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畢業(yè)設(shè)計說明書設(shè)計設(shè)計/論文題目論文題目 電視機旋鈕電視機旋鈕 班班 級級 模模 具具 3072 班班 姓姓 名名:潘海娟潘海娟 10 指指 導(dǎo)導(dǎo) 老老 師師:吳吳 治治 明明 完完 成成 時時 間間:2010.4 v一、塑料制品的工藝性分析一、塑料制品的工藝性分析v二、成型設(shè)備選擇與模塑工藝規(guī)程的編制二、成型設(shè)備選擇與模塑工藝規(guī)程的編制v三、注射模結(jié)構(gòu)設(shè)計三、注射模結(jié)構(gòu)設(shè)計v四、成型零件尺寸計算四、成型零件尺寸計算v五、注射機有關(guān)參數(shù)的校核:五、注射機有關(guān)參數(shù)的校核:v一一.塑料制品的工藝性分析塑料制品的工藝性分析v1.1.塑件的分析:塑件的分析:v ABS是丙烯、丁二烯和苯乙烯三種單體聚合而成的非結(jié)晶型的高聚物,屬于熱塑性工程塑料。v ABS塑料在一定溫度范圍內(nèi)具有較高的沖擊強度和表面硬度及耐磨性;其熱變形溫度為100左右;具有一丁的化學(xué)穩(wěn)定性和良好的介電性能;還能與其他塑料和橡膠混溶等特性;其制品尺寸穩(wěn)定性好,表面光澤,可以拋光和電鍍;ABS塑料耐熱性并不高,耐低溫性和耐紫外線性能也不好。v ABS塑料成型性較好。其流動性也較好,成型收縮性??;ABS塑料比熱容較低,在料筒中塑化效率高,在模具中凝固也較快,模塑周期短。但ABS吸水性大,成型前必須充分干燥,表面要求光澤的制品應(yīng)進行較長時間的干燥。ABS塑料可采用注射、擠出、壓延、吹塑、真空成型等方法制造塑料制品。v2.2.塑件尺寸精度分析塑件尺寸精度分析:v 此塑件上均未標注公差精度要求,所以所有尺寸均為自由尺寸,v 查塑料模塑成型技術(shù)表3-9“常用材料分類和公差等級選用”,未注公差等級選MT5級精度,屬于中等精度等級然后按表3-10“國家標準模塑件尺寸公差數(shù)值表”,查得未注尺寸公差的公差,標注如下單位:v、塑件外形尺寸:v 、;v、塑件內(nèi)形尺寸:、v3.3.塑件表面質(zhì)量分析塑件表面質(zhì)量分析v 該塑件是電視機旋鈕表面要求光亮無劃傷痕跡。v4.4.塑件結(jié)構(gòu)工藝性分析塑件結(jié)構(gòu)工藝性分析v、此塑件為圓柱回轉(zhuǎn)體類零件,高度為31,各段厚度不一,總體尺寸為20,尺寸較小;v、塑件有一長度為12mm的桿狀部分,成型此桿狀部分采用鑲件結(jié)構(gòu),塑件有圓周內(nèi)凹槽,且要求成型后表面光滑;所以必須使用兩側(cè)的側(cè)滑塊分型機構(gòu),使用斜導(dǎo)板起開合模的導(dǎo)向作用。塑件表面有一個的圓形凹槽,成型此部分采用成型推桿成型。v二、成型設(shè)備選擇與模塑工藝規(guī)程的編制二、成型設(shè)備選擇與模塑工藝規(guī)程的編制v1.1.計算塑件體積、重量計算塑件體積、重量 .計算體積:通過使用Pro/e軟件繪制旋紐零件圖,查得塑件體積:V=5.33、.估算質(zhì)量:v 查表5-1“某些熱塑性塑料的密度及壓縮比”,知ABS的密度 v =1.01.1g/,取 =1.05 g/v 塑件質(zhì)量m=v=5.331.05=5.59gv.估算澆注系統(tǒng)塑料質(zhì)量:v 查中國模具工程大典知,澆注系統(tǒng)的質(zhì)量取塑件質(zhì)量的20%100%,所以總質(zhì)量 M=4.35*m=24.32gv 初選注射機:XS-ZY-60XS-ZY-60;v 初定型腔數(shù):一模四腔一模四腔;v 注射機注射機XS-ZY-60XS-ZY-60的主要技術(shù)參數(shù):的主要技術(shù)參數(shù):v結(jié)論結(jié)論:可用注射成型可用注射成型v三三.注射模結(jié)構(gòu)設(shè)計注射模結(jié)構(gòu)設(shè)計v1 1、分型面的選擇、分型面的選擇v分型面的選擇應(yīng)遵循以下原則:v、分型面應(yīng)便于塑件的脫模;v、分型面選擇應(yīng)有利于側(cè)面分型和抽芯;v、分型面選擇應(yīng)保證塑件的外觀質(zhì)量;v、分型面選擇應(yīng)有利于防止溢料;v、分型面選擇應(yīng)有利于排氣;v、分型面選擇應(yīng)盡量使成型零件便于加工;v、分型面選擇必須考慮注射機的技術(shù)參數(shù);“一般,分型面選在塑件的最大截面處”v綜上所述,該塑件的分型面取在塑件的最大截面AA。v2 2、澆注系統(tǒng)澆注系統(tǒng)v 對澆注系統(tǒng)的要求是:將熔體平穩(wěn)的引入型腔,使之按要求填充型腔;使型腔內(nèi)的氣體順利排出;在熔體填充型腔和凝固過程中,能充分地把壓力傳到型腔各部位,以獲得組織致密、外形清晰、尺寸穩(wěn)定的塑料制品。v1、主流道:、主流道:主流道橫截面形狀通常采v用圓形。為了便于流道凝料的脫出,主流道v設(shè)計成圓錐形,其錐度 26,內(nèi)壁v粗糙度 v 小于0.4 ,小端直徑D一般取3-6,且v大于注射機噴嘴直徑d約0.5-1;主流道的長v度由定模座板和定模板厚度確定,一般L不超v過60,主流道大端與分流道相接處應(yīng)有過v渡圓角通常 取1-3以減小料流轉(zhuǎn)向時v的阻力。v 由于主流道需要與高溫塑件和噴嘴頻繁接觸,所以要設(shè)置澆口套。查模具設(shè)計與制造簡明手冊,選澆口套型,小端直徑 ,長度L為30。澆口套直接裝配到定模座板上,方便且安裝簡單。如圖所示:v22、分流道:、分流道:v 分流道是介于主流道和澆口之間的v一段流道。它是熔體由主流道流入型腔的v過渡段通道,也是使?jié)沧⑾到y(tǒng)的截面變化v和熔體流動轉(zhuǎn)向的過渡通道。v分流道截面形狀和尺寸:、分流道截面v為梯形截面,其加工容易,且熱量散失和v流動阻力也不大;所以,選梯形截面。