工作臺(tái)部分右軸架工藝及銑夾具設(shè)計(jì)
22頁 9200字?jǐn)?shù)+論文說明書+5張CAD圖紙【詳情如下】
IMG_0993.jpg
IMG_0994.jpg
右軸架毛坯圖.dwg
右軸架零件圖.dwg
工作臺(tái)部分右軸架工藝及銑夾具設(shè)計(jì)說明書.doc
數(shù)控加工刀具卡片.doc
數(shù)控加工工藝卡.doc
數(shù)控加工程序.doc
機(jī)械專業(yè)實(shí)習(xí)報(bào)告.doc
機(jī)械加工工藝過程卡片.dwg
機(jī)械外文翻譯---銑削.doc
機(jī)械實(shí)習(xí)報(bào)告.doc
銑夾具體零件圖.dwg
銑夾具總裝圖.dwg
工作臺(tái)部分右軸架工藝及夾具設(shè)計(jì)
目 錄
1 引言 1
2生產(chǎn)綱領(lǐng) 3
2.1計(jì)算生產(chǎn)綱領(lǐng)決定生產(chǎn)類型 3
2.2 計(jì)算生產(chǎn)節(jié)拍 3
3零件分析 5
3.1零件的作用 5
3.2零件的毛坯 5
4 工藝規(guī)程設(shè)計(jì) 7
4.1確定毛坯的制造形式 7
4.2基準(zhǔn)面的選擇 7
4.3制定工藝路線 9
4.4 機(jī)械加工余量、工序尺寸 12
4.5確定切削用量及基本用時(shí)計(jì) 14
5 夾具設(shè)計(jì) 15
5.1 問題的提出 18
5.2 夾具的設(shè)計(jì) 20
結(jié)束語 21
致謝 21
參考文獻(xiàn) 22
1 引言
畢業(yè)設(shè)計(jì)是對(duì)大學(xué)四年來我們所學(xué)到的基礎(chǔ)知識(shí)和專業(yè)知識(shí)的一次系統(tǒng)性的總結(jié)與綜合運(yùn)用,同時(shí)也是培養(yǎng)我們分析問題和解決問題能力的良好的機(jī)會(huì),而且畢業(yè)設(shè)計(jì)也是大學(xué)教學(xué)的最后一個(gè)重要環(huán)節(jié)。因此,認(rèn)真踏實(shí)地做好這次畢業(yè)設(shè)計(jì)不僅意味著我們能否順利畢業(yè),而且對(duì)今后我們走上工作崗位后能否很出色的做好自己的工作也有十分重要意義。另外,畢業(yè)設(shè)計(jì)還可以培養(yǎng)我們獨(dú)立思考,開發(fā)思維和協(xié)調(diào)工作的能力,這對(duì)今后踏入社會(huì)以后能否盡快地適應(yīng)社會(huì)也有很大的幫助。機(jī)械工業(yè)的生產(chǎn)水平是一個(gè)國家現(xiàn)代化建設(shè)水平的主要標(biāo)志之一。這是因?yàn)楣I(yè)、農(nóng)業(yè)、國防和科學(xué)技術(shù)的現(xiàn)代化程度,都會(huì)通過機(jī)械工業(yè)的發(fā)展程度反映出來。人們之所以要廣泛使用機(jī)器,是由于機(jī)器既能承擔(dān)人力所不能或不便進(jìn)行的工作,又能較人工生產(chǎn)改進(jìn)產(chǎn)品的質(zhì)量,特別是能夠大大提高勞動(dòng)生產(chǎn)率和改善勞動(dòng)條件。機(jī)械工業(yè)肩負(fù)著為國民經(jīng)濟(jì)各個(gè)部門提供技術(shù)裝備和促進(jìn)技術(shù)改造的重要任務(wù),在現(xiàn)代化建設(shè)的進(jìn)程中起著主導(dǎo)和決定性的作用。所以通過大量設(shè)計(jì)制造和廣泛使用各種各樣先進(jìn)的機(jī)器,就能大大加強(qiáng)和促進(jìn)國民經(jīng)濟(jì)發(fā)展的力度,加速我國的社會(huì)主義現(xiàn)代化建設(shè)。
