallyasthemeltsolidified.实际压力分布状况是浇口附近最大并随着距离的增加而降低。(记住：螺杆头处的熔体和流动着的熔体前端存在压力差是使熔体发生流动的根本原因)Theactualpressurearoundthegateisthehighestandasthedistancegoesitsgettinglowerandlower。所以，综合来讲，参数设定的一般准则:(1)尽量选用高的注射速度(螺杆前进速度)(2)尽量选用高的料筒温度(3)尽量选用高的模具温度Sothegen

4、eralprincipleswhensettingparametersare:(1)Asfastinjectionspeedaspossible(Screwforwardspeed)(2)Ashighcylindertemperatureaspossible(3)Ashighmoldtemperatureaspossible2. 基本概念：Basicconception:1 .收缩：Shrinkage:(1)收缩的原因：.a.热胀冷缩；.b.熔体结晶；.c.分子取向；对于未增强型材料，具熔体在流动方向上的收缩总是大于垂直方向；对于增强型材料，正好相反.d.状态变化Thereasonsofshr

5、inkage:a.Changfromhottocold;b.Crystallization;c.Moleculeorientation;d.Formchanging(2)收缩的阶段：Thestagesofshrinkage:它包括三个阶段：a.从注射开始到保压结束；b.从冷却时间开始至脱模前；c.脱模后Itcontainsthreestages:a.Frominjectionstagetoendofholdingstage;b.Fromcoolingstagetodemoldstage;c.Afterdemold.(3)变形：Deformation变形的根本原因时收缩的不均匀。造成收缩不均匀的

6、原因有：Therootcauseofdeformationisinhomogeneousshrinkage.Thecausesofinhomogeneousshrinkageareasfollows:a.冷去f!(即温度分布)不均匀Inhomogeneouscoolingb.壁厚不均匀Differentwallthicknessc.压力分布不均匀Notaveragelocationofpressurelocationd.分子取向Moleculeorientatione.脱模受力不均Inhomogeneousforceswhendemolding2 .结晶Crystallization:(1)什

7、么是结晶：Whatiscrystallization:简单的说，结晶就是指分子的有序排列Inashortword,itmeanstomakethemoleculeinorder.(2) 结晶的影响因素：Factorsaffectingcrystallization:结晶的影响因素：冷却速度。冷却速度越快，结晶程度越低。Thecoolingspeedaffectsthecrystallization.Thefastercoolingspeedthemorecrystallization(3)结晶对产品性能的影响：Howdoescrystallizationaffecttheparts:结晶度越高

8、：密度越高收缩越大光洁度越好强度越高韧性变差Themorecrystallization:ThehigherdensityThemoreshrinkageThebettersurfaceThestrongeroftheparts3 .粘度：(1)什么是粘度：Whatisviscosity:粘度是流体本身的一种性能，它的大小是流体流动性能的一种衡量。数值越大，流体的流动性能越差。Viscosityisacharacteroftheflowingmaterial.Itsvalueisusedtomeasuretheflowingcharacter.Thebiggervalueitis,thewor

9、seflowingcharacteritis.(2)粘度的影响因素：Whataffecttheviscosity:a.温度Temperatureb.剪切速度Shearratec.压力Pressure速度和压力的敏感程度是不同的，并且在不同的注射速度下哪一个起主导作用也是不同的4 .止回阀：Non-returnvalve:a.止回阀的功能是什么：Functionofnon-returnvalve:在注射,保压时防止熔体倒流，从而给予熔体我们所需的压力和速度。Topreventthemeltflowingbackwheninjectionandpacking.b.怎么判断止回阀或料筒损坏Howto

10、recognizethenon-returnvalveisbroken:(3)注射速度太快：易生现焦斑，飞边，内部气泡或造成熔体喷射Toofastinjectionspeed:burns,flash,airbubbleinsideormeltjet.注射速度太慢：易由现流动痕，熔接痕，并且造成表面粗糙，无光泽Tooslowinjectionspeed:Flowline;weldline,orbadsurface.*注射速度和注射时间设定的一般原则：Generalprincipleswhensettinginjectionspeedorinjectiontime:2 .转压点：Switchpoi

11、nt:(1)怎么确定转压点：Howtosetswitchpoint:一般来说，转压点是指在零保压压力的情况下把产品打到95%满时，由注射到保压的切换点。Normallytheswitchisthechangingpointofscrewfrominjectionphasetoholdingphase,whenthepartsare95%oftheirvolume.对于薄壁产品(如：扎带)：一般打到产品的98%Tothethinwallthicknessparts(Example:Cablestrap):Upto98%oftheirvolume.对于非平衡流道：一般为70%-80%,应视具体情况