v 查塑料模塑成型技術(shù)表5-5“常用分流道橫截面及其尺寸”,如圖:圓角半徑R=1.5 分流道長度L=50v 高度h=3.5 梯形長邊長度X=5 v33、澆口:、澆口:v .澆口的基本作用:使從分流道來的熔體產(chǎn)生加速,以快速充滿型腔;防止熔料倒流;便于澆口凝料與制品分離。v.澆口選用:v 點澆口:點澆口:其優(yōu)點是去除澆口后,制品上留v下的 痕跡不明顯,但壓力損失較大,制品v收縮大,而且模具應(yīng)設(shè)計成雙分型面模具,v以便脫出流道凝料,造成模具結(jié)構(gòu)復(fù)雜。v圖為點澆口:v該制品選用點澆口。塑件表面質(zhì)量有較高要求,去除澆口后,制品上留下的 痕跡不明顯。但是,模具應(yīng)設(shè)計成雙分型面模具,以便脫出流道凝料,造成模具結(jié)構(gòu)較復(fù)雜。v圖為點澆口尺寸:v4、冷料穴與拉料桿:、冷料穴與拉料桿:v 梯形拉料桿為標準件,易于選取,且v使用效果較好。其頭部有一定空間。能貯v存凝料,充當(dāng)冷料穴。如圖:v3.3.型腔設(shè)計:型腔設(shè)計:v1、型腔設(shè)計:、型腔設(shè)計:v 型腔是成型塑料制品外形的主要零件??煞譃檎w式和組合式兩類。v 組合式凹模改善了加工性,減少了熱處理變形,有利于排氣,便于模具的維修,節(jié)約了模具鋼,但裝配調(diào)整較麻煩,主要用于形狀復(fù)雜的塑料制品的成型。v 該制品外型有圓周內(nèi)凹槽,且要求成型后表面光滑;所以必須使用兩側(cè)的側(cè)滑塊分型機構(gòu),型腔需要做成兩側(cè)滑塊,采用組合組合式式。v4 4、側(cè)向分型:、側(cè)向分型:v 因為塑件有圓周內(nèi)凹槽,所以必須使用兩側(cè)的側(cè)滑塊分型機構(gòu),且塑件倒裝需要使用延時側(cè)抽。使用斜導(dǎo)板起開合模的導(dǎo)向作用。使用楔緊塊,在合模時對模具起鎖緊的作用。v5 5、推件方式:、推件方式:v 推出機構(gòu)的設(shè)計要求:v 、盡量使塑料制品留在動模上v 、保證制品不變形不損壞v 、保證制品外觀良好 v 、結(jié)構(gòu)可靠v 該塑件要求“表面光亮且無劃傷痕跡”,且該零件底面上有一個的圓形淺凹槽,可以直接使用推桿成型。綜合以上結(jié)論,選推桿推出推桿推出。v復(fù)位零件復(fù)位零件:v采用復(fù)位桿復(fù)位,使已完成推出制品任務(wù)的推桿回到注射成型狀態(tài)的位置。v6 6、冷卻與加熱系統(tǒng):、冷卻與加熱系統(tǒng):v 由于ABS塑料成型時要求模溫在50-80,生產(chǎn)批量為100萬件,但體積很小,故模具可不考慮設(shè)置加熱冷卻系統(tǒng)。v7 7、標準模架的選用:、標準模架的選用:v 該塑件最大尺寸為20,采用點澆口,其生產(chǎn)批量為100萬件,采用一模四腔,則其模具對稱,便于布置,型采腔用鑲拼式,尺寸不大,但為滿足模板的強度、剛度以及型腔布局的需要,選150200的標準模架,其閉合厚度為195,該模具的最大尺寸為200200;注射機XS-ZY-60的拉桿空間為280250,最大模具厚度200mm,所選模架能放進去。所以可使用初選的注射機XS-ZY-60,其能滿足生產(chǎn)要求。v四、四、成型零件尺寸計算成型零件尺寸計算v1.型芯、型腔計算:該塑件材料為ABS,查的該塑料的收縮率為0.40.7,取0.55。模具制造公差取v(1)、型腔徑向尺寸:由前面可知塑件尺寸及公差。按下式計算:v =(+%-)v =、v則 =6+60.55%-0.24 =5.85 v =4.34 =14.79 =16.65 =19.68 v、型腔深度尺寸、型腔深度尺寸:v =+%-=、v則 =12+120.55%-0.34 =11.83v =1.87 =10.83 v、型芯徑向尺寸:按下式計算 v =+%+=、v 則 =8+80.55%+0.24 =8.22v =2.5+2.50.55%+0.2 =2.67 v五、注射機有關(guān)參數(shù)的校核:五、注射機有關(guān)參數(shù)的校核:v1、注射量的校核:由前面知,塑件和澆注系統(tǒng)質(zhì)量都為35g,則每次注射所需注射量為:45.59g=25gv 注射機的最大注射量以最大注射容積標定時,按下式校核:v V=(5-1)v式中 -注射機最大注射容積 -一個制品的體積 vV-制品總體積(包括制品、流道凝料在內(nèi))n-型腔數(shù)v -流道凝料體積 K-注射機最大注射量的利用系數(shù),取K=0.8v由前面計算知,塑件與澆注系統(tǒng)凝料的體積相等,則每次注射所需塑料體積為:V=V+V=4*5.33 cm+2050mm=23.37 v注射機最大注射量600.8=48 23.37 故能滿足要求。v2 2、鎖模力與注射壓力的校核:、鎖模力與注射壓力的校核:.注射壓力校核:注射壓力校核:v即 P (5-6)v式中 -注射機的最大注射壓力(MPa)v P-塑料制品成型所需的注射壓力(MPa)v由于所選注射機為XS-ZY-60,其注射壓力為122 MPa,即為122MPa。v查塑料模塑成型技術(shù)附表4“常用熱塑性塑料注射成型的工藝參數(shù)”,P為60100 MPa,滿足上式要求。v.鎖模力的校核:鎖模力的校核:v需滿足 F=(5-7)v 式中-注射機的最大鎖模力 -模內(nèi)平均壓力,見表5-2v -制品、流道、澆口在分型面上的投影面積之和v由前可知,注射機XS-ZY-60的最大鎖模力為500KN,為34.4 MPa,經(jīng)計算得 為865.4 v =+=+1005+=865.4v =34.3865.4=30KN50KN 滿足上式要求。v3.3.模具厚度的校核:模具厚度的校核:v H (5-11)v式中H-模具閉合厚度(=193)v -注射機允許模具最小厚度(=70)v -注射機允許模具最大厚度(=200)v 滿足上式要求。v4 4、注射機噴嘴與模具主流道襯套關(guān)系:、注射機噴嘴與模具主流道襯套關(guān)系:v R=r+(12)D=d+(0.51)v式中 d-注射機噴嘴前端孔徑(=4)v D-模具主流道襯套的小端直徑(=5)v r-注射機噴嘴球面半徑(=12)v R-模具主流道襯套的球面半徑(=13)v滿足上式要求。