機(jī)械加工工藝是實(shí)現(xiàn)產(chǎn)品設(shè)計(jì),保證產(chǎn)品質(zhì)量、節(jié)約能源、降低成本的重要手段,是企業(yè)進(jìn)行生產(chǎn)準(zhǔn)備,計(jì)劃調(diào)度、加工操作、生產(chǎn)安全、技術(shù)檢測和健全勞動(dòng)組織的重要依據(jù),也是企業(yè)上品種、上質(zhì)量、上水平,加速產(chǎn)品更新,提高經(jīng)濟(jì)效益的技術(shù)保證。然而夾具又是制造系統(tǒng)的重要組成部分,不論是傳統(tǒng)制造,還是現(xiàn)代制造系統(tǒng),夾具都是十分重要的。因此,好的夾具設(shè)計(jì)可以提高產(chǎn)品勞動(dòng)生產(chǎn)率,保證和提高加工精度,降低生產(chǎn)成本等,還可以擴(kuò)大機(jī)床的使用范圍,從而使產(chǎn)品在保證精度的前提下提高效率、降低成本。當(dāng)今激烈的市場競爭和企業(yè)信息化的要求,企業(yè)對(duì)夾具的設(shè)計(jì)及制造提出了更高的要求。我們這些即將大學(xué)畢業(yè)的機(jī)械工程及自動(dòng)化專業(yè)的學(xué)生,要進(jìn)行對(duì)本專業(yè)所學(xué)習(xí)的知識(shí)進(jìn)行綜合的運(yùn)用和掌握,為此我們要進(jìn)行畢業(yè)設(shè)計(jì),要自己動(dòng)手進(jìn)行思考問題,為社會(huì)主義現(xiàn)代化建設(shè)的發(fā)展貢獻(xiàn)力量,也要從此邁出展現(xiàn)自己價(jià)值的第一步。
本次設(shè)計(jì)是根據(jù)生產(chǎn)的要求,設(shè)計(jì)右軸架工藝分析與夾具設(shè)計(jì)。所用機(jī)床主要是銑床、鉆床以及加工中心等。本次設(shè)計(jì)要求是單班制年產(chǎn)5000件;夾具設(shè)計(jì)須定位準(zhǔn)確,夾緊可靠。以及節(jié)約勞動(dòng)力,節(jié)約生產(chǎn)成本,提高生產(chǎn)的效率。但由于本人的水平有限,結(jié)合生產(chǎn)實(shí)際應(yīng)用設(shè)備的能力有限,故沒有能夠做到很詳細(xì)的設(shè)計(jì),而且還有許多地方有待改進(jìn),請老師給以指導(dǎo)和批評(píng)[1]。
2 生產(chǎn)綱領(lǐng)
2.1 計(jì)算生產(chǎn)綱領(lǐng)決定生產(chǎn)類型
生產(chǎn)綱領(lǐng)是企業(yè)在計(jì)劃期內(nèi)應(yīng)當(dāng)生產(chǎn)的產(chǎn)品產(chǎn)量和進(jìn)度計(jì)劃。(計(jì)劃期常為一年,所以生產(chǎn)綱領(lǐng)也稱年產(chǎn)量。)
如附圖所示的右軸架,該產(chǎn)品年產(chǎn)量為5000件,設(shè)備品率為17%機(jī)械加工廢品率為0.5%,現(xiàn)制定該零件的機(jī)械加工工藝流程。
生產(chǎn)綱領(lǐng)N
N=Qn(1+a%+b%)
=5000ⅹ(1+17%+0.5%)
=5875(件/年)
