多工(gong)位壓力(li)機進給系(xi)統(tong)在國內外汽(qi)車制造企業中得到了廣泛的(de)(de)(de)應(ying)(ying)用。該系(xi)統(tong)的(de)(de)(de)加工(gong)能力(li)直接決定著生(sheng)產線(xian)上多臺壓力(li)機的(de)(de)(de)性(xing)能和生(sheng)產效(xiao)率,能夠適應(ying)(ying)實際生(sheng)產中不同的(de)(de)(de)模具。雖(sui)然多站(zhan)(zhan)壓力(li)機已在我(wo)國工(gong)業領(ling)域的(de)(de)(de)生(sheng)產線(xian)上使用了多年,但(dan)仍存在一些問題,如(ru)送(song)料(liao)系(xi)統(tong)的(de)(de)(de)穩定性(xing)、核心技術的(de)(de)(de)探索等。針對(dui)這一問題,從多站(zhan)(zhan)饋電系(xi)統(tong)的(de)(de)(de)組成和關鍵技術入手,提出了一些改進措施,以提高(gao)設備(bei)(bei)的(de)(de)(de)可靠(kao)性(xing)和設備(bei)(bei)的(de)(de)(de)可靠(kao)性(xing)。
一般來說,多(duo)工位進給系(xi)統(tong)是一種(zhong)類似(si)于(yu)動(dong)(dong)臂的(de)裝置,其主要功能(neng)是將生產(chan)線上(shang)的(de)沖(chong)(chong)壓(ya)件從一個(ge)站(zhan)移到另一個(ge)站(zhan),使同一組(zu)模(mo)具能(neng)夠在同一臺壓(ya)力(li)機上(shang)完成(cheng)沖(chong)(chong)壓(ya)工作。在多(duo)工位進給系(xi)統(tong)運(yun)(yun)行過程(cheng)中(zhong),移動(dong)(dong)桿(gan)沿模(mo)具區域移動(dong)(dong),運(yun)(yun)動(dong)(dong)沖(chong)(chong)壓(ya)件的(de)端部拾取器一端可(ke)與運(yun)(yun)動(dong)(dong)桿(gan)連接,完成(cheng)送(song)料(liao)任務。目前在我國(guo)汽車車身沖(chong)(chong)壓(ya)廠(chang)中(zhong),常(chang)見的(de)送(song)料(liao)系(xi)統(tong)可(ke)分(fen)為如(ru)下三類:
1.1 機械式(shi)送(song)料(liao)方(fang)式(shi)
這是傳統生(sheng)產車(che)間中(zhong)的(de)常(chang)用送(song)(song)料(liao)(liao)方法,由于(yu)當時送(song)(song)料(liao)(liao)系(xi)統功(gong)能單(dan)一,因此這種送(song)(song)料(liao)(liao)模(mo)式存在諸多弊端。其(qi)運作機(ji)理(li)是依(yi)靠移動(dong)(dong)(dong)桿與(yu)傳動(dong)(dong)(dong)系(xi)統的(de)直接連接,將沖壓件在不同的(de)工(gong)位上(shang)傳動(dong)(dong)(dong),以此滿足(zu)對(dui)沖壓件的(de)加工(gong)需求。其(qi)中(zhong)凸輪與(yu)隨(sui)動(dong)(dong)(dong)器驅(qu)動(dong)(dong)(dong)匹配安裝在一起,進(jin)行協(xie)同運動(dong)(dong)(dong),再(zai)通過(guo)凸輪旋轉運動(dong)(dong)(dong)來帶動(dong)(dong)(dong)送(song)(song)料(liao)(liao)機(ji)構的(de)運行,盡管基本能完成生(sheng)產任(ren)務,但是不能保證產品精(jing)度。
1.2 電子多工位送料方式(shi)
相比(bi)機械式送(song)料(liao)方(fang)式而(er)言,這種送(song)料(liao)系(xi)統(tong)(tong)相對高(gao)(gao)級,并(bing)且運行穩定(ding),精度較高(gao)(gao)。其運作機理是(shi)(shi)依托伺服電機來(lai)控(kong)制送(song)料(liao)系(xi)統(tong)(tong),高(gao)(gao)的生產性能(neng)。另外,由(you)于(yu)該系(xi)統(tong)(tong)是(shi)(shi)由(you)計算(suan)機操(cao)控(kong),因此送(song)料(liao)方(fang)法精確(que)度較高(gao)(gao),很大(da)程(cheng)度上提高(gao)(gao)了生產效率。
