0314-棘輪型手動(dòng)壓力機(jī)及箱體工藝規(guī)程設(shè)計(jì)【CAD圖+工藝卡】
0314-棘輪型手動(dòng)壓力機(jī)及箱體工藝規(guī)程設(shè)計(jì)【CAD圖+工藝卡】,CAD圖+工藝卡,棘輪,手動(dòng),壓力機(jī),箱體,工藝,規(guī)程,設(shè)計(jì),cad
畢業(yè)設(shè)計(jì)(論文)開題報(bào)告
題目 棘輪手動(dòng)壓機(jī)設(shè)計(jì)
一、選題的依據(jù)及意義:
畢業(yè)設(shè)計(jì)(論文)選題的原則要根據(jù)教學(xué)計(jì)劃中所制定的培養(yǎng)目標(biāo)要求,能達(dá)到綜合訓(xùn)練為目的,有利于培養(yǎng)學(xué)生獨(dú)立工作能力,鞏固和提高所學(xué)知識(shí)。應(yīng)盡量選擇既滿足教學(xué)基本要求,又結(jié)合生產(chǎn)、科研實(shí)際的題目??筛鶕?jù)學(xué)生的特點(diǎn),結(jié)合個(gè)人的實(shí)際工作選擇題目。機(jī)械產(chǎn)品設(shè)計(jì)類型依據(jù)特點(diǎn)分為開發(fā)型、改進(jìn)型、技術(shù)引進(jìn)等三種類型。機(jī)械產(chǎn)品設(shè)計(jì)要求具有有效性、經(jīng)濟(jì)性、工藝性和外觀質(zhì)量。
題目類型
主要包括:機(jī)械設(shè)計(jì)類、工藝工裝設(shè)計(jì)類、機(jī)電產(chǎn)品設(shè)計(jì)、液壓系統(tǒng)及裝置設(shè)計(jì)、電氣控制系統(tǒng)設(shè)計(jì)等。 (所有專業(yè)課程的內(nèi)容,結(jié)合生產(chǎn)實(shí)際都行) 題目示例 60噸壓力機(jī)液壓系統(tǒng)與控制系統(tǒng)設(shè)計(jì)
壓力機(jī)機(jī)械結(jié)構(gòu)設(shè)計(jì),液壓系統(tǒng)設(shè)計(jì),控制系統(tǒng)設(shè)計(jì)。
由于我國(guó)壓力機(jī)技術(shù)相比國(guó)外落后點(diǎn),大型的壓力機(jī)和用于數(shù)控的比較欠缺,作為在校大學(xué)生,我就選棘輪式手動(dòng)壓力機(jī)。手動(dòng)壓力機(jī)制造簡(jiǎn)單,操作方便,造價(jià)費(fèi)用低廉。在更多的方面大型的壓力機(jī)起不到作用。所以選棘輪式的是對(duì)棘輪機(jī)構(gòu)有所掌握。
依據(jù):
(1)體現(xiàn)我國(guó)機(jī)械加工中冷壓工藝的實(shí)際發(fā)展需要
直接面向我國(guó)機(jī)械加工的當(dāng)前實(shí)際,考慮今后發(fā)展趨向;壓力機(jī)在制造領(lǐng)域和應(yīng)用領(lǐng)域的重要地位,努力實(shí)現(xiàn)標(biāo)準(zhǔn)化與自動(dòng)化。
(2)滿足畢業(yè)設(shè)計(jì)的內(nèi)容規(guī)定要求
機(jī)械專業(yè)畢業(yè)設(shè)計(jì)內(nèi)容包含初步設(shè)計(jì)和技術(shù)設(shè)計(jì)兩大部分。畢業(yè)設(shè)計(jì)不是相關(guān)課程設(shè)計(jì)內(nèi)容的簡(jiǎn)單組合與重復(fù),否則將對(duì)完成基本訓(xùn)練和培養(yǎng)獨(dú)立工作能力極為不利。設(shè)計(jì)題目具有較完整的設(shè)計(jì)原始資料,包括所要設(shè)計(jì)的設(shè)備的原始數(shù)據(jù)(工作壓力、底座尺寸、壓力機(jī)高度、最大工作行程等)相關(guān)使用要求、運(yùn)動(dòng)分析、總體強(qiáng)度受力分析、齒條工藝規(guī)程設(shè)計(jì)、成本核算等,這些原始資料都來(lái)自實(shí)有機(jī)械設(shè)備的設(shè)計(jì)實(shí)踐。
(3)適應(yīng)專業(yè)科技知識(shí)的實(shí)際水平
由于學(xué)時(shí)有限,在校所學(xué)專業(yè)課程知識(shí)的深、廣度難以滿足中型、大型設(shè)備設(shè)計(jì)工作的需要。畢業(yè)設(shè)計(jì)題目的規(guī)模和內(nèi)容幅度,是從大多數(shù)學(xué)生能掌握的專業(yè)科技知識(shí)的實(shí)際水平出發(fā),所要設(shè)計(jì)的設(shè)備型號(hào)以小型為主,工作壓力也在考慮范圍內(nèi),以中小負(fù)荷為主等。
意義:
(1)培養(yǎng)理論聯(lián)系實(shí)際的設(shè)計(jì)思想,通過(guò)課題研究回顧、總結(jié)大學(xué)三年所學(xué)。在以后工作中,
能更快速地提高專業(yè)技術(shù);
(2)綜合性地運(yùn)用幾年內(nèi)所學(xué)知識(shí)去分析、解決一個(gè)問(wèn)題。使自己的實(shí)踐動(dòng)手、動(dòng)筆能力得到
鍛煉;
(3)為工作時(shí)候的產(chǎn)品開發(fā)、改進(jìn)打下基礎(chǔ);
(4)掌握文獻(xiàn)檢索、資料查詢的基本方法以及獲取新知識(shí)的能力。
二、國(guó)內(nèi)外研究概況及發(fā)展趨勢(shì):
棘輪型手動(dòng)壓力機(jī)是機(jī)械壓力機(jī)中具有代表性的一類加工設(shè)備,該類設(shè)備結(jié)構(gòu)堅(jiān)固,提高生產(chǎn)效率,且具有操作方便、動(dòng)作靈活,經(jīng)久耐用等特點(diǎn)。它廣泛應(yīng)用于家電業(yè)、電子工業(yè)、電器端子、鐘表工業(yè)、照相機(jī)、微型馬達(dá)等制造及零部件裝配,最適用小零部件之壓入、成型、裝配、鉚合、打印、沖孔、切斷、彎曲、印花等工作要求。它的用戶幾乎包羅了國(guó)民經(jīng)濟(jì)各部門,量大面寬。現(xiàn)在我國(guó)經(jīng)濟(jì)建設(shè)蓬勃發(fā)展,壓力機(jī)的使用從大型工廠到私人手工作坊,幾乎在涉及到零件冷壓工藝的地方都可以見到。壓力機(jī)種類繁多,型式多樣,工作壓力小到幾十公斤,大到幾噸;精密程度也有很大的差別,價(jià)值由幾百元到上萬(wàn)元不等。
棘輪機(jī)構(gòu) 棘輪機(jī)構(gòu)
ratchet and pawl
由棘輪和棘爪組成的一種單向間歇運(yùn)動(dòng)機(jī)構(gòu)。