v5.5.開模行程的校核:開模行程的校核:v由于注射機XS-ZY-1000最大開模行程與模具厚度無關(guān),所以按下式校核:v S +510 5-12v式中 S-注射機最大開模行程(移動模板行程)(=180)v -制品的推出距離(=15)v -制品的總高度(=31)v滿足上式要求。v6.6.流程比的校核:流程比的校核:v熔體流程長度與厚度之比即為流程比??砂聪率接嬎悖簐 流程比 =(5-18)v所以 =(+)2=70,而ABS的流程比介于聚乙烯和聚丙烯之間,取210235。所求值小于ABS的流程比,滿足要求。v7.7.型腔側(cè)壁和底板厚度的校核:型腔側(cè)壁和底板厚度的校核:v型腔側(cè)壁計算:型腔側(cè)壁計算:(4-27)v由于其型腔為組合式型腔,型腔側(cè)壁厚度為;t=r(-1)v式中 -型腔長邊長度(=200MPa)vP-型腔內(nèi)熔體壓力(=34.3MPa)v代入上式得t=3.5:故該模具型腔壁厚可取3.5。v 22、底板厚度計算、底板厚度計算:v該模具采用兩墊塊支撐,按剛度計算的底板厚度如下:v (4-46)vL-支架間距=94 -底板總長=200v-底板上承受成型壓力部分的長度=115vE-型腔材料彈性模量(=2.1 MPa)v-型腔彈性變形增長值,見表4-6=0.05vP-型腔內(nèi)熔體壓力(=34.3MPa)v 代入上式得h=28.5.v L計算出的底板厚度h為 28.5mm,在結(jié)構(gòu)許可情況下,為使底板強度滿足可以增加一點底板厚度。所以,將底板厚度h定為32mm。第 25 頁 共 25 頁
目錄
畢業(yè)設(shè)計評分表……………………………………3
畢業(yè)設(shè)計階段性檢查表……………………………5
畢業(yè)設(shè)計(論文)答辯問題原始記錄……………6
任務(wù)書………………………………………………8
正文…………………………………………………9
1.塑料制品的工藝性分析…………………………10
2.成型設(shè)備選擇與模塑工藝規(guī)程的編制…………12
3.注射模結(jié)構(gòu)設(shè)計…………………………………13
4.成型零件尺寸計算………………………………15
5.注射機有關(guān)參數(shù)的校核:………………………17
7.裝配圖……………………………………………22
8.主要模具零件加工工藝………………………… 23
9.參考文獻…………………………………………26
陜西國防工業(yè)職業(yè)技術(shù)學(xué)院畢業(yè)設(shè)計評分表
工 程 系
機電工程系
班 級
模具3072
專 業(yè)
模具設(shè)計與制造
學(xué)生姓名
潘海娟
學(xué)生學(xué)號
12307210
指導(dǎo)教師
吳治明
畢業(yè)設(shè)計題目
電 視 機 旋 鈕
項 目
參考標準分
實 得 分
(一)課題評定成績(0.6)
1.設(shè)計過程考評成 績
設(shè)計過程中的獨立性
10分
工作態(tài)度及出勤情況
5分
按時完成任務(wù)情況
5分
2.設(shè)計質(zhì)量考評成 績
題目的難易程度,設(shè)計方案的合理性
15分
設(shè)計過程中分析、解決問題能力的表現(xiàn)
15分
掌握基礎(chǔ)理論的情況
10分
資料收集、文獻閱讀情況
10分
設(shè)計圖紙、說明書的質(zhì)量、規(guī)范程度
20分
設(shè)計的創(chuàng)新意識及應(yīng)用價值
10分
(二)答 辯 成 績(0.4)
1.個人對課題工作的總體介紹情況
40分
2.回答基本問題的正確程度
40分
3.回答較復(fù)雜問題的正確程度
20分
總評成績
課題評定成績×0.6+答辯成績×0.4= 分
成績等級
指導(dǎo)教師評語
答辯小組意見
答辯組組長簽章:
二〇〇 年 月 日
學(xué)院畢業(yè)
考核委員會意見
學(xué)院畢業(yè)考核委員會主任簽章:
二〇〇 年 月 日
畢業(yè)設(shè)計階段性檢查表
專 業(yè)
模具設(shè)計與制造
班 級
模具3072
姓 名
潘海娟
學(xué) 號
10
設(shè)計課題
電 視 機 旋 鈕
起止日期
檢 查 內(nèi) 容
完成情況
指導(dǎo)建議
設(shè)計態(tài)度
備 注
1
模具類型及結(jié)構(gòu)的確定
2
模具結(jié)構(gòu)草圖的繪制
3
繪制模具非標準零件工作圖
4
編制典型零件的制造工藝
5
編制塑件的模塑成型工藝
指導(dǎo)教師
年 月 日
畢業(yè)設(shè)計(論文)答辯問題原始記錄
設(shè)計圖存在問題
問題
1
題目記錄
回答記錄
問題
2
問題
3
問題
4
問題
5
問題
6
問題
7
問題
8
問題
9
問題
10
其他
陜西國防工業(yè)職業(yè)技術(shù)學(xué)院
模具設(shè)計與制造畢業(yè)設(shè)計任務(wù)書
班級學(xué)號
模具307210
學(xué)生姓名
潘海娟
指導(dǎo)教師
吳治明
設(shè)計題目
電 視 機 旋 鈕
任務(wù)書下達日期
2009 年 9 月 21 日 指導(dǎo)教師(簽字)_________
設(shè)計
原始
參數(shù)
1.塑件圖:見附件
2.材料:ABS
3.批量:100萬件
4.塑件精度:5級精度
設(shè)計
工作
內(nèi)容
1.編制模塑成型工藝規(guī)程(即填寫“塑件成型工藝卡”)
2.繪制塑件注射??傃b圖
3.繪制該模具零件圖一套
4.編制該模具凸模、凹模制造工藝規(guī)程
5.編寫完善模具設(shè)計說明書(按A4打印紙裝訂)
6.所有資料按要求裝訂后以文件袋形式上交輔導(dǎo)教師,并交電子稿在http://md.gfxy.com畢業(yè)設(shè)計欄目中。
一.塑料制品的工藝性分析
1. 塑件的分析:
①、ABS是丙烯、丁二烯和苯乙烯三種單體聚合而成的非結(jié)晶型的高聚物,屬于熱塑性工程塑料。
