在現今環保意識高漲下，輕量化及綠能在高分子加工中備受重視，發泡射出成型(foam injection molding, FIM)相較於傳統射出成型，其具備省料、減少週期、輕量化等優點，因此在工業上被廣泛應用。然而，在發泡射出成型中，泡體的均勻度差是一大問題。為了解決這一缺失，目前常用的技術為模內氣體反壓 (gas counter pressure, GCP)或是抽芯(core-back)，GCP 在製程上需要有額外的設備輸入氣體，且在模具設計上需有良好的絕氣性，這點和在傳統模具的設計上需有良好的逃氣性有很大的出入，反觀抽芯除了在較複雜形狀的模具較不適用，其製程相對較容易，只需在熔膠充填完成後將模仁向後退一小距離，即可透過瞬間且一致的壓力降，得到泡孔均勻的發泡材料。
而在抽芯階段前，會結合高壓發泡射出成型(high pressure foam injection molding,HFIM)將通過澆口處成核的澆口泡溶回。因此本篇研究第一部分將會探討不同的保壓壓力、保壓時間等參數對於泡孔結構的影響，但在高壓發泡射出成型中，壓降太小導致成核率太低，泡孔密度太低不利於樣品分析。
第二部分則會著重於抽芯製程對於泡體結構的改善以及發現不同的抽芯加工參數對於泡孔密度、泡孔尺寸以及表皮層各有不同的影響，並也成功利用抽芯改善了泡孔不均以及成核率低的缺陷，利用高壓發泡射出結合抽芯，能使泡孔密度從101 ~102 cells/cm3 上升到104 ~ 105 cells/cm3，並透過SEM 觀察到能有效改善泡孔均勻度的缺陷，雖然距離一般發泡材料產品應用還有許多進步空間，不過觀察到的趨勢現象是值得探討的。

With the current high awareness of environmental protection, weight reduction is highly valued in polymer processing. Compared with traditional injection molding, foam injection molding (FIM) has the advantages of material saving and cycle time reduction. However, the homogeneity of FIM parts is usually a problem. In order to solve this problem, the commonly used technology is gas counter pressure (GCP) or core-back. The GCP process needs additional equipment and has good gas sealing in the mold design, which is quite different from the traditional mold design. On the other hand, the core-back process is relatively easy but it is not suitable for mold with complex geometry. After the mold filling is completed, the core is moved back a short distance, and the foam material with uniform cells can be obtained through the instantaneous and consistent pressure drop.
Before the core-back stage, the high-pressure foam injection molding (HFIM) is combined to dissolve the gate-nucleated bubbles at the gate. Therefore, the first part of this study explored the influence of packing pressure, packing time, and other parameters on the cell structure.
The second part focused on improving the foam structure by the core-back processing.
Different core-back parameters have different effects on the cell density, cell size and surface skin layer thickness. For the defects of uneven foam structure and low nucleation rate, high-pressure foaming injection molding with core-back can increase the cell density from 101 ~ 102 cells/cm3 to 104 ~ 105 cells/cm3, and SEM observes through the defects that can effectively improve the uniformity of the cells. Although there is still a long way to go for foam material products, the observed trend phenomenon is worth exploring.

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