年產(chǎn)量為5875(件/年),現(xiàn)通過計(jì)算, 生產(chǎn)綱領(lǐng)對(duì)工廠的生產(chǎn)過程和生產(chǎn)組織有著決定性的作用,包括各工作點(diǎn)的專業(yè)化程度,加工方法,加工工藝設(shè)備和工裝等。同一種產(chǎn)品,生產(chǎn)綱領(lǐng)不同也會(huì)有完全不同的生產(chǎn)過程和專業(yè)化程度,即有著完全不同的生產(chǎn)組織類型。根據(jù)生產(chǎn)專業(yè)化程度的不同,生產(chǎn)組織類型可分為單件生產(chǎn),成批生產(chǎn),和大量生產(chǎn)三種,其中成批生產(chǎn)可分為大批生產(chǎn),中批生產(chǎn)和小批生產(chǎn),下表1是各種生產(chǎn)組織管理類型的劃分,從工藝特點(diǎn)上看單件生產(chǎn)與小批生產(chǎn)相近,大批生產(chǎn)和大量生產(chǎn)相近,因此在生產(chǎn)中一般按單件小批,中批,大批大量生產(chǎn)來劃分生產(chǎn)類型,這三種類型有著各自的工藝特點(diǎn)。
表1 生產(chǎn)組織管理類型的劃分
結(jié)束語
1 該畢業(yè)設(shè)計(jì)是培養(yǎng)我綜合運(yùn)用所學(xué)知識(shí)、發(fā)現(xiàn)、提出、分析和解決實(shí)際問題的能力。
2 回顧這次畢業(yè)設(shè)計(jì),從選題到最后的完成可以說是苦多于甜,但是這次設(shè)計(jì)鞏固了我以前所學(xué)的知識(shí),可以說是受益匪淺。
3 這次設(shè)計(jì)使我收獲了獨(dú)立分析和解決問題的方法與能力,并懂得了一個(gè)道理理論聯(lián)系實(shí)際很重要
4 設(shè)計(jì)過程中我暴露了諸多的不足,這有待我以后加以改進(jìn)和完善。
5 這次設(shè)計(jì)能夠順利完成,除了問老師查閱資料,自己的毅力也占了很大的程度。沒有我的不懈的堅(jiān)持,恐怕是不能完成這次設(shè)計(jì)的。
6 在物質(zhì)上給了我很大的幫助,我們不僅去林海看零件,還使用了的一些內(nèi)部資料,這對(duì)我完成設(shè)計(jì)有很大的幫助。
7 只有理論知識(shí)是遠(yuǎn)遠(yuǎn)不夠的,只有把所學(xué)的理論知識(shí)與實(shí)踐相結(jié)合起來,從理論中得出結(jié)論,才能真正為社會(huì)服務(wù),從而提高自己的實(shí)際動(dòng)手能力和獨(dú)立思考的能力。
這次畢業(yè)設(shè)計(jì)使我受益匪淺,為我今后的學(xué)習(xí)和工作打下了一個(gè)堅(jiān)實(shí)而良好的基礎(chǔ)。在此衷心感謝各位老師的幫助和指導(dǎo)。
致 謝
經(jīng)過近四個(gè)月的忙碌和工作,本次畢業(yè)設(shè)計(jì)已經(jīng)接近尾聲,作為一個(gè)大學(xué)生的畢業(yè)設(shè)計(jì),由于經(jīng)驗(yàn)的匱乏,難免有許多考慮不周全的地方,如果沒有導(dǎo)師的督促指導(dǎo),以及一起工作的同學(xué)們的支持,想要完成這個(gè)設(shè)計(jì)是難以想象的。
在這里首先要感謝我的指導(dǎo)老師。他平日里工作繁多,但在我做畢業(yè)設(shè)計(jì)的每個(gè)階段,從開題報(bào)告到查閱資料,設(shè)計(jì)草案的確定和修改,中期檢查,后期詳細(xì)設(shè)計(jì),裝配草圖等整個(gè)過程中都給予了我悉心的指導(dǎo)。我的設(shè)計(jì)較為復(fù)雜煩瑣,但是老師們?nèi)匀患?xì)心地糾正圖紙中的錯(cuò)誤。除了敬佩老師的專業(yè)水平外,他的治學(xué)嚴(yán)謹(jǐn)和科學(xué)研究的精神也是我永遠(yuǎn)學(xué)習(xí)的榜樣,并將積極影響我今后的學(xué)習(xí)和工作。