②、ABS塑料在一定溫度范圍內(nèi)具有較高的沖擊強度和表面硬度及耐磨性;其熱變形溫度為100℃左右;具有一丁的化學(xué)穩(wěn)定性和良好的介電性能;還能與其他塑料和橡膠混溶等特性;其制品尺寸穩(wěn)定性好,表面光澤,可以拋光和電鍍;ABS塑料耐熱性并不高,耐低溫性和耐紫外線性能也不好。
③、ABS塑料成型性較好。其流動性也較好,成型收縮性??;ABS塑料比熱容較低,在料筒中塑化效率高,在模具中凝固也較快,模塑周期短。但ABS吸水性大,成型前必須充分干燥,表面要求光澤的制品應(yīng)進行較長時間的干燥。ABS塑料可采用注射、擠出、壓延、吹塑、真空成型等方法制造塑料制品。
2、塑件尺寸精度分析
此塑件上均未標注公差精度要求,所以所有尺寸均為自由尺寸,查《塑料模塑成型技術(shù)》表3-9 “常用材料分類和公差等級選用”,未注公差等級選MT5級精度,屬于中等精度等級然后按表3-10“國家標準模塑件尺寸公差數(shù)值表”,查得未注尺寸公差的公差,標注如下﹙單位:㎜﹚
①、塑件外形尺寸: 、 、 、 、 、、、、;
②、塑件內(nèi)形尺寸: 、 、;
3 塑件表面質(zhì)量分析
該塑件是電視機旋鈕表面要求光亮無劃傷痕跡。
4 塑件結(jié)構(gòu)工藝性分析
①、此塑件為圓柱回轉(zhuǎn)體類零件,高度為31 ㎜,各段厚度不一,總體尺寸為20㎜,尺寸較小;
②、塑件有一長度為12mm的桿狀部分,成型此桿狀部分采用鑲件結(jié)構(gòu),塑件有圓周內(nèi)凹槽,且要求成型后表面光滑;所以必須使用兩側(cè)的側(cè)滑塊分型機構(gòu),使用斜導(dǎo)板起開合模的導(dǎo)向作用。 塑件表面有一個的圓形凹槽,成型此部分采用成型推桿成型。
二、成型設(shè)備選擇與模塑工藝規(guī)程的編制
1、 計算塑件體積、重量
①、 計算體積:
通過使用Pro/e軟件繪制旋紐零件圖,查得塑件體積:V =5.33㎝
② 、估算質(zhì)量:
查表5-1“某些熱塑性塑料的密度及壓縮比”,知ABS的密度=1.0~1.1g/㎝,取=1.05 g/㎝
塑件質(zhì)量m=v=5.33×1.05=5.59g
③、估算澆注系統(tǒng)塑料質(zhì)量:
查《中國模具工程大典》知,澆注系統(tǒng)的質(zhì)量取塑件質(zhì)量的20%~100%,所以總質(zhì)量 M =4.35*m =24.32g
初選注射機:XS-ZY-60;
初定型腔數(shù):一模四腔;
注射機XS-ZY-60的主要技術(shù)參數(shù):
螺桿直徑
38mm
額定注射量
60㎝
注射壓力
122Mpa
鎖模力
500KN
最大注射面積
130㎝
最大開合模行程
180mm
拉桿空間
280mm×250mm
最大模具厚度
200mm
最小模具厚度
70mm
噴嘴球頭半徑
噴嘴孔直徑
12㎜
結(jié)論: 可用注射成型
三. 注射模結(jié)構(gòu)設(shè)計
1 、分型面的選擇
分型面的選擇應(yīng)遵循以下原則: ①、分型面應(yīng)便于塑件的脫模; ②、分型面選擇應(yīng)有利于側(cè)面分型和抽芯; ③、分型面選擇應(yīng)保證塑件的外觀質(zhì)量; ④、分型面選擇應(yīng)有利于防止溢料; ⑤、分型面選擇應(yīng)有利于排氣; ⑥、分型面選擇應(yīng)盡量使成型零件便于加工; ⑦、分型面選擇必須考慮注射機的技術(shù)參數(shù); “一般,分型面選在塑件的最大截面處”
綜上所述,該塑件的分型面取在塑件的最大截面A—A 。
2、 澆注系統(tǒng)
對澆注系統(tǒng)的要求是:將熔體平穩(wěn)的引入型腔,使之按要求填充型腔;使型腔內(nèi)的氣體順利排出;在熔體填充型腔和凝固過程中,能充分地把壓力傳到型腔各部位,以獲得組織致密、外形清晰、尺寸穩(wěn)定的塑料制品。
﹙1﹚、主流道: 主流道橫截面形狀通常采用圓形。為了便于流道凝料的脫出,主流道設(shè)計成圓錐形,其錐度2°~6°,內(nèi)壁粗糙度小于0.4,小端直徑D一般取3-6㎜,且大于注射機噴嘴直徑d約0.5-1㎜;主流道的長度由定模座板和定模板厚度確定,一般L不超過60㎜,主流道大端與分流道相接處應(yīng)有過渡圓角﹙通常取1-3㎜﹚以減小料流轉(zhuǎn)向時的阻力。
由于主流道需要與高溫塑件和噴嘴頻繁接觸,所以要設(shè)置澆口套。查《模具設(shè)計與制造簡明手冊》,選澆口套Ⅰ型,小端直徑㎜,長度L為30㎜。澆口套直接裝配到定模座板上,方便且安裝簡單。如圖所示:
﹙2﹚、分流道:
分流道是介于主流道和澆口之間的一段流道。它是熔體由主流道流入型腔的過渡段通道,也是使?jié)沧⑾到y(tǒng)的截面變化和熔體流動轉(zhuǎn)向的過渡通道。
分流道截面形狀和尺寸:ⅰ、分流道截面為梯形截面,其加工容易,且熱量散失和流動阻力也不大; 所以,選梯形截面。
查《塑料模塑成型技術(shù)》表5-5“常用分流道橫截面及其尺寸”,如圖: 圓角半徑R=1.5㎜ 分流道長度L=50㎜
高度h=3.5㎜ 梯形長邊長度X=5㎜
﹙3﹚、澆口:
①、 澆口的基本作用:使從分流道來的熔體產(chǎn)生加速,以快速充滿型腔 ;防止熔料倒流;便于澆口凝料與制品分離。
②、 澆口選用:
點澆口:其優(yōu)點是去除澆口后 ,制品上留下的 痕跡不明顯,但壓力損失較大,制品收縮大,而且模具應(yīng)設(shè)計成雙分型面模具,以便脫出流道凝料,造成模具結(jié)構(gòu)復(fù)雜。圖為點澆口:
該制品選用點澆口。塑件表面質(zhì)量有較高要求,去除澆口后 ,制品上留下的 痕跡不明顯。但是,模具應(yīng)設(shè)計成雙分型面模具,以便脫出流道凝料,造成模具結(jié)構(gòu)較復(fù)雜。
圖為點澆口尺寸:
﹙4﹚、冷料穴與拉料桿:
梯形拉料桿為標準件,易于選取,且使用效果較好。其頭部有一定空間。能貯存凝料,充當(dāng)冷料穴。如圖:
3、 型腔設(shè)計:
﹙1﹚、型腔設(shè)計:型腔是成型塑料制品外形的主要零件??煞譃檎w式和組合式兩類。