1.3 混合式(shi)送料方式(shi)
混合(he)(he)式(shi)送(song)料(liao)(liao)是一種(zhong)混合(he)(he)式(shi)系統,其(qi)將(jiang)機(ji)械式(shi)送(song)料(liao)(liao)和電子(zi)多工位送(song)料(liao)(liao)進行合(he)(he)理組(zu)合(he)(he),兼具兩者(zhe)的(de)優(you)良性(xing)能(neng),能(neng)夠實現高(gao)效率的(de)送(song)料(liao)(liao)工作,并增強系統的(de)穩定(ding)性(xing)。在送(song)料(liao)(liao)過程中(zhong),由機(ji)械式(shi)送(song)料(liao)(liao)方(fang)式(shi)和電子(zi)多工位送(song)料(liao)(liao)方(fang)式(shi)分(fen)擔任務,彼此互不干擾,各司其(qi)職,達(da)到更高(gao)的(de)效率,因此應用范圍較廣。
2.1 運(yun)行原理
通常來說(shuo),多工(gong)(gong)位壓力機(ji)送(song)(song)(song)料(liao)過(guo)程(cheng)是由三(san)(san)坐(zuo)標送(song)(song)(song)料(liao)模(mo)式(shi)來實現的,具(ju)體是在壓力機(ji)內(nei)部(bu)使(shi)用三(san)(san)種不(bu)同(tong)方(fang)(fang)(fang)向和(he)目(mu)的動(dong)作,來實現對工(gong)(gong)件(jian)(jian)(jian)傳送(song)(song)(song)的目(mu)的(如圖(tu)1所示(shi))。在送(song)(song)(song)料(liao)系(xi)統運行中,設備會同(tong)時運行三(san)(san)個動(dong)作,即夾(jia)鉗(qian)退(tui)回、工(gong)(gong)件(jian)(jian)(jian)送(song)(song)(song)進和(he)物流(liu)方(fang)(fang)(fang)向,這三(san)(san)個動(dong)作彼此協調有序,互不(bu)干涉。通過(guo)對圖(tu)1逆時針(zhen)方(fang)(fang)(fang)向觀察(cha)得知,送(song)(song)(song)料(liao)系(xi)統首先(xian)用夾(jia)鉗(qian)將工(gong)(gong)件(jian)(jian)(jian)夾(jia)緊,然(ran)后再將工(gong)(gong)件(jian)(jian)(jian)傳送(song)(song)(song)到(dao)指(zhi)定位置,進一(yi)步(bu)加(jia)工(gong)(gong)成(cheng)(cheng)模(mo)具(ju),接(jie)著(zhu)通過(guo)物流(liu)方(fang)(fang)(fang)向將模(mo)具(ju)送(song)(song)(song)到(dao)另外(wai)一(yi)個工(gong)(gong)位,進而完成(cheng)(cheng)一(yi)次加(jia)工(gong)(gong)。這種送(song)(song)(song)料(liao)過(guo)程(cheng)對沖(chong)(chong)壓件(jian)(jian)(jian)的加(jia)工(gong)(gong)較為精(jing)細,容易生產出高質量的沖(chong)(chong)壓件(jian)(jian)(jian),且(qie)如果(guo)工(gong)(gong)廠有特殊需(xu)求,該裝置也可設計成(cheng)(cheng)電子式(shi)送(song)(song)(song)料(liao)模(mo)式(shi)。
2.2 硬件設計
