注塑工藝手冊

1、注塑工藝手冊工藝注塑手冊Injectionprocesshandbook1. 基本理念：Basicopinion:1 .什么是最佳的流動狀態(tài)：Whatisthebestflowstate:流體流動狀態(tài)應(yīng)該是噴泉狀的，最佳的流動狀態(tài)是流體前端的流動速度在型腔內(nèi)處處相等。由于流動方向上截面積的不同，在其變化的位置應(yīng)進行注射速度的調(diào)節(jié)（注意：機床上所能設(shè)定的注射速度是指螺桿的前進速度）。Theflowstateshouldbelikefountain,andthebestisthatthespeedofthefrontmeltisthesameeverywhereinthecavities.Ford

2、ifferentareasinthedirectionthatisverticalwiththeflowway,wemustadjusttheinjectionspeed.2 .什么是最佳的壓力，溫度分布狀態(tài)：Whatisthebestpressureandtemperaturestate最佳的壓力和溫度分布狀態(tài)是壓力和溫度分布在型腔內(nèi)部處處相等，并且隨著熔體地逐步冷卻而下降并使最終產(chǎn)品的內(nèi)應(yīng)力為零。Thebestpressureandtemperaturestateshouldbelikethisthatthepressureandtemperatureeverywhereincavitie

3、sarethesame,andmaketheforceofthepartinsidebezerofinallyasthemeltsolidified.實際壓力分布狀況是澆口附近最大并隨著距離的增加而降低。(記住：螺桿頭處的熔體和流動著的熔體前端存在壓力差是使熔體發(fā)生流動的根本原因)Theactualpressurearoundthegateisthehighestandasthedistancegoesitsgettinglowerandlower。所以，綜合來講，參數(shù)設(shè)定的一般準則:(1)盡量選用高的注射速度(螺桿前進速度)(2)盡量選用高的料筒溫度(3)盡量選用高的模具溫度Sothegen

4、eralprincipleswhensettingparametersare:(1)Asfastinjectionspeedaspossible(Screwforwardspeed)(2)Ashighcylindertemperatureaspossible(3)Ashighmoldtemperatureaspossible2. 基本概念：Basicconception:1 .收縮：Shrinkage:(1)收縮的原因：.a.熱脹冷縮；.b.熔體結(jié)晶；.c.分子取向；對于未增強型材料，具熔體在流動方向上的收縮總是大于垂直方向；對于增強型材料，正好相反.d.狀態(tài)變化Thereasonsofshr

5、inkage:a.Changfromhottocold;b.Crystallization;c.Moleculeorientation;d.Formchanging(2)收縮的階段：Thestagesofshrinkage:它包括三個階段：a.從注射開始到保壓結(jié)束；b.從冷卻時間開始至脫模前；c.脫模后Itcontainsthreestages:a.Frominjectionstagetoendofholdingstage;b.Fromcoolingstagetodemoldstage;c.Afterdemold.(3)變形：Deformation變形的根本原因時收縮的不均勻。造成收縮不均勻的

6、原因有：Therootcauseofdeformationisinhomogeneousshrinkage.Thecausesofinhomogeneousshrinkageareasfollows:a.冷去f!(即溫度分布)不均勻Inhomogeneouscoolingb.壁厚不均勻Differentwallthicknessc.壓力分布不均勻Notaveragelocationofpressurelocationd.分子取向Moleculeorientatione.脫模受力不均Inhomogeneousforceswhendemolding2 .結(jié)晶Crystallization:(1)什

7、么是結(jié)晶：Whatiscrystallization:簡單的說，結(jié)晶就是指分子的有序排列Inashortword,itmeanstomakethemoleculeinorder.(2) 結(jié)晶的影響因素：Factorsaffectingcrystallization:結(jié)晶的影響因素：冷卻速度。冷卻速度越快，結(jié)晶程度越低。Thecoolingspeedaffectsthecrystallization.Thefastercoolingspeedthemorecrystallization(3)結(jié)晶對產(chǎn)品性能的影響：Howdoescrystallizationaffecttheparts:結(jié)晶度越高