12、而定。并建议采用慢-快-慢多级注射。Tonon-balancerunners:Normallyitsupto70%to80%.Itshouldbedeterminedbythereality.Wesuggestusingstepinjectionspeed(Slow-Fast-Slow).(2)转压点太高：产品充模不足，熔接痕，凹陷，尺寸偏小等Toohighswitchpoint:emptypart,weldline,sinkmark,andsmalldimension转压点太低：飞边，脱模困难，尺寸偏大等Toolowswitch:flash,difficulttodemold,bigdime

13、nsion.3 .保压压力：Holdingpressure:(1) 怎么确定保压压力：Howtosettheholdingpressure:优化的保压压力一般为最低保压压力和最高保压压力的中间值Theoptimizedholdingpressureisinthemiddleofthemaximumandminimumnormally.最低保压压力：在准确的转压点基础上，给予一定的保压压力，当产品刚由现充模不足时的保压压力。Minimumholdingpressure:basedonthecorrectswitchpoint,thepressurewhenthepartsstarttobeemp

14、ty.最高保压压力：在准确的转压点基础上，给予一定的保压压力，当产品刚由现毛刺时的保压压力。Minimumholdingpressure:basedonthecorrectswitchpoint,thepressurewhenthepartsstarttohaveflash.(2)一般来说：Normally:PA保压压力=50%注射压力POM保压压力=80%注射压力；PP/PE保压压力=30-50%注射压力PAHoldingpressure=50%InjectionpressurePOMHoldingpressure=80%Injectionpressure;PP/PEHoldingpress

15、ure=30-50%injectionpressure4.保压时间：Holdingtime:(1)怎么确定保压时间：Howtosetholdingtime:保压时间的确定以浇口冷凝为依据。通过产品称重来确定。Holdingtimeisdeterminedbythesolidificationtimeofthegate.Wedecideitaccordingtotheweight.(2)保压时间太长：影响周期Toolongholdingtime:Wastetime保压时间太短：重量不足，产品内部空洞，尺寸偏小Tooshortholdingtime:Notenoughweight,emptyins

16、ide,smalldimension*5.螺杆转速RotationSpeed:预塑的目标是：获得均一稳定的熔体(1)怎么确定螺杆转速：Howtosettherotationspeed:作为原则，螺杆转速的确定必须使螺杆的预塑时间，回吸时间与射台的回退时间之和略短于冷却时间。Asarule,therotationspeedisdeterminedbythatthetotaldosingtime,retractofscrewandretractofinjectionunitmustbealittlebitshorterthanthecoolingtime.(2)螺杆转速太快：塑化不均(从而造成产品

17、冷料，充模不足和断裂等)，材料分解(从而造成焦斑，色差，断裂等)Toofastrotationspeed:Inhomogeneousmelt(whichcauseemptyparts,broken),materialdecomposed(whichcauseburns,differentcolor,brokenetc)螺杆转速太慢：影响周期Tooslowrotationspeed:Wastetime.6 .冷却时间：Coolingtime:作为原则，冷却时间的设定应越短越好，以产品不变形，不粘模，无过深的顶由痕为基本要求。并且：螺杆转速：PA<1.0m/s;POM<0.7m/s;A

18、sarule,thecoolingistheshorterthebetterbasedonthepartsarenotdeformed,notstickyandwithouttoodeepimpressedbyejectors.*推荐的脱模温度如下:Suggesteddemoldingtemperatureisasfollows:7 .背压：Backpressure:(1)什么是背压：Whatisbackpressure:背压是指螺杆预塑时，液压缸阻止螺杆后退的力，其大小等于螺杆前端熔体对螺杆的反作用力。Backpressureisthehydraulicforcepreventingthes

19、crewgoingbackasdosing,thevalueisequaltotheforcethatthemeltinfrontofthecylindertothescrew.(2)怎么确定背压：Hotosetthebackpressure:背压的确定取决于不同材料的性能，通常由材料供应商提供。一般来说：PA:20-80Bar;POM:50-100Bar;PP/PE:50-200BarThebackpressureisdeterminedbythematerialcharacteranditsvalueisofferedbythesupplier.Normally:PA:20-80Bar;P

