0446-差速器外殼加工工藝及鏜孔夾具設(shè)計(jì),差速器,外殼,加工,工藝,鏜孔,夾具,設(shè)計(jì) 一、選題的背景及意義 隨著機(jī)械制造業(yè)的不斷發(fā)展，社會(huì)對(duì)生產(chǎn)率的要求也越來(lái)越高，因此，大批量生產(chǎn)成為時(shí)代的需求，而組合機(jī)床就可以滿足這一需求，我們有必要來(lái)研究他，另外，箱體是機(jī)器設(shè)備中的基礎(chǔ)件和基準(zhǔn)件，它和一些軸承、軸、齒輪等零件組裝在一起，并使這些零件之間保持準(zhǔn)確的相互位置。因此，箱體的加工質(zhì)量將直接影響機(jī)器或部件的精度、性能和壽命，我們有必要對(duì)他進(jìn)行研究。 機(jī)械制造畢業(yè)設(shè)計(jì)涉及的內(nèi)容比較多，它是基礎(chǔ)課，設(shè)計(jì)基礎(chǔ)課以及專業(yè)課的綜合，是在學(xué)完機(jī)械制造技術(shù)基礎(chǔ)（含機(jī)床夾具設(shè)計(jì)）和全部專業(yè)課，并進(jìn)行了畢業(yè)實(shí)習(xí)的基礎(chǔ)上進(jìn)行的，是我們對(duì)所有課程的一次深入的綜合性的總復(fù)習(xí)，也是一次理論聯(lián)系實(shí)際的訓(xùn)練，因此，它在我們四年的大學(xué)生活中占有重要的地位。 二、國(guó)內(nèi)外研究概況及發(fā)展趨勢(shì) 制造業(yè)是國(guó)民經(jīng)濟(jì)的支柱產(chǎn)業(yè)，是國(guó)家創(chuàng)造力、競(jìng)爭(zhēng)力和綜合國(guó)力的重要體現(xiàn)。它不僅為現(xiàn)代工業(yè)社會(huì)提供物質(zhì)基礎(chǔ)，為信息與知識(shí)社會(huì)提供先進(jìn)裝備和技術(shù)平臺(tái)，也是實(shí)現(xiàn)具有中國(guó)特色軍事變革和國(guó)防安全的基礎(chǔ)。當(dāng)今世界正在發(fā)生的深刻變化，對(duì)制造業(yè)產(chǎn)生了深刻的影響，制造過(guò)程和制造工藝也有了新的內(nèi)涵。傳統(tǒng)制造業(yè)不斷吸收機(jī)械、信息、材料等方面的最新成果，并將其綜合應(yīng)用于產(chǎn)品開(kāi)發(fā)與設(shè)計(jì)、制造、檢測(cè)、管理及售后服務(wù)的制造全過(guò)程。21世紀(jì)的制造業(yè)呈現(xiàn)出高技術(shù)化、信息化、綠色化、極端化、服務(wù)增值等特點(diǎn)和趨勢(shì)。 　在高技術(shù)的帶動(dòng)下，制造技術(shù)出現(xiàn)了前所未有的新進(jìn)展，制造技術(shù)及制造工藝的高技術(shù)化應(yīng)用體現(xiàn)在以下幾個(gè)方面。 　　 （1）微加工成為常規(guī)制造技術(shù)。制造業(yè)的常規(guī)性尺度由微米級(jí)精度下移1到2個(gè)數(shù)量級(jí)，亞微米及納米級(jí)制造將成為主流。 　　 （2）特種加工技術(shù)廣泛應(yīng)用。與傳統(tǒng)的機(jī)械加工相比較，特種加工技術(shù)利用非機(jī)械能進(jìn)行加工，例如激光加工、電花加工、電解加工、電化學(xué)加工等，將成為常規(guī)的制造手段，使有些原來(lái)難加工或不能加工的零件加工成為可能。 　　 （3）生長(zhǎng)型制造的比重日益提高。快速原型制造改變了傳統(tǒng)加工“去除材料”的思維定式，通過(guò)材料的逐層累加使零件成型。在微制造領(lǐng)域，“從下而上”的制造和生長(zhǎng)／去除復(fù)合型制造將成為主要的制造方式。 　　 （4）制造技術(shù)和材料技術(shù)聯(lián)系更加緊密。特別是納米材料的應(yīng)用導(dǎo)致制造業(yè)發(fā)生巨變，無(wú)論產(chǎn)品的設(shè)計(jì)還是制造過(guò)程，都因此產(chǎn)生了根本性的改變。 　?。?）極端制造得到發(fā)展。極端制造是指在極端制造環(huán)境下，制造極端尺度或極高性能的器件和功能系統(tǒng)。 三、研究?jī)?nèi)容及設(shè)計(jì)方案 本次畢業(yè)設(shè)計(jì)使我們能綜合運(yùn)用機(jī)械制造的基本理論，并結(jié)合生產(chǎn)實(shí)踐中學(xué)到的技能知識(shí)，獨(dú)立的分析和解決問(wèn)題，初步具備設(shè)計(jì)一個(gè)中等復(fù)雜程度的零件的工藝規(guī)程的能力和運(yùn)用夾具設(shè)計(jì)的基本原理和方法，擬定夾具設(shè)計(jì)方案，完成夾具結(jié)構(gòu)設(shè)計(jì)的能力，也是熟悉的運(yùn)用有關(guān)手冊(cè)、圖表等資料及編寫技術(shù)文件等基本技能的一次實(shí)踐機(jī)會(huì)。研究?jī)?nèi)容擬解決的主要問(wèn)題編制汽車箱體零件機(jī)械加工工藝規(guī)程，完成工藝過(guò)程卡和部分加工工序卡 研究方法技術(shù)路線零件加工的工藝規(guī)程就是一系列不同工序的綜合。由于生產(chǎn)規(guī)模和具體情況的不同對(duì)同一零件的加工工序綜合可能有多種的方案。應(yīng)當(dāng)根據(jù)具體條件采用其中最完善和最經(jīng)濟(jì)的一種方案。工藝規(guī)程選擇要考慮的基本要素如下。 （1）生產(chǎn)規(guī)模是決定生產(chǎn)類型的主要因素。 （2）制造零件所用的坯料或型材的形狀、尺寸和精度。 （3）零件材料性質(zhì)。 （4）零件制造的精度，包括尺寸公差，形位公差以及零件圖上所指定的要求 （5）表面粗糙度。 （6）特殊限制條件。 （7）編制的加工規(guī)程要在生產(chǎn)規(guī)程與生產(chǎn)條件下達(dá)到最經(jīng)濟(jì)與最安全的效果。 工藝路線方案 工序5 鑄造。 工序10 熱處理：退火。 工序15 粗車Φ74、Φ66端面，倒角 工序20 鉆Φ10孔 工序25 粗鏜Φ18、Φ32、Φ47、Φ52孔 工序30 粗車法蘭盤底面 工序35 加工法蘭盤底面6個(gè)M10的螺紋通孔 工序40 車Φ56螺紋孔 工序45 粗鏜Φ54、Φ58、Φ66、Φ148孔 工序50 半精車Φ74、Φ66端面， 工序55 半精鏜Φ18、Φ32、Φ47、Φ52孔 工序60 半精車法蘭盤底面 工序65 半精鏜Φ54、Φ58、Φ66、Φ148孔 工序70 精鏜Φ32、Φ47、Φ52孔 工序75 銑凸臺(tái)平面 工序80 鉆孔，絲錐加工M14×1.5內(nèi)螺紋孔 工序85 精鏜Φ54、Φ58、Φ66 工序90 鉆Φ23孔深0.5、鉆Φ15孔深2,鉆Φ12孔，攻Φ14深15內(nèi)螺紋。 工序95 鉆Φ10孔深3、攻M8深15內(nèi)螺紋絲 工序100 去毛刺、檢查 四、目標(biāo)、主要特色及工作進(jìn)度 課題目標(biāo) 1．編制其批量生產(chǎn)的機(jī)械加工工藝規(guī)程：對(duì)零件圖進(jìn)行工藝分析，繪制零件圖（在UG NX 和AUTOCAD上），編制機(jī)械加工工藝過(guò)程卡片、機(jī)床加工 2．設(shè)計(jì)夾具 工作進(jìn)度安排 1. 搜集有關(guān)資料，熟悉零件結(jié)構(gòu)及功用，撰寫開(kāi)題報(bào)告 第 1周 2. 相關(guān)外文文獻(xiàn)資料的閱讀與翻譯（6000字符以上） 第2周 3. 零件工藝路線設(shè)計(jì) 第3周至第5周 4. 機(jī)床加工工序設(shè)計(jì) 第6周至第9周 5. 鏜孔夾具設(shè)計(jì) 第10周至第14周 6. 撰寫畢業(yè)論文 第15周至第16周 7. 答辯準(zhǔn)備及畢業(yè)答辯 第17周 五、參考文獻(xiàn) [1] 王先逵. 機(jī)械制造工藝學(xué).北京:機(jī)械工業(yè)出版社，2008 [2] 于駿一. 典型零件制造工藝.北京:機(jī)械工業(yè)出版社，1989 [3] 王凡. 實(shí)用機(jī)械制造工藝設(shè)計(jì)手冊(cè).北京:機(jī)械工業(yè)出版社，2008 [4]王啟平. 機(jī)床夾具設(shè)計(jì).哈爾濱：哈爾濱工業(yè)大學(xué)出版社，1996 [5] 張進(jìn)生，房曉東主編. 機(jī)械工程專業(yè)課程設(shè)計(jì)指導(dǎo).北京:機(jī)械工業(yè)出版社，2004 [6] Yiming (Kevin) Rong. Samuel H. Huang, Zhikun Hou. Advanced Computer-aided Fixture Design. Elsevier Academic Press, 2005 7] 曹巖，白瑀主編 機(jī)床夾具手冊(cè)與三維圖庫(kù) UGNX版.北京：化學(xué)工業(yè)出版社,2010 鈦合金攻螺紋技術(shù)及絲錐改進(jìn) 【摘要】鈦合金是一種比重小、強(qiáng)度高、耐腐蝕和耐熱等特性的金屬結(jié)構(gòu)材料。鈦合金攻螺紋切削時(shí)刀具極易磨損，刀具壽命很短。通過(guò)對(duì)鈦合金攻螺紋過(guò)程受力分析，將絲錐直槽變?yōu)槁菪?，可以使切削熱和切削力不至于過(guò)分集中于切削刃附近，改善散熱條件，也可加強(qiáng)切削刃，減少崩損。 【關(guān)鍵字】鈦合金、攻螺紋、金屬結(jié)構(gòu)材料、熱處理強(qiáng)化、絲錐直槽、螺旋槽 鈦合金是一種比重小、強(qiáng)度高、耐腐蝕和耐熱等特性的金屬結(jié)構(gòu)材料。TA7屬單相組織的型鈦合金，不能熱處理強(qiáng)化，通常在退火狀態(tài)下使用，具有良好的熱穩(wěn)定性和熱強(qiáng)性。TC4屬雙粗組織的型合金，有較高的力學(xué)性能和高溫變形能力，良好的韌性和塑性，能進(jìn)行各種熱加工和熱處理強(qiáng)化。鈦合金在100~150仍有很高的強(qiáng)度，被廣泛應(yīng)用于火箭發(fā)動(dòng)機(jī)外殼、航空發(fā)動(dòng)機(jī)氣機(jī)盤、葉片、結(jié)構(gòu)鍛件等。 1.鈦合金攻螺紋切削過(guò)程特點(diǎn) 鈦合金是一種難切削材料，突出特點(diǎn)是刀具極易磨損，刀具壽命很短。主要體現(xiàn)在： （1）切削層變形小由于鈦合金的塑性低和鈦的化學(xué)活潑性高，在高的切削溫度下化學(xué)親和性很強(qiáng)，容易與大氣中的氧、氮等元素化合，從而脆性降低，切削變形小。 （2）切削溫度高鈦合金導(dǎo)熱性很差，導(dǎo)熱系數(shù)只相當(dāng)于45鋼的1/5~1/7切削熱不容易傳出，集中在切削區(qū)和切削刃附近較小范圍內(nèi)。 （3）冷硬現(xiàn)象嚴(yán)重一是切削過(guò)程中產(chǎn)生的塑性變形，另一方面在高的切削溫度下，鈦很容易吸收空氣中的氧和氮形成硬而脆的外皮，冷硬現(xiàn)象不僅會(huì)降低零件的疲勞強(qiáng)度，而且能加劇刀具磨損程度。 （4）刀具容易磨損主要有機(jī)械磨損：毛坯余量和組織不均勻，硬皮與刀具表面接觸發(fā)生強(qiáng)烈的機(jī)械摩擦，使刀具受到不均勻的負(fù)荷造成崩刃現(xiàn)象。此外切削過(guò)程中已加工表面較大的彈性恢復(fù)，也使刀具磨損。粘接磨損：鈦合金對(duì)刀具材料的親和性很強(qiáng)，在切削溫度高和切削力大的條件下，很容易與刀具中的某些元素如C、Ti、Co等粘附在一起，隨切屑的流出帶走刀具材料中的質(zhì)點(diǎn)。 