8、：密度越高收縮越大光潔度越好強度越高韌性變差Themorecrystallization:ThehigherdensityThemoreshrinkageThebettersurfaceThestrongeroftheparts3 .粘度：(1)什么是粘度：Whatisviscosity:粘度是流體本身的一種性能，它的大小是流體流動性能的一種衡量。數(shù)值越大，流體的流動性能越差。Viscosityisacharacteroftheflowingmaterial.Itsvalueisusedtomeasuretheflowingcharacter.Thebiggervalueitis,thewor

9、seflowingcharacteritis.(2)粘度的影響因素：Whataffecttheviscosity:a.溫度Temperatureb.剪切速度Shearratec.壓力Pressure速度和壓力的敏感程度是不同的，并且在不同的注射速度下哪一個起主導(dǎo)作用也是不同的4 .止回閥：Non-returnvalve:a.止回閥的功能是什么：Functionofnon-returnvalve:在注射,保壓時防止熔體倒流，從而給予熔體我們所需的壓力和速度。Topreventthemeltflowingbackwheninjectionandpacking.b.怎么判斷止回閥或料筒損壞Howto

10、recognizethenon-returnvalveisbroken:(3)注射速度太快：易生現(xiàn)焦斑，飛邊，內(nèi)部氣泡或造成熔體噴射Toofastinjectionspeed:burns,flash,airbubbleinsideormeltjet.注射速度太慢：易由現(xiàn)流動痕，熔接痕，并且造成表面粗糙，無光澤Tooslowinjectionspeed:Flowline;weldline,orbadsurface.*注射速度和注射時間設(shè)定的一般原則：Generalprincipleswhensettinginjectionspeedorinjectiontime:2 .轉(zhuǎn)壓點：Switchpoi

11、nt:(1)怎么確定轉(zhuǎn)壓點：Howtosetswitchpoint:一般來說，轉(zhuǎn)壓點是指在零保壓壓力的情況下把產(chǎn)品打到95%滿時，由注射到保壓的切換點。Normallytheswitchisthechangingpointofscrewfrominjectionphasetoholdingphase,whenthepartsare95%oftheirvolume.對于薄壁產(chǎn)品(如：扎帶)：一般打到產(chǎn)品的98%Tothethinwallthicknessparts(Example:Cablestrap):Upto98%oftheirvolume.對于非平衡流道：一般為70%-80%,應(yīng)視具體情況

12、而定。并建議采用慢-快-慢多級注射。Tonon-balancerunners:Normallyitsupto70%to80%.Itshouldbedeterminedbythereality.Wesuggestusingstepinjectionspeed(Slow-Fast-Slow).(2)轉(zhuǎn)壓點太高：產(chǎn)品充模不足，熔接痕，凹陷，尺寸偏小等Toohighswitchpoint:emptypart,weldline,sinkmark,andsmalldimension轉(zhuǎn)壓點太低：飛邊，脫模困難，尺寸偏大等Toolowswitch:flash,difficulttodemold,bigdime

13、nsion.3 .保壓壓力：Holdingpressure:(1) 怎么確定保壓壓力：Howtosettheholdingpressure:優(yōu)化的保壓壓力一般為最低保壓壓力和最高保壓壓力的中間值Theoptimizedholdingpressureisinthemiddleofthemaximumandminimumnormally.最低保壓壓力：在準確的轉(zhuǎn)壓點基礎(chǔ)上，給予一定的保壓壓力，當產(chǎn)品剛由現(xiàn)充模不足時的保壓壓力。Minimumholdingpressure:basedonthecorrectswitchpoint,thepressurewhenthepartsstarttobeemp

14、ty.最高保壓壓力：在準確的轉(zhuǎn)壓點基礎(chǔ)上，給予一定的保壓壓力，當產(chǎn)品剛由現(xiàn)毛刺時的保壓壓力。Minimumholdingpressure:basedonthecorrectswitchpoint,thepressurewhenthepartsstarttohaveflash.(2)一般來說：Normally:PA保壓壓力=50%注射壓力POM保壓壓力=80%注射壓力；PP/PE保壓壓力=30-50%注射壓力PAHoldingpressure=50%InjectionpressurePOMHoldingpressure=80%Injectionpressure;PP/PEHoldingpress