其次要感謝和我一起作畢業(yè)設(shè)計(jì)的同學(xué)們,他們在本次設(shè)計(jì)中勤奮工作,克服了許多困難來完成此次畢業(yè)設(shè)計(jì),并分擔(dān)了許多工作。如果沒有他們的努力,此次設(shè)計(jì)的完成將變得非常困難。
感謝學(xué)校圖書館的開放,讓我們有足夠的資料可供參考。還要感謝大學(xué)四年來所有的老師,為我們打下機(jī)械技術(shù)專業(yè)知識(shí)的基礎(chǔ);同時(shí)還要感謝所有的同學(xué)們,正是因?yàn)橛辛四銈兊闹С趾凸膭?lì)。此次畢業(yè)設(shè)計(jì)才會(huì)順利完成。
通過畢業(yè)設(shè)計(jì),使我對(duì)機(jī)械加工工藝這門課程進(jìn)一步加深了理解。對(duì)于各方面知識(shí)之間的相互聯(lián)系有了實(shí)際的體會(huì)。同時(shí)也深深感到自己初步掌握的知識(shí)與實(shí)際需要還有相當(dāng)距離,還需在今后進(jìn)一步學(xué)習(xí)和實(shí)踐。
本設(shè)計(jì)由于時(shí)間緊和對(duì)知識(shí)的掌握程度的限制,在設(shè)計(jì)上不很周詳,許多應(yīng)該考慮的因素,可能沒在設(shè)計(jì)上體現(xiàn)出來。在這次設(shè)計(jì)過程中,我得到老師的精心指導(dǎo)和各方面的幫助,才能使設(shè)計(jì)得以順利進(jìn)行,借此我深表謝意。
最后感謝學(xué)院四年來對(duì)我的大力栽培!
參 考 文 獻(xiàn)
[1] 趙家齊. 機(jī)械制造工藝學(xué)課程設(shè)計(jì)指導(dǎo)書[M].第二版,北京:北京出版社,2008.12.
[2] 鄭修本. 機(jī)械制造工藝學(xué)[M].北京:機(jī)械工業(yè)出版社,2007.
[3] 鄭修本. 機(jī)械制造工藝學(xué)[M].第二版,北京:機(jī)械工業(yè)出版社,1999.
[5] 王先逵.機(jī)械制造工藝學(xué)[M].北京:機(jī)械工業(yè)出版社,2004.
[6] 金屬機(jī)械加工工藝人員手冊修訂組. 金屬機(jī)械加工工藝人員手冊[M]. 第一版,上海:上??茖W(xué)技術(shù)出版社,1965.6.
[7] 美國可切削性數(shù)據(jù)中心.機(jī)械加工切削數(shù)據(jù)手冊[M]. 第一版,北京:機(jī)械工業(yè)出版社,1989.9.
[8] 李慶余, 張佳等主編.機(jī)械制造裝備設(shè)計(jì)[M].北京:機(jī)械工業(yè)出版社,2007.
[9] 龔定安,蔡建國編著.機(jī)床夾具設(shè)計(jì)原理[M].西安:陜西科學(xué)技術(shù)出版社1999.
[10] 徐發(fā)仁.氣動(dòng)液壓機(jī)床夾具設(shè)計(jì)[M]. 上海:上海科學(xué)技術(shù)出版社,1982.
[12] 濮良貴,紀(jì)名剛. 機(jī)械設(shè)計(jì)[M]. 第八版,北京:高等教育出版社,2006.
[13] 薛源順.機(jī)床夾具設(shè)計(jì)[M]. 第二版,北京:機(jī)械工業(yè)出版社,2003.
