滾塑制品有時會出現一(yi)(yi)些制品的缺陷(xian)，那么(me)一(yi)(yi)般(ban)來說我們該如何將(jiang)這些缺陷(xian)解決呢(ni)？

1、氣(qi)泡或孔洞?

(1)成因分(fen)析

          時模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)內(nei)的(de)(de)(de)(de)(de)物料在(zai)(zai)受熱(re)(re)過(guo)(guo)(guo)程(cheng)(cheng)中(zhong)(zhong)，隨模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)的(de)(de)(de)(de)(de)轉動(dong)逐(zhu)漸熔(rong)(rong)(rong)融、流動(dong)、粘附在(zai)(zai)熱(re)(re)的(de)(de)(de)(de)(de)模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)內(nei)表(biao)面(mian)，模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)內(nei)部空(kong)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)受熱(re)(re)體積膨脹，氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)壓升高，通(tong)(tong)過(guo)(guo)(guo)通(tong)(tong)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)孔(kong)逐(zhu)漸向(xiang)模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)外(wai)部流動(dong)，直至(zhi)模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)內(nei)外(wai)空(kong)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)壓力(li)平衡，反(fan)之亦然。同(tong)時，模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)型腔(qiang)內(nei)保持著一定(ding)壓強(qiang)。在(zai)(zai)樹(shu)脂熔(rong)(rong)(rong)融致密(mi)化的(de)(de)(de)(de)(de)過(guo)(guo)(guo)程(cheng)(cheng)中(zhong)(zhong)，滯(zhi)留(liu)在(zai)(zai)粉末(mo)(mo)顆粒(li)(li)之間的(de)(de)(de)(de)(de)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)體被擠(ji)向(xiang)塑(su)料熔(rong)(rong)(rong)體的(de)(de)(de)(de)(de)自由表(biao)面(mian)，但(dan)由于熔(rong)(rong)(rong)體表(biao)面(mian)張力(li)的(de)(de)(de)(de)(de)存在(zai)(zai)，氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)體不足以脫離(li)熔(rong)(rong)(rong)體表(biao)面(mian)易形(xing)(xing)成(cheng)(cheng)(cheng)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)泡，從(cong)而形(xing)(xing)成(cheng)(cheng)(cheng)制品內(nei)表(biao)面(mian)的(de)(de)(de)(de)(de)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)泡和外(wai)表(biao)面(mian)的(de)(de)(de)(de)(de)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)扎，嚴(yan)重情(qing)況下(xia)形(xing)(xing)成(cheng)(cheng)(cheng)較大的(de)(de)(de)(de)(de)孔(kong)洞(dong)”。如果熔(rong)(rong)(rong)體流動(dong)性好、模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)升溫速率慢、模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)通(tong)(tong)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)孔(kong)通(tong)(tong)暢(chang)，則熔(rong)(rong)(rong)體中(zhong)(zhong)的(de)(de)(de)(de)(de)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)體可以順利地逸出，反(fan)之則熔(rong)(rong)(rong)體中(zhong)(zhong)的(de)(de)(de)(de)(de)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)體易滯(zhi)留(liu)形(xing)(xing)成(cheng)(cheng)(cheng)制品缺(que)陷。當(dang)模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)合模(mo)不嚴(yan)，模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)加(jia)熱(re)(re)過(guo)(guo)(guo)程(cheng)(cheng)中(zhong)(zhong)型腔(qiang)中(zhong)(zhong)的(de)(de)(de)(de)(de)一部分氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)體會通(tong)(tong)過(guo)(guo)(guo)合模(mo)部位的(de)(de)(de)(de)(de)縫(feng)隙(xi)向(xiang)模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)外(wai)部流動(dong)，致使存模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)相應(ying)部位的(de)(de)(de)(de)(de)產品內(nei)部產生(sheng)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)孔(kong)或氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)泡；在(zai)(zai)模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)冷卻過(guo)(guo)(guo)程(cheng)(cheng)中(zhong)(zhong)，如果模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)閉合不嚴(yan)，斟模(mo)其內(nei)外(wai)存在(zai)(zai)空(kong)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)壓力(li)差(cha)，空(kong)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)會通(tong)(tong)過(guo)(guo)(guo)合模(mo)部位(分型面(mian)處)的(de)(de)(de)(de)(de)間隙(xi)進入模(mo)其內(nei)，在(zai)(zai)制品的(de)(de)(de)(de)(de)外(wai)部產生(sheng)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)孔(kong)。孔(kong)洞(dong)的(de)(de)(de)(de)(de)形(xing)(xing)成(cheng)(cheng)(cheng)還與粉末(mo)(mo)顆粒(li)(li)的(de)(de)(de)(de)(de)形(xing)(xing)狀有關(guan)。當(dang)聚乙烯(PE)粉末(mo)(mo)顆粒(li)(li)帶(dai)有細長(chang)尾(wei)巴或呈毛發狀時，在(zai)(zai)堆(dui)積過(guo)(guo)(guo)程(cheng)(cheng)中(zhong)(zhong)會形(xing)(xing)成(cheng)(cheng)(cheng)搭橋，滯(zhi)留(liu)較多(duo)的(de)(de)(de)(de)(de)空(kong)氣(qi)(qi)(qi)(qi)(qi)(qi)(qi)。特別(bie)是在(zai)(zai)模(mo)具(ju)(ju)(ju)(ju)(ju)(ju)(ju)的(de)(de)(de)(de)(de)拐角處，粉末(mo)(mo)的(de)(de)(de)(de)(de)搭橋會導致較大的(de)(de)(de)(de)(de)孔(kong)洞(dong)形(xing)(xing)成(cheng)(cheng)(cheng)。