組合式凹模改善了加工性,減少了熱處理變形,有利于排氣,便于模具的維修,節(jié)約了模具鋼,但裝配調(diào)整較麻煩,主要用于形狀復(fù)雜的塑料制品的成型。
該制品外型有圓周內(nèi)凹槽,且要求成型后表面光滑;所以必須使用兩側(cè)的側(cè)滑塊分型機構(gòu),型腔需要做成兩側(cè)滑塊,采用組合式。
4、側(cè)向分型:
因為塑件有圓周內(nèi)凹槽,所以必須使用兩側(cè)的側(cè)滑塊分型機構(gòu),且塑件倒裝需要使用延時側(cè)抽。使用斜導(dǎo)板起開合模的導(dǎo)向作用。使用楔緊塊,在合模時對模具起鎖緊的作用。
5、推件方式:
推出機構(gòu)的設(shè)計要求:ⅰ、盡量使塑料制品留在動模上
ⅱ、保證制品不變形不損壞
ⅲ、保證制品外觀良好 ⅳ、結(jié)構(gòu)可靠
該塑件要求“表面光亮且無劃傷痕跡”,且該零件底面上有一個的圓形淺凹槽,可以直接使用推桿成型。綜合以上結(jié)論,選推桿推出。
復(fù)位零件:
采用復(fù)位桿復(fù)位,使已完成推出制品任務(wù)的推桿回到注射成型狀態(tài)的位置。
6、冷卻與加熱系統(tǒng):由于ABS塑料成型時要求模溫在50-80℃,生產(chǎn)批量為100萬件,但體積很小,故模具可不考慮設(shè)置加熱冷卻系統(tǒng)。
7、標準模架的選用:該塑件最大尺寸為20㎜,采用點澆口,其生產(chǎn)批量為100萬件,采用一模四腔,則其模具對稱,便于布置,型采腔用鑲拼式,尺寸不大,但為滿足模板的強度、剛度以及型腔布局的需要,選150㎜×200㎜的標準模架,其閉合厚度為195㎜,該模具的最大尺寸為200㎜×200㎜;注射機XS-ZY-60的拉桿空間為280㎜×250㎜,最大模具厚度200mm,所選模架能放進去。所以可使用初選的注射機XS-ZY-60,其能滿足生產(chǎn)要求。
四、 成型零件尺寸計算
1、 型芯、型腔計算: 該塑件材料為ABS,查的該塑料的收縮率為0.4﹪~0.7﹪,取0.55﹪。模具制造公差取
1、 ①、型腔徑向尺寸:由前面可知塑件尺寸及公差。按下式計算:
=(+×%-)
= 、、 、 ;
則=﹙6+6×0.55%-×0.24﹚=5.85
=4.34 =14.79
=16.65 =19.68
②、型腔深度尺寸:=﹙+%-﹚
=、、
則 =﹙12+12×0.55%-×0.34﹚=11.83
=1.87 =10.83
⑵、①、型芯徑向尺寸:按下式計算:
=﹙+%+﹚
= 、
則 =﹙8+8×0.55%+×0.24﹚=8.22
=﹙2.5+2.5×0.55%+×0.2﹚=2.67
五、注射機有關(guān)參數(shù)的校核:
1、 注射量的校核:由前面知,塑件和澆注系統(tǒng)質(zhì)量都為35g,則每次注射所需注射量為:4×5.59g=25g
注射機的最大注射量以最大注射容積標定時,按下式校核:
≥V= (5-1)
式中-注射機最大注射容積﹙﹚ -一個制品的體積﹙﹚
V-制品總體積(包括制品、流道凝料在內(nèi))﹙﹚ n-型腔數(shù)
-流道凝料體積﹙﹚ K-注射機最大注射量的利用系數(shù),取K=0.8
由前面計算知,塑件與澆注系統(tǒng)凝料的體積相等,則每次注射所需塑料體積為: V= V +V=4*5.33 cm+2050mm=23.37﹙﹚
注射機最大注射量60×0.8=48>23.37 故能滿足要求。
2、 鎖模力與注射壓力的校核:
①、 注射壓力校核:
即≥P (5-6)
式中 -注射機的最大注射壓力(MPa)
P-塑料制品成型所需的注射壓力(MPa)
由于所選注射機為XS-ZY-60,其注射壓力為122 MPa,即為122MPa。查《塑料模塑成型技術(shù)》附表4“常用熱塑性塑料注射成型的工藝參數(shù)”,P為60~100 MPa,滿足上式要求。
②、 鎖模力的校核:
需滿足 ≥F= (5-7)
式中-注射機的最大鎖模力 -模內(nèi)平均壓力,見表5-2
-制品、流道、澆口在分型面上的投影面積之和
由前可知,注射機XS-ZY-60的最大鎖模力為500KN,為34.4 MPa,經(jīng)計算得為865.4
=++=+100×5 +
=865.4
=34.3×865.4=30KN<50KN 滿足上式要求。
3、 模具厚度的校核:
≤H≤ (5-11)
式中H-模具閉合厚度(=193㎜) -注射機允許模具最小厚度(=70㎜) -注射機允許模具最大厚度(=200㎜)
滿足上式要求。
4、注射機噴嘴與模具主流道襯套關(guān)系:
R=r+(1~2)㎜ D=d+(0.5~1)㎜
式中d-注射機噴嘴前端孔徑(=4㎜) D-模具主流道襯套的小端直徑(=5㎜) r-注射機噴嘴球面半徑(=12㎜)
R-模具主流道襯套的球面半徑(=13㎜)
滿足上式要求。
5、 開模行程的校核:
由于注射機XS-ZY-1000最大開模行程與模具厚度無關(guān),所以按下式校核:
S≥++﹙5~10﹚㎜ ﹙5-12﹚
式中S-注射機最大開模行程(移動模板行程)(=180㎜)
-制品的推出距離(=15㎜) -制品的總高度(=31㎜)
滿足上式要求。
6、 流程比的校核:
熔體流程長度與厚度之比即為流程比。可按下式計算:
流程比= (5-18)
所以=(+++++++)×2=70,而ABS的流程比介于聚乙烯和聚丙烯之間,取210~235。所求值小于ABS的流程比,滿足要求。
7、 型腔側(cè)壁和底板厚度的校核:
1、 型腔側(cè)壁計算:由于其型腔為組合式型腔,型腔側(cè)壁厚度為;
t=r×(-1) (4-27)
式中 -型腔長邊長度(=200MPa)
P-型腔內(nèi)熔體壓力(=34.3MPa)
代入上式得t=3.5㎜:故該模具型腔壁厚可取>3.5㎜。
﹙2﹚、底板厚度計算:該模具采用兩墊塊支撐,按剛度計算的底板厚度如下:
h= ﹙4-46﹚
L-支架間距﹙=94㎜﹚ -底板總長﹙=200㎜﹚
-底板上承受成型壓力部分的長度﹙=115㎜﹚
E-型腔材料彈性模量(=2.1× MPa)
-型腔彈性變形增長值,見表4-6﹙=0.05㎜﹚
P-型腔內(nèi)熔體壓力(=34.3MPa)
代入上式得h=28.5㎜.