20、OM:50-100Bar;PP/PE:50-200Bar20%时：喷嘴下料口Whenone-shotquantityislessthan20%ofmaximum:b.次注射量在20%-70%之间时：喷嘴下料口c.一次注射量大于70%时：喷嘴下料口(2)熔体温度太高：材料分解(从而造成产品气泡，色差，焦斑，断裂等)Toohighmelttemperature:Materialdecomposed(Whichcauseairbubble,differentcolor,burns,brokenetc.)熔体温度太低：材料塑化不均，熔体内含冷料(从而造成充模不足，冷料，产品断裂等)Toolowmelt

21、temperature:Inhomogeneousmeltwithcoldmaterialinside(Whichcauseemptyparts,brokenpartsetc.)11.模具温度：Moldtemperature:(1)为什么需要模温：Whythemoldtemperatureisneeded:无论模具温度高低，它的作用始终是为了在稳定生产过程中使模具维持一定的温度，起冷却作用的。a.一次注射量小于总料量的真正重要的模温是指模具型腔的温度，而不是模温机上显示的温度。通常，在稳定生产过程中型腔温度会达到一个稳定的动态平衡，并高于显示温度10度左右(对于大模具在生产之前必须使模具充分加

22、热，尤其是薄壁，且流长比很大的产品模具)Whateverthemoldtemperatureishighorlow,itsfunctionistokeepthecavitytemperatureonthesamelevel.Itisforcooling.Forthebigmold,itmustbeheatedenoughbeforestartproduction.(2)模具温度会影响什么Whatthemoldtemperatureaffect:会影响熔体的流动性和冷却速度。Affectthemeltflowrateandthecoolingspeed.因为影响流动性，从而影响产品外观(表面质量

23、，毛刺)和注塑压力；Foraffectingtheflowrate,themoldtemperatureaffectstheappearanceofthepartsandtheinjectionpressure.因为影响冷却速度，从而影响产品结晶度，进而影响产品收缩率和机械强度性能.Foraffectingcoolingspeed,themoldtemperatureaffectsthecrystallizedrateandthenaffectstheshrinkageandthemechanicalstrength.（3）模温高：流动性好；结晶度高；收缩率大（从而造成尺寸偏小）；变形；需要更

24、长的冷却时间Highmoldtemperature:goodflowcharacter;high-crystallizedrate;bigshrinkage（Whichcausesmalldimension）;needmorecoolingtime模温低：流动性差（从而造成流动纹，熔接痕）；结晶度低;收缩率小（从而造成尺寸偏大）Lowmoldtemperature:badflowcharacter;high-crystallizedrate;smallshrinkage（Whichcausebigdimension）三.常见产品缺陷及其原因：Normaldefectsandthereason:

25、（1）流涎：.Materialescapingfromnozzle:a.材料烘干不彻底或材料受潮Thematerialisnotdriedenoughoritiswet.b.预塑速度（螺杆转速）太快Dosingspeedistoofast.c.喷嘴温度太高Thenozzletemperatureistoohigh.d.不好的回料（粉状）Toomuchpowderinregrinds.e.回吸量不够Notenoughretractf.喷嘴接触力不足Notenoughforcebetweenthenozzleandthemoldbush.g.喷嘴与模具浇口套尺寸不匹配Thedimensionoft

26、henozzleandthemoldbushisnotcorrect.h.喷嘴接触表面脏(造成表面不平)Dirtyinterfaceofthenozzle(2)预塑不稳：Plastificationunstable:a.回料比不合理或不无急定Regrindrateisunreasonableorunstableb.背压太低Backpressureistoolowc.长料杆架桥Longregrindd.材料受潮Wetmateriale.下料处温度不合理(太高)Unreasonablecylindertemperaturearoundthehopper(Toohigh)(3)飞边Flashesa.