2．鈦合金攻螺紋過(guò)程受力分析及改善措施 （1）切削層變化帶來(lái)的絲錐受力不均勻絲錐攻螺紋過(guò)程屬于半封閉式多刃薄切削過(guò)程，與車削螺紋相比較，切削條件惡劣。在工件底孔內(nèi)切出的螺紋，是由絲錐切削刃瓣上的各切削牙逐層切削而成的。不難看出，絲錐或工件旋轉(zhuǎn)一周后，每個(gè)切削牙都前進(jìn)一個(gè)螺距，并分別從工件上切除一層金屬。用機(jī)用絲錐攻螺紋時(shí)，隨著絲錐切入孔中，切削層總面積逐漸增加。當(dāng)切削錐全部進(jìn)入孔中工作時(shí)，切削層總面積達(dá)到最大值。當(dāng)絲錐再繼續(xù)前進(jìn)時(shí)，由于校準(zhǔn)部不起切削作用，所以切削層總面積不再增加。對(duì)于鈦合金來(lái)說(shuō)，因切削層巨大的摩擦力和塑性變形給運(yùn)動(dòng)中的絲錐受力帶來(lái)了波動(dòng)。一個(gè)最有效的改變辦法是將螺紋孔底孔直徑增加到所允許的上限，最大程度地減小切削層厚度。 （2）“陷切”造成的絲錐受力惡化攻螺紋時(shí)，作用在絲錐各切削刃上的切削力可分解為軸向力、徑向力和切向力。切向力直接決定攻螺紋扭距的大小，其他兩個(gè)分力則影響攻螺紋的切削過(guò)程。從圖2中可以看出，開(kāi)始攻螺紋時(shí)，絲錐依靠在工件上切出的JI螺紋側(cè)面被引導(dǎo)前進(jìn)。但因JI面太小，加之鈦合金塑性變形，承受不了絲錐對(duì)工件的軸向力而產(chǎn)生接觸變形，使絲錐的軸向前進(jìn)量不足，各刃瓣滯后并在螺紋表面一側(cè)切出階臺(tái)而造成“陷切”現(xiàn)象。攻螺紋繼續(xù)進(jìn)行時(shí)，在由KJ、GH、GF、CD等側(cè)刃、頂刃切削時(shí)產(chǎn)生的軸向力合力Fa(-)和由JI、EF、AB等側(cè)刃切削時(shí)產(chǎn)生的軸向力合力Fa(+)未趨平衡以前，“陷切”現(xiàn)象將繼續(xù)發(fā)生。但隨著絲錐與工件相接觸的螺紋引導(dǎo)表面的增大，“陷切”量將逐漸減??；攻螺紋的“陷切”現(xiàn)象直接影響螺紋一側(cè)面的正確成形，并使其表面粗糙度值高，嚴(yán)重時(shí)足以啃住絲錐，使之處于抱死狀態(tài)。 （3）攻螺紋過(guò)程中的擺動(dòng)容易使絲錐單向嵌入工件基體中在絲錐正常工作的條件下，如前所述，由于同時(shí)工作的絲錐各切削牙切削寬度不等，使前面切削牙的切削面積大于后面切削牙的切削面積，所以，作用在絲錐各刃瓣上的徑向力不等，也使徑向力的合力不等于零（）。顯然，在攻螺紋時(shí)，絲錐將偏向徑向力小的一邊，絲錐的軸線相對(duì)于孔的軸線將發(fā)生偏移，導(dǎo)致被加工的螺孔擴(kuò)大同時(shí)也使絲錐緊貼在一邊。當(dāng)絲錐的切削錐長(zhǎng)度較短，即導(dǎo)角較大時(shí)，各刃瓣上切削牙的切削寬度差別愈大，中徑擴(kuò)大的可能性越大，故絲錐的切削錐長(zhǎng)度不宜太短。 （4）攻螺紋扭矩的非穩(wěn)定性攻螺紋的扭矩由三個(gè)部分組成，即切削扭矩、絲錐與已加工螺紋間的摩擦扭矩和由于切屑堵塞在容屑槽內(nèi)產(chǎn)生的扭矩。在正常切削的條件下，攻螺紋扭矩主要是切削扭矩，后一種扭矩所占的比重一般很小，可忽略不計(jì)。絲錐在通孔中攻螺紋時(shí)扭矩的變化情況。隨著絲錐切入底孔，進(jìn)行切削的牙數(shù)增加，攻螺紋扭矩增大。當(dāng)切削錐全部進(jìn)入底孔時(shí)，扭矩達(dá)到最大值。當(dāng)絲錐的切削錐從孔的另一端露出時(shí)，攻螺紋扭矩開(kāi)始減小。顯而易見(jiàn)，攻螺紋扭矩基本上與絲錐切削層總面積成正比，攻螺紋扭矩的變化規(guī)律與絲錐切削層總面積的變化規(guī)律大致相同。為了避免在扭矩最大值時(shí)用力過(guò)猛，必須掌握所施加扭矩大小及緩急程度。另外還可以通過(guò)以下途徑來(lái)有效地減小攻螺紋扭矩：1、增大前角使攻螺紋扭矩減小，例如前角為時(shí)，假設(shè)扭矩為100%，那么當(dāng)前角變?yōu)闀r(shí)，則扭矩就減小到70%，前角時(shí)扭矩僅達(dá)到原來(lái)的53%，但是增大前角會(huì)使絲錐強(qiáng)度降低，也不利于散熱，這一點(diǎn)應(yīng)注意。 一．選擇盡可能少的絲錐刃瓣數(shù)即槽數(shù)，這是因?yàn)椴蹟?shù)的增加，一方面使切削厚度變薄，難以切削，另一方面增加了絲錐與工件摩擦面積，使絲錐扭矩變大，一般的四槽比三槽約增加8%的扭矩。 二．選擇對(duì)口的切削液，減小摩擦。如濃度較大的硫化油，添加15%~20%的四氯化碳，可降低表面粗糙度值和減小絲錐咬死的可能性。 3．絲錐前面導(dǎo)向部分的導(dǎo)角既不能過(guò)大也不能太小，導(dǎo)角過(guò)大，切削層厚度大，受力容易崩牙咬死，切屑也不易卷曲，但導(dǎo)角過(guò)小，切屑過(guò)薄，在硬化層上摩擦，加劇絲錐磨損。另外絲錐校準(zhǔn)部分不宜過(guò)長(zhǎng)，否則和螺紋孔壁摩擦將會(huì)加劇，一般為4~5個(gè)螺距。 4．絲錐改進(jìn)實(shí)例由于鈦合金材料在加工過(guò)程中容易產(chǎn)生表面加工硬化，特別是加工小直徑螺紋孔，成了難題。攻螺紋時(shí)由于縮孔，攻上幾扣，就抱住絲錐，切削力特別大，普通絲錐容易折斷，使工件無(wú)法繼續(xù)加工?；谏鲜鍪芰Ψ治鲞^(guò)程，將絲錐的大徑、中徑、小徑磨小并分為四個(gè)等級(jí)，每只絲錐相差0.1mm，以期減少切削力帶來(lái)的影響，但是由于切削量小，工件又容易產(chǎn)生加工硬化，加工起來(lái)比較費(fèi)勁，效率很低，攻上幾個(gè)螺紋孔就不能繼續(xù)使用了。