15、ure=30-50%injectionpressure4.保壓時間：Holdingtime:(1)怎么確定保壓時間：Howtosetholdingtime:保壓時間的確定以澆口冷凝為依據(jù)。通過產(chǎn)品稱重來確定。Holdingtimeisdeterminedbythesolidificationtimeofthegate.Wedecideitaccordingtotheweight.(2)保壓時間太長：影響周期Toolongholdingtime:Wastetime保壓時間太短：重量不足，產(chǎn)品內(nèi)部空洞，尺寸偏小Tooshortholdingtime:Notenoughweight,emptyins

16、ide,smalldimension*5.螺桿轉(zhuǎn)速RotationSpeed:預(yù)塑的目標是：獲得均一穩(wěn)定的熔體(1)怎么確定螺桿轉(zhuǎn)速：Howtosettherotationspeed:作為原則，螺桿轉(zhuǎn)速的確定必須使螺桿的預(yù)塑時間，回吸時間與射臺的回退時間之和略短于冷卻時間。Asarule,therotationspeedisdeterminedbythatthetotaldosingtime,retractofscrewandretractofinjectionunitmustbealittlebitshorterthanthecoolingtime.(2)螺桿轉(zhuǎn)速太快：塑化不均(從而造成產(chǎn)品

17、冷料，充模不足和斷裂等)，材料分解(從而造成焦斑，色差，斷裂等)Toofastrotationspeed:Inhomogeneousmelt(whichcauseemptyparts,broken),materialdecomposed(whichcauseburns,differentcolor,brokenetc)螺桿轉(zhuǎn)速太慢：影響周期Tooslowrotationspeed:Wastetime.6 .冷卻時間：Coolingtime:作為原則，冷卻時間的設(shè)定應(yīng)越短越好，以產(chǎn)品不變形，不粘模，無過深的頂由痕為基本要求。并且：螺桿轉(zhuǎn)速：PA<1.0m/s;POM<0.7m/s;A

18、sarule,thecoolingistheshorterthebetterbasedonthepartsarenotdeformed,notstickyandwithouttoodeepimpressedbyejectors.*推薦的脫模溫度如下:Suggesteddemoldingtemperatureisasfollows:7 .背壓：Backpressure:(1)什么是背壓：Whatisbackpressure:背壓是指螺桿預(yù)塑時，液壓缸阻止螺桿后退的力，其大小等于螺桿前端熔體對螺桿的反作用力。Backpressureisthehydraulicforcepreventingthes

19、crewgoingbackasdosing,thevalueisequaltotheforcethatthemeltinfrontofthecylindertothescrew.(2)怎么確定背壓：Hotosetthebackpressure:背壓的確定取決于不同材料的性能，通常由材料供應(yīng)商提供。一般來說：PA:20-80Bar;POM:50-100Bar;PP/PE:50-200BarThebackpressureisdeterminedbythematerialcharacteranditsvalueisofferedbythesupplier.Normally:PA:20-80Bar;P

20、OM:50-100Bar;PP/PE:50-200Bar20%時：噴嘴下料口Whenone-shotquantityislessthan20%ofmaximum:b.次注射量在20%-70%之間時：噴嘴下料口c.一次注射量大于70%時：噴嘴下料口(2)熔體溫度太高：材料分解(從而造成產(chǎn)品氣泡，色差，焦斑，斷裂等)Toohighmelttemperature:Materialdecomposed(Whichcauseairbubble,differentcolor,burns,brokenetc.)熔體溫度太低：材料塑化不均，熔體內(nèi)含冷料(從而造成充模不足，冷料，產(chǎn)品斷裂等)Toolowmelt

21、temperature:Inhomogeneousmeltwithcoldmaterialinside(Whichcauseemptyparts,brokenpartsetc.)11.模具溫度：Moldtemperature:(1)為什么需要模溫：Whythemoldtemperatureisneeded:無論模具溫度高低，它的作用始終是為了在穩(wěn)定生產(chǎn)過程中使模具維持一定的溫度，起冷卻作用的。a.一次注射量小于總料量的真正重要的模溫是指模具型腔的溫度，而不是模溫機上顯示的溫度。通常，在穩(wěn)定生產(chǎn)過程中型腔溫度會達到一個穩(wěn)定的動態(tài)平衡，并高于顯示溫度10度左右(對于大模具在生產(chǎn)之前必須使模具充分加

