【正文】 s misery, the cow told him to turn its hide into a pair of shoes after it died. The magic shoes whisked Niulang, who carried his two children in baskets strung from a shoulder pole, off on a chase after the empress. The pursuit enraged the empress, who took her hairpin and slashed it across the sky creating the Milky Way which separated husband from wife. But all was not lost as magpies, moved by their love and devotion, formed a bridge across the Milky Way to reunite the family. Even the Jade Emperor was touched, and allowed Niulang and Zhinu to meet once a year on the seventh night of the seventh month. This is how Qixi came to be. The festival can be traced back to the Han Dynasty (206 BCAD 220). Traditionally, people would look up at the sky and find a bright star in the constellation Aquila as well as the star Vega, which are identified as Niulang and Zhinu. The two stars shine on opposite sides of the Milky Way. Customs In bygone days, Qixi was not only a special day for lovers, but also for girls. It is also known as the Begging for Skills Festival or Daughters39。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。 202229 26 請您刪除一下內(nèi)容， O(∩ _∩ )O 謝謝?。?！ Many people have the same mixed feelings when planning a trip during Golden Week. With heaps of time, the sevenday Chinese National Day holiday could be the best occasion to enjoy a destination. However, it can also be the easiest way to ruin how you feel about a place and you may bee more fatigued after the holiday, due to battling the large crowds. During peak season, a dream about a place can turn to nightmare without careful planning, especially if you travel with children and older people. As most Chinese people will take the holiday to visit domestic tourist destinations, crowds and busy traffic are inevitable at most places. Also to be expected are increasing transport and acmodation prices, with the possibility that there will be no rooms available. It is also mon that you39。 由于能力所限，設(shè)計中還有許多不足之處，懇請各位老師，同學(xué)們批評指正。 總的來說，這次設(shè)計，是我們在基本理論的綜合運用及解決實際問題等方面得到了一次較好的訓(xùn)練。 通過此次設(shè)計，使我們基本掌握了零件的加工過程分析，工藝文件的編制，專用夾具設(shè)計的方法和步驟等。第一階段我們運用了基準(zhǔn)選擇，切削用量選擇計算，機床選用，時間定額計算 等方面的知識。 L= d+l1 + l2 + l3 =92mm Tj = infL= 92? ≈ 202229 23 ⑤ 輔助時間 Tf ：查表 5152 得啟動機床時間為 ，取量具并測量尺寸的時間為 ，啟動調(diào)節(jié)切削液的時間為 ，共計 Tf = 第八章 填寫工藝文件 202229 24 小 結(jié) 為期兩周的 課程設(shè)計已經(jīng)接近尾聲，回顧整個過程，我組七名同學(xué)在老師的指導(dǎo)下，取得了可喜的成績，課程設(shè)計作為《機械設(shè)計制造工藝學(xué)》，《機床夾具設(shè)計》課程的重要環(huán)節(jié)，使理論與實踐更加接近，加深了理論知識的理解，強化了生產(chǎn)實習(xí)中的感性認識。 