后來(lái)我從改變切削的角度入手，經(jīng)過(guò)多次反復(fù)實(shí)驗(yàn)，將絲錐直槽變?yōu)槁菪?，即在原切削牙上按螺旋角度磨?~2扣，以減小絲錐與切屑的接觸面積。前角由原來(lái)的減少至，使切屑與前刀面的接觸長(zhǎng)度小，既可以增加切屑與前刀面的接觸面積，使切削熱和切削力不至于過(guò)分集中于切削刃附近，改善散熱條件，也可加強(qiáng)切削刃，減少崩損。 參考文獻(xiàn): [ 1] 高鐘锍.機(jī)電控制工程[M].北京:清華大學(xué)出版社,2002. [2] 張建民.機(jī)電一體化系統(tǒng)設(shè)計(jì)[M].北京:北京理工大學(xué)出版社,2002. [ 3] 王貴明.數(shù)控實(shí)用技術(shù)[M].北京:機(jī)械工業(yè)出版社,2000. The alloy of titanium attacks whorl technology and screwtap to improve [Abstract] Titanium is of small specific gravity , high strength, strong corrosion resistance and heat resistance ,which are the characteristics of metallic structural materials. Titanium is a kind of material easily tapped cutting tool wear, shorting its using time . Titanium is tapping on stress analysis, tapping directly into the spiral groove that can make cutting heat and force without being unduly concentrated in the vicinity of the cutting edge ,not only improve heat dissipation, but also strengthen the cutting edge, in order to reduce losses collapse. [Key word] Titanium, Gewinde scheiden, metal structural materials, heat resistance, Straight Fluted Taps, spiral chute Titanium alloy is a kind of metal structural material , with characters of small proportion , high intensity, strong corrosion-resisting and heat-resisting and so on . TA7 belongs to the organized single-phase type of titanium alloy , which can't be strengthen under the heat treatment, used under the condition of putting out the fire in common situation , with good performence of hot stability and intensity . TC4 belongs to organized double-thick of type titanium alloy , which has higher mechanics performance and the ability of deformed under high temperature, good toughness and plasticity, which can work with all kinds of heat process and strengthen treatment. Titanium alloy still has very high intensity under. It is widely used in the outer shell of rocket engine, aviation engine chassis, blade, structural forging,etc.. 1. The characteristics of the titanium alloy’s Gewinde scheiden whorl cut the process: The titanium is a material which is very hard to cut. The outstanding characteristic is that the cutting tool is very easy to be polish and its life-span is very short . Main reflects are as following : (1)Cut layer can transfigure small because Titanium alloy is plasticity lowness and the titanium chemistry is activity . Under the high temperature of cutting that have strong affine of chemistry and easy combination with element chemical such as oxygen , nitrogen easy to hit the target with atmosphere. It is