[14] 中國亞德客企業(yè)(集團(tuán))有限公司.氣動(dòng)裝置產(chǎn)品[M]. 第三版 2005.
[15] 孫麗媛主編.機(jī)械制造工藝及專用夾具設(shè)計(jì)指導(dǎo)[M].北京:冶金工業(yè)出版社,2002.
[16] 張耀震,馬占永.機(jī)械加工工藝設(shè)計(jì)實(shí)用手冊[M].第一版,北京:航天工業(yè)出版社,1993.
[17] 美國可切削性數(shù)據(jù)中心.機(jī)械加工切削數(shù)據(jù)手冊[M]. 第一版,北京:機(jī)械工業(yè)出版社,1989.
[18] 楊叔子主編.機(jī)械加工工藝師手冊[S].北京:機(jī)械工業(yè)出版社,2001.
[19] 趙家齊.機(jī)械制造裝備設(shè)計(jì)基礎(chǔ)[M].上海:上海交通大學(xué)出版社,2004.
[20] 徐學(xué)林.互換性性與測試技術(shù)基礎(chǔ)[M].長沙:湖南大學(xué)出版社,2007.
[22] 李益民. 機(jī)械制造工藝設(shè)計(jì)簡明手冊[S].北京:機(jī)械工業(yè)出版社,2001.
[23] 張耀震.機(jī)械加工工藝設(shè)計(jì)手冊[M].第一版,北京:航天工業(yè)出版社,1987.
[24] 艾興,肖詩綱.切削用量簡明手冊[M].第一版,北京:北京出版社,1993.
南京理工大學(xué)畢業(yè)設(shè)計(jì)(論文)外文資料翻譯系 部: 機(jī)械工程系 專 業(yè): 機(jī)械工程及自動(dòng)化 姓 名: 學(xué) 號(hào): 外文出處: English in Mechanical and Electrical Engineering附 件: 1.外文資料翻譯譯文;2.外文原文。 指導(dǎo)教師評(píng)語:簽名: 年 月 日注:請將該封面與附件裝訂成冊。附件 1:外文資料翻譯譯文銑削銑削是機(jī)械加工的一個(gè)基礎(chǔ)方法。在這一加工過程中,當(dāng)工件沿垂直于旋轉(zhuǎn)刀具軸線方向進(jìn)給時(shí),在工件上形成并去除切屑從而逐漸地銑出表面。有時(shí)候,工件是固定的,而刀具處于進(jìn)給狀態(tài)。在大多數(shù)情況下,使用多齒刀具,金屬切削量大,只需一次銑削就可以獲得所期望的表面。在銑削加工中使用的刀具稱做銑刀。它通常是一個(gè)繞其軸線旋轉(zhuǎn)并且周邊帶有同間距齒的圓柱體,銑刀齒間歇性接觸并切削工件。在某些情況下,銑刀上的刀齒會(huì)高出圓柱體的一端或兩端。由于銑削切削金屬速度很快,并且能產(chǎn)生良好的表面光潔度,故特別適合大規(guī)模生產(chǎn)加工。為了實(shí)現(xiàn)這一目的,已經(jīng)制造出了質(zhì)量一流的銑床。然而在機(jī)修車間和工具模具加工中也已經(jīng)廣泛地使用了非常精確的多功能通用的銑床。車間里擁有一臺(tái)銑床和一臺(tái)普通車床就能加工出具有適合尺寸的各種產(chǎn)品。銑削操作類型:銑削操作可以分成兩大種類,每一類又有多種類型。1.圓周銑削 在圓周銑削中,使用的銑刀刀齒固定在刀體的圓周面上,工件銑削表面與旋轉(zhuǎn)刀具軸線平行,從而加工表面。使用這種方法可以加工出平面和成型表面,加工中表面橫截面與刀具的軸向外輪廓相一致。這種加工過程常被稱為平面銑削。2.端面銑削 銑削平面與刀具的軸線垂直,被加工平面是刀具位于周邊和端面的齒綜合作用形成的。刀具周邊齒完成銑削的主要任務(wù),而端面齒用于精銑。圓周銑削和端面銑削的基本概念,圓周銑削通常使用臥式銑床,而端銑削則既可在臥式銑床又可以在立式銑床上進(jìn)行。銑削面的形成:銑削時(shí)可以采用兩種完全不同的方法。應(yīng)注意,在逆銑時(shí),銑刀旋轉(zhuǎn)方向與工件進(jìn)給方向相反,而在順銑時(shí)銑刀旋轉(zhuǎn)與工件進(jìn)給方向相同。在逆銑過程中,當(dāng)銑刀齒剛切人工件時(shí),切屑是非常薄的,然后漸漸增厚,在刀齒離開工件的地方,切屑最厚。在兩種銑削方法中,切屑的形成是不同的,逆銑過程中,刀具有推動(dòng)工什丌使工件從工作臺(tái)上提升的趨勢,這種作用有助于消除銑床工作臺(tái)進(jìn)給螺桿和螺母間的間隙,從而形成平穩(wěn)的切削。然而,這種作用也有造成工件與夾緊裝置之間的松動(dòng)的趨勢,這時(shí)應(yīng)施加更大的夾緊力。此外,銑削表面的平整度主要取決于切削刃的鋒利程度。 順銑時(shí),最大切屑厚度產(chǎn)生于靠近刀具與工件接觸點(diǎn)處。由于相對(duì)運(yùn)動(dòng)趨于把工件拉向銑刀,如果采用順銑法,要消除工作臺(tái)進(jìn)給螺桿可能產(chǎn)生的松動(dòng)。因此,對(duì)于不能用于順銑的銑床,不要采用順銑方法。因?yàn)樵阢姷督Y(jié)束切削時(shí),處于切線方向的被切材料發(fā)生屈服,所以與逆銑相比,順銑的被加工表面沒有什么切痕。順銑的另一個(gè)優(yōu)勢是切削力趨于將工件壓緊在工作臺(tái)上,因此對(duì)工件的夾緊力可以小于逆銑。這一優(yōu)勢可以用于銑削較薄的工件或進(jìn)行強(qiáng)力切削。順銑的弱點(diǎn)是銑刀齒剛一切削每片鐵屑時(shí),刀齒會(huì)撞擊工件的表面。如果工件表面堅(jiān)硬,像鑄件,就會(huì)使刀齒迅速地變鈍。銑刀分類有多種方法,一種方法是根據(jù)刀具后角將銑刀分為兩大類:1.仿形銑刀 每個(gè)刀齒在切削刃的背面磨了一個(gè)很小的棱面形成后角,切削刃可以是直線或曲線的。 2.成形或凸輪形后角銑刀 每個(gè)齒的橫截面在切削刃的背面呈偏心曲線狀,以產(chǎn)生后角。偏心后角的各面與切削刃平行,具有切削刃的相同形狀。這種類型的銑刀僅需磨削齒的前刀面就可以變得鋒利,只要切削刃的外形保持不變,銑刀的另一種分類方法是根據(jù)銑刀安裝的方法進(jìn)行分類。心軸銑刀帶有一個(gè)中心孔以使銑刀安裝在心軸上。帶柄銑刀有一錐柄或直柄軸,含錐形軸柄的銑刀可以直接安裝在銑床的主軸上,而直柄軸的銑刀則是夾持在卡盤里。—平面銑刀通常用螺栓固定在刀軸的末端上。根據(jù)這種分類方法,通用型的銑刀可分類如下:心軸銑刀:圓柱形銑刀,角度銑刀,側(cè)刃銑刀,嵌齒銑刀,錯(cuò)齒銑刀,成形銑刀,開槽銑刀,高速切削刀。