計算基本時間 Tj：切削加工長度 d=85端面刀頭選用主偏角 kr=75176。 2） .鏜 ? 20 的縱向孔 ① 確定 背吃刀量 ap：孔的總加工余量為 2mm。 背吃刀量ap= 查表 5— 138 和表 5— 138 得 l1 =rpKatan +（ 23） mm，取 l1 =4mm， l2 =（ 3～ 5）mm，批量生產(chǎn) l3 =0。經(jīng)半精加工和精加工兩步完成，半精 加工一次走刀加工 ap= ： ② 半精鏜 的速度和進給量：查表 5118 得 vc=25~40mm,f=~得取 f= 因為是半精鏜所以切削速度稍低 vc=35m/r ③ 床主軸轉(zhuǎn)速 n： n=wcdv?1000 = ??? r/min≈ 根據(jù)表 56 查得相近較小的機床轉(zhuǎn)速為 500r/min 所以實際的切削速度 vc=。 取 Y=mm，切入量△ =4mm Tj=nfyl ???= 4585? ?? = ④ 計算輔助時間 fT 查表 5153得，變換刀架的時間為 ，變速或變進給量的時間為 ,啟動和調(diào)節(jié)切削液的時間為 ,共計 fT = 70 半精鏜 ? 20 的縱向孔 ， 鏜 ? 20 的縱向孔 。 切入量 Y=[2do cot ? +(12)]mm 式中， d0為鉆頭直徑。 ② 確定機床主軸轉(zhuǎn)速 n n=1000vc/π d0= 202200?? =398 r/min 根據(jù)表 55，按機床實際轉(zhuǎn)速 N=320 r/min ③ 計算基本時間 Tj。 L= d+l1 + l2 + l3 =93mm 202229 21 Tj = infL= 93? ≈ ⑥ 輔助時間 Tf ：查表 5152，裝夾工件的時間為 ，啟動機床時間為，取量具并測量尺寸的時間為 ，啟動調(diào)節(jié)切削液的時間為，共計 Tf =。 ⑤ 計算基本工時 Tj ：切削加工長度 d=85mm，車刀選用主偏角 Kr =90176。刀具壽命選 T=60min。查表 54，根據(jù)機床橫向進給量，取 f=。 L= 21dd? +l1 + l2 + l3 = Tj = infL= ? ≈ 輔助時間 Tf ：查表 5152，啟動機床時間為 ，取量具并測量尺寸的時間為 ，啟動調(diào)節(jié)切削液的時間為 ，共計 Tf =。 ⑤ 計算基本工時 Tj ：切削加工長度 L=，車刀選用主偏角 Kr =90176。刀具壽命選 T=60min。查表 54，根據(jù)機床橫向進給量，取 f=。 3).精鉸孔 ? 20 查表 5117，背吃刀量 ap =15 mm，選擇進給量 f= /r，切削速度為 vc =10 m /min，查表 53 得主軸轉(zhuǎn)速 n=392 r/min，基本時間jT=，輔助時間Tf = 40 鉗工攻螺紋 拿取時間放在夾具上為 min，夾緊工件為 min，拿取絲錐為 min，絲錐刷油為 min，攻內(nèi)螺蚊為 min，放下絲錐為 min，放松夾緊為 min，取下工件為 min，總共合計 Tf= min。 查表 5153得，取工件裝夾間為 min，啟動機床時間為 min，取下工件時間為 min，共計 Tf= min。 被加工孔長度 l=8mm 切入量 y=[2do cot ? +(1～ 2)]mm =[25 cot? +(1～ 2) ]mm =～ 取 y=3mm,切入量△ =4mm。 L= 21dd? +l1 + l2 + l3 =（ 23555? +3+0+0） mm=13mm Tj = infL= ?? min≈ 輔助時間 Tf ：查表 5153，變速時間為 ，取 202229 18 量具并測量尺寸的時間為 ，共計 Tf = 6).用成形車刀車圓弧槽 因為兩個槽均用同一把成型車刀加工故方法同上，背吃刀量 ap =15mm，進給量 f=， vc ≈ ， n≈ ，選擇的機床轉(zhuǎn)速為 100r/min，實際的切削 速度為 vc =，成形車削深輪廓時切削速度需乘以系數(shù) ，故 vc = 30 鉆孔 4 ? 5孔，擴孔 ? 20至 ? 1).鉆孔 4 ? 5孔 步驟如下： ① 確定進量 F 根據(jù)表 5113取 f=== 5=，均采用手動進給。故： vc =vv yxpmvv faT KC =（ ??????? ） m/min ≈ ④ 確定機床主軸轉(zhuǎn)速 n： n=wcdv?1000 = ??? r/min≈ 根據(jù)表 55 查得相近較小的轉(zhuǎn)速為 n=100r/min，所以實際切削速度為 。 ③ 確定切削速度 vc ：根據(jù)表 5109 和表 5110，查得 Cv =， m=， xv =0，yv =，修正系數(shù) KMv =， KHv = Khv =， K vkr=， Ktv =。 ② 確定進給量 f：根據(jù)表 5105 得， 進給量 f=~。切削加工長度 L=9mm 背加工量 ap=2mm，查表 5138和表 5139得 l1=ap/tank1+(2～ 3) mm,取 l1=4 mm， 202229 17 l2=4 mm,由于是批量生產(chǎn)， l3=0 mm. L= l1+ l2+