外文翻譯--隧道掘進(jìn)機(jī)與中國

1、<p><b>　　隧道掘進(jìn)機(jī)與中國</b></p><p>　?。溃├铄鲈?RichardJ.Robbins</p><p>　　隨著隧道掘進(jìn)機(jī)的成功應(yīng)用，掘進(jìn)機(jī)在中國已經(jīng)成為不可忽視的地下隧道快速掘進(jìn)手段。如何發(fā)展中國的隧道掘進(jìn)機(jī)產(chǎn)業(yè)？這一問題的提出源自中國迅速增長的城市地下建筑和重大工程市場要求高效低耗的項目成本這一困擾多年的難題。</p

2、><p>　　1 隧道掘進(jìn)機(jī)的歷史</p><p>　　1.1隧道掘進(jìn)機(jī)及其類型</p><p>　　隧道掘進(jìn)機(jī)全稱全斷面隧道掘進(jìn)機(jī)，主要有兩大類型：開式和閉式，本文重點(diǎn)討論開式掘進(jìn)機(jī)。</p><p>　?。?）開式隧道掘進(jìn)機(jī)</p><p>　　所謂開式掘進(jìn)機(jī)是指切削時不用控制工作面的地壓，掘進(jìn)機(jī)按出碴系統(tǒng)運(yùn)碴能力掘進(jìn)

3、。開式掘進(jìn)機(jī)用于不需要特別考慮地表下沉的地況。開式掘進(jìn)機(jī)設(shè)計剛度較大。適用于在硬地層中快速掘進(jìn)。開式掘進(jìn)機(jī)又可以分為兩類，即開式主大梁和護(hù)盾式。</p><p><b>　?。?）閉式掘進(jìn)機(jī)</b></p><p>　　閉式掘進(jìn)機(jī)又稱為地壓平衡式掘進(jìn)機(jī)（EPB），是通過控制螺旋運(yùn)輸機(jī)卸料門的開啟，使刀盤前腔的壓力與地壓平衡。因為要平衡地壓，掘進(jìn)機(jī)根據(jù)碴石運(yùn)出的速度來調(diào)

4、節(jié)掘進(jìn)速度以維持地壓，不擾動或少擾動地層，避免或減小地表的沉降。地壓平衡式掘進(jìn)機(jī)通常用于軟地層或是流動性地層。</p><p>　　1.2 國際隧道掘進(jìn)機(jī)發(fā)展歷史</p><p>　　1851 年美國工程師Charles Wilson 發(fā)明了隧道掘進(jìn)機(jī)，通常被認(rèn)為是第一臺成功地在巖石中連續(xù)掘進(jìn)的機(jī)器。</p><p>　　另一個著名的探索是Colonel Beaum

5、ont 在1881年發(fā)明的壓縮空氣驅(qū)動的隧道掘進(jìn)機(jī)，曾用于英吉利海峽的一條探測隧道。</p><p>　　此后一直沒有更多值得注意的嘗試，直到1952 年羅賓斯設(shè)計了用于South Dakota 的OaheDam 隧道的掘進(jìn)機(jī)。該機(jī)直徑為7 . 85m，切削部分由內(nèi)刀盤和外刀盤兩個旋轉(zhuǎn)的部件組成。刀盤上沿徑向布置碳化鎢的截齒，并平行布置可自由轉(zhuǎn)動的盤形滾刀，滾刀略低于碳化鎢截齒。機(jī)器由兩臺150kW 的電動機(jī)驅(qū)動

6、，設(shè)備總重達(dá)114t。盡管這臺掘進(jìn)機(jī)不是設(shè)計在硬巖中掘進(jìn)的，它在軟頁巖中的日進(jìn)尺還是達(dá)到了49m。在四條隧道的掘進(jìn)過程中共更換了356 個截齒和4 把盤形滾刀。</p><p>　　其實，第一臺成功的硬巖掘進(jìn)機(jī)是直徑3 . 28m的羅賓斯隧道掘進(jìn)機(jī)，這臺機(jī)器是1956 年為加拿大的Foundation 公司建造的，用于多倫多市的Humber Sewer 項目，掘進(jìn)一條長約4 . 5km，主要由砂巖、頁巖、含石英的