帶柄銑刀:端面銑刀,T 形槽銑刀,整體式銑刀,半圓鍵座銑刀,套式銑刀,高速切削刀,空心銑刀。銑刀的類型 圓柱形銑刀是在圓周上有直的或螺旋形的齒的圓柱形或盤形銑刀。它們可以用來銑削平面,這種銑削稱做平面銑削。螺旋形的銑刀上的每個(gè)齒是逐漸地接觸工件,在給定的時(shí)間內(nèi),一般有多齒進(jìn)行銑削,這樣可以減少震動(dòng),獲得一個(gè)較平滑的表面。因此,與直齒銑刀相比,這種類型的銑刀,通常使用得更多。 ’側(cè)刃銑刀的齒除了在圓柱刀體的一端或兩端向徑向延伸之外,與圓柱形銑刀是相似的。側(cè)刃銑刀的刀齒既可以是直線的,也可以是螺旋形的,這種銑刀一般較窄小,具有盤形的形狀。在跨式銑削加工中,常常將兩個(gè)或更多的側(cè)刃銑刀同時(shí)相間地安裝在一個(gè)刀桿上同步并行切削。雙聯(lián)槽銑刀是由兩個(gè)側(cè)刃銑刀組成,但是在銑槽時(shí),作為一組銑刀進(jìn)行操作。在兩個(gè)銑刀之間添加一些薄墊片,以調(diào)整之間的間距。錯(cuò)齒銑刀是較薄的圓柱形銑刀,刀上有相互交錯(cuò)的刀齒,相鄰刀齒具有相反的螺旋角。這種銑刀經(jīng)研磨后僅用于周銑,在每個(gè)齒突出的一邊,留有供切屑排出的縫隙。這種類型的銑刀可用于高速切削,在銑削深槽時(shí)可以發(fā)揮獨(dú)特的作用。開槽銑刀是一種薄型的圓柱形銑刀,厚度一般為 1/32—3/16 英寸。這種銑刀的側(cè)面呈盤狀,有間隙,可以防止粘連。與圓柱形銑刀相比,這種類型的銑刀每英寸直徑上的齒數(shù)更多,通常用于銑削較深的、狹窄的槽,并可用于切割加工。附件 2:外文原文MILLINGMilling is a basic machining process in which the surface is generated by the progressive formation and removal of chips of material from the workpiece as it is fed to a rotating cutter in a direction perpendicular to the axis of the cutter. In some cases the workpiece is stationary and the cutter is fed to the work. In most instances a multiple-tooth cutter is used so that the metal removal rate is high, and frequently the desired surface is obtained in a single pass of the work.The tool used in milling is known as a milling cutter. It usually consists of a cylindrical body which rotates on its axis and contains equally spaced peripheral teeth that intermittently engage and cut the workpiece. 1 In some cases the teeth extend part way across one or both Ends of the cylinder.Because the milling principle provides rapid metal removal and can produce good surface finish, it is particularly well-suited for mass-production work, and excellent milling machines have been developed for this purpose. However, very accurate and versatile milling Machines of a general-purpose nature also have been developed that are widely used in jobshop and tool and die work. A shop that is equipped with a milling machine and an engine lathe can machine almost any type of product of suitable size.Types of Milling Operations. Milling operations can be classified into two broad categories, each of which has several variations:1. In peripheral milling a surface is generated by teeth located in the periphery of the cutter body; the surface is parallel with the axis of rotation of the cutter. Both flat and formed surfaces can be produced by this method. The cross section of the resulting surface corresponds to the axial contour of the cutter. This procedure often is called slab milling.2. In face milling the generated flat surface is at right angles to the cutter axis and is the combined result of the actions of the portions of the teeth located on both the periphery and the face of the cutter. 