【正文】 Festival. In this day, girls will throw a sewing needle into a bowl full of water on the night of Qixi as a test of embroidery skills. If the needle floats on top of the water instead of sinking, it proves the girl is a skilled embroiders. Single women also pray for finding a good husband in the future. And the newly married women pray to bee pregnant quickly. Tradition transformed The love story of Niulang and Zhinu, and the Qixi Festival have been handed down for generations. Yet these ancient traditions and customs are slowly dying out. Many modern Chinese, particularly youngsters, seem to know more about St Valentine39。 9 結(jié)論 至此，本設(shè)計(jì)已基本完成。鉸孔為最后一步，不留加工余量。進(jìn)一步保證零件的質(zhì)量。 （ 4）不要在活動(dòng)鉗身的光滑表面進(jìn)行敲擊作業(yè)，以免降低配合性能； （ 5）加工時(shí)用力方向最好是朝向固定鉗身。螺桿端部有一方孔，當(dāng)用卡盤扳手轉(zhuǎn)動(dòng)某一螺桿時(shí)，相應(yīng)的卡爪即可移動(dòng)。超高 頻淬火處理的硬軌，采用周邊磨削工藝精磨，與其配合的粘貼 TurciteB 耐磨片并精細(xì)研刮，耐磨性好，精度保持長久。根據(jù)零件結(jié)構(gòu)特點(diǎn)，此零件需要進(jìn)行兩次加工，所以選擇 方案 Ⅱ，裝夾一次完成上表面加工。擴(kuò)孔的加工余量一般為 ～ 4mm。 并且根據(jù)公差要求來進(jìn)行調(diào)配。根據(jù)設(shè)計(jì)要求制定多種方案，完成對(duì) 復(fù)雜零件加 工工藝設(shè)計(jì)及數(shù)控程序編制確定裝夾方案，定位及相關(guān)的工序內(nèi)容。 零件的分析 此零件結(jié)構(gòu)比較簡(jiǎn)單， 形狀為長方形，主要由平面、外輪廓、內(nèi)型腔及平行孔系組成。所以選擇 方案 Ⅱ， 方案 Ⅰ只能達(dá)到 8級(jí)以上精度，所以它達(dá)不到零件的技術(shù)要求。 加工階段的劃分 按照零件的加工要求以及加工后所要達(dá)到的技術(shù)要求 ,該零件加工階段可劃分為粗加工 ,半精加工 ,精加工三個(gè)階段 . 粗加工階段 :由于凸臺(tái)部分要求達(dá)到 的粗糙度 ,所以不能夠一次完成 ,需要經(jīng)過多次加工 ,防止應(yīng)力過于集中 ,而 造成工件的斷列或者工件的使用壽命過短 ,所以加工過程中 ,需要進(jìn)行 熱處理 .一保證加工要求 . 半精加工階段 :此階段是一個(gè)過度階段 ,為下一步的精加工作好準(zhǔn)備 ,同時(shí) ,也可防止刀具由于切削量過大而造成的損壞 . 精加工階段 :對(duì)于該零件 ,由于精度要求較高 ,所以是必須的一步 , 工序的劃分 根據(jù)工件的結(jié)構(gòu)與尺寸要求 ,按照安裝次數(shù)劃分 ,方案 如下 方案 Ⅰ 按照粗精加工劃分，劃分為三道工序 方案 Ⅱ 按照裝夾次數(shù)劃分，分為兩道工序。 本機(jī)床的鑄件均采用樹脂砂鑄件，且經(jīng)過兩次人工時(shí)效處理，穩(wěn)定性好，強(qiáng)度高，各項(xiàng)精度穩(wěn)定可靠。工件上同軸度要求較高的表面應(yīng)在一次裝夾中車出。 由于四爪卡盤的四個(gè)卡爪是獨(dú)立移動(dòng)的，在安裝工件時(shí)須進(jìn)行仔細(xì)的找正工件，一般用劃針盤按工件內(nèi)外圓表面或預(yù)先劃出的加工線找正，其定位精度較低，為 ～ 。 孔的加工，首先選擇直徑為 10 mm 的鉆頭進(jìn)行鉆中心孔，以保證同軸度等要 求，然后 5 選擇直徑為 19 mm 的鉆頭做粗加工，然后選擇直徑為 20 mm 的鉆頭進(jìn)行最后的鉸孔，以保證質(zhì)量。 根據(jù)零件的精度要求，精加工已經(jīng)能夠達(dá)到要求，所以精加工時(shí)為最后的一步，不留加工余量 內(nèi)型腔分 進(jìn)行 幾次加工 ， 粗 加工余量為 2 mm， 半精加工余量為 mm 對(duì)于平面 半精加工余量為 1 mm。 5 加工表面的程序清單 根據(jù)加工順序選擇原則，表面 程序加工清單安排如下表 2— 1 加工順序 加工內(nèi)容 1 凸臺(tái) 2 內(nèi)型腔 3 表面 4 孔 表 2— 1表面加工程序清單 6 其它的工序設(shè)計(jì) 輔助工序的安排 根據(jù)零件圖樣的技術(shù)要求，可知，零件需要進(jìn)行去毛刺處理，以便達(dá)到光整要求，同時(shí)保證了零件的質(zhì)量，便于最后應(yīng)用于實(shí)際當(dāng)中， 熱處理工序的安排 該零件需要進(jìn)行循環(huán)切削，加工過程中會(huì)產(chǎn)生殘余應(yīng)力，所以在粗加工之后，精加工之前要安排一次熱處理，同時(shí)為了達(dá)到圖樣規(guī)定的零件強(qiáng)度，硬度和耐磨性目的，需要進(jìn)行最終熱處理，根據(jù)零件的要求，最終選擇淬火處理。