22、熱，尤其是薄壁，且流長比很大的產(chǎn)品模具)Whateverthemoldtemperatureishighorlow,itsfunctionistokeepthecavitytemperatureonthesamelevel.Itisforcooling.Forthebigmold,itmustbeheatedenoughbeforestartproduction.(2)模具溫度會影響什么Whatthemoldtemperatureaffect:會影響熔體的流動性和冷卻速度。Affectthemeltflowrateandthecoolingspeed.因為影響流動性，從而影響產(chǎn)品外觀(表面質(zhì)量

23、，毛刺)和注塑壓力；Foraffectingtheflowrate,themoldtemperatureaffectstheappearanceofthepartsandtheinjectionpressure.因為影響冷卻速度，從而影響產(chǎn)品結(jié)晶度，進而影響產(chǎn)品收縮率和機械強度性能.Foraffectingcoolingspeed,themoldtemperatureaffectsthecrystallizedrateandthenaffectstheshrinkageandthemechanicalstrength.（3）模溫高：流動性好；結(jié)晶度高；收縮率大（從而造成尺寸偏?。?；變形；需要更

24、長的冷卻時間Highmoldtemperature:goodflowcharacter;high-crystallizedrate;bigshrinkage（Whichcausesmalldimension）;needmorecoolingtime模溫低：流動性差（從而造成流動紋，熔接痕）；結(jié)晶度低;收縮率?。◤亩斐沙叽缙螅㎜owmoldtemperature:badflowcharacter;high-crystallizedrate;smallshrinkage（Whichcausebigdimension）三.常見產(chǎn)品缺陷及其原因：Normaldefectsandthereason:

25、（1）流涎：.Materialescapingfromnozzle:a.材料烘干不徹底或材料受潮Thematerialisnotdriedenoughoritiswet.b.預(yù)塑速度（螺桿轉(zhuǎn)速）太快Dosingspeedistoofast.c.噴嘴溫度太高Thenozzletemperatureistoohigh.d.不好的回料（粉狀）Toomuchpowderinregrinds.e.回吸量不夠Notenoughretractf.噴嘴接觸力不足Notenoughforcebetweenthenozzleandthemoldbush.g.噴嘴與模具澆口套尺寸不匹配Thedimensionoft

26、henozzleandthemoldbushisnotcorrect.h.噴嘴接觸表面臟(造成表面不平)Dirtyinterfaceofthenozzle(2)預(yù)塑不穩(wěn)：Plastificationunstable:a.回料比不合理或不無急定Regrindrateisunreasonableorunstableb.背壓太低Backpressureistoolowc.長料桿架橋Longregrindd.材料受潮Wetmateriale.下料處溫度不合理(太高)Unreasonablecylindertemperaturearoundthehopper(Toohigh)(3)飛邊Flashesa.

27、參數(shù)設(shè)置不準確(轉(zhuǎn)壓點太低，保壓太高，射速太快，溫度太高)Wrongsettingparameters(Toolowswitchpoint,toohighholdingpressure,toofastinjectionspeed,toohightemperatureetc)b.模具臟Moldisdirtyc.鎖模力不足Lockingforceisnotenoughd.模具問題(損壞)Moldisinjurede.設(shè)備問題(壓力不無急)Machineproblems(Unstablepressure)f.噴嘴溫度過低Toolownozzletemperatureg.塑化不均（長料桿，螺桿轉(zhuǎn)速過快

28、，背壓太低等）造成冷料Inhomogeneousmelth.回吸太小造成止回閥關(guān)閉不穩(wěn)定Toolittleretracttocausethenon-returnvalveclosingunstably(4)充模不足Incomplete:a.參數(shù)設(shè)置不準確(轉(zhuǎn)壓點太高，保壓太低，射速太慢，溫度太彳氐)Wrongsettingparameters(Toolowswitchpoint,toohighholdingpressure,toofastinjectionspeed,toohightemperatureetc)b.模具臟Moldisdirtyc.噴嘴溫度過低，結(jié)構(gòu)不合理Lowtemperatu