它將連續(xù)轉(zhuǎn)動(dòng)或往復(fù)運(yùn)動(dòng)轉(zhuǎn)換成單向步進(jìn)運(yùn)動(dòng)。棘輪輪齒通常用單向齒,棘爪鉸接于搖桿上,當(dāng)搖桿逆時(shí)針?lè)较驍[動(dòng)時(shí),驅(qū)動(dòng)棘爪便插入棘輪齒以推動(dòng)棘輪同向轉(zhuǎn)動(dòng);當(dāng)搖桿順時(shí)針?lè)较驍[動(dòng)時(shí),棘爪在棘輪上滑過(guò),棘輪停止轉(zhuǎn)動(dòng)。為了確保棘輪不反轉(zhuǎn),常在固定構(gòu)件上加裝止逆棘爪。搖桿的往復(fù)擺動(dòng)可由曲柄搖桿機(jī)構(gòu)、齒輪機(jī)構(gòu)和擺動(dòng)油缸等實(shí)現(xiàn),在傳遞很小動(dòng)力時(shí),也有用電磁鐵直接驅(qū)動(dòng)棘爪的。棘輪每次轉(zhuǎn)過(guò)的角度稱為動(dòng)程。動(dòng)程的大小可利用改變驅(qū)動(dòng)機(jī)構(gòu)的結(jié)構(gòu)參數(shù)或遮齒罩的位置等方法調(diào)節(jié),也可以在運(yùn)轉(zhuǎn)過(guò)程中加以調(diào)節(jié)。如果希望調(diào)節(jié)的精度高于一個(gè)棘齒所對(duì)應(yīng)的角度,可應(yīng)用多棘爪棘輪機(jī)構(gòu)。棘輪機(jī)構(gòu)工作時(shí)常伴有噪聲和振動(dòng),因此它的工作頻率不能過(guò)高。棘輪機(jī)構(gòu)常用在各種機(jī)床和自動(dòng)機(jī)中間歇進(jìn)給或回轉(zhuǎn)工作臺(tái)的轉(zhuǎn)位上,也常用在千斤頂上。在自行車中棘輪機(jī)構(gòu)用于單向驅(qū)動(dòng),在手動(dòng)絞車中棘輪機(jī)構(gòu)常用以防止逆轉(zhuǎn)。
棘輪機(jī)構(gòu)基礎(chǔ)知識(shí)
1棘輪機(jī)構(gòu)(ratchet mechanism)的基本型式和工作原理
圖示為機(jī)械中常用的外嚙合式棘輪機(jī)構(gòu),它由主動(dòng)擺桿,棘爪,棘輪、止回棘爪和機(jī)架組成。主動(dòng)件空套在與棘輪固連的從動(dòng)軸上,并與驅(qū)動(dòng)棘爪用轉(zhuǎn)動(dòng)副相聯(lián)。當(dāng)主動(dòng)件順時(shí)針?lè)较驍[動(dòng)時(shí),驅(qū)動(dòng)棘爪便插入棘輪的齒槽中,使棘輪跟著轉(zhuǎn)過(guò)一定角度,此時(shí),止回棘爪在棘輪的齒背上滑動(dòng)。當(dāng)主動(dòng)件逆時(shí)針?lè)较蜣D(zhuǎn)動(dòng)時(shí),止回棘爪阻止棘輪發(fā)生逆時(shí)針?lè)较蜣D(zhuǎn)動(dòng),而驅(qū)動(dòng)棘爪卻能夠在棘輪齒背上滑過(guò),所以,這時(shí)棘輪靜止不動(dòng)。因此,當(dāng)主動(dòng)件作連續(xù)的往復(fù)擺動(dòng)時(shí),棘輪作單向的間歇運(yùn)動(dòng)。
2 棘輪機(jī)構(gòu)的分類方式有以下幾種:
按結(jié)構(gòu)形式分為齒式棘輪機(jī)構(gòu)和摩擦式棘輪機(jī)構(gòu)
齒式棘輪機(jī)構(gòu)結(jié)構(gòu)簡(jiǎn)單,制造方便;動(dòng)與停的時(shí)間比可通過(guò)選擇合適的驅(qū)動(dòng)機(jī)構(gòu)實(shí)現(xiàn)。該機(jī)構(gòu)的缺點(diǎn)是動(dòng)程只能作有級(jí)調(diào)節(jié);噪音、沖擊和磨損較大,故不宜用于高速。
齒式棘輪機(jī)構(gòu) 摩擦式棘輪機(jī)構(gòu)
摩擦式棘輪機(jī)構(gòu)是用偏心扇形楔塊代替齒式棘輪機(jī)構(gòu)中的棘爪,以無(wú)齒摩擦代替棘輪。特點(diǎn)是傳動(dòng)平穩(wěn)、無(wú)噪音;動(dòng)程可無(wú)級(jí)調(diào)節(jié)。但因靠摩擦力傳動(dòng),會(huì)出現(xiàn)打滑現(xiàn)象,雖然可起到安全保護(hù)作用,但是傳動(dòng)精度不高。適用于低速輕載的場(chǎng)合。
按嚙合方式分外嚙合棘輪機(jī)構(gòu)和內(nèi)嚙合棘輪機(jī)構(gòu)
外嚙合式棘輪機(jī)構(gòu)的棘爪或楔塊均安裝在棘輪的外部,而內(nèi)嚙合棘輪機(jī)構(gòu)的棘爪或楔塊均在棘輪內(nèi)部。外嚙合式棘輪機(jī)構(gòu)由于加工、安裝和維修方便,應(yīng)用較廣。內(nèi)嚙合棘輪機(jī)構(gòu)的特點(diǎn)是結(jié)構(gòu)緊湊,外形尺寸小。
外嚙合式棘輪機(jī)構(gòu) 內(nèi)嚙合式棘輪機(jī)構(gòu)
按從動(dòng)件運(yùn)動(dòng)形式分單動(dòng)式棘輪機(jī)構(gòu)、雙動(dòng)式棘輪機(jī)構(gòu)和雙向式棘輪機(jī)構(gòu)
單動(dòng)式式棘輪機(jī)構(gòu)當(dāng)主動(dòng)件按某一個(gè)方向擺動(dòng)時(shí),才能推動(dòng)棘輪轉(zhuǎn)動(dòng)。雙動(dòng)式棘輪機(jī)構(gòu),在主動(dòng)搖桿向兩個(gè)方向往復(fù)擺動(dòng)的過(guò)程中,分別帶動(dòng)兩個(gè)棘爪,兩次推動(dòng)棘輪轉(zhuǎn)動(dòng)。
雙動(dòng)式棘輪機(jī)構(gòu)常用于載荷較大,棘輪尺寸受限,齒數(shù)較少,而主動(dòng)擺桿的擺角小于棘輪齒距的場(chǎng)合。
雙動(dòng)式棘輪機(jī)構(gòu)
以上介紹的棘輪機(jī)構(gòu),都只能按一個(gè)方向作單向間歇運(yùn)動(dòng)。雙向式棘輪機(jī)構(gòu)可通過(guò)改變棘爪的擺動(dòng)方向,實(shí)現(xiàn)棘輪兩個(gè)方向的轉(zhuǎn)動(dòng)。圖示為兩種雙向式棘輪機(jī)構(gòu)的形式,雙向式棘輪機(jī)構(gòu)必須采用對(duì)稱齒形。
雙向式棘輪機(jī)構(gòu)
3 棘輪機(jī)構(gòu)的應(yīng)用
棘輪機(jī)構(gòu)的主要用途有:間歇送進(jìn)、制動(dòng)和超越等,以下是應(yīng)用實(shí)例。
1)間歇送進(jìn)
圖示為牛頭刨床,為了切削工件,刨刀需作連續(xù)往復(fù)直線運(yùn)動(dòng),工作臺(tái)作間歇移動(dòng)。當(dāng)曲柄1轉(zhuǎn)動(dòng)時(shí),經(jīng)連桿2帶動(dòng)搖桿5作往復(fù)擺動(dòng);搖桿5上裝有雙向棘輪機(jī)構(gòu)的棘爪3,棘輪4與絲杠6固連,棘爪帶動(dòng)棘輪作單方向間歇轉(zhuǎn)動(dòng),從而使螺母(即工作臺(tái))作間歇進(jìn)給運(yùn)動(dòng)。若改變驅(qū)動(dòng)棘爪的擺角,可以調(diào)節(jié)進(jìn)給量;改變驅(qū)動(dòng)棘爪的位置(繞自身軸線轉(zhuǎn)過(guò)180°后固定),可改變進(jìn)給運(yùn)動(dòng)的方向。
2)制動(dòng)
圖示為杠桿控制的帶式制動(dòng)器,制動(dòng)輪與外棘輪2固結(jié),棘爪3鉸接于制動(dòng)輪4上A點(diǎn),制動(dòng)輪上圍繞著由杠桿5控制的鋼帶6。制動(dòng)輪4按逆時(shí)針?lè)较蜃杂赊D(zhuǎn)動(dòng),棘爪3在棘輪齒背上滑動(dòng),若該輪向相反方向轉(zhuǎn)動(dòng),則4輪被被制動(dòng)。
3)超越
