畢業(yè)論文-導(dǎo)X彈發(fā)射架導(dǎo)軌基座的加工工藝

邢臺(tái)職業(yè)技術(shù)學(xué)院畢業(yè)論文PAGE23邢臺(tái)職業(yè)技術(shù)學(xué)院畢業(yè)論文論文題目：導(dǎo)彈發(fā)射架導(dǎo)軌基座的加工工藝專業(yè)數(shù)控技術(shù)班級(jí)姓名學(xué)號(hào)28指導(dǎo)教師日期2012年6月摘要本文綜述了導(dǎo)彈發(fā)射架導(dǎo)軌基座的工藝制定過(guò)程包括零件圖的分析、毛坯的選擇、工藝過(guò)程的確定、刀具的選擇、加工余量的選擇確定等，通過(guò)零件加工原則及查閱各種工藝和切削資料得到導(dǎo)彈發(fā)射架導(dǎo)軌基座的工藝分析，同時(shí)介紹了該零件的實(shí)際加工過(guò)程總結(jié)以及相關(guān)介紹。關(guān)鍵詞：數(shù)控技術(shù)；工藝；加工目錄TOC\o"1-3"\h\z摘要 2第1章工藝分析 41.1圖紙的分析 5第2章毛坯的選擇 5第3章工藝路線設(shè)計(jì) 63.1各表面的加工方法 63.2加工階段的劃分 63.3確定加工順序 63.4基準(zhǔn)的選擇 63.4.1精基準(zhǔn)的選擇 63.4.2粗基準(zhǔn)的選擇 73.5選擇加工設(shè)備與工藝裝備 83.5.1選擇機(jī)床 83.5.2選擇夾具 93.5.3選擇刀具 113.5.4制作刀具表 113.6量具的選擇 123.7加工余量的確定 123.7.1加工余量的確定 123.7.2確定切削用量 123.8工序卡片的擬定 133.8.1制定工序卡 14第4章零件的實(shí)際加工 164.1操作過(guò)程 164.2過(guò)程總結(jié) 164.3相關(guān)介紹 174.3.1尋邊器 17參考文獻(xiàn) 19致謝 20第1章工藝分析1.1圖紙分析該零件圖主要有六個(gè)視圖組成，主視圖、俯視圖、仰視圖、局部試圖、向視圖、剖視圖；主視圖用剖視來(lái)表示內(nèi)部結(jié)構(gòu)；向視圖表示兩個(gè)M4螺紋孔的相對(duì)位置；局部試圖表示上下面板的厚度；A-A剖視圖表示螺紋孔的深度和相對(duì)位置；上表面上的12×φ4.4的位置度φ0.2；下表面上的14×M4的位置度為φ0.15。下表面斜度3.5°±1°；上表面平面度0.05；通過(guò)對(duì)零件圖的分析并考慮到工廠現(xiàn)有設(shè)備，故選擇漢川數(shù)控銑床XK714D。第二章毛坯的選擇導(dǎo)軌基座的材料要求為45鋼，45號(hào)鋼具有高的強(qiáng)度和韌性適合制造承受強(qiáng)度比較高的運(yùn)動(dòng)零件，鑄鋼的特點(diǎn)是綜合機(jī)械性能高于各類鑄鐵，不僅強(qiáng)度高，而且有優(yōu)良的塑性和韌性，此外焊接性能好，因此，適合制造形狀復(fù)雜的強(qiáng)度高的零件。根據(jù)圖紙分析下料尺寸應(yīng)保證在322×136×30.5，用氣焊下料單邊預(yù)3-4mm的普銑加工量，由普銑加工到尺寸。第3章工藝路線設(shè)計(jì)3.1各表面的加工方法首先是外形的粗加工，凹槽和兩邊的外形用φ20的牛刀去除多余材料并用φ12的立銑刀銑去殘余量，然后各個(gè)面的精加工，零件兩頭突出部分，最后是上面下面?zhèn)让娴募庸?。加工時(shí)應(yīng)考慮工廠的刀具使用情況并結(jié)合基準(zhǔn)先行、先面后孔和先主要后表面的原則進(jìn)行考慮加工。