帽蓋注射模具設(shè)計(jì)【一模兩腔】【說(shuō)明書+CAD+三維】,一模兩腔,說(shuō)明書+CAD+三維,帽蓋注射模具設(shè)計(jì)【一模兩腔】【說(shuō)明書+CAD+三維】,注射,模具設(shè)計(jì),說(shuō)明書,CAD,三維 目錄 第一章 模具設(shè)計(jì)總述 2 1.1 模具工業(yè)在國(guó)民經(jīng)濟(jì)中的地位 2 1.2 我國(guó)模具技術(shù)的現(xiàn)狀及發(fā)展趨勢(shì) 3 第二章 各類塑料模具及其特點(diǎn) 7 2.1各種模具的分類和占有量 7 2.2各類塑料模具結(jié)構(gòu) 8 第三章 塑件分析 17 3.1 塑件的二維圖紙 17 3.2 塑件原料分析 17 3.2.1 原料的物理化學(xué)特性 17 3.2.2 原料的成型性能 18 3.3 塑件分析 18 3.3.1 制品結(jié)構(gòu)分析 18 3.3.2 尺寸精度分析 19 第四章 注射機(jī)的選用 20 第五章 模具結(jié)構(gòu)的設(shè)計(jì) 21 5.1 型腔數(shù)目的設(shè)計(jì) 21 5.2 選擇分型面 21 5.3 型腔布置的設(shè)計(jì) 21 5.4 澆注系統(tǒng)的設(shè)計(jì) 22 5.4.1主流道設(shè)計(jì) 22 5.4.2分流道設(shè)計(jì) 22 5.4.3澆口的設(shè)計(jì) 22 5.4.4冷料穴設(shè)計(jì) 23 5.4.5成型零件工作尺寸的計(jì)算 23 5.5冷卻裝置的設(shè)計(jì) 23 第六章 模具設(shè)計(jì)計(jì)算與驗(yàn)算 25 6.1注射量的校核 25 6.2鎖模力的校核 25 6.3安裝尺寸的校核 25 6.4 開模行程的校核 26 第七章 模具的工作原理、安裝、試模和生產(chǎn) 27 7.1 模具設(shè)計(jì)工作原理; 27 參考文獻(xiàn) 28 總結(jié) 30 致謝 31 第一章 模具設(shè)計(jì)總述 1.1 模具工業(yè)在國(guó)民經(jīng)濟(jì)中的地位 模具工業(yè)是國(guó)民經(jīng)濟(jì)的基礎(chǔ)工業(yè)，是國(guó)際上公認(rèn)的關(guān)鍵工業(yè)。模具生產(chǎn)技術(shù)水平的高低是衡量一個(gè)國(guó)家產(chǎn)品制造水平高低的重要標(biāo)志，它在很大程度上決定著產(chǎn)品的質(zhì)量，效益和新產(chǎn)品的開發(fā)能力。振興和發(fā)展我國(guó)的模具工業(yè)，正日益受到人們的關(guān)注。早在1989年3月中國(guó)政府頒布的《關(guān)于當(dāng)前產(chǎn)業(yè)政策要點(diǎn)的決定》中，將模具列為機(jī)械工業(yè)技術(shù)改造序列的第一位。 模具工業(yè)既是高新技術(shù)產(chǎn)業(yè)的一個(gè)組成部分，又是高新技術(shù)產(chǎn)業(yè)化的重要領(lǐng)域。模具在機(jī)械，電子，輕工，汽車，紡織，航空，航天等工業(yè)領(lǐng)域里，日益成為使用最廣泛的主要工藝裝備，它承擔(dān)了這些工業(yè)領(lǐng)域中60％~90％的產(chǎn)品的零件，組件和部件的生產(chǎn)加工。 模具制造的重要性主要體現(xiàn)在市場(chǎng)的需求上，僅以汽車，摩托車行業(yè)的模具市場(chǎng)為例。汽車，摩托車行業(yè)是模具最大的市場(chǎng)，在工業(yè)發(fā)達(dá)的國(guó)家，這一市場(chǎng)占整個(gè)模具市場(chǎng)一半左右。汽車工業(yè)是我國(guó)國(guó)民經(jīng)濟(jì)五大支柱產(chǎn)業(yè)之一，汽車工業(yè)重點(diǎn)是發(fā)展零部件，經(jīng)濟(jì)型轎車和重型汽車，汽車模具作為發(fā)展重點(diǎn)，已在汽車工業(yè)產(chǎn)業(yè)政策中得到了明確。汽車基本車型不斷增加，2005年將達(dá)到170種。一個(gè)型號(hào)的汽車所需模具達(dá)幾千副，價(jià)值上億元。為了適應(yīng)市場(chǎng)的需求，汽車將不斷換型，汽車換型時(shí)約有80％的模具需要更換。中國(guó)摩托車產(chǎn)量位居世界第一，據(jù)統(tǒng)計(jì)，中國(guó)摩托車共有14種排量80多個(gè)車型，1000多個(gè)型號(hào)。單輛摩托車約有零件2000種，共計(jì)5000多個(gè)，其中一半以上需要模具生產(chǎn)。一個(gè)型號(hào)的摩托車生產(chǎn)需1000副模具，總價(jià)值為1000多萬(wàn)元。其他行業(yè)，如電子及通訊，家電，建筑等，也存在巨大的模具市場(chǎng)。 1.2 我國(guó)模具技術(shù)的現(xiàn)狀及發(fā)展趨勢(shì) 80年代以來(lái)，在國(guó)家產(chǎn)業(yè)政策和與之配套的一系列國(guó)家經(jīng)濟(jì)政策的支持和引導(dǎo)下，我國(guó)模具工業(yè)發(fā)展迅速，年均增速均為13%，1999年我國(guó)模具工業(yè)產(chǎn)值為245億，至2000年我國(guó)模具總產(chǎn)值預(yù)計(jì)為260-270億元，其中塑料模約占30%左右。在未來(lái)的模具市場(chǎng)中，塑料模在模具總量中的比例還將逐步提高。 我國(guó)塑料模工業(yè)從起步到現(xiàn)在，歷經(jīng)半個(gè)多世紀(jì)，有了很大發(fā)展，模具水平有了較大提高。在大型模具方面已能生產(chǎn)48英寸大屏幕彩電塑殼注射模具、6.5kg大容量洗衣機(jī)全套塑料模具以及汽車保險(xiǎn)杠和整體儀表板等塑料模具；精密塑料模具方面，已能生產(chǎn)照相機(jī)塑料件模具、多型腔小模數(shù)齒輪模具及塑封模具。如天津津榮天和機(jī)電有限公司和煙臺(tái)北極星I.K模具有限公司制造的多腔VCD和DVD齒輪模具，所生產(chǎn)的這類齒輪塑件的尺寸精度、同軸度、跳動(dòng)等要求都達(dá)到了國(guó)外同類產(chǎn)品的水平，而且還采用最新的齒輪設(shè)計(jì)軟件，糾正了由于成型收縮造成的齒形誤差，達(dá)到了標(biāo)準(zhǔn)漸開線齒形要求。還能生產(chǎn)厚度僅為0.08mm的一模兩腔的航空杯模具和難度較高的塑料門窗擠出模等等。注塑模型腔制造精度可達(dá)0.02～0.05mm，表面粗糙度Ra0.2μm，模具質(zhì)量、壽命明顯提高了，非淬火鋼模壽命可達(dá)10～30萬(wàn)次，淬火鋼模達(dá)50～1000萬(wàn)次，交貨期較以前縮短，但和國(guó)外相比仍有較大差距。 但是近年許多模具企業(yè)加大了用于技術(shù)進(jìn)步的投資力度，將技術(shù)進(jìn)步視為企業(yè)發(fā)展的重要?jiǎng)恿ΑＲ恍﹪?guó)內(nèi)模具企業(yè)已普及了二維CAD，并陸續(xù)開始使用UG、Pro/Engineer、I-DEAS、Euclid-IS等國(guó)際通用軟件，個(gè)別廠家還引進(jìn)了Moldflow、C-Flow、DYNAFORM、Optris和MAGMASOFT等CAE軟件，并成功應(yīng)用于沖壓模的設(shè)計(jì)中。 ?在制造技術(shù)方面，CAD/CAM/CAE技術(shù)的應(yīng)用水平上了一個(gè)新臺(tái)階，以生產(chǎn)家用電器的企業(yè)為代表，陸續(xù)引進(jìn)了相當(dāng)數(shù)量的CAD/CAM系統(tǒng)，如美國(guó)EDS的UGⅡ、美國(guó)Parametric Technology公司的Pro/Emgineer、美國(guó)CV公司的CADS5、英國(guó)Deltacam公司的DOCT5、日本HZS公司的CRADE、以色列公司的Cimatron、美國(guó)AC-Tech公司的C-Mold及澳大利亞Moldflow公司的MPA塑模分析軟件等等。這些系統(tǒng)和軟件的引進(jìn)，雖花費(fèi)了大量資金，但在我國(guó)模具行業(yè)中，實(shí)現(xiàn)了CAD/CAM的集成，并能支持CAE技術(shù)對(duì)成型過(guò)程，如充模和冷卻等進(jìn)行計(jì)算機(jī)模擬，取得了一定的技術(shù)經(jīng)濟(jì)效益，促進(jìn)和推動(dòng)了我國(guó)模具CAD/CAM技術(shù)的發(fā)展。近年來(lái)，我國(guó)自主開發(fā)的塑料模CAD/CAM系統(tǒng)有了很大發(fā)展，主要有北航華正軟件工程研究所開發(fā)的CAXA系統(tǒng)、華中理工大學(xué)開發(fā)的注塑模HSC5.0系統(tǒng)及CAE軟件等，這些軟件具有適應(yīng)國(guó)內(nèi)模具的具體情況、能在微機(jī)上應(yīng)用且價(jià)格較低等特點(diǎn)，為進(jìn)一步普及模具CAD/CAM技術(shù)創(chuàng)造了良好條件。 據(jù)有關(guān)方面預(yù)測(cè)，模具市場(chǎng)的總體趨熱是平穩(wěn)向上的，在未來(lái)的模具市場(chǎng)中，塑料模具的發(fā)展速度將高于其它模具，在模具行業(yè)中的比例將逐步提高。隨著塑料工業(yè)的不斷發(fā)展，對(duì)塑料模具提出越來(lái)越高的要求是正常的，因此，精密、大型、復(fù)雜、長(zhǎng)壽命塑料模具的發(fā)展將高于總量發(fā)展速度。同時(shí)，由于近年來(lái)進(jìn)口模具中，精密、大型、復(fù)雜、長(zhǎng)壽命模具占多數(shù)，所以，從減少進(jìn)口、提高國(guó)產(chǎn)化率角度出發(fā)，這類高檔模具在市場(chǎng)上的份額也將逐步增大。建筑業(yè)的快速發(fā)展，使各種異型材擠出模具、PVC塑料管材管接頭模具成為模具市場(chǎng)新的經(jīng)濟(jì)增長(zhǎng)點(diǎn)，高速公路的迅速發(fā)展，對(duì)汽車輪胎也提出了更高要求，因此子午線橡膠輪胎模具，特別是活絡(luò)模的發(fā)展速度也將高于總平均水平；以塑代木，以塑代金屬使塑料模具在汽車、摩托車工業(yè)中的需求量巨大；家用電器行業(yè)在“十五”期間將有較大發(fā)展，特別是電冰箱、空調(diào)器和微波爐等的零配件的塑料模需求很大；而電子及通訊產(chǎn)品方面，除了彩電等音像產(chǎn)品外，筆記本電腦和網(wǎng)機(jī)頂盒將有較大發(fā)展，這些都是塑料模具市場(chǎng)的增長(zhǎng)點(diǎn)。 加入世貿(mào)組織后，一些國(guó)家紛紛將制造業(yè)向我國(guó)轉(zhuǎn)移，模具工業(yè)正面臨空前的發(fā)展機(jī)遇。據(jù)上海模具工業(yè)協(xié)會(huì)透露，“九五”期間，國(guó)內(nèi)模具行業(yè)產(chǎn)值年增長(zhǎng)幅度約為13%，高檔模具比例提高，模具商業(yè)化程度提高近10%，模具行業(yè)的進(jìn)出口比例趨向合理，進(jìn)口量占市場(chǎng)總量的20%，金額近10億美元，出口額已達(dá)1億美元。? 