7、石灰?guī)r組成的隧道，巖石的抗壓強(qiáng)度為5 ～ 186MPa。</p><p>　　從20 世紀(jì)50 年代至今，羅賓斯制造了數(shù)百臺隧道掘進(jìn)機(jī)，大約300 臺套掘進(jìn)機(jī)開掘了3500km多的巖石隧道，其直徑從1 . 6m 到11 . 87m。</p><p>　　1.3 中國隧道掘進(jìn)機(jī)發(fā)展歷史</p><p>　　隨著國外廣泛地應(yīng)用隧道掘進(jìn)機(jī)，20 世紀(jì)70年代初掘進(jìn)機(jī)開始出

8、現(xiàn)在中國。政府的各個部門如煤炭部、水電部和軍工部門都設(shè)計、制造和使用過多臺隧道掘進(jìn)機(jī)。</p><p>　　從20 世紀(jì)70 年代到80 年代，中國的各個部門至少建造了20 臺隧道掘進(jìn)機(jī)，僅煤炭部就建造了12 臺隧道掘進(jìn)機(jī)。值得注意的是在這些掘進(jìn)機(jī)的最高月進(jìn)尺只有250m，而且其中多數(shù)機(jī)組未投入使用。</p><p>　　20 世紀(jì)80 年代后期開始，隨著中國的改革開放，多數(shù)情況下由國外建

9、筑承包商或是中國建筑公司購買國外掘進(jìn)機(jī)承擔(dān)中國工程建設(shè)項目。</p><p>　　應(yīng)該指出，上述項目中由中國公司建設(shè)的多數(shù)項目之所以掘進(jìn)速度較低，是受地質(zhì)、管理和其它條件的綜合影響。</p><p>　　2 隧道掘進(jìn)機(jī)的應(yīng)用和新技術(shù)</p><p>　　從19 世紀(jì)50 年代中期以來，隧道掘進(jìn)機(jī)主要在三個方向上發(fā)展：適用于規(guī)模大、堅硬而且高磨蝕性巖石中掘進(jìn)；既適用于

10、穩(wěn)定的、有自支護(hù)力的地層，又適用于不穩(wěn)定巖石的地層；能經(jīng)濟(jì)地開掘隧道。</p><p>　　地質(zhì)條件和隧道設(shè)計的因素及要求將直接影響掘進(jìn)機(jī)的設(shè)計和隧道的經(jīng)濟(jì)性，掘進(jìn)機(jī)的制造商應(yīng)該在規(guī)劃設(shè)計前期即得到盡可能準(zhǔn)確的有關(guān)條件和要求。良好的隧道設(shè)計再加上好的掘進(jìn)機(jī)系統(tǒng)才能成功而且高效地完成隧道項目。</p><p><b>　　2.1 地質(zhì)因素</b></p>

11、<p>　　影響掘進(jìn)機(jī)設(shè)計的地質(zhì)因素有：巖石的強(qiáng)度和彈性模量，巖石的類型和磨蝕性，巖石的完整性或裂隙情況，相關(guān)隧道的傾角和走向，覆蓋巖層和原地巖石應(yīng)力，斷層區(qū)和支護(hù)時間，水、瓦斯氣、周圍巖層的溫度。</p><p>　　為了克服隧道中不利的地質(zhì)條件，掘進(jìn)機(jī)設(shè)計裝備了以下功能：后裝式刀盤，刀盤能反轉(zhuǎn)且轉(zhuǎn)速可變，支撐力和推進(jìn)力成比例，配有錨桿鉆機(jī)以實現(xiàn)支護(hù)，配有超前探鉆以探測和注漿。在混合地層的條件下，應(yīng)特

12、別注意刀盤特性的設(shè)計，諸如：低廊線的鏟斗、封閉的鏟斗門、后裝式滾刀、超挖能力、表面堆焊耐磨材料，設(shè)計中還應(yīng)該特別注意減少刀盤的暴露部分。</p><p>　?。?）隧道掘進(jìn)機(jī)的設(shè)計受其工作的隧道地質(zhì)條件的影響極大，掘進(jìn)機(jī)制造商必須考慮所有已得到的地質(zhì)資料，并根據(jù)其中最主要的數(shù)據(jù)進(jìn)行正確的設(shè)計。</p><p>　　（2）堅硬和規(guī)模大的巖石需要較大的推力以高效地切削巖石，這就要求設(shè)備各部件剛