3.2加階段的劃分粗加工階段對(duì)毛坯進(jìn)行外形銑削；精加工階段對(duì)個(gè)表面進(jìn)行加工并保證各個(gè)表面尺寸要求；3.3確定加工順序由普銑車間送來(lái)毛坯料322×136×30.5，在數(shù)控銑床上進(jìn)行粗銑外形和挖槽，裝夾方式為臺(tái)虎鉗裝夾，上表面需用百分表打平誤差在0.01——0.02毫米間保證合理的定位精度，同時(shí)應(yīng)注意臺(tái)虎鉗左右兩邊的毛坯預(yù)留尺寸，因?yàn)閮蛇吺潜患庸げ课?，粗銑完成后送去熱處理按圖紙要求應(yīng)達(dá)到23~28HRC,然后開(kāi)始精銑，首先是兩邊凸頭和上邊肋板的加工，同樣在臺(tái)虎鉗上裝夾，精銑底面并打中心孔，精銑頂面的凹槽和上斜面，精銑凹槽外側(cè)面裝夾方法用壓板壓兩邊，然后在臺(tái)虎鉗上將凹槽外側(cè)面加緊拉平斜面打孔，最后去毛刺并送往鉗工車間做后處理。3.4基準(zhǔn)的選擇定位基準(zhǔn)有粗基準(zhǔn)和精基準(zhǔn)之分，常先確定精基準(zhǔn)，再確定粗基準(zhǔn)。3.4.1精基準(zhǔn)的選擇選擇精基準(zhǔn)時(shí)，主要考慮的問(wèn)題是如何保證零件的加工精度以及安裝可靠。選擇原則：基準(zhǔn)重合原則即采用設(shè)計(jì)基準(zhǔn)作為定位基準(zhǔn)才稱為基準(zhǔn)重合。為避免基準(zhǔn)不重合而引起的基準(zhǔn)不重合誤差，保證加工精度應(yīng)遵循基準(zhǔn)重合原則。基準(zhǔn)統(tǒng)一原則即在工件的加工過(guò)程中盡可能的統(tǒng)一的定位基準(zhǔn)。自為基準(zhǔn)原則即當(dāng)某些表面精加工要求加工余量小而均勻時(shí)，選擇加工表面作為定位基準(zhǔn)?；榛鶞?zhǔn)原則即為了使加工面有較高的位置精度，又為了使其他加工余量小而均勻，可采用反復(fù)加工，互為基準(zhǔn)的原則。導(dǎo)軌基座的技術(shù)要求，以及圖形中所給出的條件，應(yīng)選擇左端面和后端面作為精基準(zhǔn)，零件上的很多表面都可以采用它作為基準(zhǔn)進(jìn)行加工，即遵循了“基準(zhǔn)統(tǒng)一”的原則，因?yàn)樵摿慵谒椒较蛏系某叽缍嘁栽摱嗣孀鳛榛鶞?zhǔn)，實(shí)現(xiàn)了設(shè)計(jì)基準(zhǔn)和工藝基準(zhǔn)重合的原則，即實(shí)現(xiàn)了“基準(zhǔn)重合”的原則，保證了被加工表面的技術(shù)要求。3.4.2粗基準(zhǔn)的選擇選擇粗基準(zhǔn)時(shí)，主要考慮的問(wèn)題是如何使用各道工序均有足夠的加工余量以及工件安裝的穩(wěn)定性。選擇原則：1、為了保證加工面與不加工面的位置要求，應(yīng)選不加工面為粗基準(zhǔn)；若工件上有幾個(gè)不需加工的表面，應(yīng)選其中與加工表面間的位置精度要求較高者為粗基準(zhǔn)。2、合理分配各加工表面的余量：第一，為了保證各加工表面都有足夠的加工余量，應(yīng)選擇毛坯余量最小的面為粗基準(zhǔn)；第二，為了保證重要加工面的余量均勻，應(yīng)選擇毛坯重要加工面為粗基準(zhǔn)。盡量選用面積大而平整的表面為粗基準(zhǔn)，以保證定位基準(zhǔn)、加緊可靠。粗基準(zhǔn)一般不重復(fù)使用，同一尺寸方向的粗基準(zhǔn)一般只能使用一次。根據(jù)粗基準(zhǔn)的選擇原則，導(dǎo)軌基座粗基準(zhǔn)應(yīng)選為底面。3.5選擇加工設(shè)備與工藝裝備3.5.1選擇機(jī)床漢川機(jī)械數(shù)控銑床XK714D主要技術(shù)規(guī)格