目前，世界模具市場(chǎng)總體上供不應(yīng)求，市場(chǎng)量維持600億~650億美元。我國(guó)汽車、家電、通訊等領(lǐng)域的高性能模具鋼年需求約20萬(wàn)噸，其中相當(dāng)一部分依靠進(jìn)口。為盡快改變這種局面，去年底，上鋼五廠與上海大學(xué)聯(lián)合開發(fā)我國(guó)第一條精品模具鋼專業(yè)生產(chǎn)線，達(dá)到國(guó)際先進(jìn)水平，年產(chǎn)量可達(dá)3.8萬(wàn)噸，這個(gè)精品模具基地，將有力地促進(jìn)汽車模具的國(guó)產(chǎn)化。 據(jù)分析，未來(lái)我國(guó)模具的9大發(fā)展趨勢(shì)是：? 　　1、模具日趨大型化。? 　　2、模具的精度將越來(lái)越高。10年前精密模具的精度一般為5微米，現(xiàn)已達(dá)到2-3微米，1微米精度的模具也將上市。? 　　3、多功能復(fù)合模具將進(jìn)一步發(fā)展。新型多功能復(fù)合模具除了沖壓成型零件外，還擔(dān)負(fù)疊壓、攻絲、鉚接和鎖緊等組裝任務(wù)，對(duì)鋼材的性能要求越來(lái)越高。? 　　4、熱流道模具在塑料模具中的比重也將逐漸提高。? 　　5、隨著塑料成型工藝的不斷改進(jìn)與發(fā)展，氣輔模具及適應(yīng)高壓注塑成型等工藝的模具也將隨之發(fā)展。? 　　6、標(biāo)準(zhǔn)件的應(yīng)用將日益廣泛。模具標(biāo)準(zhǔn)化及模具標(biāo)準(zhǔn)件的應(yīng)用將極大地影響模具制造周期，還能提高模具的質(zhì)量和降低模具制造成本。? 　　7、快速經(jīng)濟(jì)模具的前景十分廣闊。? 　　8、隨著車輛和電機(jī)等產(chǎn)品向輕量化發(fā)展，壓鑄模的比例將不斷提高。同時(shí)對(duì)壓鑄模的壽命和復(fù)雜程度也將提出越來(lái)越高的要求。? 　　9、以塑代鋼、以塑代木的進(jìn)程進(jìn)一步加快，塑料模具的比例將不斷增大。由于機(jī)械零件的復(fù)雜程度和精度的不斷提高，對(duì)塑料模具的要求也越來(lái)越高。? 　 第二章 各類塑料模具及其特點(diǎn) 2.1各種模具的分類和占有量 模具主要類型有：沖模，鍛摸，塑料模，壓鑄模，粉末冶金模，玻璃模，橡膠模，陶瓷模等。除部分沖模以外的的上述各種模具都屬于腔型模，因?yàn)樗麄円话愣际且揽咳S的模具形腔是材料成型。 （1）沖模：沖模是對(duì)金屬板材進(jìn)行沖壓加工獲得合格產(chǎn)品的工具。沖模占模具總數(shù)的50％以上。按工藝性質(zhì)的不同，沖模可分為落料模，沖孔模，切口模，切邊模，彎曲模，卷邊模，拉深模，校平模，翻孔模，翻邊模，縮口模，壓印模，脹形模。按組合工序不同，沖模分為單工序模，復(fù)合模，連續(xù)模。 （2）鍛模：鍛模是金屬在熱態(tài)或冷態(tài)下進(jìn)行體積成型是所用模具的總稱。按鍛壓設(shè)備不同，鍛模分為錘用鍛模，螺旋壓力機(jī)鍛模，熱模鍛壓力鍛模，平鍛機(jī)用鍛模，水壓機(jī)用鍛模，高速錘用鍛模，擺動(dòng)碾壓機(jī)用鍛模，輥鍛機(jī)用鍛模，楔橫軋機(jī)用鍛模等。按工藝用途不同，鍛?？煞譃轭A(yù)鍛模具，擠壓模具，精鍛模具，等溫模具，超塑性模具等。 （3）塑料模：塑料模是塑料成型的工藝裝備。塑料模約占模具總數(shù)的35％，而且有繼續(xù)上升的趨勢(shì)。塑料模主要包括壓塑模，擠塑模，注射模，此外還有擠出成型模，泡沫塑料的發(fā)泡成型模，低發(fā)泡注射成型模，吹塑模等。 （4）壓鑄模：壓鑄模是壓力鑄造工藝裝備，壓力鑄造是使液態(tài)金屬在高溫和高速下充填鑄型，在高壓下成型和結(jié)晶的一種特殊制造方法。壓鑄模約占模具總數(shù)的6％。 （5）粉末冶金模：粉末冶金模用于粉末成型，按成型工藝分類粉末冶金模有：壓模，精整模，復(fù)壓模，熱壓模，粉漿澆注模，松裝燒結(jié)模等。 模具所涉及的工藝繁多，包括機(jī)械設(shè)計(jì)制造，塑料，橡膠加工，金屬材料，鑄造（凝固理論），塑性加工，玻璃等諸多學(xué)科和行業(yè)，是一個(gè)多學(xué)科的綜合，其復(fù)雜程度顯而易見。 2.2各類塑料模具結(jié)構(gòu) 塑料模是保證塑件形狀、尺寸、精度和表面質(zhì)量的主要工藝裝備，塑料模種類繁多，可根據(jù)塑料類型、塑件結(jié)構(gòu)、生產(chǎn)批量、成型方法和成型設(shè)備的不同，采用各種不同形式的模具。常見塑料模有壓縮模、壓注模、注射模、移動(dòng)式、固定式、單型腔、多型腔等。要掌握模具設(shè)計(jì)技術(shù)，必須認(rèn)識(shí)和了解常見模具結(jié)構(gòu)的工作原理、功能作用、技術(shù)要求、應(yīng)用范圍等內(nèi)容，方能在實(shí)際生產(chǎn)中，正確選擇和應(yīng)用模具結(jié)構(gòu)。下面分別介紹塑料模中常用的幾類機(jī)構(gòu)： 圖（1）是單分型面注塑模的典型結(jié)構(gòu)。其工作原理是：開模時(shí)，動(dòng)模后退，模具從分型面分開，塑件包緊在型芯 13 上隨動(dòng)模部分一起向左移動(dòng)而脫離凹模14，同時(shí)，澆注系統(tǒng) 凝料在拉料桿10的作用下，和塑件制作一起向左移動(dòng)。移動(dòng)一定距離后，當(dāng)注射機(jī)的頂桿接觸推板9時(shí)，脫模機(jī)構(gòu)開始動(dòng)作，推桿 11推動(dòng)塑件從型芯13上脫下來(lái)，澆注系統(tǒng)凝料同時(shí)被拉料桿推出。 圖（1） 技術(shù)要求：推桿與推桿孔之間一般采用H7/f8配合，型芯與型芯孔采用了導(dǎo)柱和導(dǎo)套之間采用間隙配合一般采用H7/f7 的配合，型芯與動(dòng)模板采用了間隙配合一般采用 H7/f6 的配合。模具上需設(shè)有冷卻或加熱裝置。 圖（2）是雙分型面注塑模。其工作原理是：開模時(shí)，動(dòng)模后退，在彈簧2的作用下，流道板13同時(shí)向左移動(dòng)，模具從 A-A 分型面分開。當(dāng)A-A 分型面分開一定距離后，定距拉板1通過(guò)固定在流道板13上的限位銷3將中間板拉住，使中間板停止運(yùn)動(dòng)。動(dòng)模繼續(xù)后退，此時(shí) B-B 分型面分開。因塑料制件包緊在型芯16上，將澆口自行拉斷，從A-A 分型面將澆注系統(tǒng)凝料取出。動(dòng)模部分繼續(xù)后退，注射機(jī)的推桿接觸推板9時(shí)，脫模機(jī)構(gòu)開始工作，11推動(dòng)推件板5將塑件從型芯16上脫下。 功能及其作用：這種模具結(jié)構(gòu)較復(fù)雜，重量大，成本高，主要用于采用點(diǎn)澆口的單型腔或多型腔注射模。 圖（2） 圖（3）是側(cè)向分型抽芯注射模。其工作原理：開模時(shí)，動(dòng)模部分左移。側(cè)型芯滑塊3可在型芯固定板5上開設(shè)的導(dǎo)滑槽中滑動(dòng)。動(dòng)模左移時(shí)，在導(dǎo)滑槽的作用下，側(cè)型芯滑塊3在斜導(dǎo)柱 2 的作用下沿著斜導(dǎo)柱軸線方向移動(dòng)，相對(duì)動(dòng)模向模具外側(cè)移動(dòng)，進(jìn)行抽芯動(dòng)作。當(dāng)斜導(dǎo)柱和側(cè)型芯滑塊脫開的時(shí)候，側(cè)型芯滑塊被定位，相對(duì)動(dòng)模不再移動(dòng)。動(dòng)模繼續(xù)左移，由推桿11將塑件從動(dòng)模邊頂出，澆注系統(tǒng)凝料同時(shí)被頂出。合模時(shí)，在斜導(dǎo)柱的作用下使側(cè)型芯滑塊復(fù)位，為防止成型時(shí)在料的壓力作用下移位去由楔緊塊對(duì)側(cè)型芯滑塊鎖緊。脫模機(jī)構(gòu)由復(fù)位桿復(fù)位。 圖（3） 圖（4）是溢式壓縮模的結(jié)構(gòu)。其工作原理是：把塑料放入型腔加熱，再進(jìn)行合模，保溫、保壓、固化后開模，利用推桿推出。 功能及其作用：機(jī)構(gòu)簡(jiǎn)單、造價(jià)低、耐用、安裝嵌件方便，塑件容易取出，但塑件帶有飛邊，去除困難，且浪費(fèi)塑料。 技術(shù)要求：模具無(wú)加料室，模腔總高度h基本上就是塑件的高度。 應(yīng)用范圍：適用于壓制扁平、尺寸小和形狀簡(jiǎn)單的塑件，壓制小批量或試制，低精度和強(qiáng)度沒(méi)有嚴(yán)格要求的塑件。不宜壓制壓縮率高的塑料，如：帶狀、片狀或纖維填料的塑料，不宜成型薄壁或壁厚均勻性要求很高的塑件。 圖（4） 圖（5）是半溢式壓縮模。其工作原理是：把塑料放入型腔加熱，再進(jìn)行合模，保溫、保壓、固化后開模，利用推桿推出。 功能及其作用：塑件承受壓力大，溢料量極少，密實(shí)性好，機(jī)械強(qiáng)度高。 技術(shù)要求：導(dǎo)柱和導(dǎo)向孔之間的配合為 H7/f7 。凸模與凹模有高度不大的間隙配合，一般每邊間隙值約 0.075mm 左右。凸模與凹模的密切配合。必須設(shè)推出裝置。 圖（5） 圖（6）是固定式壓注模。其工作原理：開模時(shí)，壓力機(jī)滑塊帶動(dòng)上?；爻?，上模部分與加料室在I — I處分形，以便從該分型面處往加料室。當(dāng)上?；爻痰揭欢ǜ叨葧r(shí)，拉桿 20 迫使拉鉤 19 轉(zhuǎn)動(dòng)并與下模部分脫開，接著定距拉桿發(fā)揮作用，帶動(dòng)上凹模板及加料室在Ⅱ—Ⅱ處與下模分型，以便推出機(jī)構(gòu)將塑件從該型面處推出。 功能及其作用：使用方便、生產(chǎn)效率高、勞動(dòng)強(qiáng)度小、模具使用壽命長(zhǎng)，但是模具結(jié)構(gòu)復(fù)雜、造價(jià)高、且安裝嵌件不方便。 技術(shù)要求： 推桿與推桿孔之間一般采用 H7/f8 配合。上、下模分別與壓力機(jī)的餓滑塊和工作臺(tái)面固定聯(lián)接。 應(yīng)用范圍：適用于產(chǎn)量大、尺寸大的塑件生產(chǎn)。 圖（6） 2.3注塑模具的典型結(jié)構(gòu) 機(jī)構(gòu)是模具中重要的組成部件，選擇和設(shè)計(jì)機(jī)構(gòu)是模具設(shè)計(jì)中的重要內(nèi)容，正確選擇和設(shè)計(jì)機(jī)構(gòu)是保證模具結(jié)構(gòu)科學(xué)合理的前提。塑料模工作動(dòng)作相對(duì)較多，因此所涉及的機(jī)構(gòu)類型和數(shù)量也比較多，主要包括合模導(dǎo)向機(jī)構(gòu)、脫模機(jī)構(gòu)、側(cè)向分型與抽芯機(jī)構(gòu)、先行復(fù)位機(jī)構(gòu)、順序定距分型機(jī)構(gòu)等。要掌握模具設(shè)計(jì)技術(shù)，必須認(rèn)識(shí)和了解常用機(jī)構(gòu)的工作原理、功能作用、技術(shù)要求、應(yīng)用范圍等內(nèi)容，方能在實(shí)際生產(chǎn)中，正確選擇和應(yīng)用機(jī)構(gòu)。下面分別介紹塑料模中常用的幾類機(jī)構(gòu)： 1．脫模機(jī)構(gòu)（推出機(jī)構(gòu)） 圖（7）是一級(jí)推桿脫模機(jī)構(gòu)。