13、度大，而系統(tǒng)的功率也較大。</p><p>　?。?）不同類型的巖石及其中的磨粒性物質(zhì)會影響滾刀的選擇和刀盤的設(shè)計。</p><p>　　（4）較多的斷層或是很短的支護(hù)時間需采用護(hù)盾式掘進(jìn)機(jī)，還可能需要預(yù)制隧道支護(hù)系統(tǒng)。</p><p>　　2.2 隧道設(shè)計因素</p><p>　　影響掘進(jìn)機(jī)設(shè)計的隧道設(shè)計因素有：隧道的走向和曲率、傾角、巖石

14、支護(hù)要求、注漿、超前探鉆、隧道的允許誤差、地壓極限、能用于組裝和作業(yè)的區(qū)域、環(huán)境要求和隧道掘進(jìn)作業(yè)計劃。比如在傾斜的隧道中作業(yè)，就要特別考慮掘進(jìn)機(jī)的主驅(qū)動系統(tǒng)、液壓系統(tǒng)、潤滑和皮帶運(yùn)輸系統(tǒng)。</p><p><b>　　2.3 成本控制</b></p><p>　　在硬巖中建造隧道，最重要的是既順利和安全，又要適當(dāng)控制成本。相對于傳統(tǒng)的硬巖隧道開挖方法，隧道掘進(jìn)機(jī)提供

15、了一種高效低耗的選擇，尤其是對大直徑和長距離的隧道。使用掘進(jìn)機(jī)開掘硬巖隧道，其成本主要由勞動力、設(shè)備費(fèi)用和消耗品組成。勞動力費(fèi)用的控制有二大影響因素，即掘進(jìn)時間和作業(yè)人數(shù)。任何一方面的節(jié)省即意味著勞動力費(fèi)用的降低，其中每一因素又會受到其它方面的影響。減少掘進(jìn)時間會相應(yīng)地減少掘進(jìn)進(jìn)尺、降低掘進(jìn)速度和掘進(jìn)機(jī)的利用率。作業(yè)人數(shù)包括掘進(jìn)工作人員和后勤人員、管理人員和維修人員。</p><p>　　隨著近幾年來滾刀和刀座制

16、造技術(shù)的發(fā)展，已經(jīng)能生產(chǎn)出配有高質(zhì)量刀圈的強(qiáng)力滾刀，使得更高的掘進(jìn)速度成為可能。另一個減少掘進(jìn)時間的考慮是加快掘進(jìn)速度，即提高刀盤的旋轉(zhuǎn)速度。但是提高轉(zhuǎn)速受制于掘進(jìn)機(jī)的振動、出碴系統(tǒng)的能力和滾刀的溫度限制。近年來，出現(xiàn)了用于掘進(jìn)機(jī)的可靠的變頻驅(qū)動裝置（VFD），使我們可以選擇適宜的刀盤轉(zhuǎn)速。變頻驅(qū)動裝置的優(yōu)點(diǎn)在于高的起動扭矩、基本頻率下100%的扭矩、無級變速、沖擊載荷下電流較小和高效率。</p><p>　　提

17、高掘進(jìn)機(jī)的利用率能減少工作時間。一般掘進(jìn)機(jī)的利用率在40%到50%之間。相關(guān)的工作如檢查、更換刀具，掘進(jìn)機(jī)的修理、維護(hù)，其中更換刀具耗時最多，約占11%。大尺寸高質(zhì)量刀圈使用時間長而較少更換，能提高掘進(jìn)機(jī)的能力和利用率。改進(jìn)刀具的安裝型式也能減少更換刀具的時間。</p><p>　　通過改進(jìn)掘進(jìn)機(jī)系統(tǒng)的設(shè)計可以減少作業(yè)人員，如提高自動化程度、采用連續(xù)皮帶機(jī)等。采用連續(xù)皮帶機(jī)的好處在于不用設(shè)置軌道道叉，只需要少量功

18、率較小的機(jī)車，減小巷道中的交通量和擁堵程度，減少對新鮮空氣的需求量，加大出碴能力、提高掘進(jìn)機(jī)的利用率。</p><p>　　隧道建設(shè)成本中另一大部分是設(shè)備和消耗品的費(fèi)用。通過標(biāo)準(zhǔn)化程序和靈活的制造策略就可能建造低成本高質(zhì)量的掘進(jìn)機(jī)，譬如在全球范圍綜合降低勞動成本和降低匯率的優(yōu)勢。</p><p>　　3 建立中國的隧道掘進(jìn)機(jī)產(chǎn)業(yè)</p><p>　　隨著中國經(jīng)濟(jì)的高

