第一篇:機械工程文化
動力電池工程機械
在新能源電動汽車中,以動力電池(鉛酸蓄電池、鎳氫電池、鋰離子電池、氫燃料電池、超級電容器等)驅動的汽車稱為純電動汽車,而以動力電池驅動的工程機械雖然也是純電動的機動車,但還有不少工程機械,如塔機、施工升降機等是以交流電力驅動的純電動機械。為了與以交流電驅動的純電動工程機械相區(qū)別,本文對用動力電池驅動的純電動工程機械稱為動力電池工程機械。
事實上,以動力電池(傳統(tǒng)鉛酸蓄電池)驅動的工程機械早在數十年前就已存在,如蓄電池叉車(俗稱電瓶叉車)。雖然電瓶叉車不耗燃油、零排放,但傳統(tǒng)鉛酸蓄電池是非密封的,電解液易潑灑、污染大,維護使用不方便,能量密度小、充電時間長,電池組重量大、體積大,這些缺點限制了傳統(tǒng)蓄電池在其他工程機械機種的應用。近幾年來,鉛酸蓄電池技術有了較大的進步,出現了閥控鉛酸蓄電池、雙極性密封鉛酸蓄電池、膠體電池等新型鉛酸蓄電池,它們無電解液體外泄的缺陷,免維護、能量密度增大、充電時間縮短,重量、體積減小。另外能量密度更大,重量體積更小的新型動力電池,如鎳氫電池、鋰離子電池、超級電容器也相繼問世,大大促進了動電池工程機械的開發(fā),應用機種日益增多。如俄羅斯“TETP” 公司開發(fā)的通用型市政工程電動車,以膠體電池為動力源,動力傳動路線為膠體電池一直流電動機一液壓泵~ 行走和作業(yè)機構。其中通過分動箱驅動2個液壓泵,一為柱塞泵,供油給行走的輪轂油馬達(左、右后輪各1);一為齒輪泵,供油給作業(yè)機構動作油缸。作業(yè)機構可更換,有裝載斗(斗寬1m)、推土板(板長1m)、牽引重量250kg,最大起重高度2m、起重量150~200kg,車速~0km/h,連續(xù)作業(yè)時間4~ 5h。隨機配充電器,可插電充電,可完成小型市政工程和住宅區(qū)環(huán)衛(wèi)的裝載、管溝挖掘、起重、拖運、推土、鏟雪等作業(yè)。日本三菱~卡特彼勒公司開發(fā)的蓄電池驅動微型液壓挖掘機,斗容0.02 m3,最大挖掘深度2860mm,無駕駛室,采用有線或無線遙控。我國天津商業(yè)大學開發(fā)了蓄電池運輸臺車,武漢科技大學等單位聯合開發(fā)了蓄電池路面清掃車等。
動力電池工程機械不耗油、零排放;雙動力工程機械在作業(yè)時使用交流電,不耗油、零排放、作業(yè)成本低;混合動力工程機械省油,污染物排放量少。另外,使用電動輪的混合動力工程機械由于行走系使用柔性的電纜連接,比傳統(tǒng)的機械和液壓連接行走系運動零部件少60 左右(省去了變速箱、傳動軸、萬向節(jié)等剛性連接件),因此,有效功率系數可達26(液壓傳動的為12 ~13 9/5)。
第二篇:機械工程求職信(共)
機械工程求職信匯編五篇
時間是箭,去來迅疾,沒想到也到了自己找工作的時間,是時候靜下心來寫一封求職信了哦。但是求職信要寫什么內容才是恰當的呢?下面是小編整理的機械工程求職信6篇,僅供參考,大家一起來看看吧。
機械工程求職信 篇1尊敬的
您好!我的名字叫XX,我是XXX工業(yè)職業(yè)技術學院機械工程系的一名學生,即將面臨畢業(yè)。
XXX工業(yè)職業(yè)技術學院是由國家教育部,XX批準的普通??茖W校,是我國工程類人才的重點培養(yǎng)基地,具有先進的教學設施,并且堅持以“以人為本,質量立校,讓每個同學走向成功”而著稱。XX工業(yè)職業(yè)技術學院機械工程系則是全國機械類人才的重點培養(yǎng)基地之一。在這樣的學習環(huán)境下,無論是在知識能力,還是在個人素質修養(yǎng)方面,我都受益非淺。
三年來,在師友的嚴格教益及個人的努力下,我具備了扎實的專業(yè)基礎知識,系統(tǒng)地掌握了機械設計、機械制造等有關理論;熟悉涉外工作常用禮儀;具備較好的英語聽、說、讀、寫、譯等能力;能熟練操作計算機辦公。同時,我利用課余時間廣泛地涉獵了大量書籍,不但充實了自己,也培養(yǎng)了自己多方面的技能。更重要的是,嚴謹的學風和端正的學習態(tài)度塑造了我樸實、穩(wěn)重、創(chuàng)新的性格特點。
此外,我還積極地參加各種社會活動,抓住每一個機會,鍛煉自己。大學三年,我深深地感受到,與優(yōu)秀學生共事,使我在競爭中獲益;向實際困難挑戰(zhàn),讓我在挫折中成長。祖輩們教我勤奮、盡責、善良、正直;平頂山工業(yè)職業(yè)技術學院培養(yǎng)了我實事求是、開拓進取的作風。我熱愛貴單位所從事的事業(yè),殷切地期望能夠在您的
收筆之際,鄭重地提一個小小的要求:無論您是否選擇我,尊敬的
此致
敬禮!
求職人:xx
XXX年XX月XX日
機械工程求職信 篇2
尊敬的公司領導:
您好!