圖示的棘輪機(jī)構(gòu)可以用來(lái)實(shí)現(xiàn)快速超越運(yùn)動(dòng)。運(yùn)動(dòng)由蝸桿傳到蝸輪,通過(guò)安裝在蝸輪上的棘爪3驅(qū)動(dòng)棘輪固連的輸出軸5按圖示方向慢速轉(zhuǎn)動(dòng)。當(dāng)需要軸快速轉(zhuǎn)動(dòng)時(shí),可按輸出軸的方向快速轉(zhuǎn)動(dòng)輸出軸上的手柄,這時(shí)由于手動(dòng)轉(zhuǎn)速大于蝸輪轉(zhuǎn)速,所以棘爪在棘輪齒背滑過(guò),從而在蝸輪繼續(xù)轉(zhuǎn)動(dòng)時(shí),可用快速手動(dòng)來(lái)實(shí)現(xiàn)輸出軸超越蝸輪的運(yùn)動(dòng)。
4 棘輪機(jī)構(gòu)的設(shè)計(jì)要點(diǎn)
棘輪機(jī)構(gòu)的設(shè)計(jì)主要應(yīng)考慮:棘輪齒形的選擇 、模數(shù)齒數(shù)的確定 、齒面傾斜角的確定 、行程和動(dòng)停比的調(diào)節(jié)方法
現(xiàn)以齒式棘輪機(jī)構(gòu)為例,說(shuō)明其設(shè)計(jì)方法
1)棘輪齒形的選擇
圖示為常用齒形,不對(duì)稱梯形用于承受載荷較大的場(chǎng)合;當(dāng)棘輪機(jī)構(gòu)承受的載荷較小時(shí),可采用三角形或圓弧形齒形;矩形和對(duì)稱梯形用于雙向式棘輪機(jī)構(gòu)。
2)模數(shù)、齒數(shù)的確定
與齒輪相同,棘輪輪齒的有關(guān)尺寸也用模數(shù)m作為計(jì)算的基本參數(shù),但棘輪的標(biāo)準(zhǔn)模數(shù)要按棘輪的頂圓直徑da來(lái)計(jì)算。
m = da/z
棘輪齒數(shù)z一般由棘輪機(jī)構(gòu)的使用條件和運(yùn)動(dòng)要求選定。對(duì)于一般進(jìn)給和分度所用的棘輪機(jī)構(gòu),可根據(jù)所要求的棘輪最小轉(zhuǎn)角來(lái)確定棘輪的齒數(shù)(z ≤250,一般取z = 8~30),然后選定模數(shù)。
3)齒面傾斜角的確定
棘輪齒面與徑向線所夾α稱為齒面傾斜角。棘爪軸心O1與輪齒頂點(diǎn)A的連線O1A與過(guò)A點(diǎn)的齒面法線nn的夾角β稱為棘爪軸心位置角。
為使棘爪在推動(dòng)棘輪的過(guò)程中始終緊壓齒面滑向齒根部,應(yīng)滿足棘齒對(duì)棘爪的法向反作用力N對(duì)O1軸的力矩大于摩擦力Ff沿齒面)對(duì)O1軸的力矩,即
N·O1Asinβ > Ff·O1Acosβ
則 Ff/N < tanβ
因?yàn)?f = tan = Ff/N
所以 tanβ > tan
即 β >
式中f和分別為棘爪與棘輪齒面間的摩擦系數(shù)和摩擦角,一般f取0.13 ~0.2。
5. 行程和動(dòng)停比的調(diào)節(jié)方法
1)采用棘輪罩
通過(guò)改變棘輪罩的位置,使部分行程棘爪沿棘輪罩表面滑過(guò),從而實(shí)現(xiàn)棘輪轉(zhuǎn)角大小的調(diào)整。
2)改變擺桿擺角
通過(guò)調(diào)節(jié)曲柄搖桿機(jī)構(gòu)中曲柄的長(zhǎng)度,改變搖桿擺角的大小,從而實(shí)現(xiàn)棘輪機(jī)構(gòu)轉(zhuǎn)角大小的調(diào)整。
3) 采用多爪棘輪機(jī)構(gòu)
要使棘輪每次轉(zhuǎn)動(dòng)的角度小于一個(gè)輪齒所對(duì)應(yīng)的中心角γ時(shí),可采用棘爪數(shù)為m的多爪棘輪機(jī)構(gòu)。
如n=3的棘輪機(jī)構(gòu),三棘爪位置依次錯(cuò)開γ/3 ,當(dāng)擺桿轉(zhuǎn)角Ф1在γ≥Ф1≥γ/3 范圍內(nèi)變化時(shí),三棘爪依次落入齒槽,推動(dòng)棘輪轉(zhuǎn)動(dòng)相應(yīng)角度Ф2為 γ≥Ф2≥γ/3 范圍內(nèi)γ/3 整數(shù)倍。
我國(guó)許多企業(yè)自“八五” 以來(lái),通過(guò)技術(shù)攻關(guān)、自行設(shè)計(jì),以及從德國(guó)舒勒、美國(guó)維爾森、日本小松等著名公司引進(jìn)設(shè)計(jì)制造技術(shù),或采取與國(guó)外廠商合作生產(chǎn)的方式,將國(guó)內(nèi)壓力機(jī)的技術(shù)水平提升到了國(guó)際先進(jìn)水平。目前國(guó)內(nèi)生產(chǎn)的一些大型機(jī)械壓力機(jī)及其生產(chǎn)線已跨出國(guó)門,走向世界。小型手動(dòng)壓力機(jī)雖然剛度差,降低了模具壽命和制件質(zhì)量。但是它成本低、操作方便,容易安裝機(jī)械化裝置。并且由于手動(dòng)壓力機(jī)總體處于質(zhì)量穩(wěn)定、大批量廉價(jià)市售狀態(tài),由國(guó)情決定,其市場(chǎng)需求量仍將保持在一個(gè)較高的水平。
冷壓設(shè)備質(zhì)量的好壞,它直接影響到設(shè)備的安全和合理使用,也關(guān)系到生產(chǎn)中產(chǎn)品質(zhì)量、生產(chǎn)效率及成本,以及模具壽命等一系列重要問(wèn)題。隨著科學(xué)技術(shù)的發(fā)展,壓力機(jī)的精度也有了相當(dāng)大的提高:
(1)小型高速精密壓力機(jī)主要用于生產(chǎn)電傳打字機(jī)、復(fù)印機(jī)、照相機(jī)等較厚的精密制件。其制件的種類、材料厚度、沖壓工藝的難度、形狀及尺寸各異,種類較多??倝毫σ话悴怀^(guò)2500kN。該壓力機(jī)采用滑塊式機(jī)械傳動(dòng),剛性好,導(dǎo)向精度高,適應(yīng)性強(qiáng),工作可靠,操作維修方便,應(yīng)用較廣。法因圖爾(Feintool AG LYSS)公司是目前世界上最大的精密壓力機(jī)生產(chǎn)廠商。
(2)步?jīng)_壓力機(jī)是由計(jì)算機(jī)數(shù)控,并帶有模具庫(kù)的數(shù)控壓力機(jī),它不但能自動(dòng)進(jìn)行板料制作,而且還可以利用步?jīng)_輪廓的特性,突破傳統(tǒng)加工離不開專用模具的概念,具有很大的通用性。目前已發(fā)展到帶有激光切削,進(jìn)一步降低了對(duì)于模具的依賴。日本的天田、村田公司和德國(guó)的通快機(jī)械公司更生產(chǎn)的設(shè)備都是集切、步?jīng)_、成形和等離子切割于一體的通用數(shù)控壓力機(jī)。
(3)BEAT系列高速壓力機(jī)。由日本京利公司制造的BEAT系列高速壓力機(jī),其結(jié)構(gòu)特點(diǎn)為四柱框架式結(jié)構(gòu),送料器按壓力機(jī)的大小專門配備,送料精度高。適用于集成電路、接插件、高頻頭及小型、超小型電機(jī)的定子、轉(zhuǎn)子等制件的生產(chǎn)。
(4)A2系列高速壓力機(jī)。德國(guó)舒勒公司制造的A2系列高速壓力機(jī),A2系列壓力機(jī)共有從500~4000kN十個(gè)規(guī)格,采用框架式機(jī)架,結(jié)構(gòu)緊湊。壓力機(jī)設(shè)有凸輪式精密自動(dòng)送料裝置。適用于電器小零件的加工,不適宜于淺拉深。
