【正文】 具情況來確定切削用量，計(jì)算每道工序的切削時(shí)間t1 及相應(yīng)的輔助時(shí)間 t2，對(duì)大型加工中心每次交換道具時(shí)間約為 46 秒，因此單工序時(shí)間為 t=t1+t2+5s 發(fā)動(dòng)機(jī)下缸體機(jī)加工第一工序共有 24 個(gè)工步共需 24 把刀具換刀時(shí)大約為 120秒，整個(gè)工序所需時(shí)間大約為 720 秒。若所選加工中心作為單機(jī)使用，不準(zhǔn)備用于柔性加工單元或柔性制造系統(tǒng)，刀庫容量不宜選的太大。 銑圓精度 銑圓精度綜合反映了機(jī)床兩軸聯(lián)動(dòng)時(shí)，伺服運(yùn)動(dòng)特性和數(shù)控系統(tǒng)的插補(bǔ)功能。規(guī)格相近的（指工作臺(tái)寬度）臥式加工中心比立式的價(jià)格要高５０％～１００％， 臥式加工中心比立式的加工工時(shí)也多５０％～１００％，因此，完成同樣工藝內(nèi)容，采用立式加工中心要比第二章 加工設(shè)備選取 11 臥式加工中心經(jīng)濟(jì)。 的連接孔等。 （ 2） 具有高度柔性，便于研制、開發(fā)新產(chǎn)品。 機(jī)械本體 是加工和中心結(jié)構(gòu)中的基礎(chǔ)部件，由床身、立柱和工作臺(tái)等大件組成。 7）工件大致尺寸： 970*500*400（ mm） 第二章 加工設(shè)備選取 8 第二章 加工設(shè)備的選取 加工中心的基本概念和分類 加工中心的基本概念 加工中心（ Machining Center）簡(jiǎn)稱 MC，是由機(jī)械設(shè)備與數(shù)控系統(tǒng)組成的，適用于復(fù)雜零件加工的高效自動(dòng)化機(jī)床。 刀具選取方案參照說明。各個(gè)夾具設(shè)計(jì)方案見說明。 （ 5）系統(tǒng)投資大回收期長(zhǎng)。 2) 通過 位置環(huán)的前饋減少跟蹤誤差。 (3) 自適應(yīng)性 柔性加工線能夠進(jìn)行局部調(diào)整，在線地適應(yīng)加工設(shè)備的故障，增減及加工任務(wù)的一定變化。要滿足這種變化，發(fā)動(dòng)機(jī)制造業(yè)的生產(chǎn)柔性化、高速化是走向 之一。 汽車發(fā)動(dòng)機(jī)缸體國內(nèi)外發(fā)展現(xiàn)狀 我國汽車與國際先進(jìn)水平相比，還有一定的差距，從而導(dǎo)致了相同的產(chǎn)品不同的價(jià)格，國產(chǎn)重卡僅及國外同類產(chǎn)品的三分之一。定位方式主要有底面完全定位方式和兩銷完全定位方式等。發(fā)動(dòng)機(jī)缸體每道加工工序精度控制對(duì)缸體加工質(zhì)量有著重要的影響，如缸體加工過程中發(fā)生加工變形，直接影響到缸體的加工精度和加工質(zhì)量，最終影響整個(gè)發(fā)動(dòng)機(jī)的使用性能，因此對(duì)發(fā)動(dòng)機(jī)缸體的制造研究極為重要。 雖然我國在汽車發(fā)動(dòng)機(jī)基礎(chǔ) 理論及相關(guān)技術(shù)研究方面取得較大的進(jìn)步，但是生產(chǎn)設(shè)備基本靠進(jìn)口，工藝標(biāo)準(zhǔn)依賴國外企業(yè)標(biāo)準(zhǔn)，以合資為主。 關(guān)鍵詞 發(fā)動(dòng)機(jī)缸體；定位基準(zhǔn)；加工精度；加工中心 Abstract II Abstract The quality of the engine’s manufacturing influenced the performance of the car, as the engine is the heart of the motor vehicles. The accuracy of the manufacturing of the engine block has an important relationship with the overall performance, because the engine block is the fundamental part in the system of the engine. We have to control the machining accuracy and machining quality. With the development of our economy and rapidly growing demand for cars in China, how to improve the production efficiency and processing quality of auto parts, is crucial to the development of automobile industry. Engine cylinder block is one of the five major parts, and its production efficiency and processing quality are directly related to production efficiency and performance of the car. The traditional method to improve production efficiency and processing quality is trying to shorten the auxiliary time and adopt the way of a rigid line, which is already out of date in the current production. Therefore, how to improve the efficiency of engine cylinder block production and processing quality is an important research, and the WD615 engine used in heavy vehicles, including all kinds of engineering machinery, buses, power generation equipment, ships and other ideal power of engine, its cylinder processing design has greater significance. In this paper, we focus on the first step of the process and made research on the process. The engine block belongs to the block pieces, which is plicated in structure and easy to be deformed. We could adopt crankshaft bore as the positioning datum to ensure the accuracy. As the junction surface has a big area and a high demand of the accuracy and roughness, including high amount of the machining parts and high demand of the machining and the long routine of the processing, we have to adopt Horizontal machining center to improve the machining quality and efficiency. The task of the paper is mainly about the reasonable choice on the machining tools and calculation on the fixtures. Keyword: Engine cylinder Positioning reference Machining accuracy Machining center 目錄 目 錄 摘 要 ................................................................................................................................ I Abstract ............................................................................................................................II 第一章 緒論 .................................................................................................................... 1 汽車發(fā)動(dòng)機(jī)加工工藝概述 .................................................................................. 2 發(fā)動(dòng)機(jī)缸體加工工藝流程 ......................................................................... 2 缸體加工特點(diǎn) .......................................................................................... 2 汽車發(fā)動(dòng)機(jī)缸體國內(nèi)外發(fā)展現(xiàn)狀 ........................................................................ 3 柔性加工的特 點(diǎn) ....................................................................................... 3 高速柔性加工的優(yōu)點(diǎn) ................................................................................ 4 高速柔性加工存在的一些缺點(diǎn) .................................................................. 4 本次設(shè)計(jì)的主要內(nèi)容 ......................................................................................... 5 定位基準(zhǔn)選擇 ............................................................................................ 5 夾具的設(shè)計(jì)方案選取 ................................................................................ 5 刀具的選取 .............................................................................................. 5 設(shè)備選取 ................................................................................................. 6 設(shè)備工藝布置設(shè)計(jì) ................................................................................... 6 本次設(shè)計(jì)的目的及要求 ...................................................................................... 6 本次設(shè)計(jì)的目的 ....................................................................................... 6 本次設(shè)計(jì)的要求 ....................................................................................... 6 第二章 加工設(shè)備的選取 ................................................................................................. 8 加工中心的基本概念和分類 ................................................................................ 8 加工中心的基本概念 ................................................................................. 8 加工中心的分類 ....................................................................................... 8 加工中心的結(jié)構(gòu)和工作原理 ................................................................................ 8 加工中心的結(jié)構(gòu) ....................................................