很高興您能耐心閱讀我的求職信。
我是一名大四的學生,修讀xxx工業(yè)大學機械學院,機械工程及自動化專業(yè),機械電子工程方向。想為自己找一份工作,在實際中鍛煉自己,發(fā)揮自己所長,檢驗自己所學。
機械工程及自動化是我選擇的專業(yè)方向,對于大四的我,工作經驗不足是我的一個不足之處,但是我在大學期間學習的專業(yè)課,如機械制圖與cad,工程材料與成行技術,機械制造基礎,專業(yè)外語,公差與技術測量,液壓與氣壓傳動,機械cad/cam基礎,測等,讓我掌握了理論專業(yè)知識,并且在生產實習中很好地把理論和實踐結合起來,這也成為我的寶貴經驗。
我是個好學吃苦的人,在平時的學習生活中,總能把事情做的很好,在豐富的學校生活中擔任了很多角色,在擔任班級干部時,由我親手整理和編寫的申請材料,使得班級獲得了優(yōu)秀班集體的榮譽。
也曾有幸加入到北京城市志愿者的行列,在充實的志愿服務工作中,我感受到了人們愛國的熱情,并也深受感染;出任過社團組織委員和運動會領隊隊長,負責組織活動和協(xié)調團隊參加比賽,獲得了老師和同學們的一致肯定,同時也增加了更寶貴的團隊意識。
本人的再學習能力也比較強,可能剛開始有些事情還不能做得好棒,但我相信我會快把它做的很好。值此鍛煉機會來臨之際,特試向貴單位自薦,給我一個就業(yè)鍛煉的機會,還您一份成績。一顆真誠的心在期望您的信任。在以后工作學習中我更會虛心學習、積極工作、盡忠盡責做好本職工作。
最后,再次感謝你的閱讀,等待您的回音!
此致
敬禮!
求職人:
機械工程求職信 篇3尊敬的領導:
您好!
我是***學院機械工程系模具設計與制造專業(yè)20__屆畢業(yè)生。我叫***,來自重慶,本次是從學院就業(yè)中心獲得的信息,貴公司的企業(yè)文化深深的吸引了我,我真心希望能加入貴公司,竭盡我所能為貴公司的發(fā)展獻出一份力量。
我自20__年進入***學院以來,在師友的嚴格教益及憑借自己扎實的><基礎和頑強拼搏的奮斗精神,經過幾年不斷的學習,在各方面都取得了長足的發(fā)展。
在專業(yè)知識的學習上,我本著實事求是的態(tài)度努力培養(yǎng)自己的實踐動手能力,多次參加學院組織的校內、校外實習,掌握了一定的專業(yè)技能,并于20__年通過了焊工(中級)技能考試,20__年還通過了數控(中級)技能考試,為今后的學習打下了堅實的基礎。
為了培養(yǎng)我的'社會實踐能力,豐富我的大學文化生活,20__年加入院團委網絡部,20__年又加入外聯部,這一段工作經歷都提高了我的組織管理能力,對團隊合作意識有了更深的認識,在業(yè)余時間,相繼學習了文字排板、VF6.0、C語言等應用軟件,掌握了一定的計算機技術,在專業(yè)方面,具有扎實的專業(yè)基礎,掌握了機械制圖,機械設計,工差技術,冷沖壓技術,模具工藝學等專業(yè)知識。
望貴公司領導給我一個展示自我的一個舞臺,我有信心把領導交給的工作做好。思想上我積極要求進步,20__年參加黨課培訓,現已畢業(yè),在校期間踴躍參加各項體育文藝活動,以此培養(yǎng)團隊協(xié)作精神,并展示了自己的才華,長期擔任學生干部,設計并組織了多項活動,有一定的組織能力。這許多的榮譽并不是我在炫耀,而只是想證明我的能力,我愿意從最基層做起,可以積累更多的經驗,了解更多的情況,愿您能給我一次實現自己夢想的機會,愿我可以為貴公司的發(fā)展添微薄之力。
我渴盼貴公司的佳音,再次感謝您。
此致
敬禮!
求職人:
XXXX年XX月XX日
機械工程求職信 篇4尊敬的領導:
你好!當您打開這封,您已經快看到了希望!我是xxxx機械工業(yè)學校的機械工程專業(yè)的畢業(yè)生,真誠希望成為貴公司的一員。
在校期間,在師友的嚴格教益及個人的努力下,我具備了扎實的基礎知識,系統(tǒng)的掌握了機械制圖,AutocAD極限配合與公差技術測量,金屬材料與熱處理,東工工藝,數控編程,數控工藝,機械基礎,電工學,刀具與切削原理,等理論知識熟悉涉外禮儀,同時在課外也學習了許多日常應用軟件,不但充實了自己,也培養(yǎng)了自己多方面的技能。更重要的是,嚴謹的學風和端正的學習態(tài)度,塑造了我樸實穩(wěn)重,創(chuàng)新的性格。
在實踐上,我不僅努力學好專業(yè)知識,還積極參加各種社會實踐活動,抓住了每一個機會,不斷鍛煉自己。假期時間,去外出打工。在這其中,我深感受到,在競爭中獲益非淺,在困難中勇敢面對,在挫折中成長。
通過對貴公司的認真了解后,我熱愛貴公司所從事的事業(yè),很希望能夠在您的領導下,為這一光榮事業(yè)添磚加瓦,并且,在實踐中不斷學習進步。
希望領導能夠對我予以考慮,我熱切期盼您的回音,謝謝!
祝愿貴公司事業(yè)蒸蒸日上,屢創(chuàng)佳績!
此致
敬禮!