brittleness lessening , cutting deformation are minor. (2)Cut temperature high titanium alloy heat conductivity very bad, heat conduction coefficient whether 45 steel of 1/5~1/7s cut hot only, in smaller range near concentrating on the cutting area and cutting the edge. (3)Cold hard phenomenon serious one cut out of shape plasticity that course produce, on the other hand at high cutting temperature, titanium very apt oxygen and nitrogen to absorb air form hard and fragile crust, the hard phenomenon of cold not only will reduce fatigue strength of the part but also can aggravate the cutter and wear and tear the intensity. (4)The cutter is apt to wear and tear and mainly have machinery that is worn and torn: Blank surplus and organization even, hard skin with cutter surface exposed to, take place strong machinery rub, make the cutter caused and broken out the edge phenomenon by the load not even. Cut course process surface loud elasticity resume, make the cutter wear and tear too already. Sticking wears and tears: Titanium alloy affinity of material very strong to cutter, in cut temperature to be high cutting strength under the heavy terms, it is very easy to seize with some elements in the cutter such as C, Ti, Co,etc. together, with flowing out the particle taken away in the cutter material of smear metal. 2. Titanium alloy attacks the whorl course and is analyzed and improved the measure by strength. (1)Cut layers of screwtap that change bring specialize in strength even screwtap whorl course belong to semi-closed many edge thin to cut the course, compared with whorl of turning, it is abominable to cut the condition. Whorl that cut out in work piece underport, to cut by screwtap edge every of petal cut tooth chase layers of cut, as shown in Fig. 1. It is easy to find out, after the screwtap or work piece rotates a circle, each one cuts the tooth and advances a pitch, and excise a layer of metal from work piece separately. Specialize in whorl, cut hole with machine with screwtap with screwtap, cut one layer of the whole area increase. When cutting all awls and entering and working in the hole, cut one layer of the whole area and reach the maximum. When the screwtap continues advancing again, do not play a cutting role because of the department of regulating, cut one layer of the whole area to no longer increase. To alloy of titanium, cut layers of enormous frictional force and plasticity deformation give screwtap of sport bring, fluctuate strength. A most effective change method increases underport diameters of hole of the whorl to