其工作原理：開模時(shí)，靠注射機(jī)的機(jī)械推桿使脫模機(jī)構(gòu)運(yùn)動(dòng)，推動(dòng)塑件脫落。功能及其作用：推桿加工簡(jiǎn)單，更換方便滑動(dòng)阻力小，脫模效果好。技術(shù)要求：推桿與推桿孔之間一般采用 H7/f8 配合。應(yīng)用范圍：適用于板狀塑件。 圖（7） 2．側(cè)向分型與抽芯機(jī)構(gòu) 圖（8）是斜銷分型與抽芯機(jī)構(gòu)。其工作原理：成型塑件上側(cè)孔的側(cè)型芯5隨著滑塊8在開模過(guò)程中側(cè)移離開塑件，而滑塊8的側(cè)移離開塑件，而滑塊8的側(cè)移則是斜銷3則固定在定模上下不能運(yùn)動(dòng)，著就迫使滑塊8在開模運(yùn)動(dòng)的同時(shí)作側(cè)向分型抽芯動(dòng)。功能及其作用：機(jī)構(gòu)緊湊、動(dòng)作安全可靠、加工制造方便。保證閉模時(shí)斜導(dǎo)柱能很準(zhǔn)確地插入滑塊的斜孔，使滑塊復(fù)位。技術(shù)要求：斜銷與其固定的模板之間采用過(guò)度配合H7/m6。應(yīng)用范圍：適用于抽芯力不大及抽芯距小于60∽80mm的場(chǎng)合。 圖（8） 圖（9）是斜桿導(dǎo)滑的內(nèi)側(cè)分型抽芯機(jī)構(gòu)。其工作原理：塑件內(nèi)側(cè)的凸臺(tái)由斜桿5的頭部成型(該結(jié)構(gòu)斜桿與成型滑塊合為體),在型芯7上開有斜孔,滑座2固定在推桿固定板l上,斜桿的成型端可在型芯的斜孔內(nèi)滑動(dòng),而另一端與滑座T形槽配合。推出時(shí),推桿固定 板使斜桿沿斜孔移動(dòng),推出塑件并進(jìn)行內(nèi)側(cè)抽芯,同時(shí)斜桿的底端可在滑座的T形槽內(nèi)滑動(dòng),保證不致卡死。斜桿由復(fù)位桿3復(fù)位。 功能及其作用：推出時(shí)，推桿固定板使斜桿沿斜孔移動(dòng)，推出塑件并進(jìn)行內(nèi)側(cè)抽芯，同時(shí)斜孔的底端可在滑座的T形槽內(nèi)滑動(dòng)，保證不致卡死。推板可通過(guò)支架、滾輪、可帶動(dòng)斜桿進(jìn)行抽拔和復(fù)位。技術(shù)要求：斜銷與其推件板鑲塊之間采用過(guò)度配合H7/m6。應(yīng)用范圍：適用于不宜采用斜桿導(dǎo)滑的外側(cè)分型抽芯機(jī)構(gòu)的情況下。 圖（9） 第三章 塑件分析 3.1 塑件的二維圖紙 如圖1-1 圖1-1 3.2 塑件原料分析 在尼龍中添加玻璃纖維、增韌劑等共混材料的力學(xué)性能·結(jié)果表明隨玻纖含量的增加，材料的拉伸強(qiáng)度、彎曲強(qiáng)度有大幅度的提高，沖擊強(qiáng)度則較為復(fù)雜，增韌劑加入，材料的韌性大幅度的提高·添加30%～35%的玻纖，8%～12%的增韌劑，材料的綜合力學(xué)性能最佳。 3.2.1 原料的物理化學(xué)特性 1. GFR-nylon 在尼龍樹脂中加入一定量的玻璃纖維進(jìn)行增強(qiáng)而得到的塑料(FR-PA)?？煞譃橛冒卜ㄖ频玫拈L(zhǎng)玻璃纖維增強(qiáng)尼龍(纖維和塑料顆粒等長(zhǎng)，一般約10mm)和以短切纖維經(jīng)混煉，或連續(xù)纖維導(dǎo)入雙螺桿擠出機(jī)連續(xù)剪切混煉制得的短玻璃纖維增強(qiáng)尼龍(玻纖長(zhǎng)度約0.2～0.7mm)。 2. 尼龍屬于聚酰胺，在它的主鏈上有氨基。氨基具有極性，會(huì)因氫鍵的作用而相互吸引。所以尼龍容易結(jié)晶，可以制成強(qiáng)度很高的纖維。聚酰胺為韌性角質(zhì)狀半透明或乳白色結(jié)晶性樹脂，常制成圓柱狀粒料，作塑料用的聚酰胺分子量一般為1.5萬(wàn)～2萬(wàn)。 3. 在PA 加入30% 的玻璃纖維，PA 的力學(xué)性能、尺寸穩(wěn)定性、耐熱性、耐老化性能有明顯提高，耐疲勞強(qiáng)度是未增強(qiáng)的2.5 倍。 4. 用增強(qiáng)材料來(lái)提高尼龍性能，增強(qiáng)材料有玻璃纖維，石棉纖維，碳纖維，鈦金屬等，其中以玻璃纖維為主，提高尼龍的耐熱性，尺寸穩(wěn)定性，剛性，機(jī)械性能（拉伸強(qiáng)度和彎曲強(qiáng)度），特別是機(jī)械性能提高明顯，成為性能優(yōu)良的工程塑料。玻璃纖維增強(qiáng)尼龍有長(zhǎng)纖維增強(qiáng)和短纖維增強(qiáng)尼龍兩種， 3.2.2 原料的成型性能 玻璃纖維的成型工藝與未增強(qiáng)時(shí)大致相同，但因流動(dòng)較增強(qiáng)前差，所以注射壓力和注射速度要適當(dāng)提高，機(jī)筒溫度提高10-40℃。由于玻纖在注塑過(guò)程中會(huì)沿流動(dòng)方向取向，引起力學(xué)性能和收縮率在取向方向上增強(qiáng)，導(dǎo)致制品變形翹曲，因此，模具設(shè)計(jì)時(shí)，澆口的位置、形狀要合理，工藝上可以提高模具的溫度，制品取出后放入熱水中讓其緩慢冷卻。另外，加入玻纖的比例越大，其對(duì)注塑機(jī)的塑化元件的磨損越大，最好是采用雙金屬螺桿、機(jī)筒。廣泛運(yùn)用于齒輪、軸承、風(fēng)扇葉片、泵葉、自行車零部件、汽車工業(yè)零配件、漁具及一些精密工程制品?！【哂辛己玫哪湍バ浴⒛蜔嵝?、耐油性及耐化學(xué)藥品性，還大大降低了原材料的吸水率和收縮率，具有優(yōu)良的尺寸穩(wěn)定性及優(yōu)異的機(jī)械強(qiáng)度?！?與純尼龍相比，增強(qiáng)尼龍機(jī)械強(qiáng)度、剛性、耐熱性、耐蠕變性和耐疲勞強(qiáng)度大幅度提高，伸長(zhǎng)率、模塑收縮率、吸濕性、耐磨性下降 . 性能主要決定于纖維與樹脂的黏合強(qiáng)度、含量、長(zhǎng)徑比和取向度。可注塑和擠出成型。廣泛用于宇航、汽車、機(jī)械、化工等領(lǐng)域制造耐熱受力結(jié)構(gòu)塑料零部件。 3.3 塑件分析 3.3.1 制品結(jié)構(gòu)分析 脫模斜度設(shè)計(jì)：查書P22表2—1可得，該塑件型腔脫模斜度為25′～45′,型芯脫模斜度為20′～45′。 壁厚設(shè)計(jì)：查書P23表2—4可得，該塑件為大制品塑件，壁厚取2.4～3.2mm，根據(jù)圖紙，壁厚稍取小些，取壁厚為2mm。 加強(qiáng)筋與薄壁容器設(shè)計(jì)： 加強(qiáng)筋厚度A=1/2δ，A=1mm；加強(qiáng)筋高度L=（1～3）δ，L=4mm； 加強(qiáng)筋底部圓角R=1/4δ，R=0.5mm；加強(qiáng)筋頂部圓角r=1/8，r=0.25mm 加強(qiáng)筋錐角a=2′～5′。 支承面：在支承面上設(shè)置加強(qiáng)筋，則筋的高度應(yīng)低于支承面約0.5mm左右。 圓角：圓角R=1 孔設(shè)計(jì)：該塑件無(wú)孔 3.3.2 尺寸精度分析 塑料收縮率波動(dòng)公差δB：δB=L（S1-S2） 模具成型零件部件的制造公差δZ：模具成型零件部件的制造公差應(yīng)不超過(guò)塑件公差的1/3。 模具成型零部件的表面摩損公差δC ：一般模具δC的值可取0.02～0.04mm。 其他公差δQ：各項(xiàng)誤差的累積數(shù)值δ，應(yīng)不大于塑件的公差△。即 △≥δ=δZ+δB+δC+δQ 塑件尺寸公差：可根據(jù)制品成型后的尺寸穩(wěn)定性參照選擇等級(jí)。 1.3.3 表面質(zhì)量分析 表面粗糙度：查書P41表2—20可得，該塑件的表面粗糙度Ra=1.6～0.1μm。 第四章 注射機(jī)的選用 （1）XS-ZY-125型注射機(jī)為螺桿式。聚丙烯可以采用此類型注射機(jī)成型，據(jù)查有關(guān)資料可列出該注射機(jī)的主要技術(shù)參數(shù)見表4-1 序號(hào) 主要技術(shù)參數(shù)項(xiàng)目 參數(shù)數(shù)值 1 額定注射量/㎝3 250 2 鎖模力/kN 900 3 注射壓力/MPa 119 4 最大注射面積/cm2 320 5 動(dòng)、定模模板最大安裝尺寸最/mm×mm 420×450 6 最大模具厚度/mm 300 7 最小模具厚度/mm 200 8 模板最大行程/mm 300 9 噴嘴前端球面半徑/mm 9 10 噴嘴孔直徑/mm 4 11 定位圈直徑/mm Ф100mm 第五章 模具結(jié)構(gòu)的設(shè)計(jì) 5.1 型腔數(shù)目的設(shè)計(jì) n=（0.8G-m2）/m1，n=（0.8×125-2.8）/13.961=6（個(gè)）為了方便加工，這里取一模兩腔。 5.2 選擇分型面 該塑件為花形帽，在選擇分型面時(shí)，根據(jù)分型面的選擇原則，考慮不影響塑件外觀質(zhì)量，便于清除毛刺及飛邊，有利于排除模具型腔內(nèi)的氣體、分模后塑件留在動(dòng)模一側(cè)以便于取出塑件等因素，分型面應(yīng)選擇在塑件外形輪廓的最大處。為了提高自動(dòng)化程度和生產(chǎn)率，減少降低聚苯乙烯的取向變形以及保證塑件表面質(zhì)量，采用點(diǎn)澆口。如圖5-1 圖5-1 5.3 型腔布置的設(shè)計(jì) 采用一模兩腔，如圖5-2 圖5-2 5.4 澆注系統(tǒng)的設(shè)計(jì) 5.4.1主流道設(shè)計(jì) 由表1-1可知，SX-ZY-125型注射機(jī)噴嘴有關(guān)尺寸為： 噴嘴孔直徑d 0=4mm 噴嘴前端球面半徑SR 0=9mm 根據(jù)模具主流道與噴嘴的關(guān)系得到： 主流道進(jìn)口端球面半徑SR= SR 0+（1~2）=10+（1~2）mm，取SR=11 為了便于將凝料從主流道中拔出，將主流道設(shè)計(jì)成圓柱形，其斜度取6度；同時(shí)為了使熔料順利進(jìn)入分流道，在主流道出口端設(shè)計(jì)圓弧過(guò)渡。主流道襯套采用可拆卸更換的澆口套，其形狀及尺寸按照交口套設(shè)計(jì)；為了能與注塑機(jī)的定位圈相配合，采用外加定位環(huán)方式，這樣不僅減小了澆口套的總體尺寸，還能避免了澆口套在使用中的磨損。 5.4.2分流道設(shè)計(jì) 該塑件體積較小，形狀不叫簡(jiǎn)單，壁厚均勻，且塑料流動(dòng)性好，可以采用單點(diǎn)進(jìn)料的方式。為便于加工，采用最常用的U形截面分流道。查有關(guān)資料，選取分流道截面形狀及其相應(yīng)直徑尺寸，在此取U形分流道截面半徑R=3mm，深度h=2.1mm。如圖3-3 5.4.3澆口的設(shè)計(jì) 由于該塑件外觀質(zhì)量要求較高，所以澆口的位置和大小應(yīng)以不影響塑件的外觀質(zhì)量為前提。同事也應(yīng)盡量使模具結(jié)構(gòu)更簡(jiǎn)單，。根據(jù)對(duì)該塑件結(jié)構(gòu)的分析，并結(jié)已確定的分形面的位置，選擇如圖3-4所示的點(diǎn)澆口進(jìn)料方式。 圖5-3分流道截面形狀 5.4.4冷料穴設(shè)計(jì) 聚苯乙烯性脆易裂，容易出現(xiàn)裂紋的特點(diǎn)要求采用Z字行拉料桿的冷料穴。分形式拉料桿將主流道的凝料拔出。實(shí)現(xiàn)澆注系統(tǒng)與塑件的自動(dòng)分離與脫出，自動(dòng)化程度高，勞動(dòng)力度小。 5.4.5成型零件工作尺寸的計(jì)算 該塑件材料是一種收縮范圍較大的塑料，因此成型零件的尺寸均按平均值法計(jì)算。