機械工程求職信 篇5尊敬的公司領導:
您好!我是XX大學機械電子工程專業(yè)畢業(yè)生,我真心希望加入貴公司,竭盡我所能為貴公司的發(fā)展出一份力量。
我自進入XX大學以來,憑借自身扎實的基礎和頑強拼搏的奮斗精神,經過幾年不斷的學習,在各方面都取得了長足的發(fā)展。在專業(yè)知識的學習上,我本著實事求是的態(tài)度,努力培養(yǎng)自己的實踐動手能力。綜合分在整個學院名列前茅,并通過了國家英語四級考試和計算機二級考試,并取得優(yōu)秀,為今后外語和計算機的學習打下了堅實基礎;在專業(yè)外語上,有一定的實踐基礎,有較強的翻譯能力。在業(yè)余時間,相繼學習了C語言、FORTRAN語言及OFFICE、AUTOCADR、CAM、PHOTOSHOP、ME等應用軟件。
同時具有較強的硬件基礎。工業(yè)PC機編程能力強,能設計PC機程序控制系統(tǒng),熟悉MCS—51系列單片機實用接口技術。在專業(yè)方面,具有扎實的專業(yè)基礎,我的各門專業(yè)課都在80分以上,大部分過了90分,對機電液一體化設計有濃厚的興趣,特別是在動力傳動系統(tǒng)及控制方面有豐富的實踐經驗和理論基礎?,F剛接過導師分給的課題,為下學期的畢業(yè)設計收集參數。望貴公司領導相信,我有決心,也有能力把領導交給的工作做好。
我積極要求進步,被發(fā)展為入黨積極分子,并參加了黨校學習班,現已畢業(yè),并獲“優(yōu)秀共青團員”稱號,還被發(fā)展為重點積極分子;后被列為預備黨員發(fā)展計劃。在校期間,我踴躍參加各項體育、文娛活動,以此培養(yǎng)團結協(xié)作精神,并發(fā)展自己的才華。我長期擔任班級干部,設計并組織過多項活動,有一定的組織能力。
穩(wěn)重但不缺乏熱情,銳意進取又能與人和睦相處,這是年輕的我的真實寫照,愿成為貴公司的一員,憑借我的熱情和才能,不遺余力的和大家一起為貴公司的騰飛做貢獻。我相信,這對我們雙方,都將是一次正確的選擇。
此致
敬禮!
求職人:
XXXX年XX月XX日
第三篇:機械工程專業(yè)自薦信
尊敬的公司領導:
您好!感謝您在百忙之中抽出寶貴的時間閱覽我這份自薦信。我叫劉為進,是江西應用工程職業(yè)學院機械工程系汽車應用技術專業(yè)2009屆畢業(yè)生。在即將結束大學學習階段之際,我強烈希望能加入貴公司,貢獻自己的才能和熱情。
隨著社會競爭的日益激烈,對人才的要求也越來越高,為了畢業(yè)后能更好地適應社會,在大學里,我注重培養(yǎng)自己全面發(fā)展。思想上積極要求進步,努力向黨組織靠攏,信念堅定,注重自身道德修養(yǎng)的培養(yǎng)與提高,同時被推薦為建黨對象。學習態(tài)度端正,勇于探索,刻苦勤奮,成績優(yōu)良,曾連續(xù)三次榮獲“三好學生”稱號和兩次“國家勵志獎學金”。在能力培養(yǎng)上,充分地利用課余時間參加學生會、社團和班級工作,積極參加并舉辦一些活動,努力發(fā)掘自己多方面潛質,發(fā)揮特長,同時積累一些工作經驗。在假期里,先后在合肥紫蓬灣國際高爾夫有限公司和東莞距旺鞋業(yè)有限公司工作;通過各種課外活動及社會實踐工作,培養(yǎng)了我邏輯分析與實際操作能力,更使我懂得了團隊精神的可貴。
熱切期望我這拳拳寸草心、濃濃赤誠情能與您同呼吸、共命運、同發(fā)展、求進步。如有幸能成為貴公司的一員,我將以滿腔熱情、高度的責任感和敬業(yè)精神,發(fā)揮特長,為貴公司的事業(yè)騰飛貢獻自己的力量。
感謝您在百忙之中給予我關注,衷心祝愿貴公司事業(yè)蒸蒸日上,屢創(chuàng)佳績。祝您的事業(yè)百尺竿頭,更進一步。
第四篇:機械工程工作小結
工作小結
轉眼間我在實業(yè)公司見習已經6個月了,加入實業(yè)的半年里,對于我來說是一種成長與進步的歷程。從頭開始學習我完全陌生的一種工作方式,工作內容,以及工作程序。第一次操作車床,第一次磨削車刀,第一次加工產品。做這些之前我首先都是要用心去向師傅學習,然后必須要熟練運用在工作中的每一個細節(jié)里。現根據自身工作的實際情況,我對自己的工作做出分析評定,總結經驗教訓,提出改進方法,以便使自己在今后的工作中能懲前毖后,揚長補短,為今后不斷改進工作方法,提高工作效率提供依據。
1、端正思想,擺正位置,全心投入工作
工作中,本人自覺樹立“實業(yè)人,做實在事”的思想,堅持以廠為家,切實增強責任感和使命感,以飽滿的工作熱情和端正的工作態(tài)度,認真做好自己的本職工作;自覺樹立正確的價值觀和道德觀,始終愛崗敬業(yè),恪盡職守;自覺樹立奉獻意識,一心撲在工作上,不遲到,不早退,即使加班加點也毫無怨言。
2、加強學習,虛心求教,努力提高工作能力
作為一名實業(yè)公司的新員工,本人深知自己的工作能力與公司的要求還有一定差距。為此,對待工作我不敢有絲毫懈怠,我要求自己做到手勤,要多記工作筆記,多做記錄,盡量把工作中的得失和每次出現的問題記錄下來以吸取經驗教訓;口勤,要多問,遇到疑難問題或工作中遇到的困難就向師傅請教;耳勤,多聽取老師傅們與同事們提出的好的意見建議,改進工作方法,提高工作效率,努力使自己在工作中精益求精。積極學習公司有關安全制度和規(guī)定,增強安全防范意識,確保工作中不出現紕漏。
3、積極進取,扎實工作,努力完成各項工作任務
美國思想家富蘭克林說過:“你要推動事業(yè),而不是讓事業(yè)推動你”?!澳阋非蠊ぷ?,別讓工作追求你”。我理解這兩句話的意思是,既要提高工作的自覺性,又要積極主動地去工作,變被動工作為主動工作。
在實際工作中,領導和師傅們許多非常優(yōu)秀品質,如認真扎實細致的工作作風以及從他們身上體現出的高度敬業(yè)奉獻的精神,給我留下了深刻的印象,時刻在激勵著我,感染著我,促使我努力工作,督促自己要始終保持愉快的接受安排的工作任務,并不折不扣的完成任務的工作態(tài)度。在工作中做到有始有終。
綜觀6個月來的各項工作,雖然較好的履行了崗位職責,對工作的學習在本職工作上也得到了有效體現,但也存在不少問題,主要表現在:一是車刀的磨削技巧還存在不足,二是自己的獨立工作能力還有待提高。針對自己工作上的問題,本人在下步工作中需要認真加以改進和完善,扎實工作,努力學習,爭取在以后的工作中取得更大的成績。
第五篇:機械工程英語翻譯
Unit1
1、What is the difference between an alloy and a pure metal? Pure metals are elements which come from a particular area of the periodic table.Examples of pure metals include copper in electrical wires and aluminum in cooking foil and beverage cans.合金與純金屬的區(qū)別是什么?純金屬是在元素周期表中占據特定位置的元素。例如電線中的銅和制造烹飪箔及飲料罐的鋁。
Alloys contain more than one metallic element.Their properties can be changed by changing the elements present in the alloy.Examples of metal alloys include stainless steel which is an alloy of iron, nickel, and chromium;and gold jewelry which usually contains an alloy of gold and nickel.合金包含不止一種金屬元素。合金的性質能通過改變其中存在的元素而改變。金屬合金的例子有:不銹鋼是一種鐵、鎳、鉻的合金,以及金飾品通常含有金鎳合金。
2、Why are metals and alloys used? Many metals and alloys have high densities and are used in applications which require a high mass-to-volume ratio.為什么要使用金屬和合金?許多金屬和合金具有高密度,因此被用在需要較高質量體積比的場合。
Some metal alloys,such as those based on aluminum, have low densities and are used in aerospace applications for fuel economy.Many alloys also have high fracture toughness, which means they can withstand impact and are durable.某些金屬合金,例如鋁基合金,其密度低,可用于航空航天以節(jié)約燃料。許多合金還具有高斷裂韌性,這意味著它們能經得起沖擊并且是耐用的。
3、The atomic bonding of metals also affects their properties.In metals, the outer valence electrons are shared among all atoms, and are free to travel everywhere.Since electrons conduct heat and electricity, metals make good cooking pans and electrical wires.金屬的原子連結對它們的特性也有影響。在金屬內部,原子的外層階電子由所有原子共享并能到處自由移動。由于電子能導熱和導電,所以用金屬可以制造好的烹飪鍋和電線。