技術(shù)參數(shù)XK714D（1）系統(tǒng)機(jī)配用數(shù)控系統(tǒng)SIEMENS802S（2）工作臺(tái)工作臺(tái)面積400x900mm

T形槽3x18H8mm

T型槽距離125mm

工作臺(tái)最大承重600kg（3）行程X向,Y向,Z向行程630x400x500mm

主軸端面至工作臺(tái)面距離125-625mm

主軸中心至立柱導(dǎo)軌面距離420mm（4）主軸主軸轉(zhuǎn)速608000rpm

主軸電機(jī)功率連續(xù)/30分7.5/11kw

主軸孔錐度NO.40-

三向進(jìn)給

切削進(jìn)給速度1-5000mm/min

快速移動(dòng)速度2000mm/min（5）精度定位精度±0.012/300mm

重復(fù)定位精度±0.006mm三坐標(biāo)拖動(dòng)電機(jī)（6）電機(jī)轉(zhuǎn)速2000--3000rpm

X,Y,Z向進(jìn)給速度15000mm/min

X,Y軸快速移動(dòng)速度20000mm/min

Z軸快速移動(dòng)速度15000mm/min

3.5.2選擇夾具夾具主要選用的是通用夾具，因?yàn)榇肆慵募庸げ恍枰彪s的裝夾，所以用通用夾具工廠中都有的，有壓板，機(jī)用臺(tái)鉗（加工精度很高能保證零件的加工精度）如圖1。圖1機(jī)用虎鉗壓板加緊工件時(shí)所用的工具比較簡(jiǎn)單，主要是壓板，墊塊，T型螺栓和螺母如圖2。圖2壓板3.5.3選擇刀具導(dǎo)軌基座選用的刀具為φ20的牛刀、φ16的牛刀、φ20的刀片刀、φ12的立銑刀、φ10的合金立銑刀、φ8的合金立銑刀、φ6的球刀、φ3的中心鉆、φ4.4的鉆頭等。3.5.4制作刀具表刀具表序號(hào)刀具號(hào)刀具名稱數(shù)量刀柄型號(hào)刀具半徑R/mm1T1牛刀1BT40102T2刀片刀1BT40103T3牛刀1BT4084T10立銑刀1BT4085T4立銑刀1BT4066T5合金立銑刀1BT4057T6合金立銑刀1BT4048T7合金球刀1BT4039T8中心鉆1BT40φ310T9麻花鉆1BT40Φ4.43.6.量具的選則主要量具有外徑千分尺，游標(biāo)卡尺。游標(biāo)卡尺原理：0.02毫米的游標(biāo)卡尺刻線原理，尺寸每小格一毫米，尺身上的49毫米剛好等于游標(biāo)上的50格是游標(biāo)每格長(zhǎng)為50分之49即0.98毫米，尺身的每格相差1-0.98=0.02。因此，它的測(cè)量精度為0.02毫米。外徑千分尺是一種精密的量具。生產(chǎn)中常使用千分尺的測(cè)量精度為0.01毫米。它的精度比游標(biāo)卡尺的精度高，并且比較靈活，因此，對(duì)于加工精度要求比較高的零件尺寸，要用千分尺來(lái)測(cè)量。千分尺的種類很多，有外徑千分尺，內(nèi)徑千分尺，深度千分尺，其中以外徑千分尺用的比較多。各量具的作用：主要是測(cè)量零件的長(zhǎng)度尺寸，深度。3.7.機(jī)加工余量的確定3.7.1加工余量加工時(shí)每道工序都選用兩把刀，第一把刀去除大量多余材料多選用牛刀或刀片刀，因?yàn)榈镀D(zhuǎn)動(dòng)方向后可再次使用并且易于更換，第二把刀完成零件的最終加工保證每項(xiàng)尺寸符合公差要求。查閱機(jī)械加工工藝手冊(cè)結(jié)合加工情況確定加工余量，在精加工階段每道加工工序第一把刀留0.5mm給第二把刀。3.7.2切削用量切削用量包括切削速度、進(jìn)給速度、背吃刀量和側(cè)吃刀量。按照切削用量選取的基本原則并參靠《數(shù)控加工工藝》第197頁(yè)表5-5各種銑刀每齒進(jìn)給量，表5-6銑刀的切削速度及銑刀銑削時(shí)的切削速度主要運(yùn)用的公式是：VC=πdn/1000VC切削速度d銑刀直徑n切削轉(zhuǎn)速粗銑外形選用Φ20牛刀，選擇每次的背吃刀量ap=3mm，查切削用量手冊(cè)，加工45鋼（225~290HBS）時(shí)的切削速度為Vc=130~150m/min，根據(jù)銑刀直徑和公式Vc=dn/1000計(jì)算主軸轉(zhuǎn)速，得到其轉(zhuǎn)速為n=1700~2200r/min，粗銑取n=1800r/min，根據(jù)牛刀為2個(gè)齒，查切削用量手冊(cè)中給出的每齒進(jìn)給量為fz=0.06—0.04mm/Z，根據(jù)公式F=z×fz×n，得到其進(jìn)給速度為F=1300—1500mm/min，粗銑取F=1400mm/min。去除余量選擇Φ12的高速鋼立銑刀，銑時(shí)選擇每次的背吃刀量為ap=5mm。查切削用量手冊(cè)，高速鋼加工鋼件（225—290HBS）時(shí)的切削速度為vc=130—150m/min，每齒進(jìn)給量為fz=0.05—0.075mm/z。根據(jù)公式Vc=dn/1000計(jì)算主軸轉(zhuǎn)速n=298—596r/min。銑時(shí)取n=520r/min。立銑刀為3個(gè)齒，根據(jù)公式F=z×fz×n，得到其進(jìn)給速度為F=78—117mm/min，銑削取F=100mm/min。3.8工序卡片的擬定序號(hào)刀具規(guī)格刀具號(hào)工序內(nèi)容定位基準(zhǔn)主軸轉(zhuǎn)速r/min進(jìn)給量1Φ20T1粗銑外形底面180014002Φ12T4去除余量底面5201003Φ12T4精銑外形左端面中心480804Φ10T5去除余量左端面中心840805Φ20T2銑肋板底面左、端面180020006Φ8T4銑肋板底面左、端面12001007Φ20T1底面底面200020008Φ10T5去除余量底面11401009Φ3T8定位孔10008010Φ16T1凹槽底面2000170011Φ10T5去除余量底面120010012Φ20T2斜面頂面1800180013Φ6T7精銑斜面頂面2000180014Φ20T1銑側(cè)面頂面、中心線1800180015Φ16T10精銑側(cè)邊頂面、中心線42010016Φ3T8定位孔10008017Φ4.4T9打孔800403.8.1工序卡片工序號(hào)程序編號(hào)夾具名稱使用設(shè)備車間6臺(tái)虎鉗、壓板數(shù)控銑床XK714D數(shù)控車間工步號(hào)工步內(nèi)容加工面刀具號(hào)刀具規(guī)格/mm主軸速r/min進(jìn)給速度mm/min背吃刀量/mm1粗銑外形凹槽、兩端部分T1Φ20牛刀、180014003T4Φ12立銑刀5201000.52熱處理精銑外形凹槽、兩端部分Φ12立銑刀480805Φ10立銑刀840800.53精銑兩端肋板部分T2Φ20刀片刀180020002T6Φ8合金立銑刀120010000.54底面底面T1Φ20牛刀200020002T5Φ10合金立銑刀114010000.5Φ3中心鉆5凹槽上面T3Φ16牛刀200017000.2T5Φ10合金立銑刀12001000.56斜面上面T2Φ20刀片刀180018001.5T7Φ6合金球刀200018000.57側(cè)邊兩面T2Φ20刀片刀180018002T1Φ16立銑刀4201000.58打孔上面T8、Φ3中心鉆100080T9Φ4.4麻花鉆80040編制審核編號(hào)第4章零件的實(shí)際加工4.1操作過(guò)程(1)機(jī)床的操縱首先檢查數(shù)控銑床的氣壓，潤(rùn)滑油是否符合標(biāo)準(zhǔn)，打開(kāi)電源開(kāi)關(guān)接著拔出急停開(kāi)關(guān)伺服啟動(dòng)回操考點(diǎn)。