 (2)、解決方案

         調整通(tong)氣管或起相(xiang)同作(zuo)用(yong)(yong)的(de)金(jin)(jin)屬(shu)(shu)亂絲卷制(zhi)的(de)長條至模(mo)(mo)具內部適(shi)(shi)當距離。通(tong)氣管一(yi)般采(cai)用(yong)(yong)薄壁的(de)金(jin)(jin)屬(shu)(shu)氟(fu)(fu)塑料管，其(qi)直徑(jing)由(you)制(zhi)品(pin)尺寸和(he)物(wu)料性能(neng)決定。(一(yi)般薄壁制(zhi)品(pin)按每(mei)立方(fang)米模(mo)(mo)具設定10—12?mm孔徑(jing))，管子長度根據(ju)制(zhi)品(pin)型腔深度應保(bao)證其(qi)末(mo)端伸(shen)入到(dao)模(mo)(mo)腔中心或到(dao)合適(shi)(shi)位(wei)置。為避免模(mo)(mo)具旋轉時樹脂粉末(mo)從排氣口溢出(chu)，通(tong)氣管內要用(yong)(yong)玻(bo)璃絲、鋼絲絨、石墨粉等充(chong)(chong)填。模(mo)(mo)具適(shi)(shi)當緩(huan)慢升溫(wen)、提高爐溫(wen)(熔(rong)融溫(wen)度)或延(yan)(yan)長加熱時間(jian)，確(que)保(bao)物(wu)料充(chong)(chong)分(fen)熔(rong)融和(he)氣體(ti)排出(chu)。在(zai)(zai)模(mo)(mo)具內表面涂覆特氟(fu)(fu)龍(聚四氟(fu)(fu)乙烯)涂層(ceng)替代各種脫模(mo)(mo)劑，保(bao)持模(mo)(mo)具內部干(gan)燥。如(ru)果是嵌件因素影(ying)響，可(ke)對嵌件及其(qi)周圍部分(fen)區域進行預熱。在(zai)(zai)產品(pin)、模(mo)(mo)具設計過(guo)程(cheng)中，充(chong)(chong)分(fen)考慮以下(xia)有利于(yu)(yu)消(xiao)除氣泡或氣孔的(de)措施：采(cai)用(yong)(yong)熔(rong)體(ti)流動速率(MFR)較(jiao)高的(de)物(wu)料、采(cai)用(yong)(yong)密度較(jiao)低的(de)物(wu)料、改善模(mo)(mo)具壁厚均(jun)勻(yun)性、延(yan)(yan)長自然(ran)冷卻(que)時間(jian)、延(yan)(yan)緩(huan)噴(pen)霧(噴(pen)水)冷卻(que)、制(zhi)品(pin)上的(de)凸(tu)筋或突出(chu)部位(wei)不(bu)宜過(guo)窄(zhai)或過(guo)高(對應于(yu)(yu)模(mo)(mo)具上的(de)凹槽(cao)不(bu)能(neng)太窄(zhai)、太深)等。

2、樹脂包覆不(bu)良

(1)、成(cheng)因分析(xi)