L計算出的底板厚度h為 28.5mm,在結(jié)構(gòu)許可情況下,為使底板強度滿足可以增加一點底板厚度。所以,將底板厚度h定為32mm。
五、 模具裝配圖:
該模具結(jié)構(gòu)較復(fù)雜,且采用一模四腔,屬于多分型面模具。
其主要地方在于側(cè)滑塊和型腔的加工,須嚴格保證其加工,以滿足生產(chǎn)需要。
模具整體尺寸較小,但局部采用鑲拼式結(jié)構(gòu),裝配時需保證
其安裝精度,以保證制品質(zhì)量。其各個零件圖詳見塑模裝配圖。
模具開模動作說明:
開模時,由于拉鉤27拉著滑塊30,以至使模具首先由定模座板3和鑲塊固定板4分開,使?jié)部谀夏苋〕觥H缓?,?dāng)動模開行到壓塊29將滑塊30打入使拉鉤與滑塊脫離,且壓板29又將滑板30拉住,使鑲塊固定板4固定在那不再向下運動;然后模具繼續(xù)分型,由側(cè)導(dǎo)板2導(dǎo)向(延時側(cè)抽),先是將塑件從上型腔中抽出,再進行側(cè)向分型;側(cè)向分型完成以后,最后由成型推桿將塑件推出。
六、 主要模具零件加工工藝:
1、型腔鑲件的加工工藝過程:
材料:CrWMn 熱處理:淬火,回火 HRC54~58
工序號
工序名稱
工序內(nèi)容
設(shè)備
1
備料
按尺寸35㎜×25㎜的圓棒料切斷
鋸床
2
車端面
車端面保證長度22.5㎜,鉆中心孔;
調(diào)頭車端面保證長度20.3㎜,鉆中心孔,留磨余量0.3㎜。
臥式車床
3
車外圓
車長度為17的外圓至22.2㎜,且保證其臺肩高度尺寸為3.1㎜;
臥式車床
4
銑
銑高度為3mm,外型尺寸為28mm×22mm,到尺寸
加工中心
5
平磨
磨臺肩尺寸保證3㎜;
調(diào)頭磨保證長度尺寸為20㎜,留0.05㎜研磨量;
磨22㎜的圓至尺寸。
平面磨床
6
鉗工
鉆錐形孔5.6mm錐度36深7mm;
和鉆1mm深1mm的孔,至尺寸。
7
熱處理
按熱處理工藝進行,淬火、回火,硬度HRC54~58
8
電火花
加工深度為11.83的孔,至公差要求。
電火花成型機
9
研磨
研磨所有孔內(nèi)面至尺寸
10
檢驗
2、測滑板的加工工藝過程:
材料:Cr12 熱處理:淬火 54~58HRC
工序號
工序名稱
工序內(nèi)容
設(shè)備
1
備料
鍛造毛坯130mm×80mm×25mm
2
銑床
銑上下平面保證高度尺寸23.4mm
銑床
3
鉗工劃線
劃出工件外形尺寸,和方形斜楔通孔位置,以及四個型腔和拉料桿孔位置;
4
銑
銑出工件的外形輪廓尺寸,方形斜楔孔;
銑出工件底面的燕尾形的高5mm的臺階的大致尺寸50mm×59mm;
到尺寸,并保留0.1的磨削余量;
加工中心
5
銑
四個型腔,拉料桿孔;
至尺寸,型腔粗處尺寸保留0.05的研磨余量;
加工中心
6
線切割
切割出燕尾形臺階,至尺寸;
線切割機
7
鉗工
鉆出燕尾形臺階底面處的6mm深3mm沉孔;
及板兩凸出部位側(cè)面的8mm的兩通孔;
鉆床
8
熱處理
按熱處理工藝進行,淬火、回火,硬度HRC 54~58;
9
平磨
磨板的各平面,至尺寸;及磨兩8mm的兩通孔
平面磨床
10
研磨
研磨所有型腔及孔至尺寸
11
檢驗
七、 參考文獻:
機械工業(yè)出版社:《塑料模塑成型技術(shù)》-翁其金 主編
《中國模具工程大典》
《實用模具技術(shù)手冊》
《模具設(shè)計與制造簡明手冊》
塑件成型工藝卡
塑 件 名 稱
電視機旋鈕
塑件草圖
材 料 牌 號
ABS
單 件 重 量
5.39g
成型設(shè)備型號
XS-ZY-60
每 模 件 數(shù)
4件
成型工藝參數(shù)
材料干燥
干燥設(shè)備名稱
溫度 /℃
85℃
時間 /h
3h
成型過程
料筒溫度
后段 /℃
150℃~170℃
中段 /℃
165℃~180℃
前段 /℃
180℃~210℃
噴嘴 /℃
175℃~190℃
模具溫度 /℃
60℃至75℃
時間
注射 /s
10~25s
保壓 /s
0~5s
冷卻 /s
15~50s
壓力
注射 /MPa
60~100MPa
保壓 /MPa
后 處 理
溫度 /℃
__70℃__
時間 /min
___2~4h__
編 制
日 期
審 核
日 期
_ Corresponding author: Alban Agazzi, Universit de Nantes-Laboratoire de thermocintique de Nantes, La Chantrerie, rue Christian Pauc, BP 50609, 44306 Nantes cedex 3-France, phone : +332 40 68 31 71, fax :+332 40 68 31 41 email : alban.agazziuniv-nantes.fr A METHODOLOGY FOR THE DESIGN OF EFFECTIVE COOLING SYSTEM IN INJECTION MOULDING A.Agazzi 1* , V.Sobotka 1 , R. Le Goff 2 , D.Garcia 2, Y.Jarny 1 1 Universit de Nantes, Nantes Atlantique Universits, Laboratoire de Thermocintique de Nantes, UMR CNRS 6607, rue Christian Pauc, BP 50609, F-44306 NANTES cedex 3, France 2 Ple Europen de Plasturgie, 2 rue Pierre et Marie Curie, F- 01100 BELLIGNAT, France ABSTRACT: In thermoplastic injection moulding, part quality and cycle time depend strongly on the cooling stage. Numerous strategies have been investigated in order to determine the cooling conditions which minimize undesired defects such as warpage and differential shrinkage. In this paper we propose a methodology for the optimal design of the cooling system. Based on geometrical analysis, the cooling line is defined by using conformal cooling concept. It defines the locations of the cooling channels. We only focus on the distribution and intensity of the fluid temperature along the cooling line which is here fixed. We formulate the determination of this temperature distribution, as the minimization of an objective function composed of two terms. It is shown how this two antagonist terms have to be weighted to make the best compromise. The expected result is an improvement of the part quality in terms of shrinkage and warpage. KEYWORDS: Inverse problem, heat transfer, injection moulding, cooling design 1 INTRODUCTION In the field of plastic industry, thermoplastic injection moulding is widely used. The process is composed of four essential stages: mould cavity filling, melt packing, solidification of the part and ejection. Around seventy per cent of the total time of the process is dedicated to the cooling of the part. Moreover this phase impacts directly on the quality of the part 12. As a consequence, the part must be cooled as uniformly as possible so that undesired defects such as sink marks, warpage, shrinkage, thermal residual stresses are minimized. The most influent parameters to achieve these objectives are the cooling time, the number, the location and the size of the channels, the temperature of the coolant fluid and the heat transfer coefficient between the fluid and the inner surface of the channels. The cooling system design was primarily based on the experience of the designer but the development of new rapid prototyping process makes possible to manufacture very complex channel shapes what makes this empirical former method inadequate. So the design of the cooling system must be formulated as an optimization problem. 1.1 HEAT TRANSFER ANALYSIS The study of heat transfer conduction in injection tools is a non linear problem due to the dependence of parameters to the temperature. However thermophysical parameters of the mould such as thermal conductivity and heat capacity remain constant in the considered temperature range. In addition the effect of polymer crystallisation is often neglected and thermal contact resistance between the mould and the part is considered more often as constant. The evolution of the temperature field is obtained by solving the Fouriers equation with periodic boundary conditions. This evolution can be split in two parts: a cyclic part and an average transitory part. The cyclic part is often ignored because the depth of thermal penetration does not affect significantly the temperature field 3. Many authors used an average cyclic analysis which simplifies the calculus, but the fluctuations around the average can be comprised between 15% and 40% 3. The closer of the part the channels are, the higher the fluctuations around the average are. Hence in that configuration it becomes very important to model the transient heat transfer even in stationary periodic state. In this study, the periodic transient analysis of temperature will be preferred to the average cycle time analysis. It should be noticed that in practice the design of the cooling system is the last step