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值,可選用SZ60/450臥式注塑機(jī)(上海第一塑料機(jī)械廠),見表11.表11注射機(jī)主要技術(shù)參數(shù)理論注射容量/60鎖模力 /kN400螺桿直徑/mm30拉桿內(nèi)間距/mm220300注射壓力/Mpa180移模行程/mm250注射速率(g/s) 70最大模厚/mm250塑化能力(g/s) 最小模厚/mm150螺桿轉(zhuǎn)速(r/min)0200定位孔直徑/mm80噴嘴球半徑/mm20噴嘴孔直徑/mm3鎖模方式雙曲肘4.型腔數(shù)量及注射機(jī)有關(guān)工藝參數(shù)的校核由注射機(jī)料筒塑化速率校核模具的型腔個(gè)數(shù)n型腔數(shù)合格。(8)有力于排氣。(4)有利于保證塑件的尺寸精度。因此分型面的選擇是注射模設(shè)計(jì)中的關(guān)鍵因素。(5)ABS樹脂的蓉蓉溫度較低,熔融溫度范圍寬,流動(dòng)性好,有利于成型。3)ABS的成型特性(1)ABS表面極易潮,使成型塑件表面出現(xiàn)斑痕、云紋等缺陷,為此成型錢必須進(jìn)行干燥處理。 ABS塑料的性能特點(diǎn)、成型特點(diǎn)、用途及工藝參數(shù)1)ABS是丙烯晴、丁二烯和苯乙烯三種單體的共聚物即:(1)丙烯晴使ABS有較高的強(qiáng)度、硬度、耐熱性及耐化學(xué)腐蝕性。(2)丁二烯使ABS有彈性和較高的沖擊強(qiáng)度。(2)ABS比熱熔底,在注塑機(jī)料筒中能很快加熱,因而塑化效率高,在模具中凝固比聚快,故模塑周期短。 ABS的主要性能指標(biāo)密度(g/cm3)屈服強(qiáng)度/MPa5356收縮率(%)0.抗拉強(qiáng)度/MPa5356比熱容(J/())11001400拉伸彈性模量/GPa吸水率24h/(%)彎曲強(qiáng)度/MPa84質(zhì)量體積(cm3/g)彎曲彈性模量/GPa玻璃化溫度()8090抗壓強(qiáng)度/MP熔點(diǎn)()170剪切強(qiáng)度/MP2.?dāng)M定模具結(jié)構(gòu)形式在塑件設(shè)計(jì)階段,就應(yīng)該考慮成型時(shí)分型免得形狀和位置,否則無法用模具成型。1)分型面的選擇原則(1)有利于保證塑件的外觀質(zhì)量。(5)盡可能滿足塑件的使用要求。(9)有力簡化模具結(jié)構(gòu)。式中:M注射機(jī)的額定塑化量()t成型周期(30s)1)注射量校核注射量以容積表示,最大注射容積為式中模具型腔和流道的最大容積v指定型號與規(guī)格的注射機(jī)注射容積該注射機(jī)為:。由于影響型腔壓力P與損耗系數(shù)k的因素較復(fù)雜,因此在采用通用塑料生產(chǎn)中小型制品的時(shí)候,模腔內(nèi)塑料壓力常取2040Mpa取P為30Mpa則其F=450KN校核合格。6)澆口套總長。2)分流道冷料穴的設(shè)計(jì)當(dāng)分流道較長時(shí),可將分流道端部沿料流前進(jìn)方向延長作為分流道冷料穴,以貯存前鋒冷料。該流道形式是由模具模具結(jié)構(gòu)形式所確定。5)分流道截面形狀(梯形分流道)6)從理論,分流道可比截面小10%,但為了刀具的統(tǒng)一和加工方便,在分型面上的分流道采用一樣的截面。澆口截面積形狀多為矩形和圓形兩種。設(shè)計(jì)斜導(dǎo)柱時(shí),先要根據(jù)塑件要計(jì)算出所需的抽拔力與抽芯距,然后再根據(jù)其他因素確定斜導(dǎo)柱的結(jié)構(gòu),直徑及長度。取部分直徑1040mm,則取d=16mm 固定臺階O=d+5mm=25mm3.)斜導(dǎo)柱的長度 L=D/2tg+h/cos+s/sin+d/2tg(1015)=63 1)滑塊和導(dǎo)滑槽的設(shè)計(jì):由于成型型芯尺寸不大工,故采用整體式滑塊。 滑塊孔與斜導(dǎo)柱的配合:斜銷端部卡在導(dǎo)滑槽中,當(dāng)模板向下與動(dòng)時(shí),使斜頂桿產(chǎn)生水平的橫向位移,而這時(shí),頂桿卡在滑塊中,帶動(dòng)滑塊一起在導(dǎo)滑槽上產(chǎn)生水平運(yùn)動(dòng),從而使斜頂桿端部從制件內(nèi)側(cè)脫出,完成側(cè)抽運(yùn)動(dòng)。(3)型腔深度按平均收縮率計(jì)算:==+.+==型腔按IT8級精度制造,其制造公差為=若型腔易修淺則==按極限尺寸計(jì)算:==校核塑件最小高度是否合格(1)+≥()+=17故滿足要求,型腔深為mm,按平均收縮率計(jì)算更偏深一些便于修模。(6)寬度方向型芯按平均收縮率計(jì)算=++=+=30+==++=模具型腔按IT8級精度制造,其制造偏差=如按極限尺寸計(jì)算:===—==校核塑件可能出現(xiàn)最小尺寸:(——)(1—)左邊()()=,故型芯長度為長度方向中心距按平均收縮率和按極限尺寸計(jì)算時(shí),其尺寸都用下面的公式=(++)177。倆板之間應(yīng)有分模間隙及在裝配、試調(diào)、維修過程中可以方便地分開倆塊。7)墊塊(38250mm、厚70mm)8)動(dòng)模座板(250mm250mm、厚)材料45鋼。t agree with the disciplinary action your employer has taken against you your employer dismisses you and you think that you have been dismissed unfairly. For more informu, take advice from one of the organisations listed undertt charge you more than 35% of your pensation nearest CAB.For more information about making a claim to an employment tribunal, sees Premier League match at Chelsea on Sunday.I am going to be at the match tomorrow and I have asked to meet Ya ya Toure, he told BBC Sport.For me it39。City39。s plaint. In a statement the Russian side added: We found no racist insults from fans of CSKA.Age has reached the end of the beginning of a word. May be guilty in his seems to passing a lot of different life became the appearance of the same day。二十年的人生軌跡深深淺淺,突然就感覺到有些事情,非做不可了。 Then in high school, think don39。A person39。嫌惡過自己的怯懦,最終卻發(fā)現(xiàn)有很多緣分,有很多錯(cuò)過,好像冥冥之中真的已經(jīng)注定。 From the corner at the beginning of deep friendship。Baumgartner the disappointing news: Mission aborted. r plays an important role in this mission. Starting at the ground, conditions have to be very calm winds less than 2 mph, with no precipitation or humidity and limited cloud cover. The balloon, with capsule attached, will move through the lower level of the atmosphere (the troposphere) where our daytoday weather lives. It will climb higher than the tip of Mount Everest ( miles/ kilometers), drifting even higher than the cruising altitude of mercial airliners ( miles/ kilometers) and into the stratosphere. As he crosses the boundary layer (called the tropopause),e can expect a lot of turbulence. We often close ourselves off when traumatic events happen in our lives。下面六個(gè)方法有助于你更完滿透徹地敞開心扉。2. Embrace the unfortable We all know what that twinge of anxiety feels like. We know how fear feels in