熱封(feng)時(shi)間(jian)主要由(you)制袋機(ji)的速度決定(ding)。
速度快，熱(re)(re)(re)封(feng)(feng)(feng)時間(jian)(jian)(jian)就短(duan)；速度慢，熱(re)(re)(re)封(feng)(feng)(feng)時間(jian)(jian)(jian)就長(chang)。熱(re)(re)(re)封(feng)(feng)(feng)時間(jian)(jian)(jian)也(ye)是(shi)影響(xiang)焊(han)縫封(feng)(feng)(feng)合強度和外(wai)觀(guan)的(de)(de)一個關鍵因素。相同的(de)(de)熱(re)(re)(re)封(feng)(feng)(feng)溫度和壓力(li)(li)下(xia)，熱(re)(re)(re)封(feng)(feng)(feng)時間(jian)(jian)(jian)長(chang)，則熱(re)(re)(re)封(feng)(feng)(feng)層(ceng)熔(rong)(rong)合更充分(fen)，結合更牢固；但(dan)(dan)熱(re)(re)(re)封(feng)(feng)(feng)時間(jian)(jian)(jian)太長(chang)，容易造成焊(han)縫起(qi)皺變形，影響(xiang)平整度和外(wai)觀(guan)。熱(re)(re)(re)封(feng)(feng)(feng)后的(de)(de)焊(han)縫若冷(leng)卻不(bu)(bu)好，不(bu)(bu)但(dan)(dan)會影響(xiang)焊(han)疑(yi)的(de)(de)外(wai)觀(guan)平整度，而且(qie)對熱(re)(re)(re)封(feng)(feng)(feng)強度有一定(ding)的(de)(de)影響(xiang)，冷(leng)卻過程(cheng)就是(shi)通過在(zai)一定(ding)的(de)(de)壓力(li)(li)下(xia)，用(yong)較(jiao)低的(de)(de)溫度對剛熔(rong)(rong)融熱(re)(re)(re)封(feng)(feng)(feng)后的(de)(de)焊(han)縫進(jin)行定(ding)形。因此，壓力(li)(li)不(bu)(bu)夠(gou)，冷(leng)卻和循(xun)環不(bu)(bu)暢，循(xun)環量不(bu)(bu)夠(gou)，水溫太高或冷(leng)卻不(bu)(bu)及時，都會致使冷(leng)卻不(bu)(bu)良，熱(re)(re)(re)封(feng)(feng)(feng)強度降低。