the upper limit allowed, reduce and cut one layer of thickness to the greatest extent. (2)" Fall into, cut " screwtap that cause worsen, specialize in whorl, act on in screwtap cutting strength cutting strength at the edge can resolve axial force, radial strength and tangential force into each ", as shown in Fig. 2. Tangential force determine, specialize in whorl size to sprain distance directly, other two component force influence cutting course to specialize in the whorl. Can find out begin specialize in whorl, JI that screwtap rely on at work piece cutting out lead, advance to the side of the whorl in 2 Fig.. But because JI too light, in addition titanium alloy plasticity out of shape, bear screwtap axial force in work piece produce, keep in touch out of shape, make the axial of the screwtap insufficient in advancing amount, every edge one lags behind and cuts out the steps platform and causes the " fall into and cut " phenomenon on one side of the surface of whorl. Specialize in whorl continue go on, by KJ, GH, GF, CD side edge, carry edge axial force that produce join forces cut, join forces Fa by JI, EF, axial force that AB produce when the side edge is cut '), trend towards before such as equilibrium, " fall into and cut " the phenomenon will continue taking place ". But the whorl contacted with the screwtap and work piece guides superficial increase, " fall into and cut " quantity will be reduced gradually "; Attack " falls into and cuts " the phenomenon influences the taking shape correctly of a side of whorl directly "ing of whorl, make surface its roughness enough to gnaw live in screwtap when being value serious high, make it in, embrace state extremely. (3)Specialize in whorl swing of course apt to make screwtap to be one-way to imbed work piece of the matrices on terms that the screwtap work normally, as noted previously, because the screwtap working at the same time each cuts the tooth and cuts the width, make the cutting area of cutting the tooth above cut the cutting area of the tooth in the back of greater thanning, so, the radial strength of acting on screwtap every edge one makes the resultant of forces of radial strength not equal zero（）As shown in Fig. 3. Obviously, while attacking the whorl, screwtap agree more on radial to be strength little axis axis in hole of screwtap take place skew, cause, expand at the same time making screwtap stick to aside closely spiral shell hole that process. Cutting in screwtap awl length relatively short, lead when angle heavy, every edge cut cutting of tooth width difference