           上一(yi)般(ban)有(you)許多(duo)金(jin)屬鑲(xiang)嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)，通(tong)過滾(gun)塑(su)(su)(su)形成制品(pin)(pin)上的(de)(de)(de)一(yi)部分，以增(zeng)強制品(pin)(pin)局部度(du)(du)。在滾(gun)塑(su)(su)(su)時(shi)(shi)，嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)相當于模(mo)具(ju)(ju)上的(de)(de)(de)一(yi)部分，使得(de)(de)此處模(mo)具(ju)(ju)壁(bi)厚(hou)增(zeng)加，嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)末端(duan)不(bu)(bu)易獲得(de)(de)與(yu)模(mo)具(ju)(ju)同(tong)樣的(de)(de)(de)溫(wen)度(du)(du)，導(dao)(dao)致(zhi)嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)上的(de)(de)(de)樹(shu)脂(zhi)(zhi)包(bao)覆(fu)不(bu)(bu)良。尤其是大(da)(da)型(xing)(xing)嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)，如果嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)結構(gou)設(she)計(ji)不(bu)(bu)合理，使得(de)(de)嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)傳(chuan)熱(re)性能不(bu)(bu)良，不(bu)(bu)能獲得(de)(de)與(yu)模(mo)具(ju)(ju)同(tong)樣的(de)(de)(de)溫(wen)度(du)(du)，更(geng)易導(dao)(dao)致(zhi)樹(shu)脂(zhi)(zhi)涂覆(fu)不(bu)(bu)均或(huo)達(da)不(bu)(bu)到設(she)計(ji)要求，降低嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)與(yu)制品(pin)(pin)結合的(de)(de)(de)強度(du)(du)。旋轉(zhuan)滾(gun)塑(su)(su)(su)成型(xing)(xing)的(de)(de)(de)轉(zhuan)速(su)通(tong)常(chang)較(jiao)低，不(bu)(bu)同(tong)于制作鑄型(xing)(xing)尼龍產品(pin)(pin)的(de)(de)(de)離心(xin)澆(jiao)鑄，嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)相對制品(pin)(pin)表面(mian)太(tai)(tai)(tai)高時(shi)(shi)出現(xian)樹(shu)脂(zhi)(zhi)包(bao)覆(fu)不(bu)(bu)良的(de)(de)(de)幾(ji)率更(geng)高一(yi)些。一(yi)般(ban)來(lai)說嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)上的(de)(de)(de)塑(su)(su)(su)料(liao)(liao)(liao)壁(bi)厚(hou)與(yu)制品(pin)(pin)壁(bi)厚(hou)差(cha)別很大(da)(da)，這與(yu)滾(gun)塑(su)(su)(su)時(shi)(shi)嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)傳(chuan)熱(re)性能不(bu)(bu)良和嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)太(tai)(tai)(tai)厚(hou)有(you)直接關系(xi)。嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)的(de)(de)(de)位置太(tai)(tai)(tai)靠(kao)近(jin)制品(pin)(pin)相鄰的(de)(de)(de)側表面(mian)時(shi)(shi)，由于嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)阻擋了物料(liao)(liao)(liao)的(de)(de)(de)流動(dong)，會導(dao)(dao)致(zhi)此處物料(liao)(liao)(liao)堆(dui)積(ji)少或(huo)嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)與(yu)側喪向不(bu)(bu)能完全搭橋，制品(pin)(pin)易出現(xian)較(jiao)大(da)(da)孔洞或(huo)嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)包(bao)覆(fu)不(bu)(bu)嚴(yan)的(de)(de)(de)缺陷(xian)。特(te)別指出的(de)(de)(de)是，嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)具(ju)(ju)有(you)較(jiao)好(hao)的(de)(de)(de)傳(chuan)熱(re)性能不(bu)(bu)僅就(jiu)其材料(liao)(liao)(liao)本身而(er)言，其結構(gou)也應(ying)使嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)具(ju)(ju)有(you)較(jiao)好(hao)的(de)(de)(de)傳(chuan)熱(re)性能，如空(kong)腔不(bu)(bu)能太(tai)(tai)(tai)大(da)(da)或(huo)滾(gun)塑(su)(su)(su)時(shi)(shi)設(she)法用金(jin)屬封(feng)堵大(da)(da)的(de)(de)(de)空(kong)腔，在設(she)計(ji)大(da)(da)型(xing)(xing)嵌(qian)(qian)(qian)(qian)(qian)(qian)件(jian)(jian)時(shi)(shi)尤其要考慮這一(yi)點。

(2)、解(jie)決方案

          使嵌(qian)件(jian)具有良好的傳(chuan)熱(re)結構，盡量消除(chu)不利于嵌(qian)件(jian)傳(chuan)熱(re)的因素。??在滿足條件(jian)(jian)和(he)嵌(qian)件(jian)(jian)強度需求的(de)(de)前提下，嵌(qian)件(jian)(jian)相(xiang)對(dui)制(zhi)品表面(mian)高(gao)度和(he)體積盡量小(xiao)。嵌(qian)件(jian)(jian)上的(de)(de)止轉或防(fang)拉槽的(de)(de)深度和(he)寬度與滾(gun)塑要(yao)求相(xiang)適宜。滾(gun)塑時，視(shi)情(qing)況對(dui)嵌(qian)件(jian)(jian)進(jin)行預熱(re)會取得比較(jiao)良(liang)好(hao)的(de)(de)效果，對(dui)大型(xing)嵌(qian)件(jian)(jian)尤其有效