熱封(feng)時(shi)間(jian)主要(yao)由制袋機的速度決定。
速度(du)(du)(du)快，熱(re)(re)封(feng)(feng)(feng)時(shi)間就(jiu)短；速度(du)(du)(du)慢，熱(re)(re)封(feng)(feng)(feng)時(shi)間就(jiu)長(chang)。熱(re)(re)封(feng)(feng)(feng)時(shi)間也是(shi)影響(xiang)(xiang)焊(han)(han)縫封(feng)(feng)(feng)合強度(du)(du)(du)和(he)(he)外觀的一個關鍵因素。相同的熱(re)(re)封(feng)(feng)(feng)溫(wen)度(du)(du)(du)和(he)(he)壓(ya)力(li)下(xia)，熱(re)(re)封(feng)(feng)(feng)時(shi)間長(chang)，則(ze)熱(re)(re)封(feng)(feng)(feng)層(ceng)熔(rong)合更充分，結合更牢固；但熱(re)(re)封(feng)(feng)(feng)時(shi)間太長(chang)，容(rong)易造成焊(han)(han)縫起(qi)皺(zhou)變形(xing)，影響(xiang)(xiang)平(ping)(ping)整度(du)(du)(du)和(he)(he)外觀。熱(re)(re)封(feng)(feng)(feng)后(hou)的焊(han)(han)縫若冷卻不(bu)(bu)好，不(bu)(bu)但會影響(xiang)(xiang)焊(han)(han)疑(yi)的外觀平(ping)(ping)整度(du)(du)(du)，而(er)且(qie)對熱(re)(re)封(feng)(feng)(feng)強度(du)(du)(du)有一定(ding)的影響(xiang)(xiang)，冷卻過(guo)程就(jiu)是(shi)通過(guo)在一定(ding)的壓(ya)力(li)下(xia)，用較低的溫(wen)度(du)(du)(du)對剛熔(rong)融熱(re)(re)封(feng)(feng)(feng)后(hou)的焊(han)(han)縫進行定(ding)形(xing)。因此，壓(ya)力(li)不(bu)(bu)夠(gou)，冷卻和(he)(he)循環不(bu)(bu)暢，循環量不(bu)(bu)夠(gou)，水溫(wen)太高或冷卻不(bu)(bu)及時(shi)，都會致使冷卻不(bu)(bu)良，熱(re)(re)封(feng)(feng)(feng)強度(du)(du)(du)降低。