19、速發(fā)展，國內(nèi)對隧道掘進(jìn)機(jī)的需求越來越強(qiáng)烈。為了降低成本，為了自身發(fā)展的需要和將來出口，發(fā)展中國自己的隧道掘進(jìn)機(jī)產(chǎn)業(yè)已經(jīng)迫在眉睫。</p><p>　　3.1 羅賓斯隧道掘進(jìn)機(jī)在中國</p><p>　　1992 年以來，羅賓斯公司先后與中國二十余家公司合作生產(chǎn)隧道掘進(jìn)機(jī)的部件、完成掘進(jìn)機(jī)的總裝、制造整套掘進(jìn)機(jī)后配套系統(tǒng)。這些公司中有：國營淮南煤礦機(jī)器廠、上海冶金機(jī)械廠、廣州重型機(jī)器廠、太原

20、重型機(jī)器廠、上海隧道機(jī)械廠、二重集團(tuán)公司等。羅賓斯還將與掘進(jìn)機(jī)相關(guān)的產(chǎn)品發(fā)包給中國的一些私營和民營企業(yè)。羅賓斯公司還是上海博泰克機(jī)械有限公司的控股股東，上海博泰克擁有經(jīng)過羅賓斯培訓(xùn)的工程師，為羅賓斯公司在中國的訂貨提供杰出的技術(shù)支</p><p>　　持和質(zhì)量控制。羅賓斯不僅向中國出口極具競爭力的掘進(jìn)機(jī)，而且還用中國生產(chǎn)的部分結(jié)構(gòu)件和部件在中國總裝掘進(jìn)機(jī)。在羅賓斯的直接指導(dǎo)和質(zhì)量控制下，大多數(shù)合作項目都十分成功。

21、羅賓斯還委托中國制造商如四川德陽的二重集團(tuán)公制造用于海外的羅賓斯掘進(jìn)機(jī)的零部件。2000 年羅賓斯公司受CMC 公司的委托，在山西太原檢查和改建了一臺雙護(hù)盾羅賓斯硬巖掘進(jìn)機(jī)，該掘進(jìn)機(jī)用于引黃工程五號標(biāo)。改建工作提前完成，由CMC 公司承擔(dān)的隧道工程進(jìn)展也十分順利，最高日成洞113 . 21m，創(chuàng)造了新的世界紀(jì)錄。</p><p>　　3.2 建立中國隧道掘進(jìn)機(jī)產(chǎn)業(yè)的幾點(diǎn)建議</p><p>

22、;　?。?）建立中國隧道掘進(jìn)機(jī)產(chǎn)業(yè)的有利因素和不</p><p><b>　　利因素：</b></p><p>　　有利因素：快速增長的經(jīng)濟(jì)和巨大的市場潛力；勞動力成本和管理費(fèi)用較低；良好的勞動力素質(zhì)和制造能力資源；節(jié)約運(yùn)輸費(fèi)用；交貨期短；良好的備配件供應(yīng)；提供現(xiàn)場服務(wù)。</p><p>　　不利因素：項目資金不足；缺乏國際市場信息；缺乏技術(shù)信

23、息；缺乏現(xiàn)代項目管理的知識；暫不具備生產(chǎn)可靠的掘進(jìn)機(jī)零件的能力。</p><p>　?。?）建立中國隧道掘進(jìn)機(jī)產(chǎn)業(yè)的幾點(diǎn)建議學(xué)習(xí)和改善如何管理使用隧道掘進(jìn)機(jī)；將掘進(jìn)機(jī)用戶或買主的經(jīng)濟(jì)效益與項目的效益聯(lián)系起來；改進(jìn)對項目預(yù)算和成本控制的認(rèn)識；重新評價和比較人工開挖與使用隧道掘進(jìn)機(jī)的成本，特別是對那些要求盡快完成的戰(zhàn)略性項目；分析隧道掘進(jìn)機(jī)的應(yīng)用次序；對隧道掘進(jìn)機(jī)及其部件給予政策上的優(yōu)惠，如免除關(guān)稅和增值稅；對為整機(jī)