(5)BSTA與FP系列高速壓力機(jī)。日本三井公司生產(chǎn)的BSTA系列高速壓力機(jī)和山田公司生產(chǎn)的FP系列高速壓力機(jī)結(jié)構(gòu)類似,精度高。適用于中、小型制件的彎曲、淺拉深等較精密的工藝。當(dāng)與材料開卷機(jī)、矯平機(jī)及自動(dòng)送料裝置、以及收卷機(jī)等聯(lián)合使用后,對(duì)于像集成電路的引線框架一類的平板型制件,此類壓力機(jī)具有很高的生產(chǎn)率。
(6)SP系列高速壓力機(jī)。日本山田公司生產(chǎn)的SP系列高速壓力機(jī)為小型壓力機(jī),適用與電子工業(yè)的接插件、電位器、電容器等小型電子元件的制件生產(chǎn)。
(7)脈沖星型(普爾薩型)超高速精密壓力機(jī)。美國(guó)明斯特公司生產(chǎn)的脈沖星型(普爾薩型)超高速壓力機(jī),其結(jié)構(gòu)特點(diǎn)是:機(jī)架為框架式,運(yùn)動(dòng)平穩(wěn),精度高,模具的閉合高度調(diào)整用數(shù)字顯示等。該壓力機(jī)不僅速度高,而且運(yùn)動(dòng)精密,可制作出高精密的制件。它是專門為集成電路引線框等導(dǎo)線板和終端接頭等精密制件設(shè)計(jì)的。
(8)多工位自動(dòng)傳遞壓力機(jī)。我國(guó)目前引進(jìn)的大多是日本旭精機(jī)公司生產(chǎn)的TP系列多工位自動(dòng)傳遞壓力機(jī),其特點(diǎn)是結(jié)構(gòu)緊湊,集約程度高。該型壓力機(jī)還可配置多種附屬裝置,以滿足不同類型的精密、復(fù)雜制件的自動(dòng)連續(xù)加工,主要加工小型拉深件。
三、研究?jī)?nèi)容及實(shí)驗(yàn)方案:
內(nèi)容:
(1)開題報(bào)告;
(2)總體設(shè)計(jì);
(3)常規(guī)設(shè)計(jì);
(4)成本核算;
(5)箱體工藝規(guī)程設(shè)計(jì);
(6)編寫畢業(yè)設(shè)計(jì)說(shuō)明書;
(7)外文資料翻譯。
方案:
(1)獨(dú)立思考,繼承和創(chuàng)新
設(shè)計(jì)時(shí),要認(rèn)真閱讀參考資料,繼承或借鑒前人的設(shè)計(jì)經(jīng)驗(yàn)和成果,但不能盲目地全盤抄襲,應(yīng)根據(jù)具體的設(shè)計(jì)條件和要求,獨(dú)立思考,大膽地進(jìn)行改進(jìn)和創(chuàng)新。只有這樣,才能做出高質(zhì)量地設(shè)計(jì)。
(2)全面考慮機(jī)械零部件地強(qiáng)度、剛度、工藝性、經(jīng)濟(jì)性和維護(hù)等要求
任何零部件的機(jī)構(gòu)和尺寸,除去考慮它的強(qiáng)度剛度外,還應(yīng)該綜合考慮零件本身及整個(gè)部件的工藝性要求、經(jīng)濟(jì)性要求、使用要求等才能確定。
(3)采用“三邊”設(shè)計(jì)方法
機(jī)械設(shè)計(jì)中,多數(shù)零件可以由計(jì)算確定零件的基本尺寸,再通過(guò)草圖設(shè)計(jì)決定其具體結(jié)構(gòu)和尺寸;而有些零件,則需先經(jīng)初算和繪草圖,得出初步符合設(shè)計(jì)條件的基本結(jié)構(gòu)尺寸,然后再進(jìn)行必要得計(jì)算,根據(jù)計(jì)算的結(jié)果,再對(duì)結(jié)構(gòu)和尺寸進(jìn)行修改。因此,計(jì)算和畫圖互為依據(jù),交叉進(jìn)行。這種邊計(jì)算、邊畫圖、邊修改的“三邊”設(shè)計(jì)方法是經(jīng)常采用的方法。
(4)使用標(biāo)準(zhǔn)和規(guī)范
設(shè)計(jì)時(shí)應(yīng)盡量使用標(biāo)準(zhǔn)和規(guī)范,這有利于零件的互換性和工藝性,同時(shí)也可減少設(shè)計(jì)工作量、節(jié)省設(shè)計(jì)時(shí)間,對(duì)于國(guó)家標(biāo)準(zhǔn)或部門規(guī)范,一般都要嚴(yán)格遵守和執(zhí)行。因此,課程設(shè)計(jì)中,凡是有標(biāo)準(zhǔn)或規(guī)范的,應(yīng)該盡量采用。
四、目標(biāo)、主要特色及工作進(jìn)度
目標(biāo):
(1)通過(guò)畢業(yè)設(shè)計(jì),提高并鞏固所學(xué)的理論知識(shí);
(2)通過(guò)畢業(yè)設(shè)計(jì),培養(yǎng)自己科學(xué),嚴(yán)謹(jǐn),實(shí)務(wù)和創(chuàng)新的 工作作風(fēng);
(3)通過(guò)畢業(yè)設(shè)計(jì),綜合利用自己所學(xué)的理論知識(shí),分析解決工作中遇到的問(wèn)題;
(4)為工作時(shí)候的產(chǎn)品開發(fā)、改進(jìn)打下基礎(chǔ);
(5)培養(yǎng)獨(dú)立思考,獨(dú)立工作的態(tài)度。
特色:
(1)協(xié)調(diào)性
整個(gè)機(jī)器由許多零件組成,雖然各零件的功能不同、性能各異,但它們?cè)诮M合時(shí)必須按照機(jī)器整體功能的需要。因各個(gè)零件都是為了共同實(shí)現(xiàn)整體的目標(biāo),所以,各零件應(yīng)該有機(jī)地聯(lián)系在一起。一個(gè)系統(tǒng)的好壞,最終要由其整體功能來(lái)體現(xiàn)。若各個(gè)子系統(tǒng)設(shè)計(jì)合理、能協(xié)調(diào)工作,系統(tǒng)運(yùn)行后的整體功能會(huì)大于各子系統(tǒng)功能的簡(jiǎn)單代數(shù)和,即符合系統(tǒng)的增益規(guī)律。若各個(gè)子系統(tǒng)設(shè)計(jì)不合理,導(dǎo)致各部分間存在矛盾,組成的系統(tǒng)運(yùn)行后會(huì)出現(xiàn)內(nèi)耗,從而造成整體功能小于各部分的功能之和。因此,性能不匹配或達(dá)不到整體目標(biāo)的設(shè)計(jì),無(wú)論其局部的功能和性能設(shè)計(jì)的多么好,都是失敗的設(shè)計(jì)。
(2)相關(guān)性
構(gòu)成整個(gè)系統(tǒng)的各要素之間也是互相關(guān)聯(lián)的,它們之間有著相互作用、相互制約的特定關(guān)系。某個(gè)要素性能的變化將影響對(duì)相關(guān)要素的作用,從而對(duì)整個(gè)系統(tǒng)產(chǎn)生影響。
(3)內(nèi)外結(jié)合性