27、参数设置不准确(转压点太低，保压太高，射速太快，温度太高)Wrongsettingparameters(Toolowswitchpoint,toohighholdingpressure,toofastinjectionspeed,toohightemperatureetc)b.模具脏Moldisdirtyc.锁模力不足Lockingforceisnotenoughd.模具问题(损坏)Moldisinjurede.设备问题(压力不无急)Machineproblems(Unstablepressure)f.喷嘴温度过低Toolownozzletemperatureg.塑化不均（长料杆，螺杆转速过快

28、，背压太低等）造成冷料Inhomogeneousmelth.回吸太小造成止回阀关闭不稳定Toolittleretracttocausethenon-returnvalveclosingunstably(4)充模不足Incomplete:a.参数设置不准确(转压点太高，保压太低，射速太慢，温度太彳氐)Wrongsettingparameters(Toolowswitchpoint,toohighholdingpressure,toofastinjectionspeed,toohightemperatureetc)b.模具脏Moldisdirtyc.喷嘴温度过低，结构不合理Lowtemperatu

29、reinthetipofnozzle,andwrongstructured.止回阀或料筒损坏Non-returnvalveorcylinderisbrokene.浇口，流道尺寸太小Toosmallgate,runnersf.不干净的回料(含杂料)Othermaterialintheregrindg.材料受潮Wetmaterialh.设备问题(压力不足)Machineproblem(Notenoughpressure)I.射台没对准Thenozzleisnotinthecentreoftherunner.h.回吸太小造成止回阀关闭不稳定Toolittleretracttocausethenon-

30、returnvalveclosingunstably(5)不时充模不足：SometimesIncomplete:a.射速太低(特别是PA,POM)Injectionspeedistoolow(EspeciallyforPOM)b.对大产品，熔体温度不够Melttemperatureistoolowc.塑化不均(背压太低，转速太快)Nothomogeneousmelt(Backpressureistoolow,rotationspeedistoofast)d.喷嘴温度不够Nozzletemperatureistoolowe.止回阀或料筒损坏Non-returnvalveorcylinderisb

31、rokenf.杂质Othermaterialsinsideg.模具脏Moldisdirtyh.材料烘干不彻底或材料受潮MaterialiswetI.射台没对准Thenozzleisnotinthecentreoftherunner.h.回吸太小造成止回阀关闭不稳定Toolittleretracttocausethenon-returnvalveclosingunstably(6)焦斑c.产品顶由不均Partisejectednotbalanced.冷去f!时间不够Notenoughcoolingtimee.射速太低Toolowinjectionspeedf.压力太大造成粘模Toohighpre

32、ssuretocausestickyoncavitiesg.塑化不均造成内应力Nothomogeneousmelttocauseforceinsideh.模具温度分布不均Moldtemperaturenotuniform(9)尺寸不稳Dimensionnotstablea.参数控制不稳（模温，料温，保压太低或太高，冷却时间)Parametercontrolnotisprecise(moldtemperature,melttemperature,coolingtime)b.回料比不合理或不无急定Regrindrateisunreasonableorunstablec.止回阀或料筒损坏Non-re

33、turnvalveorcylinderisbrokend.回吸太小造成止回阀关闭不稳定Toolittleretracttocausethenon-returnvalveclosingunstably(10)重量不稳定Unstableweighta.参数设置不准确(模温，料温，保压太低或太高，冷却时间，保压时间不够)Notcorrectsettingparameter(moldtemperature,melttemperature,coolingtime)b.喷嘴温度太低Nozzletemperatureistoolowc.保压时间太短Holdingtimeistoolowd.止回阀或料筒损坏N

34、on-returnvalveorcylinderisbrokene.回料比不无急定Unstableregrindratef.回吸太小造成止回阀关闭不稳定Toolittleretracttocausethenon-returnvalveclosingunstably(11)产品易断裂Easilybrokenpartsa.熔体温度太高或太低Melttemperatureistoohighortoolowb.材料湿Wetmaterialc.射速太低或太高Injectionspeedistoolowortoofastd.模具温度太高或太低Moldtemperatureisnotreasonablee.

35、熔接痕Weldinglinef.杂质Othermaterialsinsideg.塑化不均(背压太低，转速太快，回料长料杆)Nothomogeneousmelt(Backpressureistoolow,rotationspeedistoofast,longsprue)h.模具锐边Moldsharpplacei.不稳定回料比Unstableregrindrate(12)熔接痕：Weldingline:a.射速太慢Toolowinjectionspeedb.熔体温度太彳氐Toolowmelttemperaturec.模具温度太低Toolowmoldtemperatured.排气不畅Badventd.色母；塑化不均Pigment;inhomogeneousmelte.模具，产品设计不合理Designofmoldorpartsnotreasonable(13)表皮分层:Delamination:a.材料潮湿Wetmaterialb.杂料Mixedmaterialc.色母有问题Pigmentproblemd.射速太快Toofastinjectionspeed四.当产品由现问题时：Whenthereisaproblem:(1)你必须搞清楚问题：Youm