輥式冷彎成型是以金屬薄板或帶卷為原料,并通過多架裝配了具有一定形狀的成型輥對坯料逐架次進行彎曲變形,從而得到均一最面的產品的塑性加工方法。
一般每架成型(xing)機(ji)裝有一對或多對成型(xing)輥(gun),每列成型(xing)機(ji)組由兩(liang)架以(yi)上的(de)(de)成型(xing)機(ji)組線。在輥(gun)式冷(leng)彎(wan)(wan)(wan)成型(xing)過程中只有彎(wan)(wan)(wan)曲(qu)變形(xing)。除(chu)坯(pi)料彎(wan)(wan)(wan)曲(qu)角局(ju)部有輕微減薄(bo)外(wai)(wai),變形(xing)材料的(de)(de)厚度在成型(xing)過程中保持(chi)不變。這種加工方法特別適合于外(wai)(wai)形(xing)縱長(chang)、批量(liang)較(jiao)大的(de)(de)高精(jing)度產品的(de)(de)加工,此外(wai)(wai),在輥(gun)式冷(leng)彎(wan)(wan)(wan)成型(xing)過程中,可以(yi)很容易地將沖裁、打孔、壓印(yin)、縱彎(wan)(wan)(wan)等輔助加工引(yin)入進來。
輥式冷彎(wan)成(cheng)型(xing)工(gong)(gong)(gong)藝(yi)可分為(wei)四種,即單(dan)張(或單(dan)件(jian))成(cheng)型(xing)工(gong)(gong)(gong)藝(yi)、成(cheng)卷成(cheng)型(xing)工(gong)(gong)(gong)藝(yi)、連續成(cheng)型(xing)工(gong)(gong)(gong)藝(yi)和聯合加工(gong)(gong)(gong)工(gong)(gong)(gong)藝(yi)。每一種工(gong)(gong)(gong)藝(yi)都(dou)可分為(wei)3個階段(duan),即成(cheng)型(xing)前坯料準備(bei)階段(duan)、成(cheng)型(xing)加工(gong)(gong)(gong)階段(duan)、型(xing)材精(jing)整階段(duan)。
單張成(cheng)(cheng)(cheng)型(xing)(xing)(xing)工(gong)藝(yi)就是預定尺(chi)坯(pi)料(liao)的(de)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)方法。這(zhe)(zhe)種(zhong)方法在(zai)坯(pi)料(liao)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)之前(qian)將坯(pi)料(liao)切成(cheng)(cheng)(cheng)定尺(chi)長度,然后(hou)用送料(liao)輥(gun)(gun)將坯(pi)料(liao)送進(jin)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)輥(gun)(gun),成(cheng)(cheng)(cheng)型(xing)(xing)(xing)后(hou)的(de)型(xing)(xing)(xing)材(cai)(cai)不必經剪切即可收集入(ru)庫(ku)。采(cai)用這(zhe)(zhe)種(zhong)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)工(gong)藝(yi)的(de)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)輥(gun)(gun)的(de)速度一般(ban)在(zai)15~75m/min.這(zhe)(zhe)種(zhong)工(gong)藝(yi)主要應用于(yu)小批(pi)量(liang)、成(cheng)(cheng)(cheng)型(xing)(xing)(xing)后(hou)型(xing)(xing)(xing)材(cai)(cai)鋸(ju)切比較困難的(de)情況(kuang)下。采(cai)用單張成(cheng)(cheng)(cheng)型(xing)(xing)(xing)工(gong)藝(yi)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)機組的(de)設(she)備較簡單、工(gong)具(ju)費用少、投資低。但用這(zhe)(zhe)種(zhong)生(sheng)產工(gong)藝(yi)得到的(de)型(xing)(xing)(xing)材(cai)(cai)邊部(bu)縱向拉(la)伸較大(da),因而(er)只有利用側(ce)立輥(gun)(gun)才能得到比較精確的(de)產品形。
成(cheng)(cheng)(cheng)卷(juan)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)工(gong)(gong)藝(yi)(yi)(yi)和(he)連(lian)(lian)續(xu)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)工(gong)(gong)藝(yi)(yi)(yi)基(ji)本相同,所不(bu)同的是連(lian)(lian)續(xu)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)時前(qian)一卷(juan)帶材(cai)(cai)的尾部與后一卷(juan)帶材(cai)(cai)的頭(tou)(tou)部經過(guo)齊(qi)對焊(han),使坯(pi)料帶材(cai)(cai)連(lian)(lian)續(xu)不(bu)斷地進人成(cheng)(cheng)(cheng)型(xing)(xing)(xing)機進行(xing)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)。