前面已查得聚苯乙烯的收縮率為0.2%。 根據(jù)塑件尺寸公差的要求，模具的制造公差取δz=△/3 成型零件尺寸的計(jì)算見表5-1。 成型零件尺寸的計(jì)算表5-1 塑件尺寸 計(jì)算公式 工作尺寸 型腔內(nèi)型尺寸 20 LM=(ls+ ls S-△) 19.67+0.17 0 R10 9.96+0.12 0 R5 4.875+0.1 0 型芯外形尺寸 22 Lm=(Ls+ Ls S+△) 22.830-0.17 R7 7.410-0.12 R8 8.43 0-0.12 型腔深度尺寸 12 HM=(hs+ hs S-△) 12.39+0.143 0 6 6.320 -0.1 型芯高度尺寸 10 Hm=(Hs+ Hs S+△) 10.440 -0.12 6 5.92+0.1 0 中心距尺寸 4 CM=Cs+CsS±δz） 60±0.02 5.5冷卻裝置的設(shè)計(jì) 該塑件采用大批量生產(chǎn)，應(yīng)盡量縮短成型周期，提高生產(chǎn)率。聚苯乙烯的熱變形溫度低，成型時(shí)需要一般冷卻。因此，該模具的凹模冷卻實(shí)在定模板上開出冷卻水道，采用一般水進(jìn)行冷卻型腔，動(dòng)模板處的冷卻也采用冷卻水道的冷卻方式。但由于型芯、型腔為鑲嵌式，所以冷卻水道采取堵密封墊料或插入銅管。冷卻水道如圖5-4所示 圖5-4 冷卻水道設(shè)計(jì) 第六章 模具設(shè)計(jì)計(jì)算與驗(yàn)算 6.1注射量的校核 15.3407979×6＝92，92＜125×80%=100 6.2鎖模力的校核 鎖模力是指注射機(jī)的合模機(jī)構(gòu)對(duì)模具所能施加的最大夾緊力。注射機(jī)的鎖模力的校核關(guān)系式為 F≥kpA 式中 F：注射機(jī)鎖模力，查《塑料模設(shè)計(jì)手冊(cè)》附錄8得XS-ZY-125型螺桿式注射機(jī)的鎖模力為900KN； k：壓力損耗系數(shù)，一般取1.1~1.2； p：型腔內(nèi)熔體的壓力，可取注射成型壓力的25%~50%，本塑件p=60MP A：塑件及澆注系統(tǒng)在分型面上的投影面積之和，本模具A=9.7×10㎡ 計(jì)算得 kpA=1.2×60×10×9.7×10×10=698KN＜900KN 故注射機(jī)的鎖模力足夠，滿足鎖模要求。 6.3安裝尺寸的校核 本模具采用的是型號(hào)A3-250250-27-A3（GB/T12556.1-1991）的標(biāo)準(zhǔn)模架，模具外形尺寸為180mm×200mm，模具閉合高度為H=75+40+32+63=210mm，查資料得SX-ZY-125型注射機(jī)動(dòng)、定模模板最大安裝尺寸為420×450，允許模具最小厚度H=200mm，最大厚度H=300mm，即模具的外形尺寸不超過(guò)注射機(jī)動(dòng)、定模模板最大安裝尺寸，模具閉合高度滿足H≤H≤H的安裝條件，故該模具滿足SX-ZY-125型螺桿式注射機(jī)的安裝要求。 6.4 開模行程的校核 注射機(jī)的開模行程是有限的，取出制品所需的開模行程距離必須小與注射機(jī)的最大開模距離，本模具為單分型面，SX-ZY-125型螺桿式注射機(jī)的最大開模行程與模后無(wú)關(guān)，校核關(guān)系式為 S＞H+ H+（5~10） 式中 S：注射機(jī)的最大開模行程，S=300 H ：塑件脫模所需的推出距離，該塑件的脫模推出距離為25mm； H：塑件的高度（不包括澆注系統(tǒng)高度），該塑件的高度為12mm。 計(jì)算得 H+ H+（5~10）=25+12+10=47mm＜ S=300 SX-ZY-125型螺桿式注射機(jī)的開模行程足夠。 以上分析證明，SX-ZY-125型螺桿式注射機(jī)能滿足要求，故可以采用。 第七章 模具的工作原理、安裝、試模和生產(chǎn) 7.1 模具設(shè)計(jì)工作原理; (1) 對(duì)塑料進(jìn)行烘干，并裝入料斗。 (2) 清理模具型芯、型腔，并噴上脫模劑，進(jìn)行適當(dāng)?shù)念A(yù)熱。 (3) 合模。鎖緊模具、 (4) 對(duì)塑料進(jìn)行預(yù)塑化，注射裝置準(zhǔn)備注射。 (5) 注射過(guò)程包括充模、保壓、倒流。澆口凍結(jié)后的冷卻和脫模。 (6) 脫模過(guò)程。制件的推出同一般注射模具推出方式相同，即由注射機(jī)推桿推動(dòng)模具推板，從而推動(dòng)推件桿將制件頂出 參考文獻(xiàn) [1]宋愛平主編.CAD/CAM技術(shù)綜合實(shí)訓(xùn)指導(dǎo)書； [2]李建軍，李德群主編 ．模具設(shè)計(jì)基礎(chǔ)及模具CAD [M]．機(jī)械工業(yè)出版社，2005． [3] 屈華昌. 塑料成型工藝與模具設(shè)計(jì). 機(jī)械工業(yè)出版社，1995 [4] 彭建聲. 簡(jiǎn)明模具工實(shí)用技術(shù)手冊(cè). 機(jī)械工業(yè)出版社，1993 [5]葉久新，王群主編．塑料制品成型及模具設(shè)計(jì)[M]．湖南科學(xué)技術(shù)出版社，2005． [6]孫玉芹等主編．機(jī)械精度設(shè)計(jì)基礎(chǔ)[M]．科學(xué)出版社，2004． [7]陳再枝，藍(lán)德年編著．模具鋼手冊(cè)[M]．冶金工業(yè)出版社，2002． [8]（美國(guó)）T．A．奧斯瓦德，L．特恩格 P．J．格爾曼編著，吳其曄譯．注射成型手冊(cè)[M]．化學(xué)工業(yè)出版社，2005． [9]洪慎章編著．實(shí)用注塑成型及模具設(shè)計(jì)[M]．機(jī)械工業(yè)出版社，2006． [10]中國(guó)模具工業(yè)協(xié)會(huì)標(biāo)準(zhǔn)件委員會(huì)編．中國(guó)模具標(biāo)準(zhǔn)件手冊(cè)[M]．上?？茖W(xué)普及出版社，1989． [11]（加拿大）H．瑞斯著，朱元吉譯．模具工程——第二版[M]化學(xué)工業(yè)出版社，2005． [12]王文廣，田雁主編．塑料配方設(shè)計(jì)——第二版[M]．化學(xué)工業(yè)出版社，2004． [13]詹友剛編著．PRO/ENGINEER中文野火版2.0基礎(chǔ)教程[M]．清華大學(xué)出版社． [14]李預(yù)斌編著．精通PRO/ENGINEER中文野火版[M]．中國(guó)青年出版社． [15]《塑料模設(shè)計(jì)手冊(cè)》編寫組. 塑料模設(shè)計(jì)手冊(cè). 機(jī)械工業(yè)出版社，1994 [16]李世國(guó)等編著．PEO/ENGINEER WILDFIRE中文版范例教程[M]．機(jī)械工業(yè)出版社，2004． [17] 馮炳堯，韓泰榮，蔣文生. 模具設(shè)計(jì)與制造簡(jiǎn)明手冊(cè). 上?？茖W(xué)技術(shù)出版社，1998 [18]張祥杰等編著．PRO/ENGINEER 模具設(shè)計(jì)WILDFIRE[M]．中國(guó)鐵道出版社，2004． [19]《塑料模具技術(shù)手冊(cè)》編委會(huì)編著．塑料模具技術(shù)手冊(cè)[M]．機(jī)械工業(yè)出版社，2001． [20]伍先明等編著．塑料模具設(shè)計(jì)指導(dǎo)[M]．國(guó)防工業(yè)出版社，2006． [21]大連理工大學(xué)工程畫教研室編著．機(jī)械制圖（第四版）[M]．高等教育出版社，2002． 總結(jié) 隨著經(jīng)濟(jì)的發(fā)展，社會(huì)的進(jìn)步，塑料工業(yè)將繼續(xù)呈現(xiàn)蓬勃發(fā)展之勢(shì)。本論文主要介紹了塑料模具的設(shè)計(jì)，冷流道注塑模具無(wú)外乎包括四大系統(tǒng)：澆注系統(tǒng)、溫度調(diào)節(jié)系統(tǒng)、頂出系統(tǒng)和機(jī)構(gòu)系統(tǒng)（其實(shí)也可以歸為頂出系統(tǒng)，該系統(tǒng)如斜導(dǎo)柱、滑塊和開閉器等）。在澆注系統(tǒng)的設(shè)計(jì)中根據(jù)經(jīng)驗(yàn)公式取流道橫截面形狀，確定澆口尺寸；溫度調(diào)節(jié)系統(tǒng)說(shuō)明了設(shè)計(jì)的一般步驟，確定冷卻時(shí)間，計(jì)算體積流量等；頂出系統(tǒng)著重說(shuō)明了推桿，推管的安裝要求，并進(jìn)行強(qiáng)度校核；該模具有滑塊抽芯機(jī)構(gòu)。做完這些工作之后，該模具的設(shè)計(jì)到此結(jié)束。 在設(shè)計(jì)的過(guò)程中發(fā)現(xiàn)經(jīng)驗(yàn)公式有不一致的地方，不同公式的計(jì)算結(jié)果有的相差很大。在完成圖紙之后發(fā)現(xiàn)塑件的設(shè)計(jì)有的地方是不合理的，比如說(shuō)壁厚，雖然有經(jīng)驗(yàn)可循，但從實(shí)際中看顯然本設(shè)計(jì)的塑件壁厚過(guò)大；還有就是推管處的設(shè)計(jì)不合理，按該塑件加工，則標(biāo)準(zhǔn)推管需要再加工；從這里可以知道，注塑件的設(shè)計(jì)與模具設(shè)計(jì)關(guān)系密切，好的塑件結(jié)構(gòu)可以簡(jiǎn)化模具結(jié)構(gòu)，降低生產(chǎn)成本。 單分型面注射模是最為簡(jiǎn)單和常見的一種結(jié)構(gòu)形式，約占全部注射模具的70%左右，但目前傳統(tǒng)冷流道模具設(shè)計(jì)還是以經(jīng)驗(yàn)為主，很難對(duì)注射各參量進(jìn)行嚴(yán)密的數(shù)學(xué)建模，因?yàn)楦鲄⒘肯嗷ビ绊?，關(guān)系復(fù)雜。隨著科技的進(jìn)步及注射理論的突破，熱流道模具發(fā)展的越來(lái)越迅速，隨著技術(shù)的成熟，熱流道模的生產(chǎn)控制將會(huì)變得比以前更為輕松，產(chǎn)品質(zhì)量將會(huì)得到更好提高，所以，以后注射模具的研究會(huì)以熱流道模具為主。 最后還用PRO/E軟件建立三維造型，在使用PRO/E的過(guò)程中，發(fā)現(xiàn)該軟件功能強(qiáng)大，其功能可以延伸到CAM及CAE領(lǐng)域，是一種多功能的3D軟件，廣泛應(yīng)用于機(jī)械，電子，航空航天，產(chǎn)品設(shè)計(jì)，模具設(shè)計(jì)等各個(gè)領(lǐng)域。 致謝 經(jīng)過(guò)三個(gè)月的畢業(yè)設(shè)計(jì)忙碌之后，設(shè)計(jì)最終完成，心理有一種說(shuō)不出的輕松，設(shè)計(jì)過(guò)程中遇到許多的問(wèn)題，在眾多師友的幫助下予以解決。首先要感謝宋愛平老師對(duì)我的指導(dǎo)和督促，給我指出了正確的設(shè)計(jì)方向，使我加深了對(duì)知識(shí)的理解,同時(shí)也避免了在設(shè)計(jì)過(guò)程中少走彎路，宋愛平老師淵博的知識(shí)、對(duì)學(xué)術(shù)嚴(yán)謹(jǐn)?shù)淖黠L(fēng)及活躍的思維方式給我留下了深刻的印象，在今后的學(xué)習(xí)中必將給我很好的指導(dǎo)。