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《常用热塑性塑料加工特性（processing characteristics of commonly used thermoplastics）》由会员上传分享，免费在线阅读，更多相关内容在教育资源-天天文库。
1、常用热塑性塑料加工特性（Processingcharacteristicsofcommonlyusedthermoplastics）ThisarticleiscontributedbyghtengDOCdocumentsmayexperiencepoorbrowsingontheWAPside.ItisrecommendedthatyoufirstselectTXT,ordownloadthesourcefiletothelocalview.Commonthermoplastics;processingcharacteristics
2、;plasticnames;moldingproperties1无定型塑料,吸湿性小,不易分解,性脆易裂,热膨胀系数大,易产生应力开裂2流动性能较好,溢边值0.03mm左右3塑件壁厚应均匀,不宜有嵌件(如有嵌件应预热),缺口,尖角,各面应圆滑连接聚苯乙烯4可用螺杆或柱塞式注塑机加工,喷嘴可用直通式或自锁式(PS)5宜用高料温,高模温,低注射压力,延长注射时间有利于降低内应力,防止缩孔,变形(尤其对厚壁塑件),但料温高易出银丝,料温低或脱模剂多则透明性差6可采用各种形式进料口,进料口与塑件应圆弧连接,防止去除浇口时损坏塑件,脱模斜度宜
3、取2℃以上,推出均匀以防止脱模不良发生开裂,变形,可用热浇道系统1结晶Plastic,hygroscopic2excellentmobility,theoverflowboundaryvalueabout0.02mm,theliquidityofthepressuresensitive3possiblemeltrupture,contactwiththeorganicsolventcanbecracked4heatingtimeistoolong,decomposition,burningpolyethylene(PE)5slowc
4、oolingrate,andthereforemustbefullycooled,coldmaterialshouldbeestablished6,moldcoolingsystemduetoshrinkagerange,shrinkage,directional,deformation,warping,effectofcoolingconditionsonthecrystallinityandthemoldshrinkagerateishigh,shouldmaintaincontrolofthemoldtemperature,c
5、oolinguniformity,stabilityof7suitablecryogenichighpressureinjection,thematerialtemperatureuniformity,fillingspeedshouldbefast,fullpressure8notbydirectfeeding,otherwiseeasytoincreasetheinternalstress,orunevenshrinkage,obviousorientation,deformationincreases,shouldpayatt
6、entiontothechoiceoffeedpositionandquantity,preventtheshrinkage,warpageanddeformationofthe9softeasytomold,plasticpartswithashallowconcavesideWhenthegroove1forceddemouldingamorphousplastics,hygroscopic,butinordertoimproveliquidityandpreventtheoccurrenceofbubbles,shouldfi
7、rstdry2poormobility,easydecomposition,especiallyunderhightemperatureandstiffness,coppermetalcontactmoreeasilydecomposed,thedecompositiontemperatureof200DEGC,polyvinylchloride(RPVC)decompositionatthecorrosionandirritationofthe3gasformingtemperaturerangeissmall,muststric
8、tlycontrolthetemperatureofmaterialswith4screwtypeinjectionmoldingmachineandthroughthenozzleapertureshouldbelarge,topr