It is impossible to see through metals, since these valence electrons absorb any photons of light which reach the metal.No photons pass through.因為這些階電子吸收到達金屬的光子,所以透過金屬不可能看得見。沒有光子能通過金屬.4、Some of the useful properties of ceramics and glasses include high melting temperature, low density, high strength, stiffness, hardness, wear resistance, and corrosion resistance.陶瓷和玻璃的特性高熔點、低密度、高強度、高剛度、高硬度、高耐磨性和抗腐蝕性是陶瓷和玻璃的一些有用特性。
Many ceramics are good electrical and thermal insulators.Some ceramics have special properties: some ceramics are magnetic materials;some are piezoelectric materials;and a few special ceramics are superconductors at very low temperatures.Ceramics and glasses have one major drawback: they are brittle.許多陶瓷都是電和熱的良絕緣體。某些陶瓷還具有一些特殊性能:有些是磁性材料,有些是壓電材料,還有些特殊陶瓷在極低溫度下是超導體。陶瓷和玻璃都有一個主要的缺點:它們容易破碎。
5、An optical fiber contains three layers: a core made of highly pure glass with a high refractive index for the light to travel, a middle layer of glass with a lower refractive index known as the cladding which protects the core glass from scratches and other surface imperfections, and an out polymer jacket to protect the fiber from damage.光導纖維有三層:核心由高折射指數高純光傳輸玻璃制成,中間層為低折射指數玻璃,是保護核心玻璃表面不被擦傷和完整性不被破壞的所謂覆層,外層是聚合物護套,用于保護光導纖維不受損。
In order for the core glass to have a higher refractive index than the cladding, the core glass is doped with a small, controlled amount of an impurity, or dopant, which causes light to travel slower, but does not absorb the light.為了使核心玻璃有比覆層大的折射指數,在其中摻入微小的、可控數量的能減緩光速而不會吸收光線的雜質或攙雜劑。
Because the refractive index of the core glass is greater than that of the cladding, light traveling in the core glass will remain in the core glass due to total internal reflection as long as the light strikes the core/cladding interface at an angle greater than the critical angle.由于核心玻璃的折射指數比覆層大,只要在全內反射過程中光線照射核心/覆層分界面的角度比臨界角大,在核心玻璃中傳送的光線將仍保留在核心玻璃中。The total internal reflection phenomenon, as well as the high purity of the core glass, enables light to travel long distances with little loss of intensity.全內反射現象與核心玻璃的高純度一樣,使光線幾乎無強度損耗傳遞長距離成為可能。Unit7
1、The importance of machining processes can be emphasised by the fact that every product we use in our daily life has undergone this process either directly or indirectly.機加工過程的重要性可通過日常生活使用的每件產品都直接或間接經歷這一過程的事實來強調。(1)In USA, more than $100 billions are spent annually on machining and related operations.(2)A large majority(above 80%)of all the machine tools used in the manufacturing industry have undergone metal cutting.(3)An estimate showed that about 10 to 15% of all the metal produced in USA was converted into chips.(1)在美國,每年花在機加工及其相關作業(yè)上的費用都多于千億美元
(2)用于制造業(yè)的全部機床中的大多數(多于80%)都經歷過金屬切削。(3)有估計顯示美國生產的所有金屬中約10到15%轉變成了切屑。
2、Chip Formation 切屑的形成
Metal cutting process is a very complex process.Fig.7.2 shows the basic material removal operation schematically.金屬切削過程是一個很復雜的過程。圖7.2用圖的形式顯示了基本材料去除作業(yè)。The metal in front of the tool rake face gets immediately compressed, first elastically and then plastically.This zone is traditionally called shear zone in view of fact that the material in the final form would be removed by shear from the parent metal.在刀具前傾面前的金屬直接受到壓縮,首先彈性變形然后塑性變形??紤]到最終形狀中的材料是通過剪切從母體金屬去除的,此區(qū)域傳統(tǒng)上稱為剪切區(qū)。The actual separation of the metal starts as a yielding or fracture, depending upon the cutting conditions, starting from the cutting tool tip.Then the deformed metal(called chip)flows over the tool(rake)face.金屬的實際分離始于屈服或斷裂(視切削條件而定),從切削刀尖開始。然后變形金屬(稱為切屑)流過刀具(前傾)面。
If the friction between the tool rake face and the underside of the chip(deformed material)is considerable, then the chip gets further deformed, which is termed as secondary deformation.The chip after sliding over the tool rake face is lifted away from the tool, and the resultant curvature of the chip is termed as chip curl.如果刀具前傾面與切屑(變形金屬)底面之間的摩擦相當大,那么切屑進一步變形,這也叫做二次變形。滑過刀具前傾面的切屑被提升離開刀具,切屑彎曲的結果被稱為切屑卷。
3、Discontinuous Chip.The segmented chip separates into short pieces, which may or may not adhere to each other.Severe distortion of the metal occurs adjacent to the face, resulting in a crack that runs ahead of the tool.間斷切屑:分段的切屑分散成小碎片,既可能相互附著也可能不相互附著。在靠近切削面處發(fā)生金屬的劇烈變形,導致在運動刀具前方金屬層產生裂縫。Eventually, the shear stress across the chip becomes equal to the shear strength of the material, resulting in fracture and separation.With this type of chip, there is little relative movement of the chip along the tool face, Fig.7.3a.最后,橫過切屑的剪切應力與材料的剪切強度相等,造成斷裂和分離。生成這類切屑時,切屑沿刀具面幾乎沒有相對運動,見圖7.3a。