同時(shí)還要感謝宿舍同學(xué)，是大家營(yíng)造了良好的學(xué)習(xí)環(huán)境，在做設(shè)計(jì)的過(guò)程中互幫互助，使我的CAD和PRO/E操作水平比以前有了很大提高，同時(shí)較全面的掌握了Word的編輯功能。 大學(xué)生活至此劃上了圓滿的句號(hào)，最后再次感謝各位老師和同學(xué)。 arXiv:1003.5062v1 physics.gen-ph 26 Mar 2010Automatic polishing process of plastic injection molds on a 5-axismilling centerJournal of Materials Processing TechnologyXavier Pessoles, Christophe Tournier*LURPA, ENS Cachan, 61 av du pdt Wilson, 94230 Cachan, Francechristophe.tournierlurpa.ens-cachan.fr, Tel : 33 147 402 996, Fax : 33 147 402 211AbstractThe plastic injection mold manufacturing process includes polishing operations whensurface roughness is critical or mirror effect is required to produce transparent parts. Thispolishing operation is mainly carried out manually by skilled workers of subcontractorcompanies. In this paper, we propose an automatic polishing technique on a 5-axis millingcenter in order to use the same means of production from machining to polishing andreduce the costs. We develop special algorithms to compute 5-axis cutter locations onfree-form cavities in order to imitate the skills of the workers. These are based on bothfilling curves and trochoidal curves. The polishing force is ensured by the compliance ofthe passive tool itself and set-up by calibration between displacement and force based ona force sensor. The compliance of the tool helps to avoid kinematical error effects on thepart during 5-axis tool movements. The effectiveness of the method in terms of the surfaceroughness quality and the simplicity of implementation is shown through experiments ona 5-axis machining center with a rotary and tilt table.KeywordsAutomatic Polishing, 5-axis milling center, mirror effect, surface roughness, Hilbertscurves, trochoidal curves1Geometric parametersCE(XE,YE,ZE)tool extremity point(u,v)coordinates in the parametric spaceTrochoidal curve parametersscurvilinear abscissaC(s)parametric equation of the guiding curveP(s)parametric equation of the trochoide curven(s)normal vector of the guiding curvepstep of the trochoidDtrdiameter of the usefull circle to construct the trochoidAamplitude of the trochoidStepstep between two loops of trochoideTechnological parametersDtool diameterDeffeffective diameter of the tool during polishingEamplitude of the envelope of the polishing stripedisplacement induced by the compression of the tooltilt angle of the tool axisu(i,j,k)tool axisftangent vector of the guide curveCcpoint onto the trochoidal curveMachining parametersNspindle speedVccutting speedVffeed speedfzfeed per cutting edgeapcutting depthatworking engagementTmachining time2Surface roughness parametersRaarithmetic average deviation of the surface (2D)Saarithmetical mean height of the surface (3D)Sqroot-mean-square deviation of the surfaceSskskewness of topography height distributionSkukurtosis of topography height distribution31IntroductionThe development of High Speed Machining (HSM) has dramatically modified the or-ganization of plastic injection molds and tooling manufacturers. HSM in particular hasmade it possible to reduce mold manufacturing cycle times by replacing spark machiningin many cases. In spite of these evolutions, HSM is not enable to remove the polishingoperations from the process. In this paper, we deal with the realization of surfaces withhigh quality of surface finishing and mirror effect behavior. This means that the partmust be perfectly smooth and reflective, without stripes. Such a quality is for examplenecessary on injection plastic mold cavities in order to obtain perfectly smooth or com-pletely transparent plastic parts. From an economic point of view, polishing is a long andtiresome process requiring much experience. As this process is expensive in terms of priceand downtime of the mold, automatic polishing has been developed. Our objective is touse the same means of production from machining to polishing, leading to cost reduction.The aim of the paper is thus to propose a method of automatic polishing on a 5-axismachine tool.Literature provides various automated polishing experiments. Usually, the polishing iscarried out by an anthropomorphic robot, 1. Anthropomorphic robots are used for twomain reasons. First, their number of axes enables them to have an easy access to any areaof complex form. Second, it is possible to attach a great variety of tools and particularlyspindles equipped with polishing force control mechanisms. Automatic polishing studieshave been also carried out on 3 or 5-axis NC milling machine with specially designed toolto manage polishing force 2 as well as on parallel robots 3.Indeed, the polishing force is a key parameter of the process. The abrasion rate in-creases when the polishing pressure increases 4. But as mentioned in 3 the contactpressure depends on the polishing force and also on the geometrical variations of the part.An adequate polishing force facilitates the removal of cusps and stripes left on the partduring milling or previous polishing operations. Nevertheless, the contact stress has tobe as constant as possible