任何系統(tǒng)必定存在于一定的社會(huì)和物質(zhì)環(huán)境中,機(jī)械系統(tǒng)也不例外。環(huán)境的變化必將引起系統(tǒng)輸入的變化,從而也將導(dǎo)致其輸出的變化。應(yīng)在調(diào)查研究的基礎(chǔ)上,搞清外部環(huán)境對(duì)該機(jī)械系統(tǒng)的作用和影響。如市場(chǎng)對(duì)該機(jī)械的要求(功能、價(jià)格、數(shù)量、尺寸、重量、工期和外觀等)和約束條件(基金、材料、設(shè)備、技術(shù)、使用環(huán)境、基礎(chǔ)和地基以及法律與政策等),這些都對(duì)內(nèi)部設(shè)計(jì)有直接的影響,影響其可行性、經(jīng)濟(jì)性、可靠性和使用壽命等指標(biāo),在進(jìn)行總體方案設(shè)計(jì)時(shí),必須考慮這些影響。否則,可能導(dǎo)致設(shè)計(jì)失敗。同時(shí),也不能忽略內(nèi)部系統(tǒng)對(duì)外部環(huán)境的作用和影響,如系統(tǒng)運(yùn)行后或產(chǎn)品投產(chǎn)后對(duì)周圍環(huán)境的影響,對(duì)操作人員的影響等。內(nèi)部系統(tǒng)與外部環(huán)境相一致是系統(tǒng)設(shè)計(jì)的另一特點(diǎn)。它可以使設(shè)計(jì)盡量做到周密、合理,少走彎路,避免不必要的返工和浪費(fèi)。從而,以盡可能少的投資獲取盡可能大的效益。
進(jìn)度:畢業(yè)設(shè)計(jì)(論文)工作內(nèi)容及完成時(shí)間:
1、開題報(bào)告 第 1周
2、總體方案設(shè)計(jì) 第2周
3、常規(guī)設(shè)計(jì) 第3周—第 7周
4、箱體工藝規(guī)程設(shè)計(jì) 第8周—第10周 5、編寫畢業(yè)設(shè)計(jì)說(shuō)明書 第11周—第14周
6、外文資料翻譯(不少于6000字符) 第15周
五、參考文獻(xiàn)
(1)機(jī)械設(shè)計(jì)手冊(cè) 第4卷 液壓、氣動(dòng)與液力傳動(dòng)與控制 北京:機(jī)械工業(yè)出版社 2004
(2)沈紉秋主編《工程材料與制造工藝教程》 北京:航空工業(yè)出版社 1991.5
(3)張鼎承主編 沖壓機(jī)械化與自動(dòng)化 北京:機(jī)械工業(yè)出版社 1982
(4)[日]日本塑性加工學(xué)會(huì)編 壓力加工手冊(cè) 北京:機(jī)械工業(yè)出版社 1984
(5)德國(guó) OPTIMA 夾緊技術(shù)公司產(chǎn)品樣本 沖鍛壓模具的快速夾緊 2001
(6)Pearce,R.Sheet Matal Forming,Bristol、philadelphia:Adam hilger c1991
(7)青島市機(jī)械系統(tǒng)翻譯網(wǎng)譯 青島市機(jī)械工業(yè)局科技情報(bào)站 1985
(8) 濮良貴、紀(jì)名剛主編《機(jī)械設(shè)計(jì)》第八版 北京:高等教育出版社,2006.5.
(9) 孟憲源 姜琪編著?機(jī)構(gòu)構(gòu)型與應(yīng)用? 機(jī)械工業(yè)出版社
(10)清華大學(xué)何德譽(yù)主編?專用壓力機(jī)? 機(jī)械工業(yè)出版社
(11) 趙呈林主編?鍛壓設(shè)備? 西北工業(yè)大學(xué)出版社
畢業(yè)設(shè)計(jì)(論文)外文翻譯
題目 模擬氣體運(yùn)動(dòng)的快速壓縮機(jī)
Machine design theory
The machine design is through designs the new product or improves the old product to meet the human need the application technical science. It involves the project technology each domain, mainly studies the product the size, the shape and the detailed structure basic idea, but also must study the product the personnel which in aspect the and so on manufacture, sale and use question.
Carries on each kind of machine design work to be usually called designs the personnel or machine design engineer. The machine design is a creative work. Project engineer not only must have the creativity in the work, but also must in aspect and so on mechanical drawing, kinematics, engineerig material, materials mechanics and machine manufacture technology has the deep elementary knowledge.
If front sues, the machine design goal is the production can meet the human need the product. The invention, the discovery and technical knowledge itself certainly not necessarily can bring the advantage to the humanity, only has when they are applied can produce on the product the benefit. Thus, should realize to carries on before the design in a specific product, must first determine whether the people do need this kind of product
Must regard as the machine design is the machine design personnel carries on using creative ability the product design, the system analysis and a formulation product manufacture technology good opportunity. Grasps the project elementary knowledge to have to memorize some data and the formula is more important than. The merely service data and the formula is insufficient to the completely decision which makes in a good design needs. On the other hand, should be earnest precisely carries on all operations. For example, even if places wrong a decimal point position, also can cause the correct design to turn wrongly.