而成(cheng)(cheng)(cheng)卷(juan)成(cheng)(cheng)(cheng)型(xing)(xing)(xing)時帶卷(juan)頭(tou)(tou)尾不(bu)對焊(han),進行(xing)單卷(juan)供料成(cheng)(cheng)(cheng)型(xing)(xing)(xing)。與單張成(cheng)(cheng)(cheng)型(xing)(xing)(xing)工(gong)(gong)藝(yi)(yi)(yi)相比,這兩種成(cheng)(cheng)(cheng)型(xing)(xing)(xing)工(gong)(gong)藝(yi)(yi)(yi)更(geng)加高效、高產、通用。這兩種成(cheng)(cheng)(cheng)型(xing)(xing)(xing)工(gong)(gong)藝(yi)(yi)(yi)的主要優點是:
①. 帶卷(juan)成(cheng)本(ben)低(di)、切損少,因而降低(di)了材(cai)料總(zong)成(cheng)本(ben)。
②. 由于需(xu)要(yao)的成(cheng)(cheng)型機架(jia)數(shu)少(shao)且不需(xu)要(yao)額外(wai)的導衛裝置,因(yin)而工具成(cheng)(cheng)本低。
③. 可(ke)以加工形狀比單(dan)張成型工藝更復雜的(de)型材。
④. 型材的(de)頭尾部扭曲及張開度減(jian)小。
⑤. 由(you)于操作幾(ji)乎(hu)是連續的,因(yin)而生產率得到(dao)提高(gao)。
但這(zhe)兩(liang)種(zhong)成(cheng)型(xing)(xing)工(gong)藝(yi)需要(yao)開卷(juan)機(ji)(ji)(ji)、活套器、對焊機(ji)(ji)(ji)、定尺飛鋸或飛剪等輔助設備,因而其機(ji)(ji)(ji)組(zu)(zu)設備投資較大、占地較大。成(cheng)型(xing)(xing)機(ji)(ji)(ji)組(zu)(zu)的成(cheng)型(xing)(xing)速度一般為30~90m/min.目前投產(chan)的絕大多數輥式(shi)冷彎(wan)成(cheng)型(xing)(xing)機(ji)(ji)(ji)組(zu)(zu)均是采用(yong)這(zhe)兩(liang)種(zhong)工(gong)藝(yi),因此后面將以這(zhe)兩(liang)種(zhong)成(cheng)型(xing)(xing)工(gong)藝(yi)為例進行重點闡述(shu),圖5-1給出了其工(gong)藝(yi)流(liu)程(cheng)示(shi)意(yi)圖。
聯(lian)合加(jia)(jia)工工藝用于加(jia)(jia)工具有特定要求的(de)(de)冷(leng)(leng)彎(wan)型(xing)鋼(gang),如(ru)高(gao)強(qiang)度冷(leng)(leng)彎(wan)型(xing)鋼(gang)、閉口(kou)焊接(jie)冷(leng)(leng)彎(wan)型(xing)鋼(gang)、熱處(chu)理強(qiang)化冷(leng)(leng)彎(wan)型(xing)鋼(gang)、周期波(bo)紋板(ban)沖孔冷(leng)(leng)彎(wan)型(xing)鋼(gang),涂層冷(leng)(leng)彎(wan)型(xing)鋼(gang)等(deng)。聯(lian)合加(jia)(jia)工成型(xing)機組的(de)(de)設(she)備(bei)最(zui)復雜(za)、投資最(zui)高(gao)。根據產品的(de)(de)要求這(zhe)種(zhong)機組可包括如(ru)下設(she)備(bei):直(zhi)縫焊機、對焊機、輥(gun)式(shi)沖孔機、輥(gun)式(shi)壓印機、涂層機、熱處(chu)理設(she)備(bei)等(deng)。
輥式冷(leng)彎(wan)(wan)(wan)成(cheng)(cheng)型(xing)(xing)(xing)是(shi)用一(yi)組(zu)成(cheng)(cheng)型(xing)(xing)(xing)輥將帶材(cai)逐漸(jian)壓彎(wan)(wan)(wan)成(cheng)(cheng)所(suo)需的斷面型(xing)(xing)(xing)材(cai),現以(yi)冷(leng)彎(wan)(wan)(wan)角鋼(gang)為例,圖(tu)5-2是(shi)由4個機架組(zu)成(cheng)(cheng)的輥式冷(leng)彎(wan)(wan)(wan)成(cheng)(cheng)型(xing)(xing)(xing)機組(zu),第一(yi)機架完成(cheng)(cheng)帶材(cai)的平整和(he)送進工作,第二(er)~第四機架各承擔(dan)一(yi)定(ding)的壓彎(wan)(wan)(wan)成(cheng)(cheng)型(xing)(xing)(xing)任(ren)務,使帶材(cai)通過后被彎(wan)(wan)(wan)曲(qu)壓制成(cheng)(cheng)角型(xing)(xing)(xing)材(cai)。每一(yi)對(dui)成(cheng)(cheng)型(xing)(xing)(xing)輥所(suo)分(fen)擔(dan)的彎(wan)(wan)(wan)曲(qu)變(bian)形量,決定(ding)了該機架孔型(xing)(xing)(xing)設計的基本尺(chi)寸。不過至今的孔型(xing)(xing)(xing)設計主要(yao)還是(shi)依(yi)靠(kao)經(jing)驗的積累,尚缺乏理(li)論(lun)解析(xi)方法。