4、Cutting Fluids 切削液
The functions of cutting fluids(which are often erroneously called coolants)are: ? To cool the tool and workpiece ? To reduce the friction ? To protect the work against rusting ? To improve the surface finish ? To prevent the formation of built-up edge ? To wash away the chips from the cutting zone 切削液(經常誤稱為冷卻液)的功能如下:
? 冷卻刀具和工件 ? 減少摩擦 ? 保護工件不生銹 ? 改善表面光潔度
? 防止切屑瘤的形成 ? 從切削區(qū)沖掉切屑
However, the prime function of a cutting fluid in a metal cutting operation is to control the total heat.This can be done by dissipating the heat generated as well as reducing it.The mechanisms by which a cutting fluid performs these functions are: cooling action and lubricating action.然而,在金屬切削作業(yè)中切削液的主要功能是控制總熱量。這可通過既散發(fā)又減少所產生的熱量來達到。切削液實現這些功能的機理是:冷卻作用和潤滑作用
5、Lubricating action.The best improvement in cutting performance can be achieved by the lubricating action since this reduces the heat generated, thus reducing the energy input to the metal cutting operation.潤滑作用:切削作業(yè)的最大改善可通過潤滑作用來達到,由于它減少了熱量的產生因而減少了金屬切削作業(yè)的能量輸入。
However, if the cutting fluid is to be effective, it must reach the chip tool interface.But it is not easy to visualize how it is accomplished in the case of a continuous turning with a single point turning tool, specially when the chip-tool contact pressure is as high as 70 MPa.可是,如果要使切削液起作用就必須讓它到達切屑刀具接觸界面。但如何在采用單尖刀具連續(xù)車削的場合尤其是切屑-刀具接觸壓力高達70MPa時實現并非易事。
Merchant thought that minute asperities existed at the chip-tool interface and the fluid was drawn into the interface by the capillary action of the interlocking network of these surface asperities.Merchant認為:在切屑與刀具接觸界面上存在微小的粗粒,切削液通過這些表面的微小粗粒組成連鎖的網絡的毛細管被吸入到切屑與刀具的接觸界面上。
第八單元
1、Grinding is a manufacturing process that involves the removal of metal by employing a rotating abrasive wheel.The latter simulates a milling cutter with an extremely large number of miniature cutting edges.磨削是通過采用旋轉磨輪去除金屬的制造工藝。磨輪用非常大量的微型切削刃模仿銑刀進行切削。
Generally, grinding is considered to be a finishing process that is usually used for obtaining high-dimensional accuracy and better surface finish.Grinding can be performed on flat, cylindrical, or even internal surfaces by employing specialized machine tools, which are referred to as grinding machines.一般而言,磨削被認為是一種通常用于獲得高尺寸精度和較好表面光潔度的精加工作業(yè)。磨削通過采用被稱為磨床的特殊機床能在平面、圓柱面甚至內表面上進行。
Obviously, grinding machines differ in construction as well as capabilities, and the type to be employed is determined mainly by the geometrical shape and nature of the surface to be ground, e.g., cylindrical surfaces are ground on cylindrical grinding machines.顯然,磨床根據結構和功能的不同有所區(qū)別,使用何種形式的磨床主要取決于被磨削表面的幾何形狀和物理性質。例如,圓柱面在外圓磨床上磨削。
2、Internal grinding.Internal grinding is employed for grinding relatively short holes, as shown in Fig.8.3.The workpiece is held in a chuck or a special fixture.Both the grinding wheel and the workpiece rotate during the operation and feed is applied in the longitudinal direction.內表面磨削:內表面磨削用于相對較短的孔,如圖8.3所示。工件安裝在卡盤或特殊夾具上。作業(yè)時砂輪和工件都回轉并且采用縱向進給。
Any desired depth of cut can be obtained by the cross feed of the grinding wheel.A variation from this type is planetary internal grinding, which is recommended for heavy workpieces that cannot be held in chucks.通過砂輪的橫向進給能得到任意所需的切削深度。這種方法的一個變體是行星式內表面磨削,當工件較重不能用卡盤固定時推薦使用。
In that case, the grinding wheel not only spins around its own axis but also rotates around the centerline of the hole that is being ground.在這種情況下,砂輪不但繞自身軸線回轉,同時還繞被磨削孔的中心線旋轉。
3、Grinding Wheels 砂輪
Grinding wheels are composed of abrasive grains having similar size and a binder.The actual grinding process is performed by the abrasive grains.Pores between the grains within the binder enable the grains to act as separate single-point cutting tools.砂輪由具有相近尺寸的磨料顆粒和粘合劑組成。實際磨削作業(yè)由磨粒完成。在粘合劑中磨粒之間的孔隙使磨粒能象獨立的單刃切削刀具一樣工作。These pores also provide space for the generated chips, thus preventing the wheel from clogging.In addition, pores assist the easy flow of coolants to enable efficient and prompt removal of the heat generated during the grinding process.這些孔隙同時還為產生的切屑提供空間以防砂輪堵塞。另外孔隙幫助冷卻液容易流動,從而使在磨削作業(yè)中產生的熱量能有效而迅速地散發(fā)。
Grinding wheels are identified based on their shape and size, kind of abrasive, grain size, binder, grade(hardness), and structure.砂輪根據它們的形狀和尺寸、磨料的類型、磨粒的大小、粘合劑、等級(硬度)和結構組織來分類