2 The major portion of the cutting is done by the peripheral portions of the teeth with the face portions providing a finishing action.The basic concepts of peripheral and face milling are illustrated in Fig. 16-1. Peripheral milling operations usually are performed on machines having horizontal spindles, whereas face milling is done on both horizontal- and vertical-spindle machines.Surface Generation in Mimng. Surfaces can be generated in milling by two distinctly different methods depicted in Fig. 16-2. Note that in up milling the cutter rotates againsi the direction of feed the workpiece, whereas in down milling the rotation is in the same direction as the feed. As shown in Fig. 16-2, the method of chip formation is quite different in the two cases. In up milling the c hip is very thin at the beginning, where the tooth first contacts the work, and increases in thickness, becoming a maximum where the tooth leaves the work. The cutter tends topush the work along and lift it upward from Tool-work relationshios in peripheral and face milling the table. This action tends to eliminate any effect of looseness in the feed screw and nut of the milling machine table and results in a smooth cut. However, the action also tends to loosen the work from the clamping device so that greater clamping forcers must be employed. In addition, the smoothness of the generated surface depends greatly on the sharpness of the cutting edges. In down milling, maximum chip thickness cecum close to the point at which the tooth contacts the work. Because the relative motion tends to pull the workpiece into the cutter, all possibility of looseness in the table feed screw must be eliminated if down milling is to be used. It should never be attempted on machines that are not designed for this type of milling. Inasmush as the material yields in approximately a tangential direction at the end of the tooth engagement, there is much less tendency for the machined surface to show tooth marks than when up milling is used. Another considerable advantage of down milling is that the cutting force tends to hold the work against the machine table, permitting lower clamping force to be employed. 3 This is particularly advantageous when milling thin workpiece or when taking heavy cuts.Sometimes a disadvantage of down milling is that the cutter teeth strike against the surface of the work at the beginning of each chip. When the workpiece has a hard surface, such as castings do, this may cause the teeth to dull rapidly.Milling Cutters. Milling cutters can be classified several ways. One method is to group them into two broad classes, based on tooth relief, as follows:1. Profile-cutters have relief provided on each tooth by grinding a small land back of the cutting edge. The