（2）機(jī)床的操縱完畢以后開(kāi)始把臺(tái)虎鉗裝在工作臺(tái)靠右邊部分，預(yù)留壓板安裝加工的空間，用百分表打臺(tái)虎鉗鉗口內(nèi)側(cè)誤差在0.01--0.02之間，固定壓緊。（3）每次工件裝夾都要重新建立坐標(biāo)系對(duì)刀。1、工件安裝用百分表找正并加緊；2、用對(duì)刀棒或?qū)み吰鳍俳⒆鴺?biāo)系；3、用相應(yīng)的刀具對(duì)Z值，沒(méi)換一次刀對(duì)一次Z值；零件的加工1、自動(dòng)狀態(tài)下選擇執(zhí)行外部程序指令；2、進(jìn)給量擰到零，轉(zhuǎn)速調(diào)到相應(yīng)值；3、從電腦上通過(guò)軟件傳送程序；4、按循環(huán)啟動(dòng)鍵，進(jìn)給量緩慢提高到相應(yīng)值；（5）按程序卡片進(jìn)行加工（6）最后加工完后進(jìn)行質(zhì)檢，用游標(biāo)卡尺和千分尺測(cè)量各部分尺寸，檢測(cè)合格后完成零件本車間的加工內(nèi)容。4.2過(guò)程總結(jié)1、在加工開(kāi)始前應(yīng)檢查潤(rùn)滑油是否滿足要求。如果潤(rùn)滑油不夠可能會(huì)導(dǎo)致在加工過(guò)程中機(jī)床因潤(rùn)滑不夠報(bào)警，機(jī)床停止加工。報(bào)警后再加油機(jī)床才能繼續(xù)加工。潤(rùn)滑油如果經(jīng)常不足會(huì)導(dǎo)致機(jī)床精度下降。2、在建立坐標(biāo)系后應(yīng)用MDI方式檢查是否正確。如果坐標(biāo)系不正確那就沒(méi)辦法保證零件的尺寸要求。3、使用牛刀或刀片刀時(shí)，因注意螺絲是否上緊。如果刀片沒(méi)有上緊，不僅會(huì)損壞刀具還會(huì)影響零件的質(zhì)量。同時(shí)還要注意螺絲有劃扣的現(xiàn)象時(shí)應(yīng)立即更換。4、加工過(guò)程中要確定加工位置、刀具、程序是否正確。5、在加工過(guò)程中要注意刀具是否有損壞的情況。有斷刀的應(yīng)立即暫停程序換刀，牛刀磨損嚴(yán)重時(shí)也要停機(jī)調(diào)整刀片。通過(guò)對(duì)導(dǎo)彈發(fā)射架導(dǎo)軌基座的零件進(jìn)行工藝分析，并且在實(shí)習(xí)期的實(shí)際加工，使我對(duì)數(shù)控銑削加工有了一定的了解，在加工過(guò)程中我接觸到了各種刀具、工裝、夾具等，使我對(duì)零件的整個(gè)加工過(guò)程有了初步的了解。4.3相關(guān)介紹4.3.1尋邊器英文名稱：touchpointsensor（opticaledgefinder）尋邊器在數(shù)控加工中，為了精確確定被加工工件的中心位置的一種檢測(cè)工具。尋邊器的工作原理是首先在X軸上選定一邊為零，再選另一邊得出數(shù)值，取其一半為X軸中點(diǎn)，然后按同樣方法找出Y軸原點(diǎn)，這樣工件在XY平面的加工中心就得到了確定。因?yàn)樯a(chǎn)的需要尋邊器有不同的類型，如光電式、防磁式、回轉(zhuǎn)式、陶瓷式、偏置式等，比較常用的是偏置式。光電式尋邊器特點(diǎn)：不需要回轉(zhuǎn)測(cè)量；2.精確度可以達(dá)到：±0.005mm偏置式尋邊器特點(diǎn)：尋邊器-偏置式偏置式尋邊器使用范例Φ10的直柄可以安裝在切削夾頭或鉆孔夾頭上；用手指輕壓測(cè)定子的側(cè)邊，使其偏心0.5mm；使其以400-600RPM的速度轉(zhuǎn)動(dòng)；彈簧力力較小，可以避免小銑刀或小鉆頭斷裂；使測(cè)定子與加工件的端面相接觸，一點(diǎn)一點(diǎn)的觸碰移動(dòng)，就會(huì)達(dá)到全接觸狀態(tài)，測(cè)定子即不會(huì)震動(dòng)，宛如靜止的狀態(tài)接觸著，如果此時(shí)加以外力，測(cè)定子就會(huì)偏移出位，此處滑動(dòng)的起點(diǎn)就是所要求的基準(zhǔn)位置；6.加工件本身的端面位置，就是加上測(cè)定子半徑5mm的坐標(biāo)位置。偏置式尋邊器使用注意事項(xiàng)：尋邊器-陶瓷式勿使用尋邊器彎曲或勉強(qiáng)拖拉，否則會(huì)影響精度；滑動(dòng)端面勿粘附異物或微塵；在測(cè)量時(shí)，轉(zhuǎn)速不能超過(guò)600RPM；偏置式尋邊器不適合在橫型的機(jī)器上使用。參考文獻(xiàn)[1]田春霞.數(shù)控加工工藝.北京：機(jī)械工業(yè)出版社，2006［2］上海市金屬切削技術(shù)協(xié)會(huì).金屬切削手冊(cè).上?？茖W(xué)技術(shù)出版社，1982［3］陳家芳.實(shí)用金屬切削加工工藝手冊(cè).上海：上?？茖W(xué)技術(shù)出版社，2005致謝本論文是在指導(dǎo)教師許麗華的悉心指導(dǎo)下完成的。許麗華老師嚴(yán)謹(jǐn)治學(xué)的態(tài)度給我樹(shù)立了榜樣，使我受益匪淺。在此特向指導(dǎo)教師的關(guān)心和幫助表示誠(chéng)摯的敬意和忠心的感謝。在論文工作的過(guò)程中，石家莊三星電子設(shè)備廠為我的課題研究提供了良好的條件，使我順利完成了論文的工作，在此向他們致以崇高的敬意。向在論文完成過(guò)程中給予我支持和幫助的老師、同學(xué)們表示謝意。請(qǐng)刪除以下內(nèi)容，O(∩_∩)O謝謝?。?！AnarbitrarytitlegiventoafuneraryworkfromancientEgyptcalledpertemhru,thetranslationofwhichis"comingforthbyday,"or"manifestedinthelight."Severalversionsorrecensionsofthisworkareknown,namelythoseofHeliopolis,Thebes,andSais,differingonlyinasmuchastheywereeditedbythecollegesofpriestsfoundedatthesecenters.Manypapyrioftheworkhavebeendiscovered,andpassagesfromithavebeeninscribeduponthewallsoftombsandpyramidsandonsarcophagiandmummy-wrappings.OneverycompletecopyisondisplayattheEgyptianMuseuminTurin,Italy.Itisundoubtedlyofextremelyearlydate;exactlyhowearlyitwouldbedifficulttosay,butinthecourseofcenturiesitwasgreatlyaddedtoandmodified.Itcontainsabout200chapters,butnocompletepapyrushasbeenfound.Thechaptersarequiteindependentofoneanother,andwereprobablyallcomposedatdifferenttimes.Themainsubjectisthebeatificationofthedead,whoweresupposedtorecitethechaptersinorderthattheymightgainpowerandenjoytheprivilegesofthenewlife.Theworkaboundsinmagicalreferences.ThewholetrendoftheBookoftheDeadisthaumaturgic,asitspurposeistoguardthedeadagainstthedangerstheyhavetofaceinreachingtheotherworld.Asinmostmythologies,thedeadEgyptianhadtoencountermalignantspiritsandwasthreatenedbymanydangersbeforereachinghishavenofrest.HealsohadtoundergojudgmentbyOsiris,andtojustifyhimselfbeforebeingpermittedtoentertherealmsofbliss.Thisheimaginedhecouldingreatpartaccomplishbytherecitationofvariousmagicalformulaandspells,whichwouldwardofftheevilinfluencesopposedtohim.TothisendeveryimportantEgyptianofmeanshadburiedwithhimapapyrusoftheBookoftheDead,containingatleastallthechaptersnecessaryforencounteringtheformidableadversariesatthegatesofAmenti,theEgyptianHades.Thesechapterswouldassisthiminmakingrepliesduringhisceremonyofjustification.Firstamongthesespellswerethe"wordsofpower."TheEgyptiansbelievedthattodiscoverthe"secret"nameofagodwastogaincompleteascendancyoverhim.SympatheticmagicwasinvogueinEgyptianburialpractice,whichexplainsthepresence,intombsofpeopleofmeans,ofpaintingsoftablesladenwithfoodanddrink,withinscriptionsattachedconveyingtheideaofboundlessliberality.Inscriptionslikethefollowingareextremelycommon—"Totheka[essentialdoubleorsoul]ofso-and-so,5,000loavesofbread,500geese,and5,000jugsofbeer."Thosededicationscostthegenerousdonorslittle,astheymerelyhadtheobjectsnamedpainteduponthewallofthetomb,imaginingthattheirkaorastralcounterpartwouldbeeatableanddrinkablebythedeceased.ThisofcourseismerelyanextensionoftheNeolithicconceptionthatarticlesburiedwithamanhadtheirastralcounterpartsandwouldbeofusetohiminanotherworld.PictorialrepresentationplayedaconsiderablepartinthemagicalritualoftheBookoftheDead.OneofthepleasuresofthedeadwastosailoverHeavenintheboatofRa,andtosecurethisforthedeceasedonemustpaintcertainpicturesandmutteroverthemwordsofpower.Regardingthisbelief,E.A.WallisBudgestatesinhisbookEgyptianMagic(1889):"Onapieceofcleanpapyrusaboatistobedrawnwithinkmadeofgreenabutmixedwithantiwater,andinitaretobefiguresofIsis,Thoth,Shu,andKhepera,andthedeceased;whenthishadbeendonethepapyrusmustbefastenedtothebreastofthedeceased,carebeingtakenthatitdoesnotactuallytouchhisbody.ThenshallhisspiritenterintotheboatofRaeachday,andthegodThothshalltakeheedtohim,andheshallsailaboutwithhimintoanyplacethathewisheth.ElsewhereitisorderedthattheboatofRabepainted'inapureplace,'andinthebowsistobepaintedafigureofthedeceased;butRawassupposedtotravelinoneboat(calledAtet)untilnoon,andanother(calledSektet)untilsunset,andprovisionhadtobemadeforthedeceasedinbothboats.Howwasthistobedone?OnonesideofthepictureoftheboatafigureofthemorningboatofRawastobedrawn,andontheotherafigureoftheafternoonboat;thustheonepicturewascapableofbecomingtwoboats.And,providedtheproperofferingsweremadeforthedeceasedonthebirthdayofOsiris,hissoulwouldliveforever,andhewouldnotdieasecondtime.Accordingtotherubrictothechapterinwhichthesedirectionsaregiven,thetextofitisasold,atleast,asthetimeofHesept,thefifthkingofthe1st.dynasty,whoreignedabout4350B.C.,andthecustomofpaintingtheboatuponpapyrusisprobablycontemporaneous."Thewordsofpowerwerenottobespokenuntilafterdeath.Theywere"agreatmystery,"but"theeyeofnomanwhatsoevermustseeit,foritisathingofabominationforeverymantoknowit.Hideit,therefore,theBookoftheLadyoftheHiddenTempleisitsname."ThiswouldseemtorefertosomespellutteredbyIsis-HathorthatdeliveredthegodRaorHorusfromtrouble,orwasofbenefittohim,thuswasconcludedtobeequallyefficaciousinthecaseofthedeceased.ManyspellswereincludedintheBookoftheDeadforthepurposeofpreservingthemummyagainstmoldingandforassistingtheownerofthepapyrustobecomeasagodandtobeabletotransformhimselfintoanyshapehedesired.Paintedofferingswerealsoprovidedsothedeceasedwouldbeabletogivegiftstothegods.ItisapparentthattheBookoftheDeadwasundoubtedlymagicalincharacter,consistingasitdidofaseriesofspellsorwordsofpower,whichenabledthespeakertohaveperfectcontroloverallthepowersofAmenti.TheonlymomentinwhichthedeadmanisnotmasterofhisfateiswhenhisheartisweighedbyThothbeforeOsiris.Ifitdoesnotconformtothestandardrequiredforjustification,heiscastout;exceptforthis,anabsoluteknowledgeoftheBookoftheDeadsafeguardedthedeceasedineverywayfromthedangerofdamnation.Anumberofthechaptersconsistofprayersandhymnstothegods,butthedirectionsastothemagicalusesofthebookareequallynumerous;theconceptofsupplicationismingledwiththeideaofcircumventionbysorceryinthemostextraordinarymanner.Thereisalsoevidenceofahigherproportionofperinatalcomplications(complicationsarisingaroundthetimeofgivingbirth)amongchildrenwithautisticsymptoms.Thesecomplicationsincludematernalbleedingafterthefirsttrimesterandmeconiumintheamnioticfluid.(Meconiumisasubstancethataccumulatesinthebowelofthedevelopingfetusandisdischargedshortlyafterbirth.)Someevidencesuggeststhattheuseofmedicationsduringpregnancymayberelatedtothedevelopmentofautisticsymptoms.Asnewborns,childrenwithautisticbehaviorsshowahigherrateofrespiratoryillnessandanemiathanhealthychildren.ALLERGIES,INFECTIONS,ANDIMMUNIZATIONS.Someprofessionalsbelievethatautisticdisordersmaybecausedbyallergiestoparticularfungi,viralinfections,andvariousfoods.Nocontrolledstudieshavesupportedthesebeliefs,butsomeparentsandprofessionalsreportimprovementwhenallergensand/orcertainfoodsareeliminatedfromthediet.Viralinfectionsofthemother,suchasrubella,oroftheyoungchild,suchasencephalitis,mumps,andmeasles,occasionallyappeartocauseautisticdisorders.Theissueisnothowhazardousboxingisbutwhetherthehazardsareacceptable.Theterm"autism"referstoaclusterofconditionsappearingearlyinchildhood.Allinvolvesevereimpairmentsinsocialinteraction,communication,imaginativeabilities,andrigid,repetitivebehaviors.Tobeconsideredanautisticdisorder,someoftheseimpairmentsmustbemanifestbeforetheageofthree.ThereferencebookusedbymentalhealthprofessionalstodiagnosementaldisordersistheDiagnosticandStatisticalManualofMentalDisorders,alsoknownastheDSM.The2000editionofthisreferencebook(theFourthEditionTextRevisionknownasDSM-IV-TR)placesautisminacategorycalledpervasivedevelopmentaldisorders.Allofthesedisordersarecharacterizedbyongoingproblemswithmutualsocialinteractionandcommunication,orthepresenceofstrange,repetitivebehaviors,interests,andactivities.Peoplediagnosedwiththesedisordersareaffectedinmanywaysfortheirentirelives.DescriptionEachchilddiagnosedwithanautisticdisorderdiffersfromeveryother,andsogeneraldescriptionsofautisticbehaviorandcharacteristicsdonotapplyequallytoeverychild.Still,thecommonimpairmentsinsocialinteraction,communicationandimagination,andrigid,repetitivebehaviorsmakeitpossibletorecognizechildrenwiththesedisorders,astheydiffermarkedlyfromhealthychildreninmanyways.Manyparentsofautisticchildrensensethatsomethingisnotquiterightevenwhentheirchildrenareinfants.Theinfantsmayhavefeedingproblems,dislikebeingchangedorbathed,orfussoveranychangeinroutine.Theymayholdtheirbodiesrigid,makingitdifficultforparentstocuddlethem.Or,theymayfailtoanticipatebeinglifted,lyingpassivelywhiletheparentreachesforthem,ratherthanholdingtheirarmsupinreturn.Mostparentsofautisticchildrenbecomeawareofthestrangenessoftheseandotherbehaviorsonlygradually.Imaginetoothestateofeventhewinner'shands,protectedonlybyhavingbeensoakedinbrine.Withtheircombinationofboxingandwrestlingmoves,earlycontestswereliterally‘noholdsbarred’;grappling,punching,tripping,andthrowingallbeingusedtoflooranopponent.Thewidely-adoptedBroughton'sRulesof1743eradicatedsomeofthebarbarismbyoutlawingthehittingofamanwhenhewasdown,andtheseizingofhairorthebodybelowthewaist,buttheystillpermittedbutting.Yetitwasnotthebrutalityoftheprize-ringwhichbroughtitsdemise,butthecorruptionwithwhichitbecameassociated.TherevivalofthesportasboxinginlateVictorianBritainsawseveralchangesdesignedtorenderitmorecivilized.Althoughsomeoftheoldpracticescontinuedforawhile—eventhefamousQueensburyRulesinitiallyallowedendurancecontests—bytheturnofthecenturythegeneralpicturewasoneofboxingingloves,limited-timerounds,pointsdecisionsafterafixednumberofroundshadelapsed,andweightdivisions,thoughthelatterhaveaccentuatedproblemsofdehydrationasfightersstruggleto‘maketheweight’.Formuchofthetwentiethcenturythehistoryofboxinghasbeenoneofcrumblingresistancetochangesintendedtoprotectfurtherthebrainsandbodiesofparticipants.Between1984and1993eightboxershaddiedsoonafterfightsintheUK;bantamweightBradleyStonewasaddedtothelistin1994.Followingareportfromamedicalworkingparty,whichincludedneurosurgeons,theBritishBoxingBoardofControlsubsequentlyintroducedmandatoryannualmagneticresonanceimagingscansforallboxerstoreplacethelesssophisticatedcomputerizedtomographywhichhadbeencompulsoryonlyforthosefightingeightroundsormore.Additionally,anyboxerknockedoutmustwait45days(previously28)beforeheagainenterstheringcompetitively,andhemustalsohaveahospitalcheck.Ringsidedoctorsmayadviserefereesonafighter'sconditionbetweenroundsandmayrecommendthatthecontestbestopped.Doctorsalsoexamineeachboxerattheconclusionoffightsandparamedicteamsmustbeonhandatallboxingbills.Themedicalprofessioninseveralcountrieshasincreasinglyadoptedananti-boxingstance,citingirreversiblebraindamageasitsmajorobjectiontothesport.Thisisakeypointfor,inabsolutetermsofdeathsandseriousinjuries,othersportssuchashorseracing,mountaineering,However,headguards,whilstabsorbingenergyfrompunches,presentanevenlargertargettobehitandthusthenumberofblowsstrikinghomemaywellincrease.Indeed,studieshaveshownthatnon-boxingsportsmenoutperformevenamateurfightersinneurologicaltestsand,notwithstandingthesafetyprecautions,threeamateurfightershavesufferedseriousbraininjuryinBritishringssince1988.Forcenturiesboxinghasbeentheepitomeofovertmasculinity,ademonstrationofmanlinessanditsembodyingcharacteristicsofcourage,tolerationofpain,andself-discipline.Womenweremerelyornamentsdisplayingtheroundcards.Thiscontinues,butwomenhavesuccessfullydemandedequalrightsinthering.InBritain,girlsfromtheageof10arenowallowedtosparinamateurboxinggyms,andrecentlyprofessionalism,too,hasbeenrecognizedforwomen—significantlylaterthanitsacceptanceintheUSwherefightsforwomenhaveappearedontheundercardofworldchampionshipevents.Themoraldilemmaofboxingisthatitprovidesanhonestopportunitytoescapepoverty,butitalsomeansforsomealegalbeatingandforallthethreatofpermanentdamage.Hittingbelowthebeltisoutlawedtoprotectthegenitals,butsurelythebraindeservesevenmoreprotection,byreducingtheconcussivepoweroftheboxingglove,developingsaferheadgear,excludingtheheadasatarget—orbybanningthesportaltogether.Impairmentsinsocialinteractionareusuallyamongtheearliestsymptomstodevelop.Themostcommonsocialimpairmentisakindofindifferencetootherpeople,oraloofness,eventowardsparentsandclosecare-givers.Thebabymayfailtorespondtohisorhernamebeingcalledandmayshowverylittlefacialexpressionunlessextremelyangry,upset,orhappy.Babieswithautismmayresistbeingtouched,andappeartobelostintheirownworld,farfromhumaninteraction.Betweensevenand10monthsofage,mostinfantsoftenresistbeingseparatedfromaparentorwell-knowncaregiver,buttheseinfantsmayshownodisturbancewhenpickedupbyastranger.Otherchildrenwithautismmaybeverypassive,althoughlessresistanttoeffortsbyotherstointeract.However,theydonotinitiatesocialinteractionthemselves.Stillothersmayattempttoengagewithadultsandpeers,butinwaysthatstrikeothersasinappropriate,orodd.Inadolescenceandadulthood,someofthehigher-functioningindividualswithautisticdisordersmayappearoverlyformalandpolite.Theymayreactwithlittlespontaneity,asifsocialinteractiondoesn'tcomenaturallyoreasilytothem,andsotheyaretryingtofollowapre-determinedsetofrules.基于C8051F單片機(jī)直流電動(dòng)機(jī)反饋控制系統(tǒng)的設(shè)計(jì)與研究基于單片機(jī)的嵌入式Web服務(wù)器的研究MOTOROLA單片機(jī)MC68HC（8）05PV8/A內(nèi)嵌EEPROM的工藝和制程方法及對(duì)良率的影響研究基于模糊控制的電阻釬焊單片機(jī)溫度控制系統(tǒng)的研制基于MCS-51系列單片機(jī)的通用控制模塊的研究基于單片機(jī)實(shí)現(xiàn)的供暖系統(tǒng)最佳啟停自校正（STR）調(diào)節(jié)器單片機(jī)控制的二級(jí)倒立擺系統(tǒng)的研究基于增強(qiáng)型51系列單片機(jī)的TCP/IP協(xié)議棧的實(shí)現(xiàn)基于單片機(jī)的蓄電池自動(dòng)監(jiān)測(cè)系統(tǒng)基于32位嵌入式單片機(jī)系統(tǒng)的圖像采集與處理技術(shù)的研究基于單片機(jī)的作物營(yíng)養(yǎng)診斷專家系統(tǒng)的研究基于單片機(jī)的交流伺服電機(jī)運(yùn)動(dòng)控制系統(tǒng)研究與開(kāi)發(fā)基于單片機(jī)的泵管內(nèi)壁硬度測(cè)試儀的研制基于單片機(jī)的自動(dòng)找平控制系統(tǒng)研究基于C8051F040單片機(jī)的嵌入式系統(tǒng)開(kāi)發(fā)基于單片機(jī)的液壓動(dòng)力系統(tǒng)狀態(tài)監(jiān)測(cè)儀開(kāi)發(fā)模糊Smith智能控制方法的研究及其單片機(jī)實(shí)現(xiàn)一種基于單片機(jī)的軸快流CO〈,2〉激光器的手持控制面板的研制基于雙單片機(jī)沖床數(shù)控系統(tǒng)的研究基于CYGNAL單片機(jī)的在線間歇式濁度儀的研制基于單片機(jī)的噴油泵試驗(yàn)臺(tái)控制器的研制基于單片機(jī)的軟起動(dòng)器的研究和設(shè)計(jì)基于單片機(jī)控制的高速快走絲電火花線切割機(jī)床短循環(huán)走絲方式研究基于單片機(jī)的機(jī)電產(chǎn)品控制系統(tǒng)開(kāi)發(fā)基于PIC單片機(jī)的智能手機(jī)充電器基于單片機(jī)的實(shí)時(shí)內(nèi)核設(shè)計(jì)及其應(yīng)用研究基于單片機(jī)的遠(yuǎn)程抄表系統(tǒng)的設(shè)計(jì)與研究基于單片機(jī)的煙氣二氧化硫濃度檢測(cè)儀的研制基于微型光譜儀的單片機(jī)系統(tǒng)單片機(jī)系統(tǒng)軟件構(gòu)件開(kāi)發(fā)的技術(shù)研究基于單片機(jī)的液體點(diǎn)滴速度自動(dòng)檢測(cè)儀的研制基于單片機(jī)系統(tǒng)的多功能溫度測(cè)量?jī)x的研制基于PIC單片機(jī)的電能采集終端的設(shè)計(jì)和應(yīng)用基于單片機(jī)的光纖光柵解調(diào)儀的研制氣壓式線性摩擦焊機(jī)單片機(jī)控制系統(tǒng)的研制基于單片機(jī)的數(shù)字磁通門傳感器基于單片機(jī)的旋轉(zhuǎn)變壓器-數(shù)字轉(zhuǎn)換器的研究基于單片機(jī)的光纖Bragg光柵解調(diào)系統(tǒng)的研究單片機(jī)控制的便攜式多功能乳腺治療儀的研制基于C8051F020單片機(jī)的多生理信號(hào)檢測(cè)儀基于單片機(jī)的電機(jī)運(yùn)動(dòng)控制系統(tǒng)設(shè)計(jì)Pico專用單片機(jī)核的可測(cè)性設(shè)計(jì)研究基于MCS-51單片機(jī)的熱量計(jì)基于雙單片機(jī)的智能遙測(cè)微型氣象站MCS-51單片機(jī)構(gòu)建機(jī)器人的實(shí)踐研究基于單片機(jī)的輪軌力檢測(cè)基于單片機(jī)的GPS定位儀的研究與實(shí)現(xiàn)基于單片機(jī)的電液伺服控制系統(tǒng)用于單片機(jī)系統(tǒng)的MMC卡文件系統(tǒng)研制基于單片機(jī)的時(shí)控和計(jì)數(shù)系統(tǒng)性能優(yōu)化的研究基于單片機(jī)和CPLD的粗光柵位移測(cè)量系統(tǒng)