4、The grade of the bond.The grade of the bond is actually an indication of the resistance of the bond to pulling off the abrasive grains from the grinding wheel.Generally, wheels having hard grades are used for grinding soft materials and vice versa.粘結體的等級:粘結體的等級實際上是其抵抗將磨粒從砂輪上拉脫的指標。一般而言,具有較硬等級的砂輪用于磨削較軟材料,反之亦然。
If a hard-grade wheel were to be used for grinding a hard material, the dull grains would not be pulled off from the bond quickly enough, thus impeding the self-dressing process of the surface of the wheel and finally resulting in clogging of the wheel and burns on the ground surface.如果較硬等級的砂輪用于磨削較硬材料,磨鈍的磨粒將不能足夠快地脫離粘結體,這會妨礙砂輪表面的自修復,最終導致砂輪的堵塞并在被磨表面留下灼斑。In fact, the cutting properties of all grinding wheels must be restored periodically by dressing with a cemented carbide roller or a diamond tool to give the wheel the exact desired shape and remove all worn abrasive grains.實際上,所有砂輪的磨削性能都必須定期地通過使用硬質合金滾輪或金剛石修整器修整而被恢復,以求很準確地把砂輪加工成要求的形狀,并去除已磨鈍的磨粒。第十一單元
1、The Lathe and Its Construction 車床及其結構
A lathe is a machine tool used primarily for producing surfaces of revolution and flat edges.車床是主要用于生成旋轉表面和平整邊緣的機床。
Based on their purpose, construction, number of tools that can simultaneously be mounted, and degree of automation, lathes-or, more accurately, lathe-type machine tools can be classified as follows: 根據它們的使用目的、結構、能同時被安裝刀具的數量和自動化的程度,車床—或更確切地說是車床類的機床,可以被分成以下幾類:
(1)Engine lathes(2)Toolroom lathes(3)Turret lathes(4)Vertical turning and boring mills(5)Automatic lathes(6)Special-purpose lathes(1)普通車床(2)萬能車床(3)轉塔車床(4)立式車床(5)自動車床(6)特殊車床
2、The carriage.The main function of the carriage is mounting of the cutting tools and generating longitudinal and/or cross feeds.It is actually an H-shaped block that slides on the lathe bed between the head stock and tail stock while being guided by the V-shaped guide ways of the bed.大拖板:大拖板的主要功能是安裝刀具和產生縱向和/或橫向進給。它實際上是一由車床床身V形導軌引導的、能在車床床身主軸箱和尾架之間滑動的H形滑塊。
The carriage can be moved either manually or mechanically by means of the apron and either the feed rod or the lead screw.大拖板能手動或者通過溜板箱和光桿(進給桿)或絲桿(引導螺桿)機動。
3、Turning tools.Turning tools can be either finishing or rough turning tools.Rough turning tools have small nose radii and are employed when deep cuts are made.車削刀具:車削刀具可以是精車刀具或粗車刀具。粗車刀具刀尖半徑較小,用于深切削。
On the other hand, finishing tools have larger nose radii and are used for obtaining the final required dimensions with good surface finish by making slight depths of cut.Rough turning tools can be right-hand or left-hand types, depending upon the direction of feed.They can have straight,bent, or offset shanks.而精車刀具刀尖半徑較大,用于通過微量進刀深度來獲得具有較好表面光潔度的最終所需尺寸。粗車刀具按其進給方向可以是右手型的或是左手型的。它們可以有直的、彎的或偏置的刀桿。
4、Cylindrical turning.Cylindrical turning is the simplest and the most common of all lathe operations.A single full turn of the workpiece generates a circle whose center falls on the lathe axis;this motion is then reproduced numerous times as a result of the axial feed motion of the tool.圓柱面車削:圓柱面車削是所有車床操作中最簡單也是最普通的。工件旋轉一整圈產生一個圓心落在車床主軸上的圓;由于刀具的軸向進給運動這種動作重復許多次。
The resulting machining marks are, therefore, a helix having a very small pitch, which is equal to the feed.Consequently, the machined surface is always cylindrical.所以,由此產生的機加工痕跡是一條具有很小節(jié)距的螺旋線,該節(jié)距等于進給。因此機加工表面始終是圓柱形的。
The axial feed is provided by the carriage or the compound rest, either manually or automatically, whereas the depth of cut is controlled by the cross slide.軸向進給通過大拖板或復式刀架手動或自動提供,然而切削深度則由橫向滑板控制。
In roughing cuts, it is recommended that large depths of cuts(up to 0.25in.or 6mm, depending upon the workpiece material)and smaller feeds would be used.On the other hand, very fine feeds, smaller depths of cut(less than 0.05in, or 0.4mm), and high cutting speeds are preferred for finishing cuts.粗車中,推薦使用較大切削深度(根據工件材料可達0.25英寸或6毫米)和較小進給。另一方面,精車則最好采用很小的進給、較小的切削深度(小于0.05英寸或0.4毫米)和較高的切削速度。第十二單元
1、Drilling and Drills 鉆削和鉆頭
Drilling involves producing through or blind holes in a work piece by forcing a tool, which rotates around its axis, against the work piece.鉆削就是通過迫使繞自身軸線旋轉的切削刀具進入工件而在其上生成通孔或盲孔。
Consequently, the range of cutting from that axis of rotation is equal to the radius of the required hole.In practice, two symmetrical cutting edges that rotate about the same axis are employed.因此,從旋轉軸線開始的切削范圍等于所需孔的半徑。實際上,使用的是兩條圍繞相同軸線旋轉的對稱切削刃。