24、出口而臨時進(jìn)口的掘進(jìn)機(jī)零件提供方便；增加國際信息交流；生產(chǎn)用于出口的掘進(jìn)機(jī)零部件；為國際項目培訓(xùn)技術(shù)人員和操作工人；與國外的掘進(jìn)機(jī)制造商合作，共同在中國開發(fā)項目；確定近期和長期的發(fā)展目標(biāo)。</p><p>　　如果說20 世紀(jì)70 年代以前隧道掘進(jìn)機(jī)尚未進(jìn)入中國，80 年代是初步嘗試，90 年代是掘進(jìn)機(jī)在中國嶄露頭角的年代，那么今后一到三年內(nèi)將接近隧道掘進(jìn)機(jī)在中國的黃金時代。不遠(yuǎn)的將來，就可以看到越來越多的由中國

25、參與制造的隧道掘進(jìn)機(jī)，在許多國際項目現(xiàn)場將會出現(xiàn)中國造的掘進(jìn)機(jī)和中國的掘進(jìn)機(jī)專家。</p><p>　　Tunnel tunneling machine and China</p><p>　　Richard J. Robbins</p><p>　　Along with the tunnel tunneling machine success applicatio

26、n, the tunneling machine already became the noticeable underground tunnel high-speed driving method in China. How develops China's tunnel tunneling machine industry? This question proposes the source is puzzled by ma

27、ny years difficult problem from the Chinese rapid growth city underground construction and important project market request highly effective low consumption project cost this.</p><p>　　1 Tunnel tunneling mac

28、hine history </p><p>　　1.1 Tunnels tunneling machine and its the type tunnel tunneling machine full title all sections tunnel tunneling machine, mainly have two big types: Opens the type and seal, this artic

29、le discusses the type tunneling machine with emphasis.</p><p>　　(1) So-called opens the type tunnel tunneling machine to open the type tunneling machine is refers to when the cutting does not need to control

30、 the working surface the geostatic pressure, the tunneling machine according to leaves is cut by broken glass the system to transport is cut by broken glass the ability tunneling. Opens the type tunneling machine to use

31、in not to need specially to consider the surface sinks place situation. Opens the type tunneling machine design rigidity to be bigger. Is</p><p>　　(2) Seal the tunneling machine seal tunneling machine is cal

32、led the geostatic pressure balance -like tunneling machine (EPB), is through control screw conveyer dismounts the material gate opening, causes tool rest front the cavity pressure and the geostatic pressure is balanced.

33、Because must balance the geostatic pressure, the tunneling machine basis is cut by broken glass the speed which the stone ships out to adjust the tunneling speed to maintain the geostatic pressure, does not disturb or th

34、</p><p>　　1.2 international tunnels tunneling machine development history in 1851 American Engineer Charles Wilson has invented the tunnel tunneling machine, usually was considered is first successfully in t

35、he rock the continual tunneling machine. Another famous exploration is Colonel Beaumont the compressed-air drive tunnel tunneling machine which invented in 1881, once used in a English Channel survey tunnel. Hereafter al

36、ways does not have a more multiple-valued attention the attempt, Robins designed un</p><p>　　may the free rotation circular the hob, the hob slightly be lower than the tungsten </p><p>　　carbide

37、 truncation tooth. The machine by two 150kW direct motor drive, the equipment gross weight reaches 114t. Although this tunneling machine is not the design in the hard crag the tunneling, it ruler or has achieved 49m in t

38、he soft shale. Has replaced 356 truncations teeth and 4 circular hobs in four tunnels tunneling process Chinese Communist Party. Actually, the first successful hard crag tunneling machine is the diameter 3. 28m Robins tu

39、nnel tunneling machine, this machine was in 1956 cons</p><p>　　1.3 Chinese tunnel tunneling machine development history along with overseas widely applies the tunnel tunneling machine, the 20th century at th

40、e beginning of 70's the tunneling machine starts to appear in China. Government's each department like coal department, Ministry of Water Resources and Electric Power and the war industry department all designs,

41、makes and has used many tunnels tunneling machine.</p><p>　　From the 20th century 70's to the 80's, China's each department has at least constructed 20 tunnels tunneling machine, coal department

42、has only constructed 12 tunnels tunneling machine. The worth noting is the ruler only has 250m in these tunneling machine most Gao Yuejin, moreover most units have not put into the use. The 1980s later period start, alon