to avoid over-polishing and respect form deviation tolerances.Many authors have thus chosen to develop abrasive systems allowing a dynamic manage-ment of the polishing force. In 5, Nagata et al. use an impedance model following forcecontrol to adjust the contact force between the part and the sanding tool. In 6, Ryuh etal. have developed a passive tool, using a pneumatic cylinder to provide compliance and4constant contact pressure between the surface and the part. A passive mechanism is alsoused in 7. The contact force is given by the compressive force of a spring coil.In order to carry out an automatic polishing, it is important to use adapted tooltrajectories. According to 8, polishing paths should be multidirectional rather than mo-notonic, in order to cover uniformly the mold surface and to produce fewer undulationerrors. Moreover, the multidirectional polishing path is close to what is made manually.If we observe manual polishers, we can notice that they go back on surface areas accor-ding to various patterns such as trochoidal polishing paths (or cycloidal weaving paths8 (fig 1). Therefore, it could be profitable to follow such a process in order to obtainthe required part quality. For instance, some papers use fractal trajectories like the PeanoCurve fractal 9, which is an example of a space-filling curve, rather than sweepings alongparallel planes 10.ElementarypatternElementarypatternMultidirectionalpolishingMultidirectionalpolishingFigure 1 Manual polishing patternsThis brief review of the literature shows that there is no major difficulty in using a 5-axis machine for automatic polishing with a passive tool. This paper aims at showing thefeasibility of automatic polishing using 5-axis machine tools and proposing some polishingstrategies. In the first section, we expose how automatic polishing is possible using a 5-axisHSM center. In particular, we present the characteristics of the passive and flexible toolsused. A specific attention is paid to the correlation between the imposed displacement ofthe tool and the resulting polishing force. Once the feasibility of 5-axis automatic poli-shing is proved, the various dedicated polishing strategies we have developed are detailedin section 2. These strategies are for the most part issued from previous experiences asfor fractal tool trajectories coming from robotized polishing or cycloidal weaving paths5representative of manual polishing. In section 3, the efficiency of our approach is testedusing various test part surfaces. All the parts are milled then polished on the same pro-duction means : a 5-axis Mikron UCP710 milling centre. In the literature, the effectivenessof polishing is evaluated using the arithmetic roughness Ra 2. However, as it is a 2Dparameter, this criterion is not really suited to reflect correctly the 3D polished surfacequality. We thus suggest qualifying the finish quality of the polished surface through 3Dparameters. This point is discussed in the last section as well as the comparison of thesurface roughness obtained using automatic polishing with that obtained using manualpolishing, a point hardly addressed in the literature. 3D surface roughness measurementsare performed using non-contact measuring systems.2Experimental Procedure2.1Characteristics of the toolsAs said previously, our purpose is to develop a very simple and profitable system.Therefore, the tools used are the same than those used in manual polishing. The poli-shing plan is divided into two steps, pre-polishing and finishing polishing. Pre-polishing isperformed with abrasive discs mounted on a suitable support. The abrasive particle sizeis determined by the Federation of European Producers of Abrasives standard (FEPA).This support is a deformable part made in an elastomer material fixed on a steel shaftthat allows mounting in the spindle. We thus deal with a passive tool. Hence, we donot have a force feedback control but a position one. We have studied the relationshipbetween the deflection of the disc support and the polishing force applied to the part.To establish this relationship, we use a Quartz force sensor Kistler 9011A mounted on aspecially designed part-holder. The sensor is connected to a charger meter Kistler 5015itself connected to the computer through a data-collection device Vernier LabPro to savethe data. The experimental system is depicted in figure 2. In addition, the used sensor isa dynamic sensor. The effort must therefore change over time otherwise there would be adrift of the measure. To do so, the movement imposed on the tool over time is a triangularsignal.6Figure 2 Experimental set-upIn order to ensure the evacuation of micro chips during the polishing and guarantee anonzero abrasion speed at the contact between the part and the tool, the tool axis u istilted relatively to the normal vector to the polished surface n and to the feed directionf. The tilt angle (figure 3) is defined as follows :nuqfvCeCcWorkpieceCLFigure 3 Tool axis tilting7u = cos n + sin f(1)Polishing tests have been conducted considering three different tilt angles (5,10,15)between the tool axis and the normal vector to the surface in the feed direction. Thecorrelation between the tool deflection and the polishing force is shown in figure 4.Polishing?force0246810121416180,000,150,300,450,600,750,901,051,20Displacement?