熱(re)封(feng)時(shi)間主要由制袋機的速度決定。
速度(du)(du)(du)快，熱(re)封(feng)(feng)(feng)(feng)時(shi)間就(jiu)短；速度(du)(du)(du)慢(man)，熱(re)封(feng)(feng)(feng)(feng)時(shi)間就(jiu)長(chang)(chang)。熱(re)封(feng)(feng)(feng)(feng)時(shi)間也(ye)是影響焊(han)縫(feng)(feng)封(feng)(feng)(feng)(feng)合強度(du)(du)(du)和(he)外觀(guan)的(de)一(yi)個關(guan)鍵因素(su)。相同的(de)熱(re)封(feng)(feng)(feng)(feng)溫(wen)度(du)(du)(du)和(he)壓力(li)下(xia)，熱(re)封(feng)(feng)(feng)(feng)時(shi)間長(chang)(chang)，則熱(re)封(feng)(feng)(feng)(feng)層(ceng)熔合更充分(fen)，結合更牢固(gu)；但(dan)熱(re)封(feng)(feng)(feng)(feng)時(shi)間太(tai)長(chang)(chang)，容(rong)易造成(cheng)焊(han)縫(feng)(feng)起皺變形(xing)，影響平整度(du)(du)(du)和(he)外觀(guan)。熱(re)封(feng)(feng)(feng)(feng)后的(de)焊(han)縫(feng)(feng)若冷(leng)卻不(bu)好(hao)，不(bu)但(dan)會影響焊(han)疑的(de)外觀(guan)平整度(du)(du)(du)，而且對(dui)熱(re)封(feng)(feng)(feng)(feng)強度(du)(du)(du)有(you)一(yi)定(ding)的(de)影響，冷(leng)卻過(guo)程就(jiu)是通過(guo)在一(yi)定(ding)的(de)壓力(li)下(xia)，用較(jiao)低(di)的(de)溫(wen)度(du)(du)(du)對(dui)剛熔融熱(re)封(feng)(feng)(feng)(feng)后的(de)焊(han)縫(feng)(feng)進行定(ding)形(xing)。因此，壓力(li)不(bu)夠，冷(leng)卻和(he)循(xun)環(huan)不(bu)暢，循(xun)環(huan)量不(bu)夠，水溫(wen)太(tai)高或冷(leng)卻不(bu)及時(shi)，都(dou)會致使冷(leng)卻不(bu)良，熱(re)封(feng)(feng)(feng)(feng)強度(du)(du)(du)降低(di)。