loud at the petal, the bigger possibility China expanded directly, so the awl length of cutting of the screwtap should not be too short. (4)That attacked torsion of whorl is not that the torsion that stability attacks the whorl is made up of three parts, cut torsion, screwtap with process friction torsion of whorl already and because smear metal stop up in torsion that bits produce in the trough of holding. Under the terms of cutting normally, it mainly cuts the torsion to attack the torsion of whorl, the last one proportion that torsion account for generally very light, can ignore. In Fig. 3 is the change of the torsion while attacking the whorl in the open hole of the screwtap. Cut underport with screwtap, tooth cut to go on count, increase, specialize in torsion of whorl increase. When cutting all awls and entering the underport, the torsion reaches the maximum. When the cutting awl of the screwtap emerges from another end of the hole, specializing in the torsion of whorl begins to reduce. Obviously, specialize in whorl torsion cut one layer of the whole area directly proportional to with screwtap basically, specialize in whorl change law and screwtap of torsion cut layers of change of the whole area law roughly same. In order to avoid exerting oneself in the torsion maximum too quicklily, must grasp the torsion size and pressing or otherwise intensity exerted. In addition it come, reduce, specialize in whorl torsion effectively through following route: One. It is before it increase for horn make specialize in there aren't whorl the torsions,such as before horn, suppose torsion have 100%, angle turn into, torsion reduce get 70% then, the torsion only reaches original 53% when the the previous corner at present then, but the angle will make the screwtap intensity reduce before increasing, unfavorable to dispelling the heat, this should notice. Two. choose screwtap edge petal that lack as much as possible count the trough is counted promptly, this is because the increase that the trough counted, make, cut thickness thin, difficult to cut, increase screwtaps and work piece rub the area on the other hand on one hand, make the torsion of screwtap large, four general troughs nearly increase 8% of the torsion than three troughs. 