A good design personnel should dare to propose the new idea, moreover is willing to undertake the certain risk, when the new method is not suitable, use original method. Therefore, designs the personnel to have to have to have the patience, because spends the time and the endeavor certainly cannot guarantee brings successfully. A brand-new design, the request screen abandons obsoletely many, knows very well the method for the people. Because many person of conservativeness, does this certainly is not an easy matter. A mechanical designer should unceasingly explore the improvement existing product the method, should earnestly choose originally, the process confirmation principle of design in this process, with has not unified it after the confirmation new idea.
Newly designs itself can have the question occurrence which many flaws and has not been able to expect, only has after these flaws and the question are solved, can manifest new goods come into the market the product superiority. Therefore, a performance superior product is born at the same time, also is following a higher risk. Should emphasize, if designs itself does not request to use the brand-new method, is not unnecessary merely for the goal which transform to use the new method.
In the design preliminary stage, should allow to design the personnel fully to display the creativity, not each kind of restraint. Even if has had many impractical ideas, also can in the design early time, namely in front of the plan blueprint is corrected. Only then, only then does not send to stops up the innovation the mentality. Usually, must propose several sets of design proposals, then perform the comparison. Has the possibility very much in the plan which finally designated, has used certain not in plan some ideas which accepts.
How does the psychologist frequently discuss causes the machine which the people adapts them to operate. Designs personnel''s basic responsibility is diligently causes the machine to adapt the people. This certainly is not an easy work, because certainly does not have to all people to say in fact all is the most superior operating area and the operating process.
Another important question, project engineer must be able to carry on the exchange and the consultation with other concerned personnel. In the initial stage, designs the personnel to have to carry on the exchange and the consultation on the preliminary design with the administrative personnel, and is approved. This generally is through the oral discussion, the schematic diagram and the writing material carries on. In order to carry on the effective exchange, needs to solve the following problem:
(1) designs whether this product truly does need for the people? Whether there is competitive ability
(2) does this product compare with other companies'' existing similar products?
(3) produces this kind of product is whether economical?
(4) product service is whether convenient?
(5) product whether there is sale? Whether may gain?
Only has the time to be able to produce the correct answer to above question. But, the product design, the manufacture and the sale only can in carry on to the above question preliminary affirmation answer foundation in. Project engineer also should through the detail drawing and the assembly drawing, carries on the consultation together with the branch of manufacture to the finally design proposal.
Usually, can have some problem in the manufacture process. Possibly can request to some components size or the common difference makes some changes, causes the components the production to change easily. But, in the project change must have to pass through designs the personnel to authorize, guaranteed cannot damage the product the function. Sometimes, when in front of product assembly or in the packing foreign shipment experiment only then discovers in the design some kind of flaw. These instances exactly showed the design is a dynamic process. Always has a better method to complete the design work, designs the personnel to be supposed unceasingly diligently, Recent year, the engineerig material choice already appeared importantly. In addition, the choice process should be to the material continuously the unceasing again appraisal process. The new material unceasingly appears, but some original materials can obtain the quantity possibly can reduce. The environmental pollution, material recycling aspect and so on use, worker''s health and security frequently can attach the new limiting condition to the choice of material. In order to reduce the weight or saves the energy, possibly can request the use different material. Comes from domestic and international competition, to product service maintenance convenience request enhancement and customer''s aspect the and so on feedback pressure, can urge the people to carry on to the material reappraises. Because the material does not select when created the product responsibility lawsuit, has already had the profound influence. In addition, the material and between the material processing interdependence is already known by the people clearly. Therefore, in order to can and guarantees the quality in the reasonable cost under the premise to obtain satisfaction the result, project engineer makes engineers all to have earnestly carefully to choose, the determination and the use material.
Makes any product the first step of work all is designs. Designs usually may divide into several explicit stages: (a) preliminary design; (b) functional design; (c) production design. In the preliminary design stage, the designer emphatically considered the product should have function. Usually must conceive and consider several plans, then decided this kind of thought is whether feasible; If is feasible, then should makes the further improvement to or several plans. In this stage, the question which only must consider about the choice of material is: Whether has the performance to conform to the request material to be possible to supply the choice; If no, whether has a bigger assurance all permits in the cost and the time in the limit develops one kind of new material.
In the functional design and the engineering design stage, needs to make a practical feasible design. Must draw up the quite complete blueprint in this stage, chooses and determines each kind of components the material. Usually must make the prototype or the working model, and carries on the experiment to it, the appraisal product function, the reliability, the outward appearance and the service maintenance and so on. Although this kind of experiment possibly can indicate, enters in the product to the production base in front of, should replace certain materials, but, absolutely cannot this point take not earnestly chooses the material the excuse. Should unify the product the function, earnestly carefully considers the product the outward appearance, the cost and the reliability. Has the achievement very much the company when manufacture all prototypes, selects the material should the material which uses with its production in be same, and uses the similar manufacture technology as far as possible. Like this has the advantage very much to the company. The function complete prototype if cannot act according to the anticipated sales volume economically to make, or is prototypical and the official production installment has in the quality and the reliable aspect is very greatly different, then this kind of prototype does not have the great value. Project engineer is best can completely complete the material in this stage the analysis, the choice and the determination work, but is not remains it to the production design stage does. Because, is carries on in the production design stage material replacement by other people, these people are inferior to project engineer to the product all functions understanding. I
n the production design stage, is should completely determine with the material related main question the material, causes them to adapt with the existing equipment, can use the existing equipment economically to carry on the processing, moreover the material quantity can quite be easy to guarantee the supply.
In the manufacture process, inevitably can appear to uses the material to make some changes the situation. The experience indicated that, may use certain cheap materials to take the substitute. However, in the majority situation, in will carry on the production later to change the material to have in to start before the production to change the price which the material will spend to have to be higher than. Completes the choice of material work in the design stage, may avoid the most such situations. Started after the production manufacture to appear has been possible to supply the use the new material is replaces the material the most common reason. Certainly, these new materials possibly reduce the cost, the improvement product performance. But, must carry on the earnest appraisal to the new material, guarantees its all performance all to answer the purpose. Must remember that, the new material performance and the reliable very few pictures materials on hand such understood for the people. The majority of products expiration and the product accident caused by negligence case is because in selects the new material to take in front of substitution material, not truly understood their long-term operational performance causes.
The product responsibility lawsuit forces designs the personnel and the company when the choice material, uses the best procedure. In the material process, five most common questions are: (a) did not understand or cannot use about the material application aspect most newly the best information paper; (b) has not been able to foresee and to consider the dusk year possible reasonable use (for example to have the possibility, designs the personnel also to be supposed further to forecast and the consideration because product application method not when creates consequence. ecent years many products responsibilities lawsuit case, because wrongly uses the plaintiff which the product receives the injury to accuse produces the factory, and wins the decision); (c) uses the material data not entire perhaps some data are indefinite, works as its long-term performance data is the like this time in particular; (d) the quality control method is not suitable and not after the confirmation; (e) the personnel which completely is not competent for the post by some chooses the material.
Through to the above five questions analysis, may obtain these questions is does not have the sufficient reason existence the conclusion. May for avoid these questions to these questions research analyses the appearance indicating the direction. Although uses the best choice of material method not to be able to avoid having the product responsibility lawsuit, designs the personnel and the industry carries on the choice of material according to the suitable procedure, may greatly reduce the lawsuit the quantity.
May see from the above discussion, the choice material people should to the material nature, the characteristic and the processing method have comprehensive and the basic understanding.