for the tool design. Nevertheless cooling being of primary importance for the quality of the part, the thermal design should be one of the first stages of the design of the tools. DOI10.1007/s12289-010-0695-2 Springer-VerlagFrance2010 Int J Mater Form (2010) Vol. 3 Suppl 1: 16 13 1.2 OPTIMIZATION TECHNIQUES IN MOULDING In the literature, various optimization procedures have been used but all focused on the same objectives. Tang et al. 4 used an optimization process to obtain a uniform temperature distribution in the part which gives the smallest gradient and the minimal cooling time. Huang 5 tried to obtain uniform temperature distribution in the part and high production efficiency i.e a minimal cooling time. Lin 6 summarized the objectives of the mould designer in 3 facts. Cool the part the most uniformly, achieve a desired mould temperature so that the next part can be injected and minimize the cycle time. The optimal cooling system configuration is a compromise between uniformity and cycle time. Indeed the longer the distance between the mould surface cavity and the cooling channels is, the higher the uniformity of the temperature distribution will be 6. Inversely, the shorter the distance is, the faster the heat is removed from the polymer. However non uniform temperatures at the mould surface can lead to defects in the part. The control parameters to get these objectives are then the location and the size of the channels, the coolant fluid flow rate and the fluid temperature. Two kinds of methodology are employed. The first one consists in finding the optimal location of the channels in order to minimize an objective function 47. The second approach is based on a conformal cooling line. Lin 6 defines a cooling line representing the envelop of the part where the cooling channels are located. Optimal conditions (location on the cooling and size of the channels) are searched on this cooling line. Xu et al. 8 go further and cut the part in cooling cells and perform the optimization on each cooling cell. 1.3 COMPUTATIONAL ALGORITHMS To compute the solution, numerical methods are needed. The heat transfer analysis is performed either by boundary elements 7 or finite elements method 4. The main advantage of the first one is that the number of unknowns to be computed is lower than with finite elements. Only the boundaries of the problem are meshed hence the time spent to compute the solution is shorter than with finite elements. However this method only provides results on the boundaries of the problem. In this study a finite element method is preferred because temperatures history inside the part is needed to formulate the optimal problem. To compute optimal parameters which minimize the objective function Tang et al. 4 use the Powells conjugate direction search method. Mathey et al. 7 use the Sequential Quadratic Programming which is a method based on gradients. It can be found not only deterministic methods but also evolutionary methods. Huang et al. 5 use a genetic algorithm to reach the solution. This last kind of algorithm is very time consuming because it tries a lot of range of solution. In practice time spent for mould design must be minimized hence a deterministic method (conjugate gradient) which reaches an acceptable local solution more rapidly is preferred. 2 METHODOLOGY 2.1 GOALS The methodology described in this paper is applied to optimize the cooling system design of a T-shaped part (Figure 1). This shape is encountered in many papers so comparison can easily be done in particularly with Tang et al. 4. Figure 1 : Half T-shaped geometry Based on a morphological analysis of the part, two surfaces 1 and 3 are introduced respectively as the erosion and the dilation (cooling line) of the part (Figure 1). The boundary condition of the heat conduction problem along the cooling line 3 is a third kind condition with infinite temperatures fixed as fluid temperatures. The optimization consists in finding these fluid temperatures. Using a cooling line prevents to choose the number and size of cooling channels before optimization is carried out. This represents an important advantage in case of complex parts where the location of channels is not intuitive. The location of the erosion line in the part corresponds to the minimum solidified thickness of polymer at the end of cooling stage so that ejectors can remove the part from the mould without damages. 2.2 OBJECTIVE FUNCTION In cooling system optimization, the part quality should be of primarily importance. Because the minimum cooling time of the process is imposed by the thickness and the material properties of the part, it is important to reach the optimal quality in the given time. The fluid temperature impacts directly the temperature of the mould and the part, and for turbulent fluid flow the only control parameter is the cooling fluid temperature. In the following, the parameter to be optimized is the fluid temperature and the determination of the optimal distribution around the part is formulated as the minimization of an objective function S composed of two terms computed at the end of the cooling period (Equation (1). The goal of the first term S 1 is to reach a temperature level along the erosion of the part. The second term S 2 used in many works 47 aims to homogenize the temperature distribution at the surface of the part and therefore to reduce the components of 14 thermal gradient both along the surface 2 and through the thickness of the part. These two terms are weighted by introducing the variable ref T . It must be noted that when ref T the criterion is reduced to the first term. On the contrary the weight of the second term is increased when 0 ref T . () + = 2 2 2 1 1 2 . d T TT d TT TT TS rfejecinj ejec fluid (1) ejec T : Ejection temperature, inj T : Injection temperature, ref T : Reference temperature, inf T : Fluid temperature, T : Temperature field computed with the periodic conditions () ),0(,0 XtTXT f += 21 X , and f t,0 is the cooling period, = dTT 2 2 . 