3 .Chooses the fitting cutting liquid, reduce the friction. Such as density heavy vulcanization oil, add 15%0% tetrachloromethane, can reduce surface roughness value and reduce possibility that screwtap kill.4~5, Whom screwtap lead partly lead angle can too little either, lead angle to be too big, cut layers of thickness heavy, strength being apt to break out tooth kill, the smear metal is difficult to be curly, but lead horn to be too light, smear metal too thin, rub on hardening layer, aggravate screwtap wear and tear. In addition the calibration part of the screwtap should not be too long, otherwise rub against whorl hole wall and aggravate, it is generally 4 pieces of pitch. 4.The screwtap improves the embodiment and is prone to the work hardening of surface in the course of processing because of the titanium alloy material, especially process the small diameter whorl hole, become the difficult problem. Specialize in whorl, because of contract hole, several deduct attack, embrace screwtap, cut strength to be very much heavy, the ordinary screwtap is easy to break, make the work piece unable to continue processing. Because of described above to receive strength analytic process, large foot-path, hit foot-path, path rub little dividing 4 grades into of screwtap, each screwtap differs by 0.1mm, in the hope of reducing and cutting the influence that strength brings, but because the cutting amount is small, the work piece is prone to the work hardening again, process and stand up more strenuous, efficiency is very low, attack, have several whorl hole can continue and use. Later on I start with changing the angle that is cut, through testing repeatedly many times, turn spiral trough into by frank trough screwtap, in cut tooth rub, go, 1 spike according to spiral angle originally, as shown in Fig. 5, in order to reduce the contact area of screwtaps and smear metal. The previous horn come from original reduction, make smear metal and one hundred sheetses of Taxi contact length little ago, already can increase smear metal and one hundred sheetses of Taxi contact area ago, make, cut hot cutting strength to be unlikely to concentrate on, cut edge while being excessive, improve the heat dissipation condition, can also strengthen and cut the edge, reduce and break out and decrease. effect of the process parameters on the rim thickness of glass fiber and Wollastonite filled PBT by conventional and microcellular injection-molding process has been conducted. References: [1]Gao Zhongshu. The electromechanics controls the project [M]. Beijing: The publishing house of Tsing-Hua University, 2002. [2]Zhang JianMin. Electromechanics' integrated system is designed [M]. Beijing: Beijing BJ Universithy of Polytech Press, 2002. [3]Wang GuiMing. Practical technique of numerical control [M]. Beijing: The publishing house of the mechanical industry, 2000.