(1)主(zhu)控制器。主(zhu)控制器的(de)芯(xin)片可以選(xuan)擇LPC2292型號(hao),因(yin)為這種芯(xin)片性能較(jiao)為優越,CPU的(de)處(chu)理頻(pin)率較(jiao)高,且處(chu)理速度較(jiao)快,在(zai)指定(ding)(ding)時(shi)間內(nei)能夠達到預期效果。其片內(nei)資(zi)源也十分豐富,包括16k的(de)靜態RAM和512k的(de)FLASH;2個32位定(ding)(ding)時(shi)器和1個PWM單元;RTC實時(shi)時(shi)鐘;看門狗定(ding)(ding)時(shi)器;多個串行接口等,可以滿足不同(tong)企(qi)業的(de)不同(tong)生(sheng)產(chan)需求。
(2)運動(dong)控(kong)制板。根據筆(bi)者實際(ji)經驗,送(song)料(liao)系(xi)統(tong)(tong)的(de)運動(dong)控(kong)制板可(ke)以(yi)選(xuan)擇(ze)FPGA芯片,并可(ke)將EP2C15AF256C8型號作為(wei)設(she)計控(kong)制板。這種芯片的(de)處(chu)理速度(du)很(hen)快,能夠(gou)有效地處(chu)理多數據流。另外,可(ke)以(yi)把NiosII作為(wei)處(chu)理單元,使用它(ta)能夠(gou)在運動(dong)控(kong)制板上創建SOPC系(xi)統(tong)(tong),兩(liang)者契合度(du)較高。
(3)I/O控(kong)制板。I/O控(kong)制板的(de)芯片可優先選用(yong)(yong)LPC2194型號,并將(jiang)其作為微處理(li)器使用(yong)(yong),然后再(zai)內(nei)置CAN總線接口,提高系統可操(cao)作性。
(4)手控盒。筆者(zhe)認為在(zai)手控盒設計中可(ke)(ke)(ke)選(xuan)擇(ze)三星(xing)公司的S3C2410芯(xin)片作為處(chu)理器,它是(shi)一種基于(yu)ARM920T內(nei)核的32位RISC處(chu)理器,內(nei)部集成了豐富的硬件資源;顯(xian)示屏幕可(ke)(ke)(ke)選(xuan)用Sharp公司的5.7寸TFT彩(cai)色(se)液晶(jing)屏LQ057V3DG02,其接口及(ji)配套(tao)的逆(ni)變器可(ke)(ke)(ke)直接與S3C2410相連,可(ke)(ke)(ke)直接顯(xian)示送料系(xi)統的運行(xing)狀態。
圖1 三坐標送料圖
2.3 軟件設計
送料系(xi)(xi)統可采用uc/osII作為主(zhu)要控(kong)制器的(de)操作系(xi)(xi)統,該系(xi)(xi)統本身(shen)具(ju)有一(yi)定的(de)可移植性,且源代碼具(ju)開放屬性,能夠被(bei)設計人員刪減,并具(ju)備較好的(de)兼(jian)容性,實現(xian)多機器操作。
目前,大多(duo)數(shu)沖(chong)壓(ya)(ya)廠采(cai)用大型夾板多(duo)工位壓(ya)(ya)力機(ji)生產大量(liang)沖(chong)壓(ya)(ya)件(jian)(jian)(jian).在實際加(jia)工過程中,每次沖(chong)壓(ya)(ya)件(jian)(jian)(jian)移動時(shi),都需要設備來調整方位角,從而容易(yi)增(zeng)加(jia)沖(chong)壓(ya)(ya)件(jian)(jian)(jian)的(de)損(sun)傷概率或降低(di)加(jia)工精度。目前國外一(yi)(yi)些先進沖(chong)壓(ya)(ya)廠的(de)送料方式(shi)已(yi)改進為(wei)實時(shi)方位角調整方式(shi),在一(yi)(yi)定程度上解決了(le)沖(chong)壓(ya)(ya)件(jian)(jian)(jian)在實際傳動過程中的(de)定位問題,減(jian)少了(le)大量(liang)的(de)損(sun)傷問題,顯著(zhu)地提高了(le)沖(chong)壓(ya)(ya)件(jian)(jian)(jian)的(de)產量(liang)和質(zhi)量(liang)。
隨著世界汽(qi)車工業的(de)快速(su)發展,許多(duo)汽(qi)車企業對汽(qi)車零部(bu)件(jian)(jian)提(ti)出了(le)更高(gao)的(de)要求,因此必須不斷改進和提(ti)高(gao)多(duo)工位壓力(li)機(ji)進給(gei)系統的(de)性能,進而批量(liang)(liang)生產高(gao)質量(liang)(liang)的(de)汽(qi)車零部(bu)件(jian)(jian)。