1 : Average surface temperature of the part at the ejection time f t . 3 NUMERICAL RESULTS Numerical results are compared with those of Tang et al 4 who consider the optimal cooling of the T-shaped part by determining the optimal location of 7 cooling channels and the optimal fluid flow rate of the coolant. The first step was to reproduce their results (left part of Figure 2) obtained with the following conditions (case w=0.75 in 4): KT fluid 303= , fluid flow rate scmQ /364 3 = in each cooling channels, s 5.23= f t . Figure 2: Geometry Tang (left) and cooling line (right) Case 1: Cooling line versus finite number of channels for a constant fluid temperature ( fluid T ). The average distance ( cmd 5.1= ) between the 7 channels and the part surface in the cooling system determined by Tang is adopted in our system for locating the cooling line 3 . Moreover, the fluid temperature and the heat transfer coefficient values issued from Tang are imposed on the dilation of the part 3 . In Figure 3 the temperature profiles along the part surface 2 are compared at the ejection time f t . All the temperature profiles along the surfaces 3,2,1 = i i are plotted counter-clockwise only on the half part from i A to i B (Figure 1) and at the ejection time. We observe that the magnitude of the temperature is less uniform with the cooling line than with the 7 channels (15K instead of 5K). Hence the optimal cooling configuration computed with a finite number of channels is better than this with the cooling line and it will be then considered as a reference. Figure 3: Temperature profiles along the part surface 2 Case 2: Cooling line with a variable fluid temperature ( )(sT fluid ) and the weighting factor ref T . The fluid temperatures )(sT fluid are computed by minimizing the objective function of Equation 1 where the second term is ignored. The results are plotted in Figures 4 and 5. Figure 4: Temperature profiles along the erosion Figure 5: Temperature profiles along the part surface In Figure 4 the temperature profile on the erosion is much uniform and close to the ejection temperature with our method ( -5 1 1.79.10S = ) than with Tangs method ( -5 1 2.32.10=S ). However in both cases a peak remains between 0.12m and 0.14m which corresponds to the top of the rib (B 1 in Figure 1). This hotspot is due to the geometry of the part and is very difficult to cool. Nevertheless in Figure 5 we notice that the profile of temperature at the part surface is less uniform than in 15 case 1 (20K instead of 15K). In conclusion, the first term is not sufficient to improve the homogeneity at the part surface but it is adequate for achieving a desired level of temperature in the part. Case 3: Cooling line with ( )(sT fluid ) and the weighting factors KT ref 10= and KT ref 100= . The fluid temperatures )(sT fluid are now computed by minimizing the objective function of Equation 1 with KT ref 10= and KT ref 100= . Results are plotted in Figures 6 and 7. Figure 6: Temperature profiles along the part surface Figure 7: Temperature profiles along the erosion The influence of the term S 2 is shown in Figure 6. This term makes the surface temperature of the part uniform. Indeed in case KT ref 10= temperature is quasi-constant all over the surface 2 except for the hotspot as explained previously. However for this value of ref T , the temperature on the erosion is not acceptable, the mean temperature being too high (340K for a desired level of 336 K). Then the second term improves the homogeneity at the interface but hedges the solution. Making uniform the temperature at the interface meanwhile extracting the total heat flux needed to obtain a desired level of temperature in the part, become antagonistic problems if this level is too low. The best solution will be a compromise between quality and efficiency. For example, by setting KT ref 100= the level of temperature ( ejec T ) in the part is reached whereas the solution becomes less uniform than with the value of KT ref 10= . Nonetheless this solution remains more uniform than the solution given by Tang. The optimal fluid temperature profile along the dilation of the half part is plotted (Figure 8). Figure 8: Optimal fluid temperature profile 4 CONCLUSIONS In this paper, an optimization method was developed to determine the temperature distribution on a cooling line to obtain a uniform temperature field in the part which leads to the smallest gradient and the minimal cooling time. The methodology was compared with those found in the literature and showed its efficiency and benefits. Notably it does not require specifying a priori the number of cooling channels. Further work will consist in deciding a posteriori the minimal number of channels needed to match the solution given by the optimal fluid temperature profile REFERENCES 1 Pichon J. F. Injection des matires plastiques. Dunod, 2001. 2 Plastic Business Group Bayer. Optimised mould temperature control. ATI 1104, 1997. 3 S. Y. Hu, N. T. Cheng, S. C. Chen. Effect of cooling system design and process parameters on cyclic variation of mold temperatures simulation by DRBEM, Plastics, rubber and composites proc. and appl., 23:221-232, 1995 4 L. Q Tang, K. Pochiraju, C. Chassapis, S. Manoochehri. A computer-aided optimization approach fort he design of injection mold cooling systems. J. of Mech. Design, 120:165-174, 1998. 5 J. Huang, G. M. Fadel. Bi-objective optimization design of heterogeneous injection mold cooling systems. ASME, 123:226-239, 2001. 6 J. C. Lin. Optimum cooling system design of a free- form injection mold using an abductive network. J. of Mat. Proc. Tech., 120:226-236, 2002. 7 E. Mathey, L. Penazzi, F.M. Schmidt, F. Rond- Oustau. Automatic optimization of the cooling of injection mold base don the boundary element method. Materials Proc. and Design, NUMIFORM, pages 222-227, 2004. 8 X. Xu, E. Sachs, S. Allen. The design of conformal cooling channels in injection molding tooling. 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