43、g with China's reform and open policy, in the most situations purchase the overseas tunneling machine by the overseas construction contractor per</p><p>　　Tunnels tunneling machine application and the ne

44、w technology</p><p>　　Since 19th century 50's intermediate stages, the tunnel tunneling machine mainly have developed in three directions: Is suitable in a big way to the scale, is hard moreover in the h

45、igh abradability rock the tunneling; Both is suitable to being stable, has from support protection the strength stratum, and is suitable for the unstable rock stratum; Can economically dig the tunnel. The geological cond

46、ition and the tunnel design the factor and the request directly will affect the tunneling machine d</p><p>　　(1) the tunnel tunneling machine design is been enormous its work tunnel geology condition influen

47、ce, the tunneling machine manufacturer must consider all obtained the geological data, and carries on the correct design according to most main data. </p><p>　　(2) hard and a scale big rock need bigger thrus

48、t force by highly effective cuts the rock, this requests the equipment various parts rigidity in a big way, but the system power is also bigger. </p><p>　　(3) the different type rock and its the center pelle

49、t the matter can affect the hob the choice and tool rest design. </p><p>　　(4) more faults perhaps the very short support protection time must use protects the shield type tunneling machine, but also possibl

50、y needs to prefabricate the tunnel support protection system.</p><p>　　2.2 Tunnels design factor influence tunneling machine design tunnel design factor includes: The tunnel trend with the curvature, the in

51、clination angle, the rock support protection request, the note thick liquid, drilling, the tunnel allowance error, the geostatic pressure limit, can use in advance to assemble and the work region, the environment request

52、 and the tunnel tunneling work plan. For instance in the tunnel which inclines the work, must specially consider the tunneling machine host actu</p><p>　　2.3 Cost controls make the tunnel in the hard crag,

53、most importantly both smooth and is safe, and must suitably control the cost. Was opposite to the traditional hard crag tunnel excavation method, the tunnel tunneling machine has provided one kind of highly effective low

54、 consumption choice, in particular to large diameter and long distance tunnel. The use tunneling machine digging hard crag tunnel, its cost mainly by the labor force, the equipment expense and consumption goods</p>

55、<p>　　is composed. The labor charge control has two tremendous influences factors, namely tunneling time and work population. Any on the one hand saves namely meant the labor charge reducing, each factor can recei

56、ve other aspects the influence. The reduced tunneling time can correspondingly reduce the tunneling to enter the ruler, to reduce the tunneling speed and the tunneling machine use factor. Work population including tunnel

57、ing staff and rear service personnel, administrative personnel and servic</p><p>　　Another reduced tunneling time consideration speeds up the tunneling speed, namely enhancement tool rest velocity of whirl.

58、But enhances the rotational speed to be restrained the tunneling machine vibration, is cut by broken glass the system the ability and the hob temperature limit. In recent years, appeared has used in the tunneling machine

59、 reliable frequency conversion drive (VFD), enabled us to be allowed to choose is suitable tool rest the rotational speed. The frequency conversion drive me</p><p>　　Founds Chinese the tunnel tunneling machi

60、ne industry </p><p>　　Along with the Chinese economy high speed development, domestic is more and more intense to the tunnel tunneling machine demand. In order to reduce the cost, in order to own need to dev

61、elop and the future will export, developed the Chinese tunnel tunneling machine industry already to be imminent. </p><p>　　3.1 Robins tunnel tunneling machine in China 1992, after the Robins company successi

62、vely and the Chinese 20 companies cooperative production tunnel tunneling machine part, has completed the tunneling machine general equipment department, makes the entire wrap tunneling machine necessary system. In these

63、 companies has: State-operated Huai Nan coal mine machine factory, Shanghai metallurgy machine shop, Guangzhou heavy machinery and equipment plant, Taiyuan heavy machinery and equipment plant, Sha</p><p>　　3

64、.2 Establishes the Chinese tunnel tunneling machine industry several suggestions</p><p>　　(1) To establish the Chinese tunnel tunneling machine industry the favourable factor and the disadvantage factor fav

65、ourable factor: Fast growth economy and giant market potential; The labor force cost and the overhead charge are lower; Good labor force quality and manufacturing capacity resources; Saves the cartage expense; The date o