29、reinthetipofnozzle,andwrongstructured.止回閥或料筒損壞Non-returnvalveorcylinderisbrokene.澆口，流道尺寸太小Toosmallgate,runnersf.不干凈的回料(含雜料)Othermaterialintheregrindg.材料受潮Wetmaterialh.設(shè)備問題(壓力不足)Machineproblem(Notenoughpressure)I.射臺沒對準Thenozzleisnotinthecentreoftherunner.h.回吸太小造成止回閥關(guān)閉不穩(wěn)定Toolittleretracttocausethenon-

30、returnvalveclosingunstably(5)不時充模不足：SometimesIncomplete:a.射速太低(特別是PA,POM)Injectionspeedistoolow(EspeciallyforPOM)b.對大產(chǎn)品，熔體溫度不夠Melttemperatureistoolowc.塑化不均(背壓太低，轉(zhuǎn)速太快)Nothomogeneousmelt(Backpressureistoolow,rotationspeedistoofast)d.噴嘴溫度不夠Nozzletemperatureistoolowe.止回閥或料筒損壞Non-returnvalveorcylinderisb

31、rokenf.雜質(zhì)Othermaterialsinsideg.模具臟Moldisdirtyh.材料烘干不徹底或材料受潮MaterialiswetI.射臺沒對準Thenozzleisnotinthecentreoftherunner.h.回吸太小造成止回閥關(guān)閉不穩(wěn)定Toolittleretracttocausethenon-returnvalveclosingunstably(6)焦斑c.產(chǎn)品頂由不均Partisejectednotbalanced.冷去f!時間不夠Notenoughcoolingtimee.射速太低Toolowinjectionspeedf.壓力太大造成粘模Toohighpre

32、ssuretocausestickyoncavitiesg.塑化不均造成內(nèi)應(yīng)力Nothomogeneousmelttocauseforceinsideh.模具溫度分布不均Moldtemperaturenotuniform(9)尺寸不穩(wěn)Dimensionnotstablea.參數(shù)控制不穩(wěn)（模溫，料溫，保壓太低或太高，冷卻時間)Parametercontrolnotisprecise(moldtemperature,melttemperature,coolingtime)b.回料比不合理或不無急定Regrindrateisunreasonableorunstablec.止回閥或料筒損壞Non-re

33、turnvalveorcylinderisbrokend.回吸太小造成止回閥關(guān)閉不穩(wěn)定Toolittleretracttocausethenon-returnvalveclosingunstably(10)重量不穩(wěn)定Unstableweighta.參數(shù)設(shè)置不準確(模溫，料溫，保壓太低或太高，冷卻時間，保壓時間不夠)Notcorrectsettingparameter(moldtemperature,melttemperature,coolingtime)b.噴嘴溫度太低Nozzletemperatureistoolowc.保壓時間太短Holdingtimeistoolowd.止回閥或料筒損壞N

34、on-returnvalveorcylinderisbrokene.回料比不無急定Unstableregrindratef.回吸太小造成止回閥關(guān)閉不穩(wěn)定Toolittleretracttocausethenon-returnvalveclosingunstably(11)產(chǎn)品易斷裂Easilybrokenpartsa.熔體溫度太高或太低Melttemperatureistoohighortoolowb.材料濕Wetmaterialc.射速太低或太高Injectionspeedistoolowortoofastd.模具溫度太高或太低Moldtemperatureisnotreasonablee.

35、熔接痕Weldinglinef.雜質(zhì)Othermaterialsinsideg.塑化不均(背壓太低，轉(zhuǎn)速太快，回料長料桿)Nothomogeneousmelt(Backpressureistoolow,rotationspeedistoofast,longsprue)h.模具銳邊Moldsharpplacei.不穩(wěn)定回料比Unstableregrindrate(12)熔接痕：Weldingline:a.射速太慢Toolowinjectionspeedb.熔體溫度太彳氐Toolowmelttemperaturec.模具溫度太低Toolowmoldtemperatured.排氣不暢Badventd.色母；塑化不均Pigment;inhomogeneousmelte.模具，產(chǎn)品設(shè)計不合理Designofmoldorpartsnotreasonable(13)表皮分層:Delamination:a.材料潮濕Wetmaterialb.雜料Mixedmaterialc.色母有問題Pigmentproblemd.射速太快Toofastinjectionspeed四.當產(chǎn)品由現(xiàn)問題時：Whenthereisaproblem:(1)你必須搞清楚問題：Youm