2、Each of the cutting edges of a milling cutter acts as an individual single-point cutter when it engages with the workpiece metal.Therefore, each of those cutting edges has appropriate rake and relief angles.在銑刀切削工件金屬時,銑刀的每條切削刃都象一單獨的單刃刀具一樣作用。所以每條切削刃都適當的前后角。
Since only a few of the cutting edges are engaged with the workpiece at a time, heavy cuts can be taken without adversely affecting the tool life.In fact, the permissible cutting speeds and feeds for milling are three to four times higher than those for turning or drilling.由于同一時間只有部分切削刃切削工件,因此可以在對刀具壽命沒有不利影響的情況下承擔重型切削。事實上,銑削允許的切削速度和進給比車削或鉆削高三到四倍。
Moreover, the quality of the surfaces machined by milling is generally superior to the quality of surfaces machined by turning, shaping, or drilling.此外,由銑削加工的表面質量通常優(yōu)于車削、刨削或鉆削加工的表面質量。A wide variety of milling cutters is available in industry.This, together with the fact that a milling machine is a very versatile machine tool, makes the milling machine the backbone of a machining workshop.工業(yè)上可采用的銑刀類型眾多。連同銑床是極通用機床的事實,使得銑床成為機加工車間的支柱。第十四單元
1、Dimensioning 標注尺寸
The design of a machine includes many factors other than those of determining the loads and stresses and selecting the proper materials.機械設計除了計算載荷和應力、選擇合適的材料外,還包括許多其它因素。Before construction or manufacture can begin, it is necessary to have complete assembly and detail drawings to convey all necessary information to the shop men.The designer frequently is called upon to check the drawings before they are sent to the shop.Much experience and familiarity with manufacturing processes are needed before one can become conversant with all phases of production drawings.在建造或制造開始前,完成裝配圖和零件圖以把必要信息傳達給車間工人是必須的。在送往車間前設計者常常被召集來檢查圖紙。而在精通生產圖紙的所有情況之前,需要有許多經驗并熟悉制造工藝。
2、The development of production processes for large-volume manufacture at low cost has been largely dependent upon interchangeability of component parts.Thus the designer must determine both the proper tolerances for the individual parts, and the correct amount of clearance or interference to permit assembly with the mating parts.大規(guī)模低成本制造生產工藝的發(fā)展很大程度取決于組成零件的互換性。因此設計者必須確定單個零件的合適公差以及配合零件裝配允許的正確間隙或過盈量。The manner of placing tolerances on drawings depends somewhat on the kind of product or type of manufacturing process.If the tolerance on a dimension is not specifically stated, the drawing should contain a blanket note which gives the value of the tolerance for such dimensions.在圖紙上標注公差的方法相當程度上依賴于產品的性質或制造工藝的類型。如果尺寸公差沒有特別注明,圖紙應該包含一個給出這些尺寸公差值的普遍適用注釋。
However, some companies do not use blanket notes on the supposition that if each dimension is considered individually, wider tolerances than those called for in the note could probably be specified.In any event it is very important that a drawing be free from ambiguities and be subject only to a single interpretation.然而有些公司不采用普遍適用注釋,假定每個尺寸是單獨被考慮的,可能會規(guī)定出比注釋中要求的更寬的公差。在任何情況下圖紙不模棱兩可并只服從于單一的解釋是十分重要的。
3、There should be no more dimensions than are absolutely necessary, and no feature should be located by more than one dimension in any direction.除絕對需要的尺寸外,不應該有更多的尺寸;而在任意方向上,只能在一個尺寸上標注特性要求。
It may be necessary occasionally to give an auxiliary dimension for reference, possibly for inspection.When this is so, the dimension should be enclosed in a bracket and marked for reference.Such dimensions are not governed by general tolerances.偶爾也可能為了檢查而必須給出供參考的輔助尺寸。在這種情況下,尺寸應該用括號括起來,以便參考。這樣的尺寸不受通用公差控制。Unit15
1、Ultrasonic machining,elecron-beam machining,plasma-jet machining ,and laser machining are all examples of these new processes.Another modern process is chemical etching ,which,unlike the others,was developed primarily for producing complex integral shapes in soft materials,namely ,aluminum alloys ,for the aircraft industry.1超聲加工,電子束加工,等離子射流加工,激光加工等就是特種加工工藝的代表。另一種現代加工方法是化學蝕刻法,與其他方法不同,它原來是為用軟材料即鋁合金、為飛機工業(yè)生產形狀復雜的整體零件而開發(fā)的。
2、The term electrical maching may be applied to a group of processes that employ an electric current or discharge to remove material.Removal of material though an electric current or discharge eliminates the inefficient conversion of electrical power to mechanical power characteristic of conventional machining and metal-deformation processes電加工這一術語適用于使用電流或放電以去除材料的一組加工方法。雖然電流或放電消除了電能的效率,消除了傳統(tǒng)機械加工和金屬變形過程中的電功率的低效率的轉換