cutting edge may be straight or curved.2. In form or cam-reheved cutters the cross section of each tooth is an eccentric curve behind the cutting edge, thus providing relief. All sections of the eccentric relief, parallel with the cutting edge, must have the same contour as the cutting edge. Cutters of this type are sharpened by grinding only the face of the teeth, with the contour of the cutting edge thus remaining unchanged.Another useful method of classification is according to the method of mounting the cutter. Arbor cutters are those that have a center hole so they can be mounted on an arbor. Shank cutters have either tapered or straight integral shank. Those with tapered shanks can be mounted directly in the milling machine spindle, whereas straight-shank cutters are held in a chuck. Facing cutters usually are bolted to the end of a stub arbor.The common types of milling cutters, classified by this system are as follows:Types of Milling Cutters. Hain milling cutters are cylindrical or disk-shaped, having straight or helical teeth on the periphery. They are used for milling flat surfaces. This type of operation is called plain or slab milling. Each tooth in a helical cutter engages the work gradually, and usually more than one tooth cuts at a given time. This reduces shock and chattering tendencies and promotes a smoother surface. Consequently, this type of cutter usually is preferred over one with straight teeth. Side milling cutters are similar to plain milling cutters except that the teeth extend radially part way across one or both ends of the cylinder toward the :center. The teeth may be either straight or helical. Frequently these cutters are relatively narrow, being disklike in shape. Two or more side milling cutters often are spaced on an arbor to make simultaneous, parallel cuts, in an operation called straddle milling.Interlocking slotting cutters consist of two cutters similar to side mills, but made to operate as a unit for milling slots. The two cutters are adjusted to the desired width by inserting shims between them.Staggered-tooth milling cutters are narrow cylindrical cutters having staggered teeth, and with alternate teeth having opposite helix angles. They are ground to cut only on the periphery, but each tooth also has chip clearance ground on the protruding side. These cutters have a free cutting action that makes them particnlarly effective in milling deep slots.Metal-slitting saws are thin, plain milling cutters, usually from 1/32 to 3/16 inch thick, which have their sides slightly "dished" to provide clearance and prevent binding. They usually have more teeth per inch of diameter than ordinary plain milling cutters and are used for milling deep, narrow slots and for cutting-off operations.