機(jī)械設(shè)計(jì)理論
機(jī)械設(shè)計(jì)是一門通過(guò)設(shè)計(jì)新產(chǎn)品或者改進(jìn)老產(chǎn)品來(lái)滿足人類需求的應(yīng)用技術(shù)科學(xué)。它涉及工程技術(shù)的各個(gè)領(lǐng)域,主要研究產(chǎn)品的尺寸、形狀和詳細(xì)結(jié)構(gòu)的基本構(gòu)思,還要研究產(chǎn)品在制造、銷售和使用等方面的問(wèn)題。
進(jìn)行各種機(jī)械設(shè)計(jì)工作的人員通常被稱為設(shè)計(jì)人員或者機(jī)械設(shè)計(jì)工程師。機(jī)械設(shè)計(jì)是一項(xiàng)創(chuàng)造性的工作。設(shè)計(jì)工程師不僅在工作上要有創(chuàng)造性,還必須在機(jī)械制圖、運(yùn)動(dòng)學(xué)、工程材料、材料力學(xué)和機(jī)械制造工藝學(xué)等方面具有深厚的基礎(chǔ)知識(shí)。
如前所訴,機(jī)械設(shè)計(jì)的目的是生產(chǎn)能夠滿足人類需求的產(chǎn)品。發(fā)明、發(fā)現(xiàn)和科技知識(shí)本身并不一定能給人類帶來(lái)好處,只有當(dāng)它們被應(yīng)用在產(chǎn)品上才能產(chǎn)生效益。因而,應(yīng)該認(rèn)識(shí)到在一個(gè)特定的產(chǎn)品進(jìn)行設(shè)計(jì)之前,必須先確定人們是否需要這種產(chǎn)品。
應(yīng)當(dāng)把機(jī)械設(shè)計(jì)看成是機(jī)械設(shè)計(jì)人員運(yùn)用創(chuàng)造性的才能進(jìn)行產(chǎn)品設(shè)計(jì)、系統(tǒng)分析和制定產(chǎn)品的制造工藝學(xué)的一個(gè)良機(jī)。掌握工程基礎(chǔ)知識(shí)要比熟記一些數(shù)據(jù)和公式更為重要。僅僅使用數(shù)據(jù)和公式是不足以在一個(gè)好的設(shè)計(jì)中做出所需的全部決定的。另一方面,應(yīng)該認(rèn)真精確的進(jìn)行所有運(yùn)算。例如,即使將一個(gè)小數(shù)點(diǎn)的位置放錯(cuò),也會(huì)使正確的設(shè)計(jì)變成錯(cuò)誤的。
一個(gè)好的設(shè)計(jì)人員應(yīng)該勇于提出新的想法,而且愿意承擔(dān)一定的風(fēng)險(xiǎn),當(dāng)新的方法不適用時(shí),就使用原來(lái)的方法。因此,設(shè)計(jì)人員必須要有耐心,因?yàn)?所花費(fèi)的時(shí)間和努力并不能保證帶來(lái)成功。一個(gè)全新的設(shè)計(jì),要求屏棄許多陳舊的,為人們所熟知的方法。由于許多人墨守成規(guī),這樣做并不是一件容易的事。一位機(jī)械設(shè)計(jì)師應(yīng)該不斷地探索改進(jìn)現(xiàn)有的產(chǎn)品的方法,在此過(guò)程中應(yīng)該認(rèn)真選擇原有的、經(jīng)過(guò)驗(yàn)證的設(shè)計(jì)原理,將其與未經(jīng)過(guò)驗(yàn)證的新觀念結(jié)合起來(lái)。
新設(shè)計(jì)本身會(huì)有許多缺陷和未能預(yù)料的問(wèn)題發(fā)生,只有當(dāng)這些缺陷和問(wèn)題被解決之后,才能體現(xiàn)出新產(chǎn)品的優(yōu)越性。因此,一個(gè)性能優(yōu)越的產(chǎn)品誕生的同時(shí),也伴隨著較高的風(fēng)險(xiǎn)。應(yīng)該強(qiáng)調(diào)的是,如果設(shè)計(jì)本身不要求采用全新的方法,就沒(méi)有必要僅僅為了變革的目的而采用新方法。
在設(shè)計(jì)的初始階段,應(yīng)該允許設(shè)計(jì)人員充分發(fā)揮創(chuàng)造性,不受各種約束。即使產(chǎn)生了許多不切實(shí)際的想法,也會(huì)在設(shè)計(jì)的早期,即繪制圖紙之前被改正掉。只有這樣,才不致于堵塞創(chuàng)新的思路。通常,要提出幾套設(shè)計(jì)方案,然后加以比較。很有可能在最后選定的方案中,采用了某些未被接受的方案中的一些想法。
心理學(xué)家經(jīng)常談?wù)撊绾问谷藗冞m應(yīng)他們所操作的機(jī)器。設(shè)計(jì)人員的基本職責(zé)是努力使機(jī)器來(lái)適應(yīng)人們。這并不是一項(xiàng)容易的工作,因?yàn)閷?shí)際上并不存在著一個(gè)對(duì)所有人來(lái)說(shuō)都是最優(yōu)的操作范圍和操作過(guò)程。
另一個(gè)重要問(wèn)題,設(shè)計(jì)工程師必須能夠同其他有關(guān)人員進(jìn)行交流和磋商。在開始階段,設(shè)計(jì)人員必須就初步設(shè)計(jì)同管理人員進(jìn)行交流和磋商,并得到批準(zhǔn)。這一般是通過(guò)口頭討論,草圖和文字材料進(jìn)行的。為了進(jìn)行有效的交流 ,需要解決下列問(wèn)題:
(1) 所設(shè)計(jì)的這個(gè)產(chǎn)品是否真正為人們所需要?
(2) 此產(chǎn)品與其他公司的現(xiàn)有同類產(chǎn)品相比有無(wú)競(jìng)爭(zhēng)能力?
(3) 生產(chǎn)這種產(chǎn)品是否經(jīng)濟(jì)?
(4) 產(chǎn)品的維修是否方便?
(5) 產(chǎn)品有無(wú)銷路?是否可以盈利?