(mm)Force?(N)5?inclination?angle10?inclination?angle15?inclination?angleFigure 4 Polishing forces vs displacementThe green curve (5 deg) is interrupted because the abrasive disks unstick when thetool deflection is too large. In this configuration, the tilt angle is too low and the bodyof the disk support, which is more rigid, comes in contact with the workpiece, whichdeteriorates and unsticks the disk. With a 10 or 15 degrees tilt angle, this phenomenonappears for a higher value of tool deflection, outside the graph. However, low tilt angleconfigurations allow faster tool movements since the rotation axes of the 5-axis machinetool are less prompted 11. Furthermore, it has been showed that trochoidal tool pathsrequire a dynamic machine tool to respect the programmed feedrate 12. Then in si-multaneous 5-axis configurations, polishing time will be greater with low tilt angles. Inaddition, the flexibility of the tool will help to reduce or avoid 5-axis kinematic errors 13.Indeed, interfences between the tool and the part could happen because of great tool axis8orientation evolutions between two succesive tool positions. Therefore, the disc supportdeflection would avoid the alteration of the mold surface.If one considers the law of Preston 14, the material removal rate h in polishing isproportional to the average pressure of contact, P, and to the tool velocity relative to theworkpiece, V :h = KPPV(2)where KPis a constant (m2sN) including all other parameters (part material, abrasive,lubrification, etc.). Hence, in order to reach an adequate contact pressure, we must increasethe tool deflection and consequently we raise the shear stress and the disk unsticks. Froma kinematical behavior point of view, low rotational axes movements lead to decrease thepolishing time. So we must use a rather low tilt angle (5-10 degrees) and a quite high tooldeflection to ensure a satisfactory rate of material removal.2.25-axis polishing tool path planningTo generate the polishing tool path, the classical description of the tool path in 5-axis milling with a flat end cutter is used. This leads to define the trajectory of the toolextremity point CEas well as the orientation of the tool axis u (i,j,k) along the tool path.With regards to polishing strategy, we use trochoidal tool paths in order to imitate themovements imparted by the workers to the spindle. To avoid marks or specific patterns onthe part, we choose to generate trochoidal tool path on fractal curves in order to cover thesurface in a multidirectionnal manner. We use more particularly Hilberts curves whichare a special case of the Peanos curve. These curves are used in machining as they havethe advantage of covering the entire surface on which they have been generated 15. Wewill develop below the description of the Hilberts curve which is used as a guide curvefor the trochoidal curve then we will examine the trochoidal curve itself.2.2.1Hilberts curve definitionThe use of fractal trajectories presents two major interests. The first one is that toolpaths do not follow specific directions which guarantees an uniform polishing. The secondone is linked to the tool path programming. Indeed, tool paths are computed in the9parametric space u,v of the surface, that is restricted to the 0,12interval. Hilbertscurves are known as filling curves, covering the full unit square in the parametric space16, and consequently, the Hilberts curves fill the 3D surface to be polished. Hilbertscurves can be defined with a recursive algorithm, the n-order curve is defined as follows : If n = 0 :x0= 0y0= 0(3) Else :xn=0.50.5 + yn10.5 + xn10.5 + xn10.5 yn1yn=0.50.5 + xn10.5 + yn10.5 + yn10.5 xn1(4)It is then easy to compute first, second or third-order and so Hilberts curves (fig 5).-0.4-0.200.20.4-0.4-0.200.20.4-0.5-0.3-0.10.10.30.5-0.4-0.200.20.4-0.5-0.3-0.10.10.30.5-0.5-0.3-0.10.10.30.5Figure 5 Hilberts curves (first, second and third order curve)In order to maintain a tangency continuity along the Hilberts curve which is the guidecurve of the trochoidal tool path, we have decided to introduce fillets on the corners of thepolishing fractals. Otherwise, at each direction change on the fractal curve, the polishingtool path would be discontinuous. Resulting Hilberts curve is depicted in figure 6. Basedon this representation, the curve is easy to manipulate. For example, one could projectthis parametric representation directly in the 3D space or use it as the guide curve forbuilding trochoidal curves (fig 7) as can be seen in the next section.2.2.2Mathematical definition of trochoidal curvesBased on the description of trochoidal curves proposed in 17, we define a trochoidalcurve as follows. Let C(s) be a 2D parametric curve, where s