s largest virgin forest, and known for its spring and ecological environment, Arxan is marveled at by many tourists as the purest land on earth. You cannot miss out the Autumn of Arxan. It is definitely the best with brightlycolored scenery full of emotions. Autumn in the northern part of the country es earlier than the South. A September rain followed by the footprints of Autumn brings more colors to the once emerald green mountain and blooming grassland. Shutterbugs flock to see for themselves the marvel of splendid colors around the mountains and waters, many of whom have travel a long distance and even camp here only to capture a moment of the nature wonder. The silver birch turns golden, while the larch is still proudly green. You will find yourself drowned in the intoxicating red of the wild fruits as well as the glamour of flowers in full blown. And your heart will be lingering on the woods as it39。s Day! in shops, hotels and restaurants. But few young women will mark the festival with their boyfriends, or take part in traditional activities to pray for cleverness. A largescale of exhibition on the Silk Road opened to the public in the National Museum on Thursday. The exhibition displays more than 400 15 treasures from Shaanxi province, Gansu province and 14 other regions. It is largest scale exhibition that shows the history of the Silk Road in recent years. As APEC is going on in Beijing, the exhibit aims to show the world this brilliant section of history. The Silk Road is a series of trade and cultural transmission routes that were central to cultural interaction through regions of the Asian continent. It connected the West and East by linking traders, merchants, pilgrims, monks, soldiers, nomads, and urban dwellers from China and India to the Mediterranean Sea during various periods of time. I met my dear hubby in 2022 the second year I was in my school and it was the first year when he came here. We became colleagues. And there was nothing special happening during that year. He was just a kind and humble brother graduated from the same college as me. But we did not know each other till he became my colleague and his office desk was just in front of me. There was only a glass between us. So actually we could see each other when we both look up. But it is not the main reason that really draws us close. How we bee close to each other was something seems quite natural. We went out to play badminton with other colleagues and we sometimes chatted for a while. He is a man of few words but somehow sometimes will say something really humorous. Then one day, to my great surprise, I found a pot of beautiful flower on my desk. It was just the flower I had talked about with my colleague the other day, and I thought it was her who put the flower there. But the truth is not. It was the