只有時(shí)間能對(duì)上述問(wèn)題給出正確答案。但是, 產(chǎn)品的設(shè)計(jì)、制造和銷售只能在對(duì)上述問(wèn)題的初步肯定答案的基礎(chǔ)上進(jìn)行。設(shè)計(jì)工程師還應(yīng)該通過(guò)零件圖和裝配圖,與制造部門一起對(duì)最終設(shè)計(jì)方案進(jìn)行磋商。
通常 ,在制造過(guò)程中會(huì)出現(xiàn)某個(gè)問(wèn)題??赡軙?huì)要求對(duì)某個(gè)零件尺寸或公差作一些更改,使零件的生產(chǎn)變得容易。但是,工程上的更改必須要經(jīng)過(guò)設(shè)計(jì)人員批準(zhǔn),以保證不會(huì)損傷產(chǎn)品的功能。有時(shí),在產(chǎn)品的裝配時(shí)或者裝箱外運(yùn)前的試驗(yàn)中才發(fā)現(xiàn)設(shè)計(jì)中的某種缺陷。這些事例恰好說(shuō)明了設(shè)計(jì)是一個(gè)動(dòng)態(tài)過(guò)程??偸谴嬖谥玫姆椒▉?lái)完成設(shè)計(jì)工作,設(shè)計(jì)人員應(yīng)該不斷努力,尋找這些更好的方法。
近些年來(lái),工程材料的選擇已經(jīng)顯得重要。此外,選擇過(guò)程應(yīng)該是一個(gè)對(duì)材料的連續(xù)不斷的重新評(píng)價(jià)過(guò)程。新材料不斷出現(xiàn),而一些原有的材料的能夠獲得的數(shù)量可能會(huì)減少。環(huán)境污染、材料的回收利用、工人的健康及安全等方面經(jīng)常會(huì)對(duì)材料選擇附加新的限制條件。為了減輕重量或者節(jié)約能源,可能會(huì)要求使用不同的材料。來(lái)自國(guó)內(nèi)和國(guó)際競(jìng)爭(zhēng)、對(duì)產(chǎn)品維修保養(yǎng)方便性要求的提高和顧客的反饋等方面的壓力,都會(huì)促使人們對(duì)材料進(jìn)行重新評(píng)價(jià)。由于材料選用不當(dāng)造成的產(chǎn)品責(zé)任訴訟,已經(jīng)產(chǎn)生了深刻的影響。此外,材料與材料加工之間的相互依賴關(guān)系已經(jīng)被人們認(rèn)識(shí)得更清楚。因此,為了能在合理的成本和確保質(zhì)量的前提下獲得滿意的結(jié)果,設(shè)計(jì)工程師的制造工程師都必須認(rèn)真仔細(xì)地選擇、確定和使用材料。
制造任何產(chǎn)品的第一步工作都是設(shè)計(jì)。設(shè)計(jì)通常可以分為幾個(gè)明確的階段:(a)初步設(shè)計(jì);(b)功能設(shè)計(jì);(c)生產(chǎn)設(shè)計(jì)。在初步設(shè)計(jì)階段,設(shè)計(jì)者著重考慮產(chǎn)品應(yīng)該具有的功能。通常要設(shè)想和考慮幾個(gè)方案,然后決定這種思想是否可行;如果可行,則應(yīng)該對(duì)其中一個(gè)或幾個(gè)方案作進(jìn)一步的改進(jìn)。在此階段,關(guān)于材料選擇唯一要考慮的問(wèn)題是:是否有性能符合要求的材料可供選擇;如果沒(méi)有的話,是否有較大的把握在成本和時(shí)間都允許的限度內(nèi)研制出一種新材料。
在功能設(shè)計(jì)和工程設(shè)計(jì)階段,要做出一個(gè)切實(shí)可行的設(shè)計(jì)。在這個(gè)階段要繪制出相當(dāng)完整的圖紙,選擇并確定各種零件的材料。通常要制造出樣機(jī)或者實(shí)物模型,并對(duì)其進(jìn)行試驗(yàn),評(píng)價(jià)產(chǎn)品的功能、可靠性、外觀和維修保養(yǎng)性等。雖然這種試驗(yàn)可能會(huì)表明,在產(chǎn)品進(jìn)入到生產(chǎn)階段之前,應(yīng)該更換某些材料,但是,絕對(duì)不能將這一點(diǎn)作為不認(rèn)真選擇材料的借口。應(yīng)該結(jié)合產(chǎn)品的功能,認(rèn)真仔細(xì)地考慮產(chǎn)品的外觀、成本和可靠性。一個(gè)很有成就的公司在制造所有的樣機(jī)時(shí),所選用的材料應(yīng)該和其生產(chǎn)中使用的材料相同,并盡可能使用同樣的制造技術(shù)。這樣對(duì)公司是很有好處的。功能完備的樣機(jī)如果不能根據(jù)預(yù)期的銷售量經(jīng)濟(jì)地制造出來(lái),或者是樣機(jī)與正式生產(chǎn)的裝置在質(zhì)量和可靠性方面有很大不同,則這種樣機(jī)就沒(méi)有多大的價(jià)值。設(shè)計(jì)工程師最好能在這一階段完全完成材料的分析、選擇和確定工作,而不是將其留到生產(chǎn)設(shè)計(jì)階段去做。因?yàn)?,在生產(chǎn)設(shè)計(jì)階段材料的更換是由其他人進(jìn)行的,這些人對(duì)產(chǎn)品的所有功能的了解不如設(shè)計(jì)工程師。
在生產(chǎn)設(shè)計(jì)階段中,與材料有關(guān)的主要問(wèn)題是應(yīng)該把材料完全確定下來(lái),使它們與現(xiàn)有的設(shè)備相適應(yīng),能夠利用現(xiàn)有設(shè)備經(jīng)濟(jì)地進(jìn)行加工,而且材料的數(shù)量能夠比較容易保證供應(yīng)。
在制造過(guò)程中,不可避免地會(huì)出現(xiàn)對(duì)使用中的材料做一些更改的情況。經(jīng)驗(yàn)表明,可采用某些便宜材料作為替代品。然而,在大多數(shù)情況下,在進(jìn)行生產(chǎn)以后改換材料要比在開始生產(chǎn)前改換材料所花費(fèi)的代價(jià)要高。在設(shè)計(jì)階段做好材料選擇工作,可以避免多數(shù)這樣的情況。在生產(chǎn)制造開始后出現(xiàn)了可供使用的新材料是更換材料的最常見的原因。當(dāng)然,這些新材料可能降低成本、改進(jìn)產(chǎn)品的性能。但是,必須對(duì)新材料進(jìn)行認(rèn)真的評(píng)價(jià),以確保其所有性能都滿足要求。應(yīng)當(dāng)記住,新材料的性能和可靠性很少像現(xiàn)有材料那樣為人們所了解。大部分的產(chǎn)品失效和產(chǎn)品責(zé)任事故案件是由于在選用新材料作為替代材料之前,沒(méi)有真正了解它們的長(zhǎng)期使用性能而引起的。
產(chǎn)品的責(zé)任訴訟迫使設(shè)計(jì)人員和公司在選擇材料時(shí),采用最好的程序。在材料過(guò)程中,五個(gè)最常見的問(wèn)題為:(a)不了解或者不會(huì)使用關(guān)于材料應(yīng)用方面的最新最好的信息資料;(b)未能預(yù)見和考慮擦黑年品可能的合理用途(如有可能,設(shè)計(jì)人員還應(yīng)進(jìn)一步預(yù)測(cè)和考慮由于產(chǎn)品使用方法不當(dāng)造成的后果。在近年來(lái)的許多產(chǎn)品責(zé)任訴訟案件中,由于錯(cuò)誤地使用產(chǎn)品而受到傷害的原告控告生產(chǎn)廠家,并且贏得判決);(c)所使用的材料的數(shù)據(jù)不全或是有些數(shù)據(jù)不確定,尤其是當(dāng)其長(zhǎng)期性能數(shù)據(jù)是如此的時(shí)候;(d)質(zhì)量控制方法不適當(dāng)和未經(jīng)驗(yàn)證;(e)由一些完全不稱職的人員選擇材料。
通過(guò)對(duì)上述五個(gè)問(wèn)題的分析,可以得出這些問(wèn)題是沒(méi)有充分理由存在的結(jié)論。對(duì)這些問(wèn)題的研究分析可以為避免這些問(wèn)題的出現(xiàn)指明方向。盡管采用最好的材料選擇方法也不能避免發(fā)生產(chǎn)品責(zé)任訴訟,設(shè)計(jì)人員和工業(yè)界按照適當(dāng)?shù)某绦蜻M(jìn)行材料選擇,可以大大減少訴訟的數(shù)量。
從以上的討論可以看出,選擇材料的人們應(yīng)該對(duì)材料的性質(zhì),特點(diǎn)和加工方法有一個(gè)全面而基本的了解。
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