is the curvilinear length (fig8).10Figure 6 Fourth order cornered Hilberts curvef(s)CciCinirCDTROiCjnjCcjOjqiqjFigure 7 Polishing trajectories on a convex free formC(s) = (s,f(s) is the guide curve of the trochoidal curve and n(s) the normal vectorto the curve C(s) at the considered point. p is the step of the trochoidal curve and wedenote Dtrits diameter. The parametric equation of the trochoidal curve is the following :P(s) = C(s) +p2n(s) + Dtrcos(2sp)sin(2sp)sin(2sp)cos(2sp)n(s)(5)The issue is now to link the trochoidal curve parameters to the polishing parameters.The amplitude A of the trochoidal curve is equal to twice its diameter A = 2Dtr. However,11Figure 8 Trochoidal curve parametersfrom a tool path generation point of view, we are more interested in the tool envelopeamplitude than in the trochoidal curve amplitude. One of the difficulties of modellingthe envelope surface of the tool movement is the tool itself, as abrasive polishing toolsare mounted on flexible supports. The tool polishing amplitude depends on the contactsurface between the tool and the part. This contact is influenced by the tilt angle , thetool diameter D and the imposed tool displacement e to be able to polish the surface.Indeed, when the tool is laid flat, the contact area is a disk, as can be seen in figure 9.However, when the tool is tilted and a given displacement e is imposed to the tool, thecontact area is a disc portion.ZDDeffleZequFigure 9 Contact area between the tool and the partThe effective tool diameter can be computed with the following expressions :12Deff= 2s?D2?2 (l)2(6)with :l =D2sin etan(7)and :E = A + 2Deff2= 2Dtr+ Deff(8)This yields to the definition of the parameter Dtradjusted to build the trochoidalcurve.Dtr=E Deff2=Deff6=13vuut?D2?2 D2tan etan!2(9)2.2.3Tool path generationWhatever the nature of the considered surface, the polishing tool paths generationconsists of three steps : computation of the tool path in the parametric space, computationof the resulting tool path in the 3D space and computation of the tool axis orientation.Tool path generation relies on the trochoidal curve as described above. The trajectory isdefined discretly. The only difficulty is to calculate the normal vector. This is done byusing the points Ci1and Ci+1and by calculating the next cross product :ni= Z Ci1Ci+1(10)We now describe the method for calculating the direction of the tool axis u (figure3). In a first approach we only use the tilt angle defined in the plane (f;n) where f isthe tangent vector to the guide curve, i.e., the Hilberts curve and n the normal vector tothe machined surface. The tool axis u is tilted in relation to the Hilberts curve tangentf rather than to the trochoidal curve in order to minimize the movements amplitude ofthe rotational axes of the machine tool.In order to compute the tangent vector fiat the contact point CCibetween the tooland the part, the following expression is used :fi= n CCiCC(i+1) n| CCiCC(i+1)|!|z(11)13The location of the tool extremity CE, which is the driven point during machining,depends on the polishing mode, i.e., by pulling or pushing the tool. The polishing modeis defined by the parameter : OCE= OCC+ r n + (R r) v r u e z(12)with :v =u n|u n| u(13)by noting = 1 when 0 and = 1 when 0 : profile has more peaks than valleys, Ssk 3 : the distribution is wide (the surface is rather plane), Sku 3 : the distribution is tighted (the surface has a tendency to present peaksor valleys).Once the parts are polished, we perform 3D surface roughness measurements using anon-contact measuring system (Talysurf CCI 6000). We perform measurements on poli-shed parts with our approach (the plane and the convex surface) and on a plane that hasbeen polished manually by a professional (figure 11). Measurement results are reportedin table 2.It can be observed that the convex surface automatically polished presents larger geo-metric deviations as well as a higher Sa and Sq than those observed for the planar surface.In other words, the rate of material removal is not as good as on the planar surface while16Figure 11 3D surface roughness : convex surface (top), planar automatic (middle),planar manual (bottom)OperationsNVcV ffzapatTToolrpmm/minmm/minmm/toothmmmmminparallel planes94388980000,0570,20,0335End mill ( 3)Operations ToolsAStepV fNeTmmmmmm/minrpmdegmmminP grade 120 ( 18)1211000200030,415P grade 240 ( 18)1211000200030,415P grade 600 ( 18)1211000200030,415P grade 1200 ( 18)1211000200030,415Diamond abrasive emulsion (9m) ( 6)1211000200030,315Diamond abrasive emulsion (3m) ( 6)1211000200030,315Diamond abrasive emulsion (1m) ( 6)1211000200030,315Table 1 Milling and polishing operationsSurfaceSaSqSskSkuConvex Autom.7.619 nm9.543 nm-0.23142.92Plane Autom.1.085 nm1.346 nm0.1032.713Plane Manual1.014 nm1.307 nm-0.59413.748Table 2 3D Roughness parameters17trajectories are the same in the (u,v) parametric space. There are several explanationsfor this behavior. First, the used polishing pattern, generated in the parametric space, isthe same than the plan