The elimination of the mechanical stage also overcomes one difficulty inherent in conventional machining ,namely ,the increase in tool forces and tool wear encountered when machining the harder metals and alloys used in modern engineering practice 在機械加工階段也克服了傳統(tǒng)加工方法存在的困難,即,在現代工程實踐中加工較難的金屬和合金時切削力和道具磨損的增加。
3、The erosive action of electric sparks has long been known.Two recent discoveries,however,have made spark-cutting practical.A DC spark causes greater erosion of the electrode connected to the positive pole of the power supply——very important,if tool wear is to be minimized and the work erosion rate maximized.The second important discovery is that the rate of erosion by the spark is greatly increased if it is made to take place in a liquid rather than air.It must be noted that if a spark is permitted to last to long ,it will degenerate into a stationary arc which is not suitable for machining.電火花的侵蝕作用早已公知的。然而,最近的兩項發(fā)現是電火花加工能實際使用。直流電火花使在與電源正極相連的電極處產生較大的蝕除,如果要使刀具磨損最小而使工件蝕除率最大的話,這一點是非常重要的。第二個重要的發(fā)現是如果電火花的蝕除發(fā)生在液體而不是空氣中那么它的蝕除率會大大提高。必須指出的是,如果一個火花被允許長時間持續(xù),它將退化為一個不適合用于加工的穩(wěn)定電弧。V unit16
1、laser beam machining(LBM)utilises the energy from the coherent light beams called laser(light amplification by stimulated emission of radiation).The basic principle utilised in LBM is that under proper conditions light energy of a particular frequency is used to stimulate the electrons in an atom to emit additional light with exactly the same characteristics of the original light source.激光加工利用稱為激光的相干光束的能量(光受激輻射放大器)。激光加工的基本原理是在一定條件下采用特定頻率的光激發(fā)原子中的電子,是其發(fā)射特征與原光源完全相同的光 Part2 第一單元
1、The modern digital computer is an electronic machine that can perform mathematical and logical calculations and data processing functions in accordance with a predetermined program of instructions.The computer itself is referred to as hardware, whereas the various programs are referred to as software.現在數字計算機是一部能夠根據預定的程序來完成數字和邏輯運算以及數據處理功能的電子設備,計算機本身稱為硬件,而各種各樣的程序稱為軟件。In a network,all computers are connected and communicated with each other according to some kinds of enacted regulations or agreement ,which are called the “network protocols “.the main function of network protocols is realizing the orderly transmission or acceptance of information.The most common protocol which is being used is Transport Control Protocol /Internet Protocol(TCP/IP).Among many system models illustrating network protocols in the world ,the ISO/OSI network model enacted by International Standardization Organization has divided the whole system into seven layers ,each layer has its own name and function respectively.在網絡中所有的計算機都根據一些準則和協(xié)議進行連接和通信,規(guī)則和協(xié)議稱為網絡協(xié)議。網絡協(xié)議的主要功能是實現信息的有序傳遞或接受。最常用的協(xié)議是傳輸控制協(xié)議/互聯網協(xié)議(TCP / IP)。在世界上許多系統(tǒng)模型,說明網絡協(xié)議由國際標準化組織制定的ISO / OSI網絡模型將整個系統(tǒng)分為七層,每一層分別有自己的名稱和功能
2、the widest area network in the world is Internet.it is one kind of wide area virtual networks,which uses TCP/IP protocol and interconnects more than tens of million computers around the world into a gigantic network system互聯網是世界上最寬廣的區(qū)域網,它是一種大范圍的虛擬網絡,利用TCP / IP協(xié)議,使世界各地數以百萬的電腦變成一個龐大的網絡系統(tǒng)。
Each computer of internet has its sole address in the world ,thus its application can overcome the limitation of continents,countries and areas ,and make up a virtual space in which every person can receive the latest news and enjoy the fastest service even when he is in the most remote area of the world.互聯網上的每臺計算機都有唯一的地址,因此它的應用可以克服大陸、國家和地區(qū),的限制,并組成一個虛擬的空間。每個人都可以獲得的最新消息和享受最快的服務即使他是在世界最偏遠的地區(qū)。today more and more computers and devices are connected with internet system,more and more service and information can be offered by the utlization of internet,and it has become an important base for information super highway structure plan in many countries one of fastest growing +課本99頁藍體字
今天,越來越多的電腦和設備被互聯網系統(tǒng)連接,越來越多的服務和信息被互聯網的使用所提供,在許多國家信息高速公路結構計劃已成為一項重要的基礎研究?;ヂ摼W發(fā)展最快的領域之一是萬維網的應用,在互聯網中,各種信息,如文本、圖像、聲音和許多其他多媒體文件,可以通過超文本鏈接功能共同觀看和導航。with the rapid development of information and electronics technology ,internet is developing by an incredibly speed and it has become an indispensable component of human‘s civilization隨著信息和電子技術的快速發(fā)展,互聯網以一個令人難以置信的速度